What's Hot Archive
January 30, 2006
Tomato extract lowers blood pressure
A double-blind study published in the January 2006 issue of the American Heart Journal found that a high antioxidant tomato extract given to patients with hypertension lowered blood pressure when given over a two month period.
Researchers at Soroka University Medical Center in Israel recruited thirty-one men and women aged 30 to 70 with grade 1 hypertension. Without knowing whether they were receiving tomato extract or a placebo, participants were given a placebo for four weeks followed by one 250 milligram capsule of Lyc-O-Mato tomato extract for eight weeks, then the placebo for another four weeks. The tomato extract contained of 6 percent lycopene, 0.15 percent beta-carotene, 1 percent phytoene, 1 percent phytofluene, 2 percent vitamin E, 15 percent phospholipids and 0.6 percent phytosterol. No other supplements were allowed during the course of the study. Blood pressure was measured at the beginning of the trial and every two weeks until the study's conclusion, and blood samples were evaluated at the beginning of the study and after the initial placebo and treatment periods.
The subjects' systolic blood pressure declined from an average of 144 to 134 mm Hg, and diastolic was reduced from a mean 87.4 to 83.4 mm Hg during the eight week period of treatment with tomato extract. Lipid peroxidation products decreased after treatment with tomato extract as well. There were no changes observed in blood pressure during the the first placebo period, and blood pressure elevated to pretreatment values following the final placebo period.
The authors observe that reducing blood pressure from the grade 1 hypertension range to high normal, and maintaining it there, could help prevent the progression of hypertension and postpone the need for medication. They recommend larger trials for longer periods to help define tomato extract's role as an antihypertensive agent.
January 27, 2006
DHEA improves depressive symptoms among HIV patients
In an article published in the January 2006 issue of the American Journal of Psychiatry, Judith G. Rabkin, PhD, of New York State Psychiatric Institute at Columbia University and her colleagues report that DHEA improved the symptoms of HIV positive adults with nonmajor depression, a condition which is not uncommon among HIV/AIDS patients.
In a double-blind trial, 273 men and women with subsyndromal depression or dysthymia were randomized to receive DHEA per day or a placebo for eight weeks. The DHEA daily dose of 100 milligrams was increased to 200 milligrams per day during the second week, 300 milligrams per day during the third week, and 400 milligrams per day during the fifth week in the absence of improvement or significant side effects. Interviews conducted at the beginning of the study were used to confirm the participants' diagnoses, and improvement was evaluated at eight weeks.
The clinicians' ratings found a 56 percent response in the group who received DHEA, while there was a 31 percent response rate reported in the placebo group. Computer analysis determined a higher response for both groups, with 62 percent of the DHEA group and 33 percent of the placebo patients reporting improvement. No change in T cell count or RNA viral load were detected in either group.
DHEA may provide its antidepressant effect via its conversion to testosterone or estradiol, both of which have been correlated with mood. Additionally, DHEA interacts with neurotransmitter receptors in the brain that effect mood. "Given the high acceptance rate and low side effect profile for DHEA in this group of patients with HIV/AIDS, it may be appropriate to evaluate the efficacy of DHEA in other groups of physically ill patients in which mild depression is comment," the authors suggest.
January 25, 2006
Inflammation predicts cancer death
The January 23 2006 issue of the American Medical Association journal Archives of Internal Medicine published the finding of Anoop Shankar, MD, PhD of the National University of Singapore, and colleagues that having a higher white blood cell (WBC) count, a marker of inflammation, is associated with a greater risk of dying from cancer.
Dr Shankar's team evaluated data from 3,189 participants in the Blue Mountains Eye Study, a population-based cohort study of age-related eye diseases in Australia. All subjects were born prior to 1943 and were cancer free upon enrollment between 1992 and 1994. Blood samples drawn during the initial examination were analyzed for white blood cell counts, glucose and other factors. Participants were followed until the end of 2001.
At the end of the study, there were 212 cancer deaths. Men and women whose white blood count was in the top 25 percent of the study population at 7,400 cells per microliter or greater were determined to have a 73 percent higher risk of dying of cancer than those whose white blood cells were in the lowest 25 percent at 5,300 cells or less. When lung cancer was analyzed separately, having a white blood cell count in the top fourth more than doubled the risk of dying from the disease compared to those whose white blood cell counts were in the lowest quarter. Additionally, the risk of cancer death was higher among subjects with elevated white blood cells who did not take aspirin weekly compared to those who used the drug. Aspirin is well known for its anti-inflammatory action.
The authors conclude, "Our findings suggest that local inflammatory processes that have long been known to be associated with tumor progression may be reflected in the systemic inflammatory marker of higher WBC count."
January 23, 2006
Carotenoid supplements reduce DNA damage
The results of a double-blind study published in the January 2006 issue of the American Journal of Clinical Nutrition revealed that postmenopausal women given mixed carotenoids or single carotenoids had less damage to their DNA than those administered a placebo over an eight week period.
Researchers at Tufts University in Boston randomized 37 women aged 50 to 70 to receive a supplement containing a daily dose of 4 milligrams beta-carotene, 4 milligrams lutein and 4 milligrams lycopene; 12 milligrams of beta-carotene, lutein, or lycopene alone; or a placebo for 56 days. Participants were instructed to limit carotenoid-rich fruit and vegetables from two weeks prior to the study until its conclusion. Endogenous and hydrogen-peroxide challenged DNA damage to lymphocytes (a white blood cell) were evaluated from blood samples taken before the subjects began the supplement regimen, and on days 15, 29 43 and 57.
By the fifteenth day of the study, there was significantly less endogenous DNA damage among women who received mixed carotenoids or beta-carotene alone compared to that measured at the beginning of the study. By the study's conclusion all groups who received carotenoid supplements showed less hydrogen-peroxide induced DNA damage, and significantly less endogenous DNA damage compared to presupplementation levels. The authors remarked that the loss of interactions with other antioxidants when DNA damage is measured outside of the body could explain the weaker protective effects for the carotenoids against hydrogen-peroxide induced DNA damage they observed.
At the study's conclusion, all groups had less endogenous DNA damage than the placebo group, and only the group who received lycopene was found to have more hydrogen-peroxide induced damage than the placebo group. However, the lycopene group had less endogenous DNA damage measured at the end of the study than any other group.
January 20, 2006
High waist to hip ratio associated with lower vitamin C levels
A study published in the December 2005 issue of the American Journal of Clinical Nutrition reported that having lower levels of vitamin C (ascorbic acid) is associated with a greater waist to hip ratio. Recently published research suggests that waist to hip ratio may be a better predictor of cardiovascular disease than body mass index, indicating that fat distribution may be of more importance than obesity alone.
British researchers analyzed data from the European Prospective Investigation into Cancer and Nutrition (EPIC) study, a prospective population study of diet and cancer in Europe. Nineteen thousand sixty-eight participants were included in the current analysis. Weight, body mass index, waist and hip circumference, and plasma levels of vitamin C were determined upon enrollment. Seven day food diaries completed by the participants provided information on ascorbic acid intake.
It was determined that subjects who had a greater waist to hip ratio were more likely to have a higher body mass index and were less likely to be vitamin supplement users than were men and women with lower waist to hip ratios. Having a higher waist to hip ratio was associated with lower plasma levels of vitamin C as well as a lower intake of the vitamin for both men and women. The authors observed that this effect appeared to be independent of body mass index and vitamin supplement use.
Ascorbic acid levels may be reflecting a dietary pattern that promotes leaner body mass as well as a more favorable pattern of fat distribution. Alternatively, vitamin C levels could be reflecting the available pool of this antioxidant in the body, which is used up to a greater extent among individuals with conditions that put them at risk of cardiovascular disease.
January 18, 2006
Primate study shows soy does not increase breast cancer risk
A study published in the January 15 2006 issue of the journal Cancer Research concluded that the estrogenic compounds that occur in soy do not increase breast cancer risk and may even help protect some women from the disease. While population studies have found that women whose diets provide high amounts of soy have a lower incidence of breast cancer, soy isoflavones have been found to stimulate the growth of breast cancer cells in culture and in mice. Lead researcher Charles E. Wood, DVM, PhD, of Wake Forest University Baptist Medical Center remarked, "Our study sought to make sense of these seemingly contradictory data. Our hypothesis was that estrogen levels in the body may influence the effects of soy isoflavones."
Dr Wood and his Wake Forest colleagues rotated 31 postmenopausal monkeys through eight diets containing one of four isoflavone doses combined with a low or high dose of estrogen. The isoflavone doses corresponded with human levels of no isoflavone consumption, levels obtainable via a typical Asian diet, the highest levels that can be consumed through diet, or levels obtained via isoflavone supplements.
The team measured markers of breast cancer risk including cell proliferation, and found no evidence of increased proliferation in any of the monkeys who received the low estrogen dose. Among animals who received the higher estrogen dose, cell proliferation was increased in the groups who received no isoflavones or lower amounts. Monkeys who received the higher dose of estrogen as well as the higher dose of isoflavones experienced protection from estrogen's proliferative effect.
"Even at high doses, we found no evidence that the estrogen-like compounds in soy, called isoflavones, stimulate cell growth or other markers for cancer risk in breast tissue," Dr Wood stated. "The study also suggests that women who have higher levels of estrogen may actually gain a protective effect from higher doses of soy isoflavones."
January 16, 2006
A third of patients hospitalized with congestive heart failure are deficient in vitamin B1
A study published in the January 17, 2006, issue of the Journal of the American College of Cardiology reported that approximately one out of three patients hospitalized with heart failure have deficient levels of thiamin, also known as vitamin B1. According to the authors of the report, a deficiency of thiamin manifests as heart failure symptoms and may worsen pre-existing disease. The study is the largest to date of thiamin deficiency among individuals hospitalized with heart failure.
Mary E. Keith, PhD of St Michael's Hospital in Toronto, Ontario, and colleagues at St Michael's and the University of Toronto, measured thiamin levels among 100 heart failure patients and compared them with those of 50 healthy subjects. They found a deficiency of the vitamin in 33 percent of the heart failure patients compared to 12 percent of those without the disease. Dr Keith commented, "We found that one-third of congestive heart failure patients admitted to our hospital had red blood cell levels of thiamin that were lower than normal and would suggest deficiency. In contrast to some previous studies, we did not find a relationship between the development of thiamin deficiency and the amount or duration of diuretic use and urinary thiamin excretion. In fact, what was important was that a relatively small dose of thiamin from a multivitamin was protective against developing thiamin deficiency."
Dr. Keith observed that heart failure may increase the body's need for certain nutrients, so that even individuals with healthful diets may still come up short on vitamin B1. "Physicians and the public have exclusively focused on drug therapy to the detriment of at least one of the foundations of good health-appropriate nutrition," she added.
January 13, 2006
Chromium supplementation extends rat lifespan
The findings of a study presented at the 46th Annual Meeting of the American College of Nutrition, held September 22-25, 2005 in Kiawah Island, South Carolina, revealed that rats whose diets were supplemented with niacin-bound chromium (NBC) experienced a 22 percent increase in average lifespan compared to unsupplemented rats. Niacin-bound chromium, also known as chromium polynicotinate, is widely available as an over the counter nutritional supplement, and is used by many individuals to help maintain healthy blood sugar levels.
In the current study, Harry G. Preuss, MD of Georgetown University Medical Center and colleagues at Creighton University Medical Center in Omaha, Nebraska used rats bred to manifest aspects of the metabolic syndrome. One group of rats was fed a diet supplemented with niacin-bound chromium, a second group received a diet supplemented with a formula containing niacin-bound chromium plus garlic, bitter melon, fenugreek and gymnema sylvestre, and a third group received unsupplemented diets. The first group of rats received twice the amount of chromium as the second group. All animals were allowed to each as much food as they wanted.
Compared to the control group, the research team found a 21.8 percent increase in average life span, a 14.1 percent increase in median life span, and a 22 percent increase in maximum life span among mice who received the niacin-bound chromium alone. While the first death of a mouse in the control group occurred at week 47, the first death in the chromium-supplemented group occurred during week 59. The death rate among the group who received the chromium plus herbal formula was similar to that of the controls, which the researchers attribute in part to the lower dose of chromium consumed.
The authors concluded, "These studies suggest that ingesting certain levels of NBC can increase lifespan significantly, mimicking caloric restriction."
January 11, 2006
Vegetable-sourced protein associated with lower blood pressure
The January 9, 2006 issue of the American Medical Association journal Archives of Internal Medicine reported that individuals whose consume more protein from vegetables have lower blood pressure than those whose consume more protein from animal sources.
The majority of adults have either hypertension or prehypertension. Previous research has revealed that nonvegetarians tend to have higher blood pressure than those who don't eat meat.
Paul Elliott, MB, PhD of Imperial College in London, and colleagues examined data from the INTERMAP study on macronutrients, micronutrients, and blood pressure, which enrolled 2,359 men and 2,321 women aged 40 to 59 from Japan, China, the United Kingdom, and the United States. Twenty-four hour dietary recalls were obtained and blood pressure was measured eight times during four study visits over a three to six week period. Urine samples were obtained on the first and third study visits and were analyzed for sodium, potassium, urea, creatinine, calcium and magnesium.
The research team found that participants who consumed more vegetable protein were likelier to have lower blood pressure than those who consumed smaller quantities. As a possible explanation for the finding, the authors comment that specific amino acids, such as glutamic acid, cystine, proline, phenylalanine and serine, were provided in greater amounts by the diets that were higher in vegetable protein, while other amino acids were present in reduced amounts, both of which could impact blood pressure. They conclude, "Our results are consistent with current recommendations that a diet high in vegetable products be part of a healthy lifestyle for prevention of high blood pressure and related chronic diseases. Definitive ascertainment of a causal relationship between vegetable protein intake and blood pressure awaits further data from randomized controlled trials, especially regarding the effect of constituent amino acids on blood pressure."
January 9, 2006
Tomato juice prevents smoke-induced emphysema in mice
In research published in the February 2006 issue of the American Journal of Physiology-Lung Cellular and Molecular Physiology a team from Japan found that tomato juice given to mice exposed to cigarette smoke prevented them from developing emphysema.
To test the hypothesis that oxidant-antioxidant imbalance is important in emphysema, researchers led by Kuniaki Seyama, MD of Juntendo University School of Medicine in Tokyo utilized tomato juice for the experiment because of its high amounts of the potent antioxidant lycopene. "We wanted to concentrate on oxidative stress for two reasons," Dr Seyama explained. "First is because the consequences of oxidative stress during life is considered to be deeply involved in the aging process. And second, tobacco smoke contains lots of oxidants and hence puts oxidative stress on the lungs. Using our mouse model for smoke-induced emphysema, we wanted to intervene in the accumulation process by changing daily lifestyle, especially eating habits . . . We thought lycopene might be a good candidate."
By exposing two strains of senescence-accelerated mice to cigarette smoke, the researchers found that one strain, called SAMP1, developed emphysema within an eight week period, while the strain SAMR1,did not. Using the SAMP1 strain, the researchers then gave one group water containing 50 percent tomato juice while another group received unenhanced drinking water during an eight week period of regular smoke exposure.
They found that "smoke-induced emphysema was completely prevented" in the mice that received tomato juice. However, although lycopene was found in both the serum and lung tissues of animals who received the juice, the researchers could not rule out the possibility that other ingredients in tomato affected the results.
The next step the investigators would like to take is to explore how tomato juice affects human patients with chronic obstructive lung disease.
January 6, 2006
Mothers' diets can help prevent children's osteoporosis
A report published in the January 7 2006 issue of The Lancet described the findings of British researchers that mothers who have deficient levels of serum vitamin D are more likely to have children with reduced bone mineral density. Low bone mineral density in childhood increases the risk of osteoporosis and fracture later in life.
Professor Cyrpus Cooper, of the MRC Epidemiology Resource Centre of Southampton General Hospital in Southampton, England, and colleagues conducted a nine-year follow up of 198 children whose mothers' nutrition and vitamin D status had been evaluated during their pregnancies. Thirty-one percent of the mothers had insufficient and 18 percent had deficient circulating concentrations of 25(OH)-vitamin D during late pregnancy. Women who used vitamin D supplements had higher median vitamin D levels than nonsupplement users.
There was an association found between lower concentrations of serum vitamin D in late pregnancy and having children with reduced whole-body bone mineral content, bone area, and areal bone mineral density at nine years of age. For children of mothers whose vitamin D levels were less than 11 micrograms per liter, which were categorized as deficient, whole-body bone mineral content was significantly lower than that of children whose mothers' vitamin D levels were adequate. Children of women who had taken vitamin D supplements experienced significantly greater whole-body bone mineral content and bone areas than those of nonsupplement users. The authors conclude that vitamin D supplementation could lead to a reduced risk of fragility fractures in offspring during later life.
Dr Cooper commented, "The results add to a large body of evidence that intrauterine and early postnatal development contributes to bone mineral accrual and thereby osteoporosis risk; they also point to preventive strategies which now require evaluation in randomised controlled trials."
January 4, 2006
Strength training + calcium supplement = increased bone density
A report published in the December 2005 issue of Osteoporosis International revealed the findings of Timothy G. Lohman of the University of Arizona at Tucson and colleagues that increased exercise frequency combined with calcium supplementation increased bone mineral density among postmenopausal women.
One hundred sixty-seven postmenopausal participants in the Bone Estrogen Strength Training Study (BEST) were included in the current study. The women were asked to take 800 milligrams per day calcium from calcium citrate, and were assigned to a three times per week strength training program or to a control group. Control subjects were allowed to cross over to the exercise group after one year, and 55 women chose to do so. Bone mineral density was measured upon enrollment and yearly thereafter.
Over the four year course of the study, total calcium intake averaged 1,635 milligrams per day, with an average 711 milligrams derived from supplements. Average daily supplemental calcium intake was significantly associated with increased total body and site specific bone mineral density for women who were not using hormone therapy (HT).
Women whose reported exercise frequency was in the lowest third of participants experienced an average bone loss of at least 1 percent across bone sites, while those whose frequency was the greatest showed significant increases in femoral trochanter and lumbar spine bone mineral density from that measured at the beginning of the study, and compared to that experienced by the group with the least reported exercise.
"This study supports the long-term benefits of strength training exercise and calcium intake for the prevention of osteoporosis in postmenopausal women," the authors conclude. "Combined with exercise women may choose to continue HT or increase total calcium intake to around 1,700 mg/day to help prevent osteoporosis."
January 2, 2006
Dietary antioxidants substantially lower macular degeneration risk
A report published in the December 28, 2005 issue of the Journal of the American Medical Association concluded that individuals whose diets contain high amounts of the antioxidants beta-carotene, vitamin C, vitamin E and zinc have a significantly lower risk of developing age-related macular degeneration (AMD) than people whose diets contain lower levels of the nutrients. Age-related macular degeneration is the most common cause of permanent blindness in the developed world. An earlier study found that supplements containing 5 to 13 times the recommended daily allowance of these nutrients slowed the progression of the disease.
The current study included 4,176 men at women at risk of AMD who were participants in the Rotterdam Study, which enrolled 7,983 men and women aged 55 and older from 1990 to 1993 who resided in a suburb of Rotterdam, the Netherlands. Nutrient intake was determined via food frequency questionnaires completed by all subjects. Participants underwent eye examinations upon enrollment, and three times during the eight year follow-up.
Five hundred-sixty subjects were diagnosed with new macular degeneration during the follow-up period. Dietary levels of beta-carotene, vitamins C and E, and zinc that were above the median of the total participants' intake were associated with a 35 percent lower risk of age-related macular degeneration compared to having an intake of at least one of these nutrients that was below the median. When the combined effect of antioxidants from supplements and food was analyzed, a similar effect was found.
The authors concluded, "This study suggests that the risk of AMD can be modified by diet; in particular, by dietary vitamin E and zinc . . . Although in need of confirmation, our observational data suggest that a high intake of specific antioxidants from a regular diet may delay the development of AMD."
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