B Vitamins & Berries

Full Title: B Vitamins and Berries and Age-Related Neurodegenerative Disorders

April 2006
http://www.ahrq.gov/clinic/tp/berrytp.htm

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Structured Abstract

Objectives: To assess the effects, associations, mechanisms of action, and safety of B vitamins and, separately, berries and their constituents on age-related neurocognitive disorders—primarily Alzheimer's (AD) and Parkinson's disease (PD).

Data Sources: MEDLINE® and CAB Abstracts™. Additional studies were identified from reference lists and technical experts.

Review Methods: Vitamins B1, B2, B6, B12, and folate, and a dozen types of berries and their constituents were evaluated. Human, animal, and in vitro studies were evaluated. Outcomes of interest from human studies were neurocognitive function or diagnosis with AD, cognitive decline, PD, or related conditions. Intervention studies, associations between dietary intake and outcomes, and associations between B vitamin levels and outcomes were evaluated. Specific mechanisms of action were evaluated in animal and in vitro studies. Studies were extracted for study design, demographics, intervention or predictor, and neurocognitive outcomes. Studies were graded for quality and applicability.

Results: In animal studies, deficiencies in vitamins B1 or folate generally cause neurological dysfunction; supplementation with B6, B12, or folate may improve neurocognitive function. In animal experiments folate and B12 protect against genetic deficiencies used to model AD; thiamine and folate also affect neurovascular function and health.

Human studies were generally of poor quality. Weak evidence suggests possible benefits of B1 supplementation and injected B12 in AD. The effects of B6 and folate are unclear. Overall, dietary intake studies do not support an association between B vitamin intake and AD. Studies evaluating B vitamin status were mostly inadequate due to poor study design. Overall, studies do not support an association between B vitamin status and age-related neurocognitive disorders.

Only one study evaluated human berry consumption, finding no association with PD. Animal studies of berries have almost all been conducted by the same research group. Several berry constituents have been shown to affect brain and nerve tissue function. Blueberry and strawberry extract were protective of markers of disease, although effects on neurocognitive tests were less consistent. Berry extracts may protect against the deleterious effects of compounds associated with AD.

Reporting of adverse events was uncommon. When reported, actual adverse events from B vitamins were rare and minor.

Conclusions: The current research on B vitamins is largely inadequate to confidently assess their mechanisms of action on age-related neurocognitive disorders, their associations with disease, or their effectiveness as supplements. B vitamin supplementation may be of value for neurocognitive function, but the evidence is inconclusive.

The following link is related to the topic: It claims B6 is good to prevent PD. I wonder weather it is helpful to slow it down ???
http://www.newstarget.com/019868.html
Vitamin B6 found to slash risk of Parkinson's disease
Thursday, August 03, 2006 by: NewsTarget
(NewsTarget) New research in the journal Neurology indicates that increased consumption of vitamin B6 could significantly reduce the risk of Parkinson's disease.
Researchers from the Erasmus Medical Center in the Netherlands studied around 5,300 participants over the age of 55, and found that those who had the highest intake of vitamin B6 had up to a 50 percent reduction in Parkinson's disease risk.

The researchers believe that vitamin B6 may prevent the disease by decreasing levels of homocysteine -- an amino acid that is potentially toxic to brain cells. Vitamin B6 could also have an antioxidant effect that might aid in preventing Parkinson's, researchers say.

The study tracked the participants from 1990 through 2003 through questionnaires and physical examinations, including neurological exams. Ten years into the study, 72 new cases of Parkinson's had been diagnosed. The researchers found that those who had a daily vitamin B6 intake of 230.9 micrograms or more experienced a 54 percent decrease in Parkinson's risk over those with daily doses of 185.1 micrograms or less.

The researchers also studied the participants' consumption of folate and vitamin B12 and found no significant reductions in Parkinson's risk, but the authors could not entirely rule out the possible effects of those nutrients.

"This research presents yet more encouraging information about the role of nutrition in preventing degenerative diseases like Parkinson's disease," says Mike Adams, consumer health advocate and creator of the NutrientReference.com website that includes a page on vitamin B6. "Despite what conventional medicine believes, the human nervous system does not simply deteriorate after a period of time -- it stays healthy and functional for as long as it receives the necessary nutritional support and sufficient stimulation."