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Summary of the NATO advanced research workshop on
dietary omega 3 and omega 6 fatty acids: biological effects
and nutritional essentiality.
Simopoulos AP
Division of Nutritional Sciences, International Life Sciences
Institute Research Foundation
J Nutr (United States) Apr 1989, 119 (4) p521-8
A number of human studies presented at the workshop
indicate that the premature infant at birth is biochemically
deficient in docosahexaenoic acid (DHA) in both the brain and
liver phospholipids, and that DHA is essential for normal
visual acuity. The amount of DHA necessary to maintain normal
amounts of the liver and brain phospholipids postnatally is 11
mg/kg daily. Elderly patients on long-term gastric tube
feedings and others on long-term intravenous fluids and on
total parenteral nutrition are particularly prone to
deficiencies of alpha-linolenic acid, eicosapentaenoic acid
(EPA) and DHA. The amounts estimated to prevent deficiencies
in the elderly are 800-1100 mg/d of alpha-linolenic acid and
300-400 mg/d of EPA and DHA combined. Preliminary data
indicate that children with malnutrition and mucoviscidosis,
women with toxemia, and elderly people have decreased amounts
of DHA in plasma phospholipids. The omega 3 fatty acids lower
triglycerides and, at high levels, lower cholesterol. The
anti-aggregatory, anti-thrombotic and anti-inflammatory
properties of omega 3 fatty acids have been confirmed, and a
dose-response curve is emerging. Despite the increase in
bleeding time, no clinical evidence of bleeding has been noted
by the investigators in any of the studies. Clinical trials
are necessary in order to precisely define the dose and
mechanisms involved in defining the essentiality of omega 3
fatty acids in growth and development and their beneficial
effects in coronary heart disease, hypertension, inflammation,
arthritis, psoriasis, other autoimmune disorders, and cancer.
(56 Refs.) Summary of the NATO advanced research workshop on
dietary omega 3 and omega 6 fatty acids: biological effects
and nutritional essentiality.
Vasodilating agents and platelet function:
intracellular free calcium concentration, cyclic nucleotides,
and shape-change response.
Erne P; Mittelholzer E; Rogg H; Resink TJ; Buhler FR
J Cardiovasc Pharmacol (United States) 1986, 8 Suppl 8
pS102-6
The adenylate-cyclase activator forskolin, the
guanylate-cyclase stimulator sodium nitroprusside, the
phosphodiesterase inhibitor Ro 15-2041, different Ca-entry
blockers, as well as various vasodilators, and the atrial
natriuretic peptide were tested for antiplatelet activity.
Thrombin, vasopressin, ADP, arachidonic acid, and the
dihydropyridine Ca agonist CGP 28392 were used as platelet
activators. The physiological and biochemical parameters of
platelet function studied included shape-change reaction,
intracellular free-Ca modulation, and cyclic nucleotide
formation. When inhibition of the shape-change response
occurred, it was accompanied by inhibition of the increase in
intracellular free Ca. Furthermore, the results suggest a
possible intracellular site of action of Ca entry blockers in
platelets, and confirm the importance of modulation of cyclic
nucleotides in the regulation of platelet function, regardless
of the mechanism of platelet activation. Additional
antiplatelet activity of antihypertensive agents may have a
beneficial effect in reducing the associated risk of
thrombo-embolic complications in essential hypertension.
Association of macronutrients and energy intake
with hypertension.
Preuss HG; Gondal JA; Lieberman S
Dept. of Medicine, Georgetown University Medical Center,
Washington D.C. 20007, USA.
J Am Coll Nutr (United States) Feb 1996, 15 (1)
p21-35
Hypertension, a major public health problem, becomes more
prevalent during aging. Epidemiological studies suggest that
environmental factors such as nutrition may play a major role
in blood pressure (BP) regulation. It is generally accepted
that obesity and sodium/alcohol consumption are important
factors, and many believe that calcium, magnesium and
potassium consumption are regulatory as well. Less emphasis
has been placed on whether macronutrients influence blood
pressure significantly. This review focused on the ability of
excess calories and consumption of carbohydrates, fats, and
proteins to regulate blood pressure. (207 Refs.)
Relations between magnesium, calcium, and plasma
renin activity in black and white hypertensive patients
Touyz RM; Panz V; Milne FJ
Department of Medicine, University of the Witwatersrand,
Johannesburg, South Africa.
Miner Electrolyte Metab (Switzerland) 1995, 21 (6)
p417-22
The heterogeneous status of magnesium and calcium
metabolism in the hypertensive population may be related to
the plasma renin activity (PRA). This study investigates the
relationships between serum and erythrocyte magnesium (Mg2+)
and calcium (Ca2+) concentrations and PRA in black and white
essential hypertensive patients. Thirty-nine normotensive (20
black, 19 white) and 47 hypertensive (25 black, 22 white)
subjects were studied. The PRA was measured by
radioimmunoassay, Mg2+ and Ca2+ by atomic absorption
spectroscopy, and serum ionized Ca2+ by a specific electrode.
PRA and ionized Ca2+ were significantly lower in the black
hypertensive as compared with the white hypertensive group
(1.99 +/- 0.33 vs. 5.96 +/- 1.02 ng/ml/h for PRA; 1.28 +/-
0.07 vs. 1.42 +/- 0.01 mmol/l for ionized Ca2+: black
hypertensives vs. white hypertensives p < 0.05). Ionized
Ca2+ was significantly increased (p < 0.05) in the white
hypertensive patients as compared with the normotensive
controls (1.42 +/- 0.01 vs. 1.29 +/- 0.04 mmol/l). In the
black hypertensive group, serum and erythrocyte Mg2+ were
significantly (p < 0.05) decreased as compared with the
other groups. The erythrocyte Ca2+ concentration was
significantly elevated in both black and white hypertensive
patients. In the group as a whole, serum Mg2+ and PRA were
negatively correlated and ionized Ca2+ and PRA and ionized
Ca2+ and erythrocyte Ca2+ positively correlated. However, in
the subgroups, these correlations were only significant in the
white group: r = -0.67 and p < 0.05 serum Mg2+ vs. PRA; r =
0.64, and p < 0.05 ionized Ca2+ vs. PRA; r = 0.82 and p
< 0.01 ionized [Ca2+]i vs. erythrocyte Ca2+. These data
suggest a relationship between PRA, Mg2+, and Ca2+ which may
be more important in white than in black hypertensive
patients.
Effect of renal perfusion pressure on excretion of
calcium, magnesium, and phosphate in the rat.
Wu X; Sonnenberg H
Department of Physiology, University of Toronto, Ontario,
Canada.
Clin Exp Hypertens (United States) Nov 1995, 17 (8)
p1269-85
Abnormalities in renal handling of calcium, magnesium, or
phosphate have been implicated in the development and/or
maintenance of human hypertension. We have shown recently that
renal excretion of these ions is correlated to blood pressure
in Dahl salt-sensitive as well as salt-resistant rats. The
present study was designed to determine whether renal
perfusion pressure per se could affect excretion of these
ions. Urinary excretion of calcium, magnesium, and phosphate
was studied in anaesthetized Sprague-Dawley rats under basal
conditions and during an intravenous infusion of angiotensin
II (ANG II), vasopressin (AVP) or phenylephrine (PE). A cuff,
placed around the aorta between the two renal arteries,
allowed maintenance of normal perfusion pressure in the left
kidney, while that in the right kidney was allowed to rise.
Infusion of pressor agents raised mean arterial blood pressure
to comparable levels (means +/- SE): ANG II (n = 7), before =
102 +/- 4, during = 133 +/- 3 mmHg, AVP (n = 8), before = 110
+/- 7, during = 136 +/- 5 mmHg, PE (n = 6), before = 111 +/-
6, during = 141 +/- 6 mmHg. Although there was no difference
in excretion of calcium, magnesium and phosphate between the
two kidneys under basal conditions, infusion of ANG II or PE
induced hypercalciuria, hypermagnesiuria and hyperphosphaturia
in the right kidney which was exposed to the increased
arterial pressure. Such effects did not appear in the
pressure-controlled left kidney. Infusion of AVP was
associated with reduced excretion of calcium and magnesium,
and increased excretion of phosphate, in the normotensive
kidney. The response to the similarly increased renal
perfusion pressure in this group was also reduced for calcium
and magnesium, and enhanced for phosphate. The results
indicate
(1) renal excretion of calcium, magnesium and phosphate is
renal perfusion pressure-dependent; the higher the renal
perfusion pressure, the greater the excretion of these
ions.
