Vitamin A & Hip Fractures
Chester J. Zelasko, Ph.D. | January 8, 2002

There's nothing like starting the New Year with another controversy, and 2002 began with headlines that read, "Too much Vitamin A can cause hip fractures." The study published in the Journal of the American Medical Association (1) is one of the findings in the ongoing Nurses' Health Study. Briefly, this is an investigation that recruited over 120,000 female nurses in 1976 and has been tracking their health habits and disease development about every two years via medical history and questionnaire. There have been many reports from this study on the relationship of diet and the development of cardiovascular disease and ovarian and pancreatic cancer (2-5).

In the current report, the authors examined the relationship between vitamin A intake from foods and supplements and the risk of suffering a hip fracture after trauma such as falling off a chair. They selected postmenopausal women as their target population because they are at increased risk for osteoporosis and bone fractures. The concern is that too much vitamin A intake interferes with bone metabolism and contributes to osteoporosis.

They reported an increased risk of hip fractures in women who supplemented their diet with vitamin A—especially those who were not taking hormone replacement therapy (HRT). In fact, the fracture rate was almost twice as high (89%) in the group of women taking in more than 2,000 mcg of vitamin A daily from food and supplements than those taking in less than 500 mcg. (1 mcg is equivalent to about 3.3 IUs.) Women who supplemented with beta-carotene did not experience the increase in hip fractures.

While the authors reported their findings correctly, it's what they didn't say that provides perspective on the issue of vitamin A supplementation. For this study, they had 72,337 subjects that met the criteria of being postmenopausal in 1980. They divided the subject pool into quintiles, which means that each group had about 14,467 subjects. Examining the lowest vitamin A intake first, the number of hip fractures over an 18-year span was 102 or about seven out of every 1,000. Contrasting that with the group with the highest vitamin A intake, 146 hip fractures occurred or 10 out of a 1,000 women over a period of 18 years.

While statistically significant, you have to decide for yourself whether the numbers are meaningful in the real world: 7/1,000 versus 10/1,000. What the numbers really seem to be saying is that if you are a postmenopausal women, whether you supplement with vitamin A or not, your risk of fracturing a hip over an 18-year span is really pretty low.

On the other hand, here's what vitamin A can do for you (6):

  • Supports vision and prevents drying of the cornea
  • Maintains epithelial cells, the mucous membrane-secreting cells that line all the glands and organs of the body, and reduces the risk of cancer of these cells
  • Boosts immunity and reduces the risk of infections
  • Aids growth of bones, teeth, and soft tissues
  • May lessen the severity of menstrual problems, measles, and Crohn's disease
It's your decision to take food supplements and it's important to be informed before you do. Discuss all the supplements you take or are considering taking with your healthcare professional, and don't take over 10,000 IUs of vitamin A unless being monitored by your physician. We at Better Life Unlimited will continue to do our part by examining the research and providing all sides of the story so you can make the best decision for your health.

References:

  1. Feskanich, D. et. al. Vitamin A Intake and Hip Fractures Among Postmenopausal Women. JAMA. 2002. 287(1):47-54.
  2. Fung TT, et. al. Dietary patterns and the risk of coronary heart disease in women. Arch Intern Med. 2001. 161(15):1857-62.
  3. Liu S, et. al. A prospective study of dietary fiber intake and risk of cardiovascular disease among women. J Am Coll Cardiol. 2002. 39(1):49-56.
  4. Fairfield KM, et. al. Risk of ovarian carcinoma and consumption of vitamins A, C, and E and specific carotenoids: a prospective analysis. Cancer. 2001. 92(9):2318-26.
  5. Michaud DS, et. al. Physical activity, obesity, height, and the risk of pancreatic cancer. JAMA. 2001. 286(8):921-9.
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