July 31, 2006
Curry intake linked with better cognitive function
An article published online on July 26, 2006 in advance of publication in the American Journal of Epidemiology revealed an association between increased consumption of curry and improved cognitive performance in older Asians. Curry contains turmeric, in which the compound curcumin occurs, which has been demonstrated to have antioxidant and anti-inflammatory properties in addition to reducing beta-amyloid and plaque burden in the brains of animals.
Researchers at the University of Singapore utilized data from the Singapore National Mental Health Survey of the Elderly, which surveyed 1,092 men and women aged 60 or older in 2003. In-home interviews collected information on dietary intake including curry consumption. Curry consumption of less than once in six months was quantified as "never or rarely,", intake of more than once in six months but less than once a month as "occasional," and at least once per week as "often."
The Mini-Mental State Examination (MMSE) was used to assess memory, attention, language, sensorimotor skills and visuospatial ability. Participants who reported consuming curry "often" had higher MMSE test scores than those who occasionally, or "never or rarely" consumed curry, and they experienced nearly half the risk of cognitive impairment than the risk experienced by those who never or rarely consumed it. Even subjects whose intake of curry was reported as occasional experienced a 38 percent reduction in risk compared to those who rarely consumed it.
The authors observed that India, a country in which turmeric is widely consumed, has a four-fold lower prevalence of Alzheimer's disease among individuals between the ages of 70 and 79 than that which occurs among this age group in the United States. They note that the results of the current study suggest a significant benefit on cognitive function with even low to moderate levels of curry consumption.
July 28, 2006
Multivitamin use lowers preeclampsia risk
In a report published online in advance of publication of the September 1, 2006 issue of the American Journal of Epidemiology, researchers at the University of Pittsburgh revealed that lean women who used multivitamins before and during their pregnancies reduced the risk of preeclampsia. Preeclampsia is a complication of pregnancy characterized by elevated blood pressure, swelling of the extremities and protein in the urine. If untreated, the condition can progress to eclampsia, which can lead to seizures, coma, and the death of the mother or child.
For the current study, Graduate School of Public Health assistant professor of epidemiology Lisa Bodnar, PhD, MPH, RD, and her University of Pittsburgh colleagues used data from 1,835 women enrolled in the University of Pittsburgh's Pregnancy Exposures and Preeclampsia Prevention Study between 1997 and 2001. They found that women at less than 16 weeks gestation who did not use multivitamins or prenatal vitamins during the previous six months had a 4.4 percent incidence of preeclampsia, while those who reported using multivitamins experienced a 3.8 percent incidence, which conferred a 45 percent lower adjusted risk. When participants whose body mass index was less than 25 (defined as non-overweight) were separately analyzed, those who used multivitamins had a 71 percent lower risk of preeclampsia than nonusers.
"At this time, multivitamin use makes little apparent difference in preeclampsia rates for women who are overweight before pregnancy. Even so, the results suggest that regular multivitamin use in the pre-pregnancy period may help to prevent preeclampsia," Dr Bodnar stated. "It may be that typical multivitamins, which contain low nutrient doses, may not be adequate to overcome the metabolic challenges associated with the development of preeclampsia along with being overweight and pregnant," she added. "But again, more study is needed to test these ideas."
July 26, 2006
Serum magnesium levels lower in diabetic patients
Researchers in Italy have found that serum ionized magnesium concentrations were low among half of the participants included in a study of type 2 diabetics, and that having low magnesium was related to some of the criteria for metabolic syndrome. The research was published in the June, 2006 issue of the Journal of the American College of Nutrition.
The study enrolled 290 men and women with diabetes seen as outpatients at the University Hospital of Messina, Italy. Physical examination and blood testing determined the presence of metabolic syndrome diagnostic criteria, which include a waist circumference of greater than 102 centimeters for men or 88 centimeters for women, plasma triglycerides greater of at least 150 milligrams per deciliter, high density lipoprotein cholesterol of less than 40 milligrams per deciliter for men and less than 50 for women, blood pressure greater than or equal to 130 over 85 mmHg, and fasting plasma glucose of at least 6.1 micromoles per liter. Additionally, urine samples were analyzed for the presence of albumin, which can indicate kidney damage induced by high blood sugar levels, and blood serum samples were analyzed for ionized magnesium.