(2) Independently of perfusion pressure, AVP can inhibit
phosphate reabsorption and stimulate divalent cation
reabsorption.
Dietary L-arginine attenuates blood pressure in
mineralocorticoid-salt hypertensive rats.
Laurant P; Demolombe B; Berthelot
Laboratoire de Physiologie, U.F.R. Medecine et Pharmacie,
Besancon, France.
Clin Exp Hypertens (United States) Oct 1995, 17 (7)
p1009-24
The present study was designed to investigate the influence
of dietary L-arginine supplementation on blood pressure and on
ex vivo vascular reactivity in mineralocorticoid-salt
(DOCA-salt) hypertensive rats. Systolic blood pressure and
heart rate were determined throughout the experimental period
in unanaesthetized rats. Plasma and urine electrolyte levels
were measured. Vasoconstrictor response to noradrenaline and
vasodilator responses to acetylcholine and sodium
nitroprusside were evaluated in the isolated perfused
mesenteric vascular bed. DOCA-salt hypertensive rats were
divided into 2 groups: a control group and a treated group
receiving 0.8% L-arginine supplementation in drinking water.
Dietary L-arginine supplementation attenuated systolic blood
pressure in conscious DOCA-salt hypertensive rats, but did not
modify heart rate. Plasma calcium and sodium concentrations
and urinary magnesium excretion were decreased by L-arginine
supplementation. Noradrenaline-induced vasoconstriction
decreased and acetylcholine-induced vasodilatation increased,
whereas sodium nitroprusside-induced vasodilatation was not
modified, in the L-arginine-supplemented rats. It is concluded
that dietary L-arginine supplementation in the diet lowers
systolic blood pressure in DOCA-salt hypertensive rats,
probably through vascular action.
Associations between blood pressure and dietary
intake and urinary excretion of electrolytes in a Chinese
population.
Tian HG; Nan Y; Shao RC; Dong QN; Hu G; Pietinen P; Nissinen
A
Food Safety Control and Inspection Institute, Tianjin,
People's Republic of China.
J Hypertens (England) Jan 1995, 13 (1) p49-56
OBJECTIVE: To examine the associations between blood
pressure and sodium, potassium, calcium and magnesium in a
cross-sectional study by 24-h urine collections and food
weighing with 3-day food records in 328 males and 335 females
in Tianjin, People's Republic of China.
RESULTS: A very high sodium intake and sodium:potassium
ratio was confirmed in the study population. After adjusting
for confounding variables, both dietary and urinary sodium and
sodium:potassium ratio were significantly and positively
correlated with blood pressure. Although a negative
correlation was found between potassium and blood pressure,
the association was significant only between urinary potassium
and systolic blood pressure in females and in both sexes
combined. No significant associations were found between blood
pressure and either intake of or urinary excretion of calcium
and magnesium. The dietary intake correlated highly with
urinary excretion of electrolytes. In both sexes a strong
positive association was found between blood pressure and age,
and between blood pressure and body mass index. Higher blood
pressure was shown in subjects with higher sodium and alcohol
intake, higher body mass index and lower potassium intake.
CONCLUSION: The present results indicate that factors
contributing to high blood pressure in Tianjin, People's
Republic of China, are related to age, body mass index, high
sodium intake and sodium:potassium ratio.
Concentration of free intracellular magnesium in
the myocardium of spontaneously hypertensive rats treated
chronically with calcium antagonist or angiotensin converting
enzyme inhibitor
Carlier P; Smelten N; Ciancabilla F; Rorive G
Service hospitalier Frederic-Joliot, Commissariat a l'energie
atomique, Orsay.
Arch Mal Coeur Vaiss (France) Aug 1994, 87 (8)
p1041-5
In this study, we determined a) whether chronic
antihypertensive treatment could alter myocardial free
intracellular magnesium concentrations, b) whether changes in
magnesium concentration would correlate with resistance to
anoxia of hypertensive rat hearts. Six-month old male
spontaneously hypertensive (HT) rats (n = 11) were compared to
rats from the same strain treated with a calcium channel
antagonist, nitrendipine (60 mg/kg/j; n = 11) or with a
converting-enzyme inhibitor, perindopril (2 mg/kg/j; n = 9)
during three months. The hearts were perfused in retrograde
isovolumic mode and submitted to a standardized
anoxia-recovery protocol. Aortic perfusion pressure and left
ventricular pressure were constantly monitored. P-31 NMR
spectra were simultaneously recorded and allowed to quantify
the changes in myocardial inorganic phosphate, phosphocreatine
and ATP. The pH was derived from the chemical shifts of
inorganic phosphate and phosphocreatine, and the free
intracellular magnesium concentration from the alpha-beta
chemical shifts of ATP. Both treatments lowered systolic blood
pressure and reversed left ventricular hypertrophy,
perindopril being slightly more efficient at the dose
administered. Intracellular magnesium concentration,
calculated from the P-31 NMR spectra, was 277 +/- 17 microM in
the untreated hypertensive group, 311 +/- 15 microM in the
nitrendipine group and 401 +/- 17 microM in the perindopril
group (p < 0.001 versus untreated and nitrendipine). There
was a significant correlation between intracellular magnesium
concentration and left ventricular developed pressure at the
early stage of post-anoxic recovery (r = 0.61; p < 0.01).
P-31 NMR spectroscopy demonstrates an increase in myocardial
free intracellular magnesium concentration following chronic
administration of an angiotensin-converting enzyme inhibitor,
perindopril, spontaneously hypertensive rats.(ABSTRACT
TRUNCATED AT 250 WORDS)
Nonpharmacologic treatment of hypertension.
Kaplan NM
University of Texas Southwestern Medical Center at
Dallas.
Curr Opin Nephrol Hypertens (United States) Oct 1992, 1 (1)
p85-90
A variety of lifestyle modifications will lower both the
blood pressure and various other cardiovascular risk factors
that are frequently present in patients with hypertension.
Numerous recent studies document the overall efficacy of some
(weight reduction, sodium restriction, physical activity,
moderation of alcohol) and the relative lack of effect of
others (stress management and calcium, magnesium, and fish oil
supplements). In particular, the Trials of Hypertension
Prevention, Phase I (a control trial funded by the National
Heart, Lung, and Blood Institute) provides important new data
on the ability of these various modalities to prevent the
development of hypertension, an equally or even more important
goal than the reduction of already-established disease. (32
Refs.)
Micronutrient effects on blood pressure
regulation.
Reusser ME; McCarron DA
Department of Medicine, Oregon Health Sciences University,
Portland.
Nutr Rev (United States) Nov 1994, 52 (11)
p367-75
Five micronutrients have been shown to directly influence
blood pressure: sodium, calcium, potassium, magnesium, and
chloride. The data presented here are based on accumulated
findings from epidemiologic, laboratory, and clinical
investigations, many of which focused primarily on a single
nutrient. However, as also discussed here, nutrients are not
consumed in isolation, and their physiologic interactions and
combined effects on blood pressure are the subjects of much of
the current research in the area of diet and hypertension. (71
Refs.)
Role of magnesium and calcium in alcohol-induced
hypertension and strokes as probed by in vivo television
microscopy, digital image microscopy, optical spectroscopy,
31P-NMR, spectroscopy and a unique magnesium ion-selective
electrode.
Altura BM; Altura BT
Department of Physiology, State University of New York,
Health Science Center at Brooklyn 11203.
