New science in genetic polymorphisms suggests that the requirements for some of the nutrients vary, in part dependent on whether individuals possess single nucleotide polymorphisms (SNPs). SNPs are deoxyribonucleic acid (DNA) sequence variations that occur when a single nucleotide (A, T, C, or G) in the genome sequence is altered. Such genetic polymorphisms are not rare.
In setting Recommended Dietary Allowances (RDAs), the Panel on B Vitamins and Choline assumed that it had to cover only 95 percent of the population and that it did not need to address genetic mutations. For some of these nutrients, however, more than half the population has at least one genetic polymorphism. Thus, genetic mutations merit attention.
The area of epigenetics has developed tremendously since the B Vitamins and Choline Report was written. Clearly, some of the nutrients in this group, specifically the methyl donors and biotin, are part of the process of epigenetic modification. Considerable data point to the need to consider whether gene expression is being changed by changes made to the promoter regions of genes or to the histones that surround genes.
Major research gaps identified in the report included (1) human information on the requirements of children, pregnant and lactating women, and the elderly; (2) other indicators that could be used to assess function; and (3) adverse effects of high doses of the nutrient. A summary follows of progress made with regard to thiamin, riboflavin, niacin, pantothenic acid, and choline.
Little has been done to meet the research needs pertaining to thiamin.