It was found that 143 patients (49.3 percent) had low serum ionized magnesium, defined as less than 0.46 micromoles per liter. Adjusted analysis found that having low magnesium was associated with 4.7 times the risk of having elevated triglycerides, and over twice the risk of an increased waist circumference than the risk of these metabolic syndrome criteria experienced by subjects whose magnesium levels were adequate. Microalbuminuria and clinical proteinuria were also also associated with having reduced magnesium levels.
"Our findings strengthen the need to address a greater attention to magnesium metabolism disturbances in patients with type 2 diabetes mellitus," the authors conclude.
July 24, 2006
Fiber intake associated with lipid and hormone improvement in postmenopausal women
The August 2006 issue of the Journal of Nutrition published the results of a study conducted by Alok Bhargava at the University of Houston which found improved lipid and hormone profiles associated with weight loss and increased fiber intake in postmenopausal women.
The current study analyzed data from 994 women enrolled in the Women's Health Trial: Feasibility Study in Minority Populations. In this study, one group of women were given advice by a nutritionist over a one year period concerning reducing fat and increasing whole grains, fruits, and vegetables, while a control group received pamphlets which provided information on healthy eating. Dietary intake was determined via questionnaires administered at the beginning of the study and at 6 and 12 months. Height, weight, waist and hip circumferences were measured and blood samples were analyzed for lipids, estradiol, serum hormone binding globulin (SHBG, for which reduced levels have been associated with diabetes risk), glucose, and insulin before beginning the study and at its conclusion.
At the end of twelve months, women who received the nutritional advice experienced a greater decrease in HDL and LDL cholesterol, and a greater increase in SHBG compared to the control group. These changes coincided with a reduction in saturated fat and calories, and an increase in dietary fiber. Women in the treatment group also experienced a reduction in weight, and hip and waist circumference. Analysis of the data revealed greater fiber intake associated with lower insulin and triglycerides, and higher HDL levels in this group. Waist to hip ratio and BMI were found to be associated with increased insulin and lipids, and lower SHBG in both groups. "The results from our comprehensive analysis of the WHTFSMP data demonstrated the importance of reducing central obesity in particular and increasing the intakes of dietary fiber for improving the lipid, lipoprotein, and hormonal profiles of postmenopausal women," Dr Bhargava concluded.
July 21, 2006
Antioxidants reduce progression of retinitis pigmentosa
A report published in the early online edition of the Proceedings of the National Academy of Sciences revealed that treatment with antioxidants helped arrest retinal degeneration in a mouse model of retinitis pigmentosa (RP). Retinitis pigmentosa is a disease in which the photoreceptors of the rods die, followed by the progressive death of the cones, which can lead to blindness. Photoreceptor death in the rods is due to genetic mutations, but the cause of death in the cones of the eye had not been known.
By exposing mice to pure oxygen, researchers at the Johns Hopkins University led by Peter Campochiaro found that high oxygen levels in the retina destroyed both rods and cones. "This was the clue that the high oxygen levels that occur naturally in the retina after rods die was the suspect regarding cone cell death. To test this, we used antioxidants, which protect cells from oxygen damage, and since they allowed many more cones to survive, it proves that the suspect is guilty," Dr Campochiaro explained.
The team injected vitamin C, vitamin E, alpha-lipoic acid, an antioxidant similar to superoxide dismutase, or a mixture of these antioxidants to mice who develop retinal degeneration similar to retinitis pigmentosa. They found that treatment with vitamin E or alpha-lipoic resulted in survival of 40 percent of the cones, which was approximately double the amount of those that survived among mice who received the other antioxidants or no treatment.
"These data support the hypothesis that gradual cone cell death after rod cell death in RP is due to oxidative damage, and that antioxidant therapy may provide benefit," the report concludes.
"What's clear is the link between oxygen and photoreceptor damage, as well as the potential of antioxidant treatment," Dr Campochiaro commented. "These experiments suggest that an optimized regimen of antioxidants may help to protect patients with retinitis pigmentosa."
July 19, 2006
Fruit, vegetables, vitamin C associated with improved bone mineral content
The June, 2006 issue of the American Journal of Clinical Nutrition published the finding of researchers in Cambridge, England that bone mineral content in older women and adolescent boys and girls was associated with greater fruit and vegetable intake.