Alcohol Clin Exp Res (United States) Oct 1994, 18 (5)
p1057-68
It is not known why alcohol ingestion poses a risk for
development of hypertension, stroke and sudden death. Of all
drugs, which result in body depletion of magnesium (Mg),
alcohol is now known to be the most notorious cause of
Mg-wasting. Recent data obtained through the use of
biophysical (and noninvasive) technology suggest that alcohol
may induce hypertension, stroke, and sudden death via its
effects on intracellular free Mg2+ ([Mg2+]i), which in turn
alter cellular and subcellular bioenergetics and promote
calcium ion (Ca2+) overload. Evidence is reviewed that
demonstrates that the dietary intake of Mg modulates the
hypertensive actions of alcohol. Experiments with intact rats
indicates that chronic ethanol ingestion results in both
structural and hemodynamic alterations in the
microcirculation, which, in themselves, could account for
increased vascular resistance. Chronic ethanol increases the
reactivity of intact microvessels to vasoconstrictors and
results in decreased reactivity to vasodilators. Chronic
ethanol ingestion clearly results in vascular smooth muscle
cells that exhibit a progressive increase in exchangeable and
cellular Ca2+ concomitant with a progressive reduction in Mg
content. Use of 31P-NMR spectroscopy coupled with
optical-backscatter reflectance spectroscopy revealed that
acute ethanol administration to rats results in dose-dependent
deficits in phosphocreatine (PCr), the [PCr]/[ATP] ratio,
intracellular pH (pHi), oxyhemoglobin, and the mitochondrial
level of oxidized cytochrome oxidase aa3 concomitant with a
rise in brain-blood volume and inorganic phosphate. Temporal
studies performed in vivo, on the intact brain, indicate that
[Mg2+]i is depleted before any of the bioenergetic changes.
Pretreatment of animals with Mg2+ prevents ethanol from
inducing stroke and prevents all of the adverse bioenergetic
changes from taking place. Use of quantitative digital imaging
microscopy, and mag-fura-2, on single-cultured canine cerebral
vascular smooth muscle, human endothelial, and rat astrocyte
cells reveals that alcohol induces rapid
concentration-dependent depletion of [Mg2+]i. These cellular
deficits in [Mg2+]i seem to precipitate cellular and
subcellular disturbances in cytoplasmic and mitochondrial
bioenergetic pathways leading to Ca2+ overload and ischemia. A
role for ethanol-induced alterations in [Mg2+]i should also be
considered in the well-known behavioral actions of alcohol.
(90 Refs.)
Dietary management of blood pressure.
Retta TM; Afre GM; Randall OS
Department of Medicine, Howard University Medical Center,
Washington, DC.
J Assoc Acad Minor Phys (United States) 1994, 5 (4)
p147-51
Hypertension is a major cause of morbidity and mortality in
the United States, particularly in the African-American
population. Although there have been indications since the
beginning of this century that blood pressure might be
influenced by dietary factors, this has been generally
ignored, and the mainstay of hypertension treatment has been
the use of pharmacologic antihypertensives. Attention is now
being focused, however, on dietary management of hypertension
because of the high cost of drug therapy, the adverse
reactions associated with some antihypertensives, and the fact
that hypertensives treated only by pharmacologic means remain
at risk for target-organ damage. The literature is replete
with evidence that vegetarian and low-sodium dietary patterns
are associated with lower blood pressure levels. This implies
that if many people could adopt vegetarian and low-salt
dietary habits, the prevalence of hypertension would be
significantly reduced. However, most people find "unsalted"
vegetarian diets tasteless and unacceptable. We therefore need
to identify the macro- and micronutrients (other than sodium)
that directly influence blood pressure. Several studies
indicate that dietary patterns rich in fiber, calcium,
potassium, and magnesium are favorable for blood pressure
control. This review highlights some of these findings and
emphasizes the need for large clinical trials to test
blood-pressure-reducing dietary patterns by incorporating the
aforementioned macro- and micronutrients into socioculturally
acceptable and palatable menus, especially in the
African-American population. (77 Refs.)
Community-based prevention of stroke: nutritional
improvement in Japan
Yamori Y; Horie R
Kyoto University, Japan.
Health Rep (Canada) 1994, 6 (1) p181-8
OBJECTIVES: (1) To demonstrate the importance of nutrition,
especially sodium restriction and increased potassium and
protein intakes, in the prevention of hypertension and stroke
in a pilot study involving senior citizens. (2) To design a
population-based intervention in the Shimane Prefecture of
Japan concerning dietary factors such as low sodium and high
potassium, protein, magnesium, calcium and dietary fibre in
the prevention of stroke.
DESIGN AND METHODS: The intervention study was carried out
at a senior citizens' residence and included general health
education along with a reduction of dietary salt intake and
increases in vegetable and protein, especially from seafood.
Sixty-three healthy senior citizens (average age: 74.8 +/- 7.7
years) had their daily meals modified to a low
sodium/potassium ratio for four weeks without their knowledge
by the use of a potassium chloride substitute for salt, soy
sauce and bean paste, which contains much less sodium and more
potassium. Monosodium L-glutamate monohydrate used for cooking
was changed to monopotassium L-glutamate monohydrate. Blood
pressure was measured with the patient in the sitting
position. Daily dietary sodium and potassium intakes were
assessed by flame photometry from 24-hour urine specimens.
Extensive intervention programs were introduced into the
Shimane Prefecture, which has a population of 750,000, through
health education classes for housewives, home visits by health
nurses and an educational TV program for dietary improvement.
The mortality from stroke was monitored for 10 years and
compared with the average in Japan.
RESULTS: The blood pressure lowering effect of reducing the
dietary sodium/potassium ratio was confirmed through a pilot
intervention study at the senior citizens' residence. The
mortality rates for stroke in the middle-aged population from
the Shimane Prefecture during the 10 years after the
introduction of dietary improvement had a steeper decline in
hemorrhagic, ischemic and all strokes than the average for
Japan.
Impact of increasing calcium in the diet on
nutrient consumption, plasma lipids, and lipoproteins in
humans
Karanja N; Morris CD; Rufolo P; Snyder G; Illingworth DR;
McCarron DA
Department of Medicine, Oregon Health Sciences University,
Portland 97201.
Am J Clin Nutr (United States) Apr 1994, 59 (4)
p900-7
This study examined the feasibility of increasing
food-derived calcium to 1500 mg/d and the impact of this
change on plasma lipids and nutrient consumption in
hypertensive (n = 130) and normotensive (n = 196)
participants. Three interventions were applied in a
randomized, parallel, placebo-controlled fashion: 1)
counseling to increase dietary calcium through food
consumption to 1500 mg/d (n = 106), 2) a 1000-mg/d calcium
supplement (n = 109), or 3) placebo (n = 111). Plasma lipids
were measured before and after 12 wk of intervention whereas
nutrient intake was monitored throughout the study. At
baseline, hypertensive patients reported lower intakes of
carbohydrates, calcium, magnesium, phosphorus, potassium,
iron, vitamin D, thiamin, and riboflavin (all P < 0.05).
They also had lower HDL (P = 0.014) and higher LDL (P <
0.05) compared with normotensive subjects. During
intervention, calcium, magnesium, phosphorus, potassium,
thiamin, riboflavin, and vitamins C and D increased (P <
0.01) in the group receiving food calcium but not in the
placebo or supplement groups. No changes occurred in plasma
lipids or lipoproteins after 12 wk of intervention.
Electrolytes and hypertension: results from recent
studies.
Grobbee DE
Department of Epidemiology and Biostatistics, Erasmus
University Medical School, Rotterdam, The Netherlands.
Am J Med Sci (United States) Feb 1994, 307 Suppl 1
pS17-20
The effects of dietary electrolytes on blood pressure may
start as early as the prenatal period as there is evidence to
suggest that a high maternal calcium, magnesium, and potassium
intake is reflected in lower infant blood pressure levels. One
randomized trial in newborn infants suggested that, in this
early phase, high sodium intake is associated with an
increased blood pressure change. Such a sodium effect is not
present when children grow older, and between 6 and 16 years a
high potassium intake appears to limit the increase in blood
pressure. Recent observational population studies have shown
that the association between dietary sodium intake and blood
pressure level in adults is less than initially reported. In
randomized trials, the average fall in blood pressure from
moderate sodium restriction is small, although benefits may be
larger in the elderly. A high potassium intake has
consistently been shown to reduce blood pressure levels in
treated and untreated hypertensive subjects, although the
overall effects are modest. The available data on calcium are
difficult to interpret. From observational studies an inverse
association between dietary calcium intake and blood pressure
levels has repeatedly been reported. Also, several
disturbances in calcium metabolism in hypertensive subjects
have been demonstrated. Findings in randomized trials are less
consistent and indicate a marked heterogeneity in response.
