Low-carbohydrate diets can lead to folate deficiency, greater risk of birth defects

4/1/2004 3:45 PM

By: Dr. Steven H. Zeisel, UNC Health Care

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Millions of Americans are adopting one of the several popular low-carbohydrate, high-protein weight-loss regimens because they can help people lose weight. The lasting power for benefits of the low-carb diets are still being studied and there are some adverse effects.

One concern you may not have thought of is the elimination of entire food groups that supply essential nutrients. Among these nutrients is folate, a nutrient that is important at all stages of life for both men and women.

Folate is one of the B vitamins and is important in the production of red blood cells, DNA synthesis, repair and functioning, and prevention of heart disease. Some studies have shown an association between low folate levels and cancer as well as heart disease. Folate is found naturally in foods such as leafy green vegetables, legumes (dried beans), and some fruits and vegetables. Its synthetic form, folic acid, is used to fortify some ready-to-eat cereals and grain products, and it is found in multivitamin supplements. The body can use both forms.

Folate is probably best known for its role in the prevention of neural tube defects such as spina bifida. All women of childbearing age should get at least 400 micrograms of the nutrient daily (the amount supplied in a typical multivitamin supplement). The association of low folate levels to increased risk for neural tube defects in newborns is so well established that in 1998, the U.S. Food and Drug Administration began enforcing regulations that resulted in folic acid fortification of many grain products including pastas, breads, and cereals. In other words, only foods that contain carbs are required to have folic acid fortification.

Eating these foods is especially important for women of childbearing age because folate is important very early in pregnancy, often before a woman actually knows she is pregnant. The pregnancies of women who are on low-carb diets, which are low in folate, may be at increased risk for birth defects if they are not supplementing this vitamin in their diet.

While the importance of folate for young women is well known, the nutrient is equally as important to the greater adult population in the prevention of heart disease. Folate is used by the body to convert homocysteine to methionine. With low folate intake, the body can accumulate high levels of homocysteine. This condition results in increased damage to coronary arteries and clumping of platelets, which stick to arteries and contribute to plaque formation. High homocysteine has been shown to be an independent risk factor for heart disease.

Folate is used by the body to produce red blood cells, which carry oxygen throughout the body. Low folate levels can result in anemia, the consequences of which include dizziness, extreme fatigue, headache, and slowed growth in children. However, there are other conditions that can cause these symptoms. Anyone who experiences these symptoms should discuss them with a physician.

The Physician’s Committee for Responsible Medicine analyzed a day of intake for the Atkins Diet, a popular high-protein diet. They found that during the induction phase, an individual only consumes 36 percent of the recommended daily allowance for folate. During the continued weight loss phase, only 67 percent of the RDA was met. Following these regimens for any extended period of time could result in folate deficiency if you skip the recommended multivitamin pill.

It is unlikely that using a low-carb diet to lose weight will harm you if you use this diet for a short period (weeks to months) and then switch to a calorie-controlled diet containing a wide variety of foods. If you do choose to follow a high-protein/low-carbohydrate diet, you should take a daily multivitamin and mineral supplement that contains folic acid.

However, you should also be aware that this diet, with its low intake of fruits, vegetables and grains and high intake of saturated fat, is not a wise choice for use over very long periods. A diet that includes fruits, vegetables, and whole grains can reduce risk for chronic disease such as cancer and heart disease.

Steven H. Zeisel, MD, PhD, is chair of the Department of Nutrition in the schools of Medicine and Public Health at the University of North Carolina at Chapel Hill and director of the UNC Clinical Nutrition Research Center.

[QUOTE
Folate is found naturally in foods such as leafy green vegetables, legumes (dried beans), and some fruits and vegetables. Its synthetic form, folic acid, is used to fortify some ready-to-eat cereals and grain products, and it is found in multivitamin supplements. The body can use both forms.
QUOTE]

God knows we crazy low carbers would never eat leafy green vegetables, or take a multivitamin....

