Vitamin B Supplementation, Homocysteine Levels, and
the Risk of Cerebrovascular Disease
A meta-analysis published in Neurology indicates that Vitamin B supplementation to lower homocysteine levels significantly reduces the incidence of stroke events.
Objective: To perform a meta-analysis on the effect of lowering homocysteine levels via B vitamin supplementation on cerebrovascular disease risk.
Methods: Using clinical trials published before August 2012 to assess stroke events, we used relative risks (RRs) with 95% confidence intervals (95% CIs) to measure the association between B vitamin supplementation and endpoint events using a fixed-effects model and χ2 tests. We included 14 randomized controlled trials with 54,913 participants in this analysis.
Results: We observed a reduction in overall stroke events resulting from reduction in homocysteine levels following B vitamin supplementation (RR 0.93; 95% CI 0.86–1.00; p = 0.04) but not in subgroups divided according to primary or secondary prevention measures, ischemic vs hemorrhagic stroke, or occurrence of fatal stroke.
There were beneficial effects in reducing stroke events in subgroups with ≥3 years follow-up time, and without background of cereal folate fortification or chronic kidney disease (CKD). Some trials that included CKD patients reported decreased glomerular filtration rate with B vitamin supplementation.
We conducted detailed subgroup analyses for cyanocobalamin (vitamin B12) but did not find a significant benefit regarding intervention dose of vitamin B12 or baseline blood B12 concentration.
Stratified analysis for blood pressure and baseline participant medication use showed benefits with >130 mm Hg systolic blood pressure and lower antiplatelet drug use in reducing stroke risk.
Conclusions: B vitamin supplementation for homocysteine reduction significantly reduced stroke events, especially in subjects with certain characteristics who received appropriate intervention measures.
- Yan Ji, MD,
- Song Tan, MD,
- Yuming Xu, MD,
- Avinash Chandra, MD,
- Changhe Shi, MD,
- Bo Song, MD,
- Jie Qin, MD and
- Yuan Gao, MD
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In a 12 month study of 780 children in Australia and Indonesia, published in the American Journal of Clinical Nutrition, the researchers assessed the effects of adding a specific vitamin and mineral mix to a daily drink.
In Australia, children that received the daily drink with the added vitamin and mineral mix performed significantly better on mental performance tests than children in a control group that received the drink without added nutrients. In Indonesia a similar trend was observed, but only in the girls.
This study confirms that nutrition can positively influence cognitive development in schoolchildren, even in western children who are well-fed.
The scientists studied 396 well-nourished children in Australia and 384 poorly nourished children in Indonesia. In each country, the children were randomly allocated to one of four groups, receiving a drink with either a mix of micronutrients (iron, zinc, folate and vitamins A, B-6, B-12 and C) or with fish-oil (DHA and EPA), or with both added, or with nothing added (placebo).
After twelve months, children in Australia who received the drink with the nutrient mix showed higher blood levels of these micronutrients, which means that their bodies were taking up the nutrients. In addition, they performed significantly better on tests measuring their learning and memory capabilities compared to children in the other groups. A similar trend was observed in Indonesia, but only in the girls. The addition of fish oil to the fortified drink did not conclusively show any additional effects on cognition.
This study adds to the mounting evidence that nutrition plays an important role in mental development in children. Previously, deficiencies in iron and iodine have been linked to impaired cognitive development in young children; there is also emerging evidence that deficiencies in zinc, folate and vitamin B12 compromise mental development in children. More recently, fish oils (EPA, DHA) have also been linked to child cognitive development.
Most studies to date have focused on deficiencies in single nutrients in young age groups. Yet the brain continues to grow and develop during childhood and adolescence. Little is known about the role of nutrition for mental development after the age of 2, nor have many studies looked at the effect of offering a mix of nutrients. Until this study, there were very few randomized controlled intervention studies assessing the impact of a multiple-micronutrient intervention on cognitive function in schoolchildren.
This study confirms that nutrition can positively influence cognitive development in schoolchildren, even in children who are well-fed. The researchers suggest that this finding could be relevant across the western world.
The investigators recommend further research to investigate the exact role of DHA and EPA in healthy school-aged children. Another research focus is the further optimization of cognitive development tests with respect to their validity and sensitivity across cultures. The scientists suggest that the smaller effects of the vitamins and minerals in Indonesia could be a result of a lower sensitivity of the cognitive tests in that country.
This study was performed by the NEMO study group (Nutrition Enhancement for Mental Optimization), which consists of the Unilever Food and Health Research Institute (Vlaardingen, The Netherlands); CSIRO, Human Nutrition (Adelaide, Australia) and the SEAMEO-TROPMED Regional Center for Community Nutrition, University of Indonesia (Jakarta Pusat, Indonesia).