(36 Refs.)
Calcium antagonists in pregnancy as an
antihypertensive and tocolytic agent
Lechner W
Universitatsklinik fur Frauenheilkunde, Innsbruck.
Wien Med Wochenschr (Austria) 1993, 143 (19-20)
p519-21
In pregnancy calcium antagonism is of great importance. The
uterus-relaxing properties of verapamil are well known,
diltiazem shows an excellent tokolytic efficacy and is also
effective as hypotensive in pregnancy-induced hypotension. In
contrast to verapamil and diltiazem the dihydropyridines were
not clinically successful as tokolytic or hypotensive in
pregnancy. Magnesium is a therapy of first choice in the
EPH-gestosis. (44 Refs.)
Augmentation of the renal tubular dopaminergic
activity by oral calcium supplementation in patients with
essential hypertension.
Dazai Y; Iwata T; Hiwada K
Second Department of Internal Medicine, Ehime University
School of Medicine, Japan.
Am J Hypertens (United States) Nov 1993, 6 (11 Pt 1)
p933-7
We studied the effect of oral calcium supplementation on
renal tubular dopaminergic activity in patients with mild to
moderate essential hypertension. Fifteen patients aged 45 to
68 years (nine men and six women, mean age 59 +/- 7 [SD])
participated in the study. We orally administered calcium (1.0
g per day for 1 week) during hospitalization. The change in
24-h blood pressure (BP), measured by ambulatory BP
monitoring, and excretions of electrolytes and catecholamines
were investigated before and after 1 week of oral calcium
supplementation. The mean values of 24-h systolic and
diastolic BP showed no significant changes by calcium loading.
Daily urinary excretion of free dopamine, sodium clearance
(CNa), fractional excretion of sodium (FENa), and urinary
volume were significantly increased by oral calcium
supplementation. Urinary excretions of epinephrine and
norepinephrine and creatinine clearance showed no significant
changes by oral calcium treatment. CNa and FENa showed
significant correlations with urinary excretion of free
dopamine. These results suggest that oral calcium
supplementation induces natriuresis partly through
augmentation of renal tubular dopaminergic activity.
Nutrition and diseases of women: cardiovascular
disorders.
Preuss HG
Department of Medicine, Georgetown University Medical Center,
Washington, DC 20007.
J Am Coll Nutr (United States) Aug 1993, 12 (4)
p417-25
Studies of prevention, diagnosis, and intervention for
coronary heart disease and hypertension have either been
conducted largely in men, or gender differences have not
always been fully sought. This has added to a general
perception that coronary artery disease is basically a male
affliction despite the fact that coronary artery disease is
the leading cause of death among women, especially elderly
women. Many risk factors among women are similar to men, i.e.,
high blood pressure (BP), elevated serum cholesterol levels,
and cigarette smoking; however, women compared to men have
greater incidence of diabetes mellitus, congestive heart
failure, and hypertension as they become older. The risk of
cardiovascular disorders can be reduced by postmenopausal
estrogen replacement, exercising sufficiently, and ceasing
smoking. In addition, good nutrition, taking into
consideration the proper amount and forms of calories, sodium,
potassium, calcium, magnesium, and macronutrients to maintain
an ideal lipid profile and BP, is helpful in preventing
cardiovascular perturbations. (98 Refs.)
The pathogenesis of eclampsia: the 'magnesium
ischaemia' hypothesis.
Newman JC; Amarasingham JL
Department of Obstetrics, Shellharbour Hospital, Illawara
Area Health Service, NSW, Australia.
Med Hypotheses (England) Apr 1993, 40 (4) p250-6
'Magnesium ischaemia' is a term used to denote the
functional impairment of the ATP-dependent sodium/potassium
and calcium pumps in the cell membranes and within the cell
itself. The production of ATP and the functioning of these
pumps is magnesium-dependent and is critically sensitive to
acidosis. Zinc and iron deficiencies may secondarily impair
these pumps and thus contribute to 'magnesium ischaemia' (as
does acidosis). This term is two-dimensional at its simplest;
it refers to a functional magnesium deficiency, whether actual
or induced. It is argued that chronic acidosis is the most
common inducing factor. This simple hypothesis can begin to
unify diverse pathophysiologies: some spontaneous abortions,
aspects of Type II and gestational diabetes and the curious
observation that heroin addicts become diabetic. It can also
unify clinical thinking about pregnancy-induced hypertension,
pre-eclampsia/eclampsia and acute fatty liver of pregnancy, as
well as the coagulopathy of pregnancy. It makes important
predictions about perinatal morbidity and suggests that early
supplementation might prevent much pregnancy-induced
disease.
Longitudinal changes during the development of
hypertension in rats fed excess chloride and sodium.
Greger JL; Tseng E
Department of Nutritional Sciences, University of Wisconsin,
Madison 53706.
Proc Soc Exp Biol Med (United States) Jul 1993, 203 (3)
p377-85
The effects of supplemental NaCl, KCl, and Na acetate on
the blood pressure of weanling rats fed semipurified diets and
diets based on naturally high salt products, like cottage
cheese, were examined in two studies. Within 2 weeks of
initiation of dietary treatments, rats fed supplemental
chloride had elevated blood pressure and lowered plasma renin
activity, which persisted throughout the 8-week study. The
effect of supplemental sodium on blood pressure was not
significant until after 6 weeks of dietary treatment. The
initial increase in blood pressure preceded the slowed growth
observed in rats fed excess chloride or sodium. Urinary volume
and urinary excretion of calcium, magnesium, phosphorus,
sodium, and chloride were increased when supplemental chloride
or sodium was fed, but tissue electrolyte and plasma atrial
natriuretic peptide concentrations remained constant. Two
changes preceded the rise in blood pressure: rats fed
supplemental chloride had enlarged kidneys, and those fed
supplemental sodium had elevated hematocrits, suggesting a
transient shift among fluid compartments, after only 6 days of
treatment. These data suggest that the hypertension induced by
ingestion of supplemental (14.6 mg CI/g of diet) chloride is
mediated by changes in renal function. Ingestion of excess
sodium depressed bone magnesium concentrations in Study 1 and
after 24 days in Study 2; the impact of this "relative"
magnesium depletion on blood pressure deserves further
study.
Salivary electrolytes in treated hypertensives at
low or normal sodium diet.
Musumeci V; Di Salvo S; Zappacosta B; Zuppi C; Colacicco L;
Cherubini P
Cattedra di Medicina Interna CLOPD, Universita Cattolica del
S. Cuore, Roma.
Clin Exp Hypertens (United States) Mar 1993, 15 (2)
p245-56
The aim of this study was to investigate possible
abnormalities in salivary electrolytes in hypertensives
treated with ace-inhibitors (ACE-I) or calcium antagonists
(Ca-ANT) at low or normal sodium intake. Hypertensives treated
with ACE-I (n.14) or Ca-ANT (n.22) and 13 normotensives were
studied during normal or restricted Na intake. Na, K, Ca, Mg
and Cl were determined in saliva samples collected by using a
standardized adsorption procedure (SALIVETTE). Na intake was
evaluated by determination of the 24-hr urinary Na excretion.
Similar concentrations of Na, K, Ca, and Cl were found in
normotensives and in hypertensives treated with ACEI or Ca-ANT
both at low or normal Na diet. Magnesium in saliva appeared
reduced in ACEI-treated hypertensives (0.28 +/- 0.06 mmol/l)
in comparison to the similar values of normotensives (0.53 +/-
0.05) and Ca-ANT treated hypertensives (0.54 +/- 0.07). In
normotensives and in treated hypertensives lowering of Na
intake did not change the salivary content of Ca, Mg and Cl
but produced in saliva a reduction of Na associated to a rise
in K. Salivary Na/K ratio was significantly correlated with 24
hr urinary Na excretion in normotensives (r = 0.77; p <
0.05) and in hypertensives treated with ACE-I (r = 0.74; p
< 0.05) or Ca-ANT (r = 0.62; p < 0.05). The low salivary
magnesium in ACE-I-HT may have a role in the occasional
ACEI-dependent dysgeusia. Salivary Na/K ratio may be used as a
rough index of Na intake in treated hypertensives.
