Tweet
Too much of a good thing: High Vitamin A increases risk of hip fractures
Vitamin A is a fat-soluble vitamin that is involved in the formation and maintenance of healthy skin, hair and mucous membranes. It helps us see in dim light and is necessary for proper bone growth. Our main sources of Vitamin A are from beta-carotene and retinol. The body metabolizes these substances to form Vitamin A.
A recent study, published tin the Journal of the American Medical Association, shows that a diet rich in Vitamin A is associated with a higher risk of hip fractures in postmenopausal women. However, the study showed that the risk was not from beta-carotene, the type of Vitamin A found in carrots, leafy greens and some fruits. The problem came from retinol, which is far more potent than beta-carotene. This is the form of Vitamin A that is found in foods like liver, fish, fish-liver oils, eggs and whole milk. Retinol is also found in multivitamin pills, which was the greatest source of Vitamin A for the women in the study.
Some brands of multivitamins contain far too much retinol, with Vitamin A doses of 15,000 IU. That exceeds the National Academy's 10,000 IU "upper level" (UL) for retinol, which is the highest safe intake. Many brands of multivitamins use beta-carotene for 20% of their vitamin A content. But, unless it is specified as beta-carotene, the remainder is some form of retinol. The current recommendations suggest 5,000 IU (1500 micrograms) daily of Vitamin A while some nutrition organizations recommended even less (approximately 3,000 IU).
Bottom line: With this recent data suggesting that high intakes of retinol may adversely affect bone health, it is important to limit your Vitamin A intake. Fruits and vegetables are great sources of Vitamin A, which can help reduce your risk of certain cancers. It's the Vitamin A found in multivitamins that you should watch out for, since these usually contain retinol. Look for brands that use at least some beta-carotene as a source of Vitamin A and that contain a total of 5,000 IU or less of Vitamin A. Preferable goal: 3,000 IU
Vitamin A is a fat-soluble vitamin that is involved in the formation and maintenance of healthy skin, hair and mucous membranes. It helps us see in dim light and is necessary for proper bone growth. Our main sources of Vitamin A are from beta-carotene and retinol. The body metabolizes these substances to form Vitamin A.
A recent study, published tin the Journal of the American Medical Association, shows that a diet rich in Vitamin A is associated with a higher risk of hip fractures in postmenopausal women. However, the study showed that the risk was not from beta-carotene, the type of Vitamin A found in carrots, leafy greens and some fruits. The problem came from retinol, which is far more potent than beta-carotene. This is the form of Vitamin A that is found in foods like liver, fish, fish-liver oils, eggs and whole milk. Retinol is also found in multivitamin pills, which was the greatest source of Vitamin A for the women in the study.
Some brands of multivitamins contain far too much retinol, with Vitamin A doses of 15,000 IU. That exceeds the National Academy's 10,000 IU "upper level" (UL) for retinol, which is the highest safe intake. Many brands of multivitamins use beta-carotene for 20% of their vitamin A content. But, unless it is specified as beta-carotene, the remainder is some form of retinol. The current recommendations suggest 5,000 IU (1500 micrograms) daily of Vitamin A while some nutrition organizations recommended even less (approximately 3,000 IU).
Bottom line: With this recent data suggesting that high intakes of retinol may adversely affect bone health, it is important to limit your Vitamin A intake. Fruits and vegetables are great sources of Vitamin A, which can help reduce your risk of certain cancers. It's the Vitamin A found in multivitamins that you should watch out for, since these usually contain retinol. Look for brands that use at least some beta-carotene as a source of Vitamin A and that contain a total of 5,000 IU or less of Vitamin A. Preferable goal: 3,000 IU