Liver is a rich source of a host of important nutrients, including folate and vitamin B-12, as well as iron. Eating liver can also expose you to some potentially dangerous effects, such as vitamin A toxicity and contact with heavy metals. Speak to your doctor or health care provider about the positive and negative effects of eating liver.
Liver is a rich course of iron, according to Linda Vorvick, M.D., of the University of Washington School of Medicine. Iron is essential to the production of hemoglobin, the protein that transports oxygen to the cells of the body via the red blood cells. A 3-ounce serving of cooked chicken liver provides 61 percent of the daily value for iron, and the same amount of cooked beef liver provides 29 percent of the DV.
One of the most valuable effects of eating liver is access to an abundance of B vitamins in one food source. Liver is an excellent source of the B vitamins folate and vitamin B-12. Three ounces of beef liver provides 45 percent of the DV for folate and 800 percent of the DV for vitamin B-12. Both vitamin B-12 and folate decrease blood levels of homocysteine, an amino acid that contributes to cardiovascular disease when elevated, according to the National Institutes of Health Office of Dietary Supplements.
Vitamin A Toxicity
A potentially harmful effect of eating liver is vitamin A toxicity. Liver is very high in vitamin A; 3 ounces of cooked beef liver provides 444 percent of the DV for this vitamin. According to Professor Peter Aggett of the U.K.'s Scientific Advisory Committee on Nutrition, eating too much liver can interfere with your bone density and contribute to fractures because of its high vitamin A content. Other effects of vitamin A toxicity include blurred vision, trouble with muscular coordination and birth defects. Seek medical advice regarding a safe weekly intake of liver, particularly if you are already taking vitamin A supplements or multivitamins containing vitamin A.
Certain heavy metals such as cadmium, arsenic and lead tend to accumulate in the livers of beef cattle during their lifespan, according to the Environmental Protection Agency, and these accrued toxins are then passed on to the humans who eat the livers. According to the U.S. Department of Agriculture, the livers of beef cattle can also contain pesticides and veterinary drugs. In order to minimize the harmful effects of these toxins, choose liver that comes from organic, grass fed, free range beef cattle wherever possible.
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- U.S. National Library of Medicine Medline Plus: Iron in Diet
- Office of Dietary Supplements: Folate
- Office of Dietary Supplements: Vitamin B12
- Office of Dietary Supplements: Vitamin A
- BBC News: Health: Vitamin Warning for Liver Lovers
- U.S. Department of Agriculture: FSIS National Residue Program for Cattle
- U.S. Environmental Protection Agency: Effects on Cattle From Exposure to Sewage Sludge
- Office of Dietary Supplements: Iron