Can guava fruit intake decrease blood pressure and
blood lipids?
Singh RB; Rastogi SS; Singh NK; Ghosh S; Gupta S; Niaz
MA
Medical Hospital and Research Centre, Moradabad, India.
J Hum Hypertens (England) Feb 1993, 7 (1) p33-8
A randomized, single-blind, controlled trial was conducted
to examine the effects of guava fruit intake on BPs and blood
lipids in patients with essential hypertension. Of 145
hypertensives that entered the trial, 72 patients were
assigned to take a soluble fibre and a potassium-rich diet
containing 0.5-1.0 kg of guava daily (group A) and 73 patients
to their usual diet (group B), while salt, fat, cholesterol,
caffeine and alcohol intake were similar in both groups. Mean
age, mean body weight and male sex, were similar, and so were
risk factors, mean BPs, mean serum sodium, potassium, calcium,
magnesium, triglycerides, cholesterol and HDL-cholesterol in
both groups. Dietary adherence to guava intake was checked by
a questionnaire. After four weeks of follow-up on an increased
consumption of dietary potassium and low sodium/potassium
ratio, group A patients were associated with 7.5/8.5 mmHg net
decrease in mean systolic and diastolic pressures compared
with group B. Increased intake of soluble dietary fibre (47.8
+/- 11.5 vs. 9.5 +/- 0.85 g/day) was associated with a
significant decrease in serum total cholesterol (7.9%),
triglycerides (7.0%) and an insignificant increase in
HDL-cholesterol (4.6%) with a mild increase in the ratio of
total cholesterol/HDL-cholesterol in group A patients compared
with group B. It is possible that an increased consumption of
guava fruit can cause a substantial reduction in BPs and blood
lipids with a lack of decrease in HDL-cholesterol due to its
higher potassium and soluble fibre content, respectively.
Preventive nutrition: disease-specific dietary
interventions for older adults.
Johnson K; Kligman EW
Department of Family and Community Medicine, University of
Arizona College of Medicine, Tucson.
Geriatrics (United States) Nov 1992, 47 (11) p39-40,
45-9
Disease prevention through dietary management is a
cost-effective approach to promoting healthy aging. Fats,
cholesterol, soluble fiber, and the trace elements copper and
chromium affect the morbidity and mortality of CHD. Decreasing
sodium and increasing potassium intake improves control of
hypertension. Calcium and magnesium may also have a role in
controlling hypertension. The antioxidant vitamins A and
beta-carotene, Vitamin-C, vitamin E, and the trace mineral
selenium may protect against types of cancer. A decrease in
simple carbohydrates and an increase in soluble dietary fiber
may normalize moderately elevated blood glucose levels.
Deficiencies of zinc or iron diminish immune function.
Adequate levels of calcium and vitamin D can help prevent
senile osteoporosis in both older men and women. (27
Refs.)
Intracellular Mg2+, Ca2+, Na2+ and K+ in platelets
and erythrocytes of essential hypertension patients: relation
to blood pressure.
Touyz RM; Milne FJ; Reinach SG
Department of Medicine, University of the Witwatersrand
Medical School, Johannesburg, South Africa.
Clin Exp Hypertens [A] (United States) 1992, 14 (6)
p1189-209
Alterations in intracellular cation metabolism have been
implicated in the pathophysiology of essential hypertension.
Total magnesium, calcium, sodium and potassium levels were
studied in serum erythrocytes and platelets, from 154 subjects
(76 hypertensive and 78 normotensives; 104 blacks and 50
whites). In the combined black and white hypertensive group,
platelet sodium and calcium and erythrocyte calcium were
elevated and serum potassium, serum magnesium and platelet
magnesium decreased. In the black hypertensive patients,
platelet sodium and calcium and erythrocyte calcium were
increased, whereas serum magnesium, serum potassium, platelet
magnesium and erythrocyte magnesium were decreased. In the
white hypertensive group, platelet sodium and erythrocyte
calcium were raised and platelet magnesium was decreased. In
the black hypertensive patients, serum and platelet magnesium
and serum calcium were negatively and erythrocyte and platelet
calcium positively correlated with mean arterial pressure. In
the white hypertensive patients platelet sodium was directly
related to mean arterial pressure. These results suggest that
intracellular sodium and calcium overload and magnesium
depletion may be important in the pathophysiology of
hypertension. Magnesium disturbances are more consistent and
widespread in black hypertensive patients than in white
hypertensive patients.
A prospective study of nutritional factors and
hypertension among US men
Ascherio A; Rimm EB; Giovannucci EL; Colditz GA; Rosner B;
Willett WC; Sacks F; Stampfer MJ
Department of Epidemiology, Harvard School of Public Health,
Boston, MA.
Circulation (United States) Nov 1992, 86 (5)
p1475-84
BACKGROUND. An effect of diet in determining blood pressure
is suggested by epidemiological studies, but the role of
specific nutrients is still unsettled.
METHODS AND RESULTS. The relation of various nutritional
factors with hypertension was examined prospectively among
30,681 predominantly white US male health professionals, 40-75
years old, without diagnosed hypertension. During 4 years of
follow-up, 1,248 men reported a diagnosis of hypertension.
Age, relative weight, and alcohol consumption were the
strongest predictors for the development of hypertension.
Dietary fiber, potassium, and magnesium were each
significantly associated with lower risk of hypertension when
considered individually and after adjustment for age, relative
weight, alcohol consumption, and energy intake. When these
nutrients were considered simultaneously, only dietary fiber
had an independent inverse association with hypertension. For
men with a fiber intake of < 12 g/day, the relative risk of
hypertension was 1.57 (95% confidence interval, 1.20-2.05)
compared with an intake of > 24 g/day. Calcium was
significantly associated with lower risk of hypertension only
in lean men. Dietary fiber, potassium, and magnesium were also
inversely related to baseline systolic and diastolic blood
pressure and to change in blood pressure during the follow-up
among men who did not develop hypertension. Calcium was
inversely associated with baseline blood pressure but not with
change in blood pressure. No significant associations with
hypertension were observed for sodium, total fat, or
saturated, transunsaturated, and polyunsaturated fatty acids.
Fruit fiber but not vegetable or cereal fiber was inversely
associated with incidence of hypertension.
CONCLUSIONS. These results support hypotheses that an
increased intake of fiber and magnesium may contribute to the
prevention of hypertension.
The effects of nonpharmacologic interventions on
blood pressure of persons with high normal levels. Results of
the Trials of Hypertension Prevention, Phase I
JAMA (United States) Mar 4 1992, 267 (9) p1213-20
Contract/Grant No.: HL37849, HL, NHLBI; HL37852, HL, NHLBI;
HL37853, HL, NHLBI
Comment in JAMA 1992 Mar 4;267(9):1256-7; Comment in: JAMA
1992 Jul 8;268(2):198; discussion 198-9
[published erratum appears in JAMA 1992 May
6;267(17):2330]
OBJECTIVE--To test the short-term feasibility and efficacy
of seven nonpharmacologic interventions in persons with high
normal diastolic blood pressure.
DESIGN--Randomized control multicenter trials.
SETTING--Volunteers recruited from the community, treated
and followed up at special clinics.
PARTICIPANTS--Of 16,821 screenees, 2182 men and women, aged
30 through 54 years, with diastolic blood pressure from 80
through 89 mm Hg were selected. Of these, 50 did not return
for follow-up blood pressure measurements.
INTERVENTIONS--Three life-style change groups (weight
reduction, sodium reduction, and stress management) were each
compared with unmasked nonintervention controls over 18
months. Four nutritional supplement groups (calcium,
magnesium, potassium, and fish oil) were each compared singly,
in double-blind fashion, with placebo controls over 6
months.
MAIN OUTCOME MEASURES--Primary: change in diastolic blood
pressure from baseline to final follow-up, measured by blinded
observers. Secondary: changes in systolic blood pressure and
intervention compliance measures. RESULTS--Weight reduction
intervention produced weight loss of 3.9 kg (P less than .01),
diastolic blood pressure change of -2.3 mm Hg (P less than
.01), and systolic blood pressure change of -2.9 mm Hg (P less
than .01). Sodium reduction interventions lowered urinary
sodium excretion by 44 mmol/24 h (P less than .01), diastolic
blood pressure by 0.9 mm Hg (P less than .05), and systolic
blood pressure by 1.7 mm Hg (P less than .01). Despite good
compliance, neither stress management nor nutritional
supplements reduced diastolic blood pressure or systolic blood
pressure significantly (P greater than .05).
