Wednesday, October 2, 2019

Folate and Folic Acid

Folate is a B-vitamin that occurs naturally in plants – more in some than others. Folic acid is a synthetic compound incorporated into multi-vitamins, dietary supplements and used to fortify foods; once absorbed it is converted into folate. Starting about 20 years ago, the United States decided to mandate fortification of wheat flour and other grains with folic acid in order to reduce the risk of infants being born with spina bifida and other neural tube defects (NTDs). In effect, the decision was made to increase folate in 350 million people to prevent an estimated 1,000 to 1,500 birth defect births per year. At the time, concerns were raised that this folic acid fortification might have unknown health-positive and health-negative consequences, the latter including an increased incidence of cancer. So far, most of this has proven to be not true.

In general, beans, nuts and seeds are good sources of food folate, as are dark, leafy green foods (spinach, etc.) and cruciferous vegetables. Animal liver is a great source, but animal meat, dairy and eggs, not. People who adhere to a vegetarian or vegan diet should have no worries about getting adequate folate from food, although there are other vitamins for which a general-purpose vitamin/mineral supplement is recommended. Currently trendy diets need to be examined for nutrient deficiencies. A ‘keto’ (ketogenic) diet avoids carbohydrates, but if it contains enough in the way of leafy green vegetables it should not shortfall the recommended intake of food folate. Exceptions are any women who might become pregnant, as the recommendation is to be consuming 600 micrograms of folate as folate and folic acid before and during the pregnancy. “Gluten free” diets can lead to folate deficiency, especially if people are replacing wheat-based foods with alternative sources of carbohydrates. Here too, consider a general-purpose vitamin/mineral supplement.

Worldwide, there were about 300,000 live NTDs per year before any country required folic acid fortification. The U.S. and Canada were the first countries to implement fortification in early 1998. For the sixty-some countries that now require fortification of wheat flour, and/or corn meal or rice, the incidence of NTDs has dropped by 25 to 50% (higher in countries that started with low folate intake from diet). The reasoning for fortification over advising women who became pregnant to start taking a folic acid supplement was they the risk for development of neural tube defects is greatest in the first few months of pregnancy – a time when women may not even be sure they are pregnant.

In the U.S., the decision to fortify food with folic acid resulted in roughly a 50 percent increase in total folate (naturally occurring from food plus folic acid). There were hopes among researchers that requiring fortification of foods, and thus increasing folate status in everyone, not just women of child-bearing age, would also have benefits for cardiovascular and mental health. The latest reviews of evidence report no change cardiovascular disease in general, but a modest decrease in the risk of stroke in people who already had pre-existing cardiovascular disease. Evidence for the last came from trials with folic acid supplementation in amounts higher than were achieved just from the food fortification program. In the arena of mental health, there are not enough human trials to determine if there are any benefits toward mild cognitive impairment, dementia in general or Alzheimer’s disease. One promising result is evidence that adequate folate status during pregnancy reduces the risk of the child developing autism.  

As for the whole cancer thing, long-term intake of insufficient amounts of folate appears to increate the risk of several types of cancer, including breast, colorectal, lung and prostate cancer. Although there were theories that folic acid fortification of foods would increase risk of cancer, by promoting growth of preneoplastic lesions, this turned out not to be true. Even supplementation in amounts far in excess of what would be achieved by food fortification did not increase cancer risk – but with one exception – prostate cancer. Multi-year, high-dose trials with folic acid supplements resulted in a 15 to 25 percent increase in prostate cancer compared to unsupplemented control groups. 

The Wikipedia article Folate elaborates on information presented here. Major population centers not requiring mandatory fortification include China, India, the European Union and Russia. Instead, these countries have public health education programs recommending to women that a folic acid dietary supplement be consumed starting months before becoming pregnant and continuing through pregnancy. The U.S. and other countries that now require fortification found that health education alone was not sufficient.

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