The folic acid mutation story may interest some people. 10-15% of the
population are heterozygous for the C677T mutation, a thermolabile variant
of the folic acid pathway enzyme MTHFR (methylenetetrahydrofolate
reductase). This causes partial enzyme deficiency and somehow folic acid
deficiency. It is associated with mild hyperhomocysteinaemia and an increase
in the risk of coronary artery disease, and an increase in the risk of
neural tube defects. Low serum folate concentrations have been found in some
but not all studies of people homozygous for the thermolabile variant.

This helps explain the extremely long list of studies showing benefits from
folic acid supplements- reduction of heart disease, birth defects, bowel
cancer, Alzheimer's disease etc. The other factor is that many people eat so
little fruit and vegetables these days, and so have a low folic acid intake.

The reference itself focuses on paleolithic nutrition at a very complex
level. Paleolithic and hunter-gatherer diets have extremely high levels of
folate, so the C677T mutants would have no problem, and thus haven't been
weeded out by evolution. One would expect that recently acculturated
hunter-gatherers might have a higher incidence of this mutation.

Simopoulos, A. Genetic Variation and Nutrition in
Evolutionary Aspects of Nutrition and Health. Diet, Exercise, Genetics and
Chronic Disease
World Review of Nutrition & Dietetics, 1999;84:130-131.Karger Publications

Ben Balzer