My low-carb coworker and great pal Stacey just delivered a beautiful baby girl (Samantha Juliet) on March 15.

Stacey had gained 52 lbs during her high-carb pregnancy, and has lost 32 lbs since the delivery (when she went back on a low-carb diet). ["Don't tell anyone", she told me. Oops.]

Oddly, the healthy baby has exhibited no defects so far.

Do you think the low carb breads are fortified with folate also? If not why not. NO harm in reminding us to mind our nutritional requirements. Atkins shakes have30%RDA fyi.

Well, wheat products, i.e. flour is. The low carb breads use soy, nut flours, protein isolates and such. So they might not have much folate fortification. Yeah, I definitely take it in a supplement.

I take a pre-natal vitamin, but I still find this topic interesting.
I was about to say that I am certain that I now have more folate in my diet than pre Atkins, to be sure I did some research and this is what I found...

What was most striking to me is that spinach and broccoli which I eat a lot of since beginning Atkins are much higher in Folic Acid than enriched products which the exception of 100% enriched cereal. Eggs have as much folic acid as a slice of bread, and I have certainly increased my egg consumption.
Even without the supplement it is likely that I reach the reccommend folate levels for women of child bearing age.

Table of Food Sources of Folate (5)
Food Micrograms

Ready to eat cereal, fortified with 100% of the DV, 3/4 c 400 100
Beef liver, cooked, braised, 3 oz 185 45
Cowpeas (blackeyes), immature, cooked, boiled, 1/2 c 105 25
Breakfast cereals, fortified with 25% of the DV, 3/4 c 100 25
Spinach, frozen, cooked, boiled, 1/2 c 100 25
Great Northern beans, boiled, 1/2 c 90 20
Asparagus, boiled, 4 spears 85 20
Wheat germ, toasted, 1/4 c 80 20
Orange juice, chilled, includes concentrate, 3/4 c 70 20
Turnip Greens, frozen, cooked, boiled, 1/2 c 65 15
Vegetarian baked beans, canned, 1 c 60 15
Spinach, raw, 1 c 60 15
Green peas, boiled, 1/2 c 50 15
Broccoli, chopped, frozen, cooked, 1/2 c 50 15
Egg noodles, cooked, enriched, 1/2 c 50 15
Rice, white, long-grain, parboiled, cooked, enriched, 1/2 c 45 10
Avocado, raw, all varieties, sliced, 1/2 c sliced 45 10
Peanuts, all types, dry roasted, 1 oz 40 10
Lettuce, Romaine, shredded, 1/2 c 40 10
Tomato Juice, canned, 6 oz 35 10
Orange, all commercial varieties, fresh, 1 small 30 8
Bread, white, enriched, 1 slice 25 6
Egg, whole, raw, fresh, 1 large 25 6
Cantaloupe, raw, 1/4 medium 25 6
Papaya, raw, 1/2 c cubes 25 6
Banana, raw, 1 medium 20 6
Broccoli, raw, 1 spear (about 5 inches long) 20 6
Lettuce, iceberg, shredded, 1/2 c 15 4
Bread, whole wheat, 1 slice 15 4

* DV = Daily Value. DVs are reference numbers based on the Recommended Dietary Allowance (RDA). They were developed to help consumers determine if a food contains a lot or a little of a specific nutrient. The DV for folic acid is 400 micrograms (mcg). The percent DV (%DV) listed on the nutrition facts panel of food labels tells adults what percentage of the DV is provided by one serving. Percent DVs are based on a 2,000 calorie diet. Your Daily Values may be higher or lower depending on your calorie needs. Foods that provide lower percentages of the DV also contribute to a healthful diet.


This fact sheet was developed by the Clinical Nutrition Service, Warren Grant Magnuson Clinical Center, National Institutes of Health (NIH), Bethesda, MD, in conjunction with the Office of Dietary Supplements (ODS) in the Office of the Director of NIH