The current study used data from studies that included 132 boys and 125 girls between the ages of 16 to 18 who took part in the Cambridge Bone Studies, women between the ages of 23 and 37 who were a part of the Young Women's Pregnancy Study, and 70 men and 73 women aged 60 to 83 who had been recruited for the Vitamins K and D Study. Seven day food diaries provided information on fruits, vegetables and other foods consumed. Height, weight, bone mineral content, bone area and bone mineral density were determined for subjects in all three studies.
Positive associations were found between fruit, as well as combined fruit and vegetable intake and bone mineral content, bone area, and size-adjusted bone mineral density at most skeletal sites examined in boys. A relationship was also found between increased femoral neck bone mineral content and whole body, spine and femoral neck bone mineral density and vitamin C intake. For girls, combined fruit and vegetable intake was associated with whole body and spine bone mineral density, and fruit alone with spine bone mineral content and bone mineral density. Among older women, a positive association was found between spine bone mineral content and fruit intake. No associations between bone measurements and fruit and/or vegetables were found for young women or older men.
Because adolescence is a crucial period of bone growth, a greater intake of fruit and vegetables among individuals in this age group could help lower the risk of osteoporosis later in life.
July 17, 2006
DNA damage caused by choline deficiency
A report published in the July, 2006 issue of the American Journal of Clinical Nutrition revealed that humans who consumed a diet deficient in the B vitamin choline experienced increased programmed self-destruction (apoptosis) of a type of white blood cell known as lymphocytes, as well damage to lymphocyte DNA. DNA damage has been associated with choline deficiency in previous research using laboratory animals and human cell cultures.
Researchers at the University of North Carolina at Chapel Hill provided 20 men and 31 women aged 18 to 70 with diets containing adequate choline levels of 550 milligrams per 70 kilograms body weight daily for ten days, followed by a diet that provided less than 50 milligrams choline per day. Blood samples collected at the end of each phase were analyzed for lymphocyte DNA damage and apoptosis, and fasting blood samples were drawn every 3 to 4 days for blood chemistry measurements. The choline deficient diet was continued until organ dysfunction developed, as determined by elevations in serum creatine phosphokinase greater than five times that of levels measured at the beginning of the study, or by elevation of liver fat content of over 28 percent. The deficient diet was continued for 42 days among those who did not develop organ dysfunction, and all participants received choline supplementation or choline adequate diets after discontinuing the diet.
Lymphocyte DNA damage occurred in all participants after being on the choline deficient diet. Among the 33 subjects who experienced organ dysfunction, more lymphocytes underwent apoptosis following the deficient diet than after the choline replete diet.
The authors conclude that measuring lymphocyte DNA damage and apoptosis could be useful in cases of suspected choline deficiency, and could help define the human dietary requirement for the vitamin.
July 14, 2006
Red grape juice extract reduces cardiovascular disease risk factors in healthy and non-healthy patients
A report published in the July, 2006 issue of the American Journal of Clinical Nutrition revealed the findings of researchers at the Hospital Ramon y Cajal in Madrid that drinking red grape juice can help lower low density lipoprotein (LDL) cholesterol, apoplipoprotein B-100, inflammation, and oxidized low density lipoprotein (LDL), all of which, when elevated, increase the risk of cardiovascular disease.
In the current study, 26 hemodialysis patients and 15 healthy individuals were instructed to consume 100 milliliters of a red grape juice drink daily for two weeks. Twelve individuals receiving hemodialysis who did not receive grape juice served as controls. Blood samples drawn at the beginning of the study, twice during the supplementation period, and twice during the six month follow-up were analyzed for lipids, apolipoproteins, oxidized LDL, total antioxidant capacity, antioxidant vitamins including tocopherols, carotenoids, vitamin C and quercetin, and other factors.
Plasma total antioxidant capacity, high density lipoprotein (HDL) cholesterol, and apoplipoprotein A-1 (the major lipoprotein found in HDL cholesterol) increased among all of the participants who received red grape juice, while LDL cholesterol, oxidized LDL, and apoplipoprotein B-100 (apolipoprotein B is the major apolipoprotein in LDL cholesterol) were reduced at the end of the two week intervention period. These levels returned to their approximate original values by the end of the follow up period. Additionally, monocyte chemoattractant protein 1 (MCP-1), a marker of inflammation, was lowered during 3 weeks of treatment with the juice in a further study of 10 hemodialysis patients, however, other inflammation markers were unaffected.