CONCLUSIONS--Weight reduction is the most effective of the
strategies tested for reducing blood pressure in normotensive
persons. Sodium reduction is also effective. The long-term
effects of weight reduction and sodium reduction, alone and in
combination, require further evaluation.
Overview: studies on spontaneous
hypertension-development from animal models toward man.
Yamori Y
Department of Pathology, Shimane Medical University, Izumo,
Japan.
Clin Exp Hypertens [A] (United States) 1991, 13 (5)
p631-44
The development of genetic rat models for research on
hypertension, stroke and other cardiovascular diseases (CVD)
such as spontaneously hypertensive rats (SHR) and stroke-prone
SHR (SHRSP) have contributed not only to the elucidation of
the pathogenesis of hypertension-related CVD but also to their
prediction and prevention. Since both genetic and
environmental factors are involved in the pathogenesis of CVD
as extensively studied so far on these models, the detection
of the early pathogenic mechanisms related to the genetic
factors and the control of environmental factors such as
dietary improvement are useful as predictive and preventive
measures against CVD. Sympathetic overresponsiveness, early
development of cardiovascular hypertrophy, increased salt
sensitivity and membrane or transport abnormalities in
vascular smooth muscle cells (VSMC) from SHR and SHRSP,
possibly related to the pathogenesis of hypertension, are so
far regarded as predictors for hypertension partly applicable
to human hypertension. Genetic pathogenic mechanisms of stroke
in SHRSP which have been proven to be greatly influenced also
by dietary factors are hypertension-induced VSMC degeneration
and necrosis of intracerebral arteries due to local
nutritional disturbance. One of predictors of stroke related
to the pathogenic mechanisms is reduction of regional cerebral
blood flow. On the other hand, the control of environmental
factors, especially nutrition and diets such as intakes of
animal and vegetable proteins, some amino acids and fatty
acids, potassium, calcium, magnesium, dietary fibers, etc.,
have been experimentally demonstrated to be effective for the
prevention of CVD in these genetic models, and the
applicability of these experimental findings to the CVD
prevention in man is now supported from our world-wide
epidemiological studies (WHO CARDIAC Study). (50 Refs.)
Electrolytes in the epidemiology, pathophysiology,
and treatment of hypertension.
Smith HT
University of Minnesota, Department of Nephrology,
Minneapolis.
Prim Care (United States) Sep 1991, 18 (3)
p545-57
The data regarding the value of manipulating electrolytes
in hypertension are controversial. It appears there are
subsets of hypertensive patients who respond with lowering of
blood pressure in conjunction with changes in intake of
sodium, potassium, and calcium. The information regarding
phosphorus and magnesium is less convincing. This paper
examines current reports regarding these electrolytes and
their role in the pathophysiology and treatment of essential
hypertension. (52 Refs.)
Effect of migration on blood pressure: the Yi
People Study.
He J; Tell GS; Tang YC; Mo PS; He GQ
Peking Union Medical College, Beijing, People's Republic of
China.
Epidemiology (United States) Mar 1991, 2 (2)
p88-97
The Yi People Study was conducted in Puge County, Sichuan
Province, People's Republic of China. Four population groups
were surveyed for risk factors for cardiovascular disease.
Included were two groups of Yi farmers living either in a high
mountainous area in extremely remote villages at or above
2,750 meters elevation, or in a mountainside area at about
1,800 meters elevation. A third study group consisted of Yi
farmers who migrated to the county seat during the 1950s.
Local residents of the county seat, the Han people,
constituted the fourth group. Blood pressure rises very little
with age after puberty in Yi farmers, but there was a trend of
increasing blood pressure with age in Yi migrants and Han.
Mean body mass index (kg/m2) and heart rate were higher in Yi
migrants than in Yi farmers. For men, both systolic and
diastolic blood pressure were greater among Yi migrants than
among Yi farmers. These differences persisted after adjusting
for age and body mass index. Among women, after adjusting for
age, BMI, and altitude, only diastolic blood pressure was
lower among Yi farmers than Yi migrants. Yi migrants and Han
had similar blood pressures. In 1986, a sample of men
participated in more detailed studies of diet, serum, and
urine. The proportion of energy from fat ranged from less than
10% among high-mountain Yi farmers to almost 40% among Yi
migrants and Han. Compared with Yi farmers, Yi migrants
consumed more sodium and less potassium, calcium, and
magnesium, had lower serum potassium, and a greater
sodium/potassium ratio. Urinary excretion of sodium, calcium,
and the sodium/potassium ratio were all greater in Yi migrants
than in Yi farmers, while the reverse was seen for potassium.
These data suggest that changes in life-style, including
dietary changes, contribute importantly to the higher blood
pressure among Yi migrants.
Minerals and blood pressure.
Karppanen H
Department of Pharmacology and Toxicology, University of
Helsinki, Finland.
Ann Med (Finland) Aug 1991, 23 (3) p299-305
The mineral elements sodium, potassium, calcium and
magnesium play a central role in the normal regulation of
blood pressure. In particular, these mineral elements have
important interrelationships in the control of arterial
resistance. These elements, especially sodium and potassium,
also regulate the fluid balance of the body and, hence,
influence the cardiac output. Evidence shows that the present
levels of intake of mineral elements are not optimum for
maintaining normal blood pressure but predispose to the
development of arterial hypertension. Research results suggest
that without sodium chloride (common salt) and other sodium
compounds being added to the diet arterial hypertension would
be virtually non existent. Moreover, blood pressure would not
rise with age. In communities with a high consumption of added
sodium, a high intake of potassium and, possibly, magnesium
seem to protect against the development of arterial
hypertension and the rise of blood pressure with age. A marked
reduction of sodium intake is effective in treating even
severe hypertension. A moderate restriction of sodium intake
or an increase in potassium intake exert remarkable
antihypertensive effects, at least in some hypertensive
patients. Magnesium and possibly also calcium supplements may
be effective in reducing blood pressure in some hypertensives.
In hypertensive patients treated with drugs sodium restriction
and potassium and magnesium supplementation enhance the
therapeutic effect, reduce the number and dosage, and lessen
the adverse effects of prescribed antihypertensive drugs.
Hence, a fall in sodium consumption and increases in potassium
and magnesium consumption are useful in preventing and
treating arterial hypertension. (62 Refs.)
Renal function of cations excretion in children
predisposed to essential hypertension
Yang Y
Department of Child and Adolescent Health, School of Public
Health, Tongji Medical University, Wuhan.
Chung Hua Yu Fang I Hsueh Tsa Chih (China) May 1991, 25 (3)
p152-4
We studied the renal function of cations excretion in 86
normal children, aged 4-6 years old. 24-hour urinary excretion
of sodium, potassium, calcium, magnesium, copper and zinc were
measured before and after acute oral salt loading. The result
showed that urinary sodium levels were significantly lower
(101.88 mmol/24 h, 126.58 mmol/24 h, respectively, P less than
0.01) in children with family history of essential
hypertension than in those without family history after salt
loading. This suggests that the children with family history
may have hereditary functional defect in the excretion of
sodium before developing hypertension. We also found the renal
excretions of potassium, calcium and zinc showed difference
between children with and without family history of essential
hypertension.
Nutrition and blood pressure among elderly men and
women (Dutch Nutrition Surveillance System).
Lowik MR; Hofman Z; Kok FJ; Wedel M; Hulshof KF; Odink J;
Schaafsma G
Department of Human Nutrition, TNO-CIVO Toxicology and
Nutrition Institute, Zeist, The Netherlands.
