In The News

Low Vitamin D Levels Associated With Increased Risk of Death

Study Confirms Immunomodulatory Effects of Maitake Extract

Consumption of Fish and Foods With Omega-3 Fatty Acids Associated With Lower Risk of Age-related Eye Disease

Study Indicates Grape Seed Extract May Reduce Cognitive Decline Associated With Alzheimer’s Disease

Low Vitamin D Levels Associated With Increased Risk of Death

Individuals with lower blood levels of vitamin D appear to have an increased risk of death overall and especially from cardiovascular causes, according to a report in the June 23 issue of Archives of Internal Medicine.

A recent consensus panel estimated that about 50% to 60% of older individuals in North America and the rest of the world do not have satisfactory vitamin D status, and t he situation is similar for younger individuals . Blood levels of 25-hydroxyvitamin D (a measure of blood vitamin D levels ) lower than 20 to 30 ng/mL have been associated with falls, fractures, cancer, immune dysfunction, cardiovascular disease, and hypertension. These effects are thought to be mediated by the compound 1,25-dihydroxyvitamin D, which is produced by the body and also converted from 25-hydroxyvitamin D.

Harald Dobnig, MD, et al studied 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels in 3258 consecutive patients (average age 62 years) who were scheduled for coronary angiography testing at a single medical center between 1997 and 2000.

During 7.7 years of follow-up, 737 (22.6%) of participants died, including 463 (62.8%) who died of cardiovascular causes. Death rates from any cause and from cardiovascular causes were higher among individuals in the lower half of 25-hydroxyvitamin D levels and the lowest fourth of 1,25-dihydroxyvitamin D levels. These associations remained when the researchers accounted for other factors, including coronary artery disease, physical activity level, and concomitant diseases.

Low 25-hydroxyvitamin D levels also were correlated with markers of inflammation such as C-reactive protein, as well as signs of oxidative (oxygen-related) damage to cells, the authors note.

The authors conclude that based on the study’s findings, a serum 25-hydroxyvitamin D level of at least 20 ng/mL may be advised for maintaining general health.

Study Confirms Immunomodulatory Effects of Maitake Extract

A study whose results were announced recently at the Annual Meeting of American Society of Clinical Oncology in Chicago confirms the immunomodulatory effects and potential for anticancer immunotherapy of Maitake extract (Grifola frondosa). The government-funded clinical study began in 2004.

In a phase I/II dose escalation trial, 30 postmenopausal breast cancer patients who were free of disease after initial treatment were enrolled in 5 cohorts of 6 patients each. Patients took Maitake extract orally at 0.1, 0.5, 1.5, 3, or 5 mg/kg twice daily for 3 weeks. Peripheral blood was collected at day -7, 1 (before the first dosing), 7, 14, and 21 for ex vivo analyses. The primary endpoint was safety and tolerability.

No dose-limiting toxicity occurred. Pharmacodynamic activities of the extract did not follow a linear dose curve, as is often seen with immunomodulatory agents. A daily dose of 2 mg/kg was associated with the greatest increases of CD3+CD25+ or CD4+CD25+ T cells in the peripheral blood (300% of baseline, P<.001); a daily dose of 6 mg/kg was associated with the most significant increases in intracellular IL-2 production by NK-T cells (237% of baseline, P=.002) and IL-10 production by T cells (360% baseline, P=.002). Interferon gamma production by memory CD4+ T cells was attenuated to 27% of baseline at a daily dose of 7.4 mg/kg (P=0.002).

Oral administration of Maitake extract was associated with measurable changes in peripheral blood, although the clinical significance is not yet known. The dose associated with the most significant changes varies by immunological parameter. Whether oral administration of Maitake extract in humans is associated with measurable immunological change is unknown.

Consumption of Fish and Foods With Omega-3 Fatty Acids Associated With Lower Risk of Age-related Eye Disease

Eating fish and other foods high in omega-3 fatty acids is associated with reduced risk of the eye disease age-related macular degeneration (AMD), according to a meta-analysis of 9 previously published studies in the June issue of Archives of Ophthalmology. Age-related macular degeneration (AMD) is the leading cause of severe vision loss among elderly people, according to the study’s authors.

Elaine W-T. Chong, MBBS, et al conducted a systematic review of studies published before May 2007 evaluating the fish consumption and overall omega-3 fatty acid intake for the prevention of AMD. A total of 9 studies were identified with 88 974 participants, including 3 203 individuals with AMD.

When results from all 9 studies were combined, a high dietary intake of omega-3 fatty acids was associated with a 38% reduction in the risk of late (more advanced) AMD, and eating fish twice a week was associated with a reduced risk of both early and late AMD.

The accumulated evidence includes few clinical trials, however, and is insufficient to support the routine consumption of such foods for AMD prevention, the authors note.

Study Indicates Grape Seed Extract May Reduce Cognitive Decline Associated With Alzheimer’s Disease

A compound found in grape seed extract reduces plaque formation and resulting cognitive impairment in an animal model of Alzheimer’s disease, new research shows. The study appears in the June 18 issue of The Journal of Neuroscience.

Lead study author Giulio Pasinetti, MD, PhD, et al found that the grape seed extract prevents amyloid beta accumulation in cells, suggesting that it may block the formation of plaques. In Alzheimer’s disease, amyloid beta accumulates to form toxic plaques that disrupt normal brain function.

The researchers tested a grape seed polyphenolic extract product sold as MegaNatural-AZ, made by Polyphenolics, which in part supported the study. Polyphenolic compounds are antioxidants naturally found in wine, tea, chocolate, and some fruits and vegetables. To determine whether the extract could mitigate the effects of Alzheimer’s disease, the researchers used mice genetically modified to develop a condition similar to Alzheimer’s disease. They exposed pre-symptomatic “Alzheimer’s mice” to the extract or placebo daily for 5 months. The daily dose of the polyphenolic extract was equivalent to the average amount of polyphenolics consumed by a person on a daily basis.

After the 5-month period, Alzheimer’s mice were at an age at which they normally develop signs of disease. The extract exposure reduced amyloid beta accumulation and plaque formation in brains of Alzheimer’s mice and also reduced cognitive decline: compared to placebo, extract-exposed Alzheimer’s mice showed improved spatial memory. These data suggest that before symptoms begin, the grape seed extract may prevent or postpone plaque formation and slow cognitive deterioration associated with Alzheimer’s disease.

Chemical analysis showed that the major polyphenol components in the study’s grape seed extract product are catechin and epicatechin, which are also abundant in tea and cocoa. These components differ from resveratrol, a polyphenol that has been reported to reduce amyloid beta secretion in cells and generally increase lifespan by mimicking calorie restriction. Resveratrol appears to be effective only at extremely high doses, which may limit its use in people. In contrast, the catechins in the extract product studied appear to be effective at much lower doses.