![]() ![]() And some but not all observational studies, including the Nurses’ Health Study, show lower risks of cardiovascular disease, stroke, and hypertension among people with higher intakes of folate from food, those who use multivitamin supplements, or those with higher levels of serum folate. Since these early observations about homocysteine, most but not all studies have linked high levels of homocysteine with a modest increase in risk of heart disease and stroke. On the flip side, homocysteine levels drop with increasing intakes of folate, vitamin B6, and vitamin B12. Without enough folate, vitamin B6, and vitamin B12, this conversion process becomes inefficient and homocysteine levels increase. How do B vitamins fit into the homocysteine picture? Folate and vitamin B12 play key roles in converting homocysteine into methionine, one of the 20 or so building blocks from which the body builds new proteins. Putting one and one together, he hypothesized that elevated levels of this breakdown product-called homocysteine-would contribute to the artery-clogging process of atherosclerosis. Both had inherited conditions that caused them to have extremely high levels of a protein breakdown product in their blood, and both had arteries as clogged with cholesterol as those of a 65-year-old fast food addict. In 1968, a Boston pathologist investigated the deaths of two children from massive strokes. Since the advent of mandatory folic acid fortification in 1998, neural tube birth defects have dropped by 28%, and studies have shown that far fewer people have low levels of folate in their blood. Food and Drug Administration now requires that folic acid be added to most enriched breads, flour, cornmeal, pastas, rice, and other grain products, along with the iron and other micronutrients that have been added for years. That is why women of childbearing age are urged to take extra folic acid as a supplement. Enough folate, at least 400 mcg daily, isn’t always easy to get from food that is not fortified. For folate to be effective, it must be taken in the first few weeks after conception, often before a woman knows she is pregnant. Eventually, two large trials in which women were randomly assigned to take folic acid or a placebo showed that getting too little folate increased a woman’s chances of having a baby with spina bifida or anencephaly and that getting enough folate could greatly reduce the incidence of these birth defects. More than 30 years ago, British researchers found that mothers of children with spina bifida had low vitamin levels. ![]() Fifty years ago, no one knew what caused these birth defects, which occur when the early development of tissues that eventually become the spinal cord, the tissues surrounding it, or the brain goes awry. One of the advances that changed the way we look at vitamins was the discovery that too little folate is linked to birth defects of the spine (spina bifida) and brain (anencephaly). The UL for adults for folic acid from fortified food or supplements (not including folate from food) is set at 1,000 mcg a day. UL: A Tolerable Upper Intake Level (UL) is the maximum daily dose unlikely to cause adverse side effects in the general population. People who regularly drink alcohol should aim for at least 600 mcg DFE of folate daily since alcohol can impair its absorption. Pregnant and lactating women require 600 mcg DFE and 500 mcg DFE, respectively. Men and women ages 19 years and older should aim for 400 mcg DFE. RDA: The Recommended Dietary Allowance for folate is listed as micrograms (mcg) of dietary folate equivalents (DFE). Folate is also needed to produce healthy red blood cells and is critical during periods of rapid growth, such as during pregnancy and fetal development. It plays a key role in breaking down homocysteine, an amino acid that can exert harmful effects in the body if it is present in high amounts. ![]() Folate helps to form DNA and RNA and is involved in protein metabolism. It is also added to foods and sold as a supplement in the form of folic acid this form is actually better absorbed than that from food sources-85% vs. Folate is the natural form of vitamin B9, water-soluble and naturally found in many foods. ![]()
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