expert opinion

100 years of vitamins: The B-vitamins

June 15, 2012

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Helene McNulty, Ph.D., Professor of Human Nutrition & Dietetics, Northern Ireland Centre for Food and Health, University of Ulster, UK.

“Despite the availability of conclusive evidence over the past 20 years proving the beneficial role of folic acid in preventing neural tube defects (NTD), translating the resulting folic acid recommendations into practice by women of reproductive age has not been so successful. Evidence shows generally poor compliance with the current recommendation that women take folic acid from before conception until the 12th week of pregnancy. Of particular concern is evidence from 13 million birth records, showing that there has been no detectable impact on incidence of NTD throughout eight European countries over the 10­year period from 1988 to 1998, covering the time before and after current folic acid recommendations were introduced and actively promoted. Clearly there are major challenges involved in implementing current folic-acid recommendations into practice by the target group.

Achieving optimal folate status, which prevents NTD and potentially other diseases, is hindered by the well-recognized fact that bioavailability of the natural folates found in foods is incomplete compared with the synthetic vitamin, folic acid. We have published several studies on folate bioavailability over the years that have contributed to highlighting this very practical limitation in relation to natural food folates, as a means to optimize folate status. Over 20 years ago, there was a break-through discovery that the B-vitamin folic acid given to mothers before conception and in early pregnancy could prevent spina bifida and related birth defects (NTD) in their babies. Since then, scientific evidence in this area has increased greatly, and now this important vitamin is linked to the prevention of a number of other diseases that are major health concerns. In recent years, there have been a number of exciting discoveries about the role of folic acid and related

B-vitamins throughout the life cycle.

Apart from having an established role in preventing NTD in very early life, folic acid (or folate in its natural form) has other potential roles for a variety of health concerns. These are so wide-spread that it should no longer be perceived by consumers only as ‘a woman’s nutrient’. Emerging evidence suggests that an optimal status of folate may protect against heart disease and stroke, certain cancers, and may have other important roles in maintaining cognitive function and bone health in aging.

Our center’s work has contributed to accumulating evidence in this area, and, in particular, recognizing the importance for health of not only achieving an optimal intake of folate but also the related B-vitamins (vitamins B2, B6 and B12). Recent research by our center focuses on the roles of these important B-vitamins in healthy aging, the interplay between them, and the related genetic factors. This work has led our research into embracing the new challenges of how common genetic variations and their interaction with vitamins can influence disease risk and the potential for personalized nutrition.

Our center recently made an exciting discovery showing that riboflavin (vitamin B2) can lower blood pressure for people with a common genetic factor involving a folate gene. The extent of blood pressure reduction in response to riboflavin that we have seen is as effective as blood pressure-lowering drugs, and much better than that found with other dietary approaches to managing high blood pressure. Considering that high blood pressure is a major risk factor for heart disease and stroke, this work could have important implications for public health and nutrition policy.

Impaired cognitive function is a common problem of aging, ranging in severity from mild memory loss to dementia. In recent years, there has been a growing interest in the possibility that lifestyle and dietary factors may play a role in altering the risk of cognitive decline and dementia. It is sometimes difficult to interpret the evidence, since poor diet may be both a cause and a consequence of poor cognitive function. Strong evidence is now emerging that shows an important role of folate and the related vitamins (vitamins B12 and B6) in maintaining cognitive function in ageing.”