The authors conclude that "dietary supplementation with concentrated red grape juice exerts hypolipidemic, antioxidant, and antiinflammatory actions in both healthy subjects and patients with end-stage renal disease. The effect may be considered to be beneficial for the prevention of cardiovascular disease."
July 12, 2006
Healthy lifestyle confers significant reduction in women's stroke risk
The July issue of the journal Archives of Internal Medicine presented the findings of Harvard researchers that women who practice a healthy lifestyle have less than half the risk of stroke than women who smoke and fail to exercise regularly, eat healthy, and consume alcohol in moderation.
Tobias Kurth, MD, ScD, of Brigham and Women's Hospital and Harvard School of Public Health and his colleagues evaluated findings obtained in the Women's Health Study, which enrolled 39,876 female health professionals to determine the effect of aspirin and vitamin E in cardiovascular disease and cancer prevention. The current analysis included 37,636 women 45 years of age and older upon enrollment who had completed questionnaires concerning demographic, health history and lifestyle factors. Lifestyle factors were awarded zero to 20 health index points, with more points conferred for never smoking, consuming 4 to 10.5 alcoholic drinks per week, exercising at least 4 times per week, maintaining a body mass index of under 22, and consuming a healthy diet which included cereal fiber, folate, and omega-3 fatty acids, with a high ratio of polyunsaturated to saturated fat.
Over the ten year follow-up period, there were 356 ischemic strokes, 90 hemorrhagic strokes and 4 of undefined origin. Women whose scores were between 17 to 20 had a 55 percent reduction in the risk of total stroke and a 71 percent lower risk of ischemic stroke compared to participants who received 0 to 4 points.
The authors conclude, "In this large prospective cohort of apparently healthy women, a healthy lifestyle was associated with a substantial and statistically significant reduction in the risk of total and ischemic stroke with no apparent benefit in the incidence of hemorrhagic stroke. Our findings show the importance of healthy behaviors in the prevention of total and ischemic stroke."
July 10, 2006
Omega-3 fatty acid intake linked with lower CRP among Japanese
A report published in the July, 2006 issue of the American Journal of Clinical Nutrition confirmed a correlation between a higher intake of omega-3 fatty acids mainly from fish and a reduction in C-reactive protein (CRP), a marker of inflammation that has been demonstrated to be an independent risk factor for heart attack and stroke. The omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) found in fish and fish oils have been linked in previous studies with lower CRP levels, yet few studies have explored the relationship among the Japanese, whose intake of fish is significant and whose CRP levels are lower than those of the Western countries examined.
Researchers at Tohoku University Graduate School of Medicine in Sendai, Japan surveyed 401 Japanese men and 570 women aged 70 and older concerning dietary intake over the previous year, and calculated EPA and DHA intake as well as total omega-3 polyunsaturated fatty acids (including alpha-linolenic acid, commonly found in plant oils). The questionnaires also provided information on smoking and drinking status, cardiovascular disease history, and aspirin and statin use. Blood samples were analyzed for cholesterol, glucose, and C-reactive protein levels.
Participants with CRP levels of less than 1.0 milligrams per liter were categorized as having low CRP concentrations, while a CRP level of 1.0 or more was categorized as high. Subjects whose total intake of omega-3 fatty acids was in the top one-fourth of participants had a 56 percent lower adjusted risk of having a high C-reactive protein level than those whose intake was in the lowest fourth, while those whose EPA and DHA intake was highest had a 46 percent lower risk.
The results suggest that even in a population with a relatively high intake, greater omega-3 fatty acid consumption may help reduce serum CRP.
July 7, 2006
More evidence for soy isoflavones in bone loss protection
A study published online on June 8, 2006 in the European Journal of Nutrition revealed an association between reduce bone loss in postmenopausal women and consumption of isoflavones derived from soy germ, adding more evidence to protective benefits that have been found for soy against osteoporosis.
