header

Obesity101.com
THE LATEST IN OBESITY RESEARCH AND WEIGHTLOSS DRUG DEVELOPMENT

Join our list More information

Volume 4, Issue 6
June 2000

CALCIUM AND WEIGHT LOSS

Everyone knows that the stars of those "Got milk?" ads have healthy bones and teeth. Could it be that the calcium in milk also keeps them thin? Recent data from the NHANES III epidemiological survey indicates that individuals who eat high-calcium diets are thinner than those who do not. In addition, both animal and human studies show that dietary calcium increases fat metabolism.
Patrick Ewing
Patrick Ewing.

How calcium stimulates fat metabolism.

Research indicates that high levels of calcium in fat cells increase susceptibility to obesity, diabetes and hypertension. Michael Zemel, Director of the Department of Nutrition, University of Tennessee -- Knoxville, first discovered this phenomena when studying the agouti mouse, a rodent model of obesity, hypertension and hyperinsulinemia. Zemel found that the agouti gene stimulates intracellular calcium, increasing lipogenesis (fat storage) and inhibiting lipolysis (fat metabolism). But when agouti mice were put on a high-calcium diet they lost significant body fat. 10, 14 These studies suggested that low-calcium diets stimulate hormones which drive dietary calcium into fat cells.

At last fall's NAASO meeting Zemel said, "What we found is that low fat dairy products affect the way in which human fat cells do their job. What happens when you ingest higher amounts of dairy foods is that you turn off the machinery for making fat and turn on the machinery for breaking down fat." 25 Zemel found the "machinery" involved calcitrophic hormones (calcitriol), which secondary to a low-calcium diet stimulate adipocyte calcium influx and lipid storage. He hypothesized that increasing dietary calcium would suppress calcitriol in adipocytes, and reduce body fat. 11

The first observations of body weight loss in individuals on a high-calcium diet were seen during a hypertension study on African-Americans 10 years ago. It has long been known that intracellular calcium plays a key role in the development of hypertension, cardiac hypertrophy, insulin resistance, and hyperinsulinemia -- also known as syndrome x. Dietary calcium and the resulting suppression of calcitrophic hormones has long been known to decrease hypertension and possibly type-2 diabetes. These effects were demonstrated when obese African-Americans increased calcium intake from 400 to 1000 mg/day, by supplementing their diet with two daily cups of yogurt. The yogurt had the expected effect of lowering blood pressure, but it also resulted in an unexpected 4.9 kg reduction in body fat after one year. 11, 12

In all studies conducted to date, researchers have found that calcium from dairy sources was superior to calcium carbonate in promoting body fat loss.

cheese

Studies on calcium and weight loss.

Weight loss in rodents. A rodent study presented by Hang Shi and Michael Zemel of the University of Tennessee -- Knoxville, at this year's Experimental Biology meeting shows that a 30 percent calorie reduced high-calcium diet causes 30 percent more weight loss than a reduced calorie low-calcium diet. Agouti mice were fed one of four calorie-reduced diets: high-calcium, medium-dairy, high-dairy or a low-calcium control diet, Mice given the low-calcium diet lost about 11 percent of total body weight and 8 percent of total body fat, compared to mice on the high-dairy diet which lost 25 percent of their body weight and 60 percent of their body fat. The mice that received all three calcium supplemented diets also experienced a ~0.5 degree C increase in body temperature. These changes occurred despite the lack of any difference in food intake, indicating a shift in efficiency of energy metabolism from energy storage to thermogenesis in the calcium supplemented groups. 11, 16 The high-calcium diets also inhibited expression of fatty acid synthase (FAS), a key enzyme in lipogenesis, and stimulated lipolysis by 350 to 500 percent. On the other hand, the control diet caused a 260 percent increase in FAS activity. 11

NHANES data. To determine whether animal observations apply to people, Zemel analyzed data from the National Health and Nutrition Examination Survey (NHANES III). After controlling for energy intake, activity level, age, race, and ethnicity, a high-calcium diet was the major predictor of body fat. Individuals who had the highest calcium intake were the least likely to be fat, whereas those with the lowest calcium intake were the most likely to gain weight (see table). 11, 23

EFFECT OF DIETARY CALCIUM AND DAIRY INTAKE ON BODY FAT
Quartile of calcium
and dairy
consumption		 Calcium intake
(mg/day)
mean ± SEM		 Dairy consumption
(servings/month)
mean ± SEM		 Odds ration of being
in the highest body
fat quartile
1 255 + 20 14.4 + 1.9 1.00
2 484 + 13 38 + 1.3 0.75
3 773 + 28 57.2 + 1.0 0.40
4 1346 + 113 102.8 + 3.6 0.14

Calcium and weight loss in women. At the 1999 Experimental Biology meeting, Dorothy Teegarden of Purdue University presented the results of her 2-year study on dietary calcium in a cohort of 56 normal weight women ages 18-31. Teegarden found that women in the study who consumed less than 1,900 calories per day and at least 780 mg of calcium either lost body fat or maintained their weight, whereas women who consumed less than 780 mg of calcium over the same period gained body fat mass. She said, "Women who consumed an average of 1,000 mg of calcium per day, which is slightly below the recommended daily allowance for the age group showed an overall decreased in body weight as high as 6 to 7 pounds."

In Teegarden's study, subjects who got their calcium from dairy products, as opposed to non dairy sources like vegetables, nuts and beans, or supplements, maintained better weight control. Exercise helped weight loss, but the benefits of calcium evaporated when subjects ate over 1,9000 calories per day. Further studies are indicated to see if the weight loss benefits are found in women over 30. 18

Calcium metabolism and vitamin D.

Do you really have to "get milk" to reap the maximum weight loss effect from calcium? The studies seem to indicate so. According to Zemel, