THE SCIENTIFIC BASIS OF THE CALCIUM DOSAGE OF NUTRITION INVESTIGATOR

THE KEY to preventing osteoporosis is exercise. Here is a note from my reading in December, 2004. Osteoporosis on the rise - by 2020, half of Americans over 50 will be at risk for osteoporosis. A report by the Surgeon General suggests simple steps like getting 30 min of exercise per day will maintain bone health. -Bone Health and Osteoporosis: A Report of the Surgeon General; October, 2004. Note that osteoporosis is rare in nations in Africa or in India, where people get lots of exercise.

If you are interested in getting enough calcium, it is worth reading the many reports found in the litnotes, that can be accessed using the search command. The short answer is that even young women probably only benefit from 800 mg/d and do not need more than that. For any woman, the key to healthy bones is exercise, to help build/retain strong bones, retain strength and balance. [May 2007 important note: Prof. Walter Willett states "500 mg calcium is enough."]

Here is a bit of information that may be useful. The last RDA for calcium was 800-1,200 mg per day. The debate on the value of calcium supplementation continues even as the daily requirement for calcium has increased. Two factors are important to consider in this debate. In favor of supplementation, it is well established from dietary surveys such as those presented in the RDA report that most of the U.S. population does not drink as much milk as the dairy industry would like. On the other hand, calcium supplements with high dosages may be hazardous, cause unpleasant side effects, and not be effectively absorbed.

After using the method of urinary excretion to determine a saturating dosage of vitamin C, a similar study was undertaken to determine a useful dosage of calcium (reported by the Journal of the American Aging Association). Previous studies (3, 4) have established that urinary excretion is proportional to intestinal absorption of calcium. One group of pre-menopausal women and another of post-menopausal women were given different dosages of calcium to determine what dosage of calcium was effectively absorbed.

The results demonstrate that calcium from supplements is excreted over a 12 hour period. Pre- menopausal women showed the greatest absorption when given 200 mg twice daily, while post- menopausal women, with substantial variability depending on medication, showed maximal absorption at a 400 mg dose twice daily. These dosages are substantially lower than many calcium supplements presently on the market, and are less likely to lead to unpleasant side effects like diarrhea. These dosages to consider based on information from Nutrition Investigator are consistent with the difference between the average dietary intake (6) (600 mg for pre-menopausal women and 700 mg for post-menopausal women) and the NIH recommended dosages (1,000 mg for pre- and 1,500 mg for post-menopausal women).

There are other factors to consider for osteoporosis. There are sections on caffeine, and on vitamin D, Atkin's Diet protein, and potassium.

1. Nordin, B. E. and Heaney, R. P. , "Calcium Supplementation Of The Diet: Justified By The Present Evidence", British Medical Journal 300:1056-60 (1990)

A review of latest evidence supporting use of supplements, and verifying Personal Health Corporation research on need for lower doses in general, and for particular dosages chosen for younger and mature women.

2. Kanis, J. A. , and Passmore, R., "Calcium Supplementation Of The Diet: Not Justified By The Present Evidence", British Medical Journal 298:137-40 (1989)

A review of latest evidence against the use of calcium supplements, and verifying Personal Health Corporation research on need for lower doses in general, and for particular dosages chosen for younger and mature women.

3. Kesteloot J, Joossens JV: The relationship between dietary intake and urinary excretion of sodium, potassium, calcium, and magnesium. J Human Hypertension, 4:527-533, 1990.

4. Brink EJ, van Beresteijn ECH, Dekker PR: Urinary excretion of magnesium and calcium as an index of absorption is not affected by lactose intake in healthy adults. Brit J Nutr, 69:863-870, 1993.

5. NIH Panel urges increase in adult calcium intake. Pub Health Repts, 109:715-6, 1994.

6. U.S. Bureau of the Census: Statistical Abstracts Of The United States: 1995 (115th ed). Washington, DC, US Government Printing Office, 1995, pg. 146.