Investigators at Sun Yat-sen University in Guangzhou, China randomly assigned 90 nonobese postmenopausal women between the ages of 45 and 60 years to receive 84 or 126 milligrams soy isoflavones, or a placebo for 6 months. The study utilized higher doses of isoflavones than those that have produced inconsistent effects in previous bone loss prevention trials of postmenopausal women. Bone mineral density of the spine and hip, and serum osteocalcin and bone-specific alkaline phosphatase, which are markers of bone formation, were measured at the beginning of the study and at its conclusion.
After six months, bone mineral density at the lumbar spine and femoral neck of the hip increased in the groups who received soy isoflavones, with those who received the higher dose experiencing a greater increase. No significant changes in serum osteocalcin and bone specific alkaline phosphatase were observed.
Jocelyn Mathern, RD, who is a technical specialist at Acatris, the company that supplied the soy isoflavones stated, "It is imperative to find natural, safe and effective alternatives for women to help maintain bone health after menopause – without the risky side effects associated with long-term hormone replacement therapy use. This promising research is another step in advancing soy germ isoflavones as a safe, effective option."
"We are awaiting results of a large study, the Osteoporosis Prevention Using Soy (OPUS) study, a multisite, two year research study on the use of soy isoflavones to prevent bone loss in 400 postmenopausal women," she added.
July 5, 2006
The free radical theory of graying
An article published in the July, 2006 issue of the Federation of American Societies for Experimental Biology (FASEB) journal submitted the hypothesis of researchers at Humboldt University in Berlin that the destruction of pigment cells called melanocytes that leads to the production of white hair by the hair follicles is due to free radical damage caused mainly by the generation of the pigment melanin, which results in significant oxidative stress.
The researchers studied hair follicles obtained from graying donors and found an increase in melanocyte apoptosis (programmed cell self-destruction) and oxidative stress. A mitochondrial DNA deletion that is a marker for accumulating oxidative stress damage was found primarily in graying hair follicles compared to pigmented follicles. Additionally, when cultured pigmented hair follicles were exposed to a chemical that generates oxidative stress they were found to have an increase in hair bulb melanocyte apoptosis. Interestingly, unpigmented hair follicles were demonstrated to have a better capacity to grow in culture than pigmented follicles, which the authors suggest could be due in part to lower overall oxidative stress caused by the reduction in melanocytes.
In addition to oxidative stress generated within the body, the authors suggest that exogenous oxidative stress caused by ultraviolet light and other factors could also be at fault in graying hair, and note that smokers have a greater incidence of premature graying.
"The graying hair follicle therefore offers a unique model-system to study oxidative stress effects and aging and to test antioxidants and other antiaging therapeutics in their ability to slow down or even stop this process," the authors write. They suggest that clinical trials monitor hair follicle melanocytes as a measure of oxidative stress-tissue damage and the effectiveness of antiaging and antioxidant therapeutics.
July 3, 2006
Pomegranate juice stabilizes PSA
The July, 2006 issue of the journal Clinical Cancer Research published the finding of a team at UCLA's Johnsson Cancer Center that a daily glass of pomegranate juice increased the period of time during which prostate specific antigen (PSA) levels remained stable in prostate cancer patients by a factor of nearly four. Prostate specific antigen is a marker for prostate cancer that is monitored during treatment for the disease, and which should be undectable after treatment. A rapidly increasing PSA value as ascertained by PSA doubling time indicates cancer progression and an increased risk of death.
In the current study, 50 men treated for prostate cancer with surgery or radiation that subsequently experienced PSA doubling in an average of 15 months were instructed to drink 8 ounces of pomegranate juice per day. Eighty percent of the men experienced a reduction in PSA velocity, with doubling times increasing to an average of 54 months.
"That's a big increase," lead researcher and UCLA associate professor of urology, Dr Allan Pantuck commented. "I was surprised when I saw such an improvement in PSA numbers. In older men 65 to 70 who have been treated for prostate cancer, we can give them pomegranate juice and it may be possible for them to outlive their risk of dying from their cancer. We're hoping we may be able to prevent or delay the need for other therapies usually used in this population such as hormone treatment or chemotherapy, both of which bring with them harmful side effects."
"There are many substances in pomegranate juice that may be prompting this response," Dr Pantuck added. "We don't know if it's one magic bullet or the combination of everything we know is in this juice. My guess is that it's probably a combination of elements, rather than a single component."