Too Many Vitamins?
Chester J. Zelasko, Ph.D. | May 6, 2003

One of the problems with health information today is the presentation of research results via the news media. An example is a recent article in The New York Times titled "Vitamins: More May Be Too Many." (1) The author interviewed a variety of healthcare professionals on the use of vitamin and mineral supplements. The article was peppered with adjectives such as "risky" and "dangerous" that would give anyone pause. Judging by the e-mails we've received about the article, you're wondering if this is really cause for alarm. Let's take a look.

The article focuses primarily on concerns about vitamin A and the possibility of fractures. Two recent studies have focused on this topic. The first study was on the rate of hip fractures in postmenopausal women and was discussed in the Newsletter in January of last year, Vitamin A & Hip Fractures. In short, the health benefits of vitamin A are numerous and the risk of hip fractures is very low for postmenopausal women, with only a slight elevation among the group with the highest intake of vitamin A; women supplementing with beta-carotene had no additional risk of fractures. This is an important distinction; vitamin A in the form of beta-carotene, also known as pro-vitamin A, is safer than vitamin A in the form of retinol.

The second study was published recently in The New England Journal Of Medicine (2). It focused on the rate of bone fractures in a group of Swedish men compared with their serum blood levels of retinol when the study began. The men were divided into five groups by initial serum-retinol levels and followed for 24 years. The reported fracture rate was 64% higher for men with the highest levels of retinol in their blood, after statistically adjusting for socioeconomic factors and behavioral factors such as smoking. A 64% increase in the fracture rate is enough for anyone to be concerned, but is that the whole story? Here's a look at the rest of the numbers reported in the study.

The total number of subjects recruited in the study was 2,322 men who were 49-51 years old at the beginning of the study. The subjects were all from a single town in Sweden. The Swedish advantage is that because of a national hospital registry, they could be tracked easily for the next 24 years, even if they moved to another town. For statistical purposes, the total number of person-years is 54,281 (some subjects died before the study was completed). In 24 years, 266 men had one or more fractures; that's equivalent to about five men out of a thousand having a fracture each year.

Comparing the lowest serum-retinol group with the highest serum-retinol group, the difference is five men out of a thousand (0.49%) versus seven men out of a thousand (0.69%) having a fracture each year. Statistically significant? Yes. Meaningful in the real world? You have to decide for yourselves.

Other studies mentioned in the Times article that appeared to have negative outcomes were studies on vitamin E and C. In most cases, the vitamins were used as a treatment for disease, not examined for their role in preventing disease. The goal for a healthy lifestyle that includes supplementation is the prevention of disease, not treatment.

Should you be concerned about getting too much vitamin A? Probably not, but it's never a bad idea to examine your diet and supplementation program periodically (see Why Supplement). The foods with the highest vitamin A content are liver, eggs, and dairy products enriched with vitamin A, such as milk and cheese. Many manufacturers of high-quality supplements provide most of the vitamin A in the form of beta-carotene, which has not been shown to contribute to fractures. The upper limit for vitamin A intake as retinol is 10,000 IUs or about 3,000 micrograms of retinol per day. If you eat foods like those mentioned every day and you take a food supplement that has only vitamin A (retinol) and not beta-carotene, you may get more than your body needs. Scale something back if it will ease your mind.

One important point was made in the beginning of the Times article that is absolutely a fact: all the vitamin supplements in the world can't make up for a poor lifestyle. We at Better Life Unlimited wholeheartedly agree with that statement. There are no shortcuts to better health. Period.

References:

  1. Gina Kolata, Vitamins: More May Be Too Many. New York Times, April 29, 2003.
  2. Michaelsson K, et al. Serum retinol levels and the risk of fracture. N Engl J Med 2003;348(4):287-94.
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