A study came out recently (it was in our newspaper yesterday) that for the first time since they started enriching bread and cereals with folate, blood folate levels in americans are decreasing to alarming levels.
Why?
The first suspected cause is obesity...you need more folate and you absorb it poorly if you are obese
The second cause is low carb diets. Since the primary source of folic acid is enriched bread and cereal products a low carb diet will be lacking. Other good sources (fruits vegetables, legumes, fortified oj) also may be missing on a low carb diet
The 3rd cause is a trend towards whole grains. Whole grains were exempt from the folic acid fortification law because whole grains DO contain naturally occurring food folate. However food folate is not absorbed as well as the folic acid added to white bread.
Low levels of blood folate have been linked to birth defects and alzheimers. So if you are obese, on a low or reduced carb plan, or avoid processed fortified grains - please take a 400 mg folate supplement daily.