Retinol is the form of vitamin A of concern.
Retinol is commonly found in dietary supplements, fortified foods, and a few animal foods like liver, eggs and dairy products. It is usually listed in food or supplement ingredients as retinyl palmitate (vitamin A palmitate) or retinyl acetate (vitamin A acetate).
How Much Vitamin A Is in Your Supplement?
If you take a dietary supplement that provides 100 percent of the Daily Value (DV) for vitamin A, you are getting 5,000 IU of the vitamin. If your vitamin supplement is typical, all the vitamin A is in the form of retinol and you are getting too much, according to Dr. John J.B. Anderson in the Department of Nutrition at the University of North Carolina, Chapel Hill. In discussing studies of vitamin A supplement use by the elderly, Dr. Anderson stated in a recent editorial, “In general, long-term intakes of ~1500 µg (4500 IU) per day or greater have resulted in fractures.” Based on Anderson’s concerns, the vitamin A DV of 5000 IU that is used on food and supplement labels is set too high.
If you are taking a supplement with 100 percent of the DV for vitamin A (5000 IU), you may want to reconsider your use of that supplement. If you also are eating foods fortified with vitamin A, it is definitely time to do some addition and see if your total intake is too high.
Currently, the adult Recommended Dietary Allowance for vitamin A is 700 µg (2333 IU) for a woman and 900 µg (3000 IU) for a man. This appears to be the optimal level of intake for bone health.
The safest way to get your vitamin A is by eating fruits and vegetables. Remember, too little vitamin A in the diet also is associated with bone loss. So, you definitely want to get enough of this important nutrient. Also, keep in mind that there are studies that did not find this correlation between Vitamin A and fracture risk.
What About Beta-Carotene Supplements?
Taking Beta-Carotene supplements instead of vitamin A supplements does not appear to be the right answer either. There are other issues related to taking beta-carotene supplements such as a potential increased risk of certain types of cancer.
Sources
Anderson, John J.B. Oversupplementation of vitamin A and osteoporotic fractures in the elderly: to supplement or not to supplement with vitamin A. Journal of Bone and Mineral Research 17 (2002): 1359-62.Promislow Joanne H.E. and Deborah Goodman-Gruen, et al. “Retinol intake and bone mineral density in the elderly: the Rancho Bernardo Study.” Journal of Bone and Mineral Research 17 (2002): 1349-58.