J Am Coll Nutr (United States) Apr 1991, 10 (2)
p149-55
Associations between blood pressure and nutrition-related
variables (body mass index, dietary intake, and 24-hr
excretion of sodium, potassium, magnesium, and calcium in the
urine) were investigated in men (n = 138) and women (n = 117)
65-79 years old not using drugs known to affect blood pressure
and not on a diet. Among men, body mass index was positively
and creatinine clearance was inversely associated with
systolic blood pressure, whereas body mass index and urinary
sodium:potassium ratio were positively associated with
diastolic blood pressure. Among women, both age and urinary
calcium:creatinine ratio were positively associated with
systolic as well as diastolic blood pressure. Coffee
consumption was positively correlated with blood pressure and
urinary calcium:creatinine ratio among the women. From the
results it appears that, besides "normal" weight, increased
potassium intake and urinary excretion may exert a protective
effect among elderly men against hypertension when sodium
exposure is relatively high. The positive association between
urinary calcium:creatinine ratio and blood pressure among the
women may be partly due to coffee consumption.
The effect of Ca and Mg supplementation and the
role of the opioidergic system on the development of DOCA-salt
hypertension.
Hattori K; Sano H; Kubota Y; Kawahara J; Miki T; Suzuki H;
Fukuzaki H
First Department of Internal Medicine, Kobe University School
of Medicine, Japan.
Am J Hypertens (United States) Jan 1991, 4 (1 Pt 1)
p72-5
The effect of calcium and magnesium supplementation and the
role of opioidergic system was examined in deoxycorticosterone
acetate (DOCA)-salt hypertensive rats. The rats were divided
into four groups receiving standard laboratory rat diet
(control group; n = 9); a calcium-rich diet with 2% CaCl2
added (Ca-group; n = 12); a magnesium-rich diet with 0.5% MgO
added (Mg-group; n = 11); and a calcium and magnesium-rich
diet with 2% CaCl2 and 0.5% MgO added (Ca/Mg-group; n = 11);
each diet contained 7% NaCl. After four weeks on these diets,
the rats were decapitated and blood was obtained for the
measurement of plasma electrolytes, intraerythrocyte sodium,
potassium and magnesium content (RBC-Na, -K, in mEq/L cells
and RBC-Mg, in mg/dL cells) and plasma beta-endorphin
concentration (beta-END, in pg/mL). In the control group,
systolic blood pressure and RBC-Na were obviously higher than
in the other groups. Plasma beta-endorphin concentration was
45.1 +/- 13.4 in the control group, 70.7 +/- 17.4 in the
Ca-group (P less than .05 v control group), 58.0 +/- 20.1 in
the Mg-group and 83.8 +/- 24.8 in the Ca/Mg-group (P less than
.01 v control group). The blood pressure correlated
significantly with both RBC-Na (r = 0.416, P less than .01)
and beta-END (r = 0.436, P less than .005). A negative
correlation was also observed between RBC-Na and beta-END (r =
0.437, P less than .005).(ABSTRACT TRUNCATED AT 250 WORDS)
Cellular mechanisms in hypertension and therapeutic
implications in blacks
Saunders E
Department of Medicine, University of Maryland School of
Medicine and Hospital, Baltimore 21201.
Cardiovasc Drugs Ther (United States) Mar 1990, 4 Suppl 2
p317-9
The high incidence and prevalence of hypertension in the
black community in western societies led to early speculation
that the black population consumed more sodium (sodium
chloride) than the general population. However, numerous
studies have failed to support this conclusion. It seems
rather that it is the handling of sodium by the kidney
(greater salt sensitivity) by many hypertensive blacks and the
interaction of sodium with potassium, probably magnesium,
calcium, and various transport systems at the cellular level
that offer a better explanation of these observed
phenomena.
Experimental intervention of hypertension and
cardiovascular diseases
Yamori Y
Department of Pathology, Shimane Medical University, Izumo,
Japan.
Clin Exp Hypertens [A] (United States) 1990, 12 (5)
p939-52
Experimental prevention of hypertension and related
cardiovascular diseases has been studied in rat models for
hypertension and stroke and not only salt reduction but also
increased intakes of potassium, calcium, magnesium, protein,
some amino acids and fatty acids and dietary fibers have been
proven to be effective and indicated the importance of
nonpharmacological dietary prevention of cardiovascular
diseases. These experimental findings contribute to dietary
risk factor analyses and the prevention of hypertension and
its complications in man, as demonstrated by a cross-sectional
epidemiological study on cardiovascular diseases and
alimentary comparison (WHO-CARDIAC Study). (50 Refs.)
Attenuated vasodilator responses to Mg2+ in young
patients with borderline hypertension.
Fujita T; Ito Y; Ando K; Noda H; Ogata E
Fourth Department of Internal Medicine, University of Tokyo
School of Medicine, Japan.
Circulation (United States) Aug 1990, 82 (2)
p384-93
Limb vascular responses to magnesium (Mg2+) and potassium
(K+) ions were studied in 19 young patients with borderline
hypertension (BHT) and compared with those of 22 age-matched
normotensive subjects (NT) by measuring the forearm blood flow
response to intra-arterial infusion of magnesium sulfate and
potassium chloride using venous occlusion plethysmography.
Percent decrements of forearm vascular resistance with Mg2+
infusions were significantly less in BHT subjects than in NT
(-37.2 +/- 4.2% versus -53.0 +/- 2.0%, p less than 0.05,
during the infusion of 0.1 meq Mg2+/min, and -52.2 +/- 4.3%
versus -65.6 +/- 1.5%, p less than 0.05, during the infusion
of 0.2 meq Mg2+/min). Moreover, the relation of the magnitude
of Mg2+ response to initial vascular resistance in six of 10
BHT subjects lies above the 95% confidence interval for
predicted values calculated for response points in 11 NT
subjects, suggesting attenuated vasodilator responses of Mg2+
in a significant proportion of BHT subjects. In contrast, the
response points to K+ in eight of nine BHT subjects fall
within the 95% confidence interval, suggesting normal
vasodilator responses to K+ in the majority of BHT subjects.
Furthermore, the effect of small increments in local serum
calcium concentrations on Mg2(+)- and K(+)-induced
vasodilation was studied in normal volunteers. Isosmolar CaCl2
solution infused into the same brachial artery at a rate of
0.09 meq/min severely blunted the vasodilating actions of Mg2+
(-30.1 +/- 6.5% versus -65.8 +/- 3.2%, p less than 0.01,
during the infusion of 0.2 meq Mg2+/min) but did not affect
those of K+ (-63.1 +/- 3.1% versus -55.9 +/- 3.8%, NS, during
the infusion of 0.154 meq K+/min). It appears that
Mg2(+)-induced vasodilation should be due to the antagonistic
action of Mg2+ to calcium, but K(+)-induced vasodilation might
not be directly related to calcium movement. Thus, these
attenuated responses to Mg2+ but normal responses to K+ in BHT
subjects may indicate an underlying defect in vascular Mg2+
metabolism, which ultimately may be related to the alterations
in calcium handling by plasma membranes rather than to the
abnormalities of membrane Na(+)-K+ pump activity.
Dietary modulators of blood pressure in
hypertension
Singh RB; Sircar AR; Rastogi SS; Singh R
Medical Hospital and Research Centre, Uttar Pradesh,
India.
Eur J Clin Nutr (England) Apr 1990, 44 (4)
p319-27
To study the role of diet, 197 patients of essential
hypertension were randomized to either experimental diet
(group A, 97 cases) or normal diet (group B, 100 cases) with
diuretics given to both the groups. The age varied between 25
and 65 years and 154 were males. The study diet included a
significantly higher content of potassium (K), magnesium (Mg),
calcium (Ca), polyunsaturated fat, and complex carbohydrates
compared to the normal diet. At entry to the study, age, sex,
risk factors, mean blood pressures, mean serum Mg, K, Ca, and
Na, and drug therapy were comparable in both groups. After 1
year of follow-up, there were significantly fewer patients
with resistant hypertension in group A (5) than in group B
(17). Mean systolic (148.22 +/- 10.1 mm Hg) and diastolic
(90.2 +/- 4.84 mm Hg) pressures in group A were lowered
compared to mean systolic (160 +/- 12.0 mm Hg) and diastolic
(103.3 +/- 5.8 mm Hg) pressures in group B and initial mean
systolic (152.2 +/- 12.8 mm Hg) and diastolic (99.8 +/- 7.2 mm
Hg) pressures. Mean serum magnesium (1.86 +/- 9.22 mEq/l) and
potassium (4.86 +/- 0.39 mEq/l) levels in group A were
significantly higher compared to mean levels of 1.56 +/- 0.11
and 4.0 +/- 0.29 mEq/l, respectively, in group B. However
compared to initial levels, K and Mg showed no significant
changes in groups A and B. There was a significantly lower
incidence of complications in group A (58) compared to group B
(100). It is possible that a diet low in Na/K ratio and rich
in complex carbohydrates, polyunsaturates, K and Mg may cause
a significant reduction in blood pressure and its
complications.
Daily intake of macro and trace elements in the
diet. 4. Sodium, potassium, calcium, and magnesium
Cocchioni M; Pellegrini MG; Grappasonni I; Vitali C; Marsili
G
Ann Ig (Italy) Sep-Oct 1989, 1 (5) p923-42
To complete the picture of the daily dietary intake of
minerals, sodium, potassium, calcium and magnesium have now
been considered. The study has been carried out in the Italian
Marches Region after carefully evaluating the food consumption
habits of the population. The foodstuffs comprising the 70
diets examined were collected in institutional canteens and
private homes immediately prior to meals. The food was sampled
ready for consumption as it had thus undergone the various
preparation and cooking procedures, during which considerable
changes in mineral content occur. In comparison with the
various food consumption standards, the amount of sodium found
appears excessively high (4.8 g/d) whereas that of magnesium
is insufficient (0.24 g/d). A high sodium intake, and more
recently a high Na/K ratio, have been associated with
hypertension. Also a lack of magnesium and a high Ca/Mg ratio
have repeatedly been associated with hypertension risk. The
data to emerge from our study: a high sodium intake, an
insufficiency of magnesium, and thus high Na/K and Ca/Mg
ratios, would appear likely to enhance cardiovascular disease
risk. Even though not all Authors agree on the existence of
such correlations, a more correct diet as regards mineral
intake is undoubtedly something to encourage.
Fish oils modulate blood pressure and vascular
contractility in the rat and vascular contractility in the
primate
Mano MT; Bexis S; Abeywardena MY; McMurchie EJ; King RA;
Smith RM; Head RJ
CSIRO Division of Human Nutrition, Adelaide, Australia.
Blood Press (Norway) May 1995, 4 (3) p177-86
The effect of dietary fish oils on development of
hypertension and vascular response in vitro were studied in
rats and a primate. Dietary fish oils (MaxEPA and an n-3 ethyl
ester concentrate of higher EPA and DHA content) were
administered to spontaneously hypertensive (SHR), stroke-prone
spontaneously hypertensive (SHR-SP) and a backcross of SHR and
Wistar Kyoto (SHR/WKY) rats from 4-16 weeks of age. Blood
pressure was monitored during the feeding period and vascular
responses measured in the aorta and mesenteric vascular bed in
vitro. Depending on the strain of rat used and the composition
of the fish oil the attenuation in blood pressure was 10-26
mmHg. Fish oils attenuated the response mediated by
sympathetic nerve stimulation or intralumenal norepinephrine
in the perfused mesenteric vascular bed preparation from the
SHR. This attenuation was more pronounced for fish oils
enriched with eicosapentaenoic acid and docosahexaenoic acid
and was more prominent in the SHR and SHR/WKY backcross than
it was in the SHR-SP. Prostanoid synthesis or nitric oxide
modulation of alpha-adrenoceptor responses were shown not to
be involved in the attenuation of vascular responses produced
by fish oil. The maximum contraction of aortic ring
preparations in response to norepinephrine (NE) was
significantly smaller in SHR than WKY rats fed olive oil and
for SHR rats maintained on fish oils the contraction was close
to WKY olive oil values. Evidence was obtained also for a
modulation of vasoconstrictor responses by dietary fish oils
in the perfused mesenteric bed of the marmoset monkey.
Effects of fish oil, nifedipine and their
combination on blood pressure and lipids in primary
hypertension.
Landmark K; Thaulow E; Hysing J; Mundal HH; Eritsland J;
Hjermann I
Department of Internal Medicine, Ullev.ANG.al University
Hospital, Oslo, Norway.
J Hum Hypertens (England) Feb 1993, 7 (1) p25-32
In a double-blind, crossover, placebo-controlled study the
effects of four weeks' treatment with 4.55 g/day of
eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on
BP and serum lipids were assessed in 18 males with
hypertension (WHO stage I-II). At the end of the double-blind
phase, eight patients on placebo (olive oil) and ten patients
on fish oil treatment were given nifedipine 20 mg twice daily
added to their regimens for four weeks. Four weeks' fish oil
treatment slightly reduced BP values; however, compared with
placebo no changes were found. VLDL-cholesterol and
triglycerides were significantly reduced by 24%, whereas total
and LDL-cholesterol remained unchanged. Placebo did not change
BP and lipid values. When nifedipine was added to fish
oil/placebo, BP in the two groups was reduced to almost the
same extent. When nifedipine was added to fish oil, total
cholesterol was significantly reduced by 12% in comparison
with baseline value and LDL-cholesterol was reduced by 15%,
albeit insignificantly. Placebo plus nifedipine was lipid
neutral. A significant correlation was found between the
nifedipine-induced changes in supine mean arterial pressure
and total, LDL- and VLDL-cholesterol, respectively, in those
patients with and without fish oil treatment. In conclusion,
the combined administration of fish oil and nifedipine
possesses favourable antihypertensive and metabolic properties
in hypertensive males with elevated lipid levels.
Microbial infection or trauma at cardiovascular
representation area of medulla oblongata as some of the
possible causes of hypertension or hypotension.
Omura Y
Heart Disease Research Foundation, Brooklyn, N.Y.
11201.
Acupunct Electrother Res (United States) 1988, 13 (2-3)
p131-45
The author found that the onset of hypertension or
hypotension is relatively often associated with infections or
development of so-called "sneezing due to allergy to pollen or
dust," with or without headache, or due to trauma to the
occipital area of the head. Using the "Bi-Digital O-ring
Test," it was possible to demonstrate that, among bacterial
and viral infections, the most common cause of infection
associated with the appearance of hypertension is chlamydia,
herpes simplex virus, cytomegalovirus, or Epstein-Barr virus.
Particularly chlamydia and/or herpes simplex virus, with or
without coexistence of other microbes, is usually present at
the heart representation area of the medulla oblongata,
especially at the left ventricular representation area, often
accompanied by upper respiratory infection, cephalic, cervical
or facial pain, with or without coexisting genito-urinary
infection. The left ventricular representation area of the
medulla oblongata is usually located at the right side. In
most hypertensive patients, the left ventricular
representation area of the medulla oblongata is enlarged up to
3 or 4 times normal size. Sufficient antibiotic treatment of
chlamydia with erythromycin sometimes eliminated severe
hypertension which appeared after chlamydia infection. In the
presence of viral infections, such as herpes simplex, which is
also causing severe pain in the head or neck, oral
administration of acyclovir, erythromycin, or EPA (Eicosa
Pentaenoic acid)-DHA (docosa hexaenoic acid) Omega 3 fish oil
often reduced associated intractable pain and hypertension
toward the normal level. Thus, the author is proposing new
possible mechanisms as among the causes of so-called essential
hypertension as a result of microbial infection or trauma of
the cardiovascular representation area, particularly that of
the left ventricular representation area at the right side of
the medulla oblongata.
Garlic (Allium sativum)--a potent medicinal
plant
Resch KL; Ernst E
Postgraduate Medical School, University of Exeter, UK.
Fortschr Med (Germany) Jul 20 1995, 113 (20-21)
p311-5
A good deal of evidence suggests beneficial effects of the
regular dietary intake of garlic on mild hypertension and
hyperlipidemia. Garlic seems to have anti-microbial and
immunostimulating properties, enhance fibrinolytic activity,
and exert favorable effects on platelet aggregation and
adhesion. Standardised preparations guarantee exact dosing and
minimize the problem of the strong odour of raw garlic. Thus,
a traditional folk remedy has established its usefulness for
many patients with less severe forms of cardiovascular disease
as a medical drug with very few side effects. The available
evidence gives rise to the hope that the list of indications
may even be considerably extended in the future. (43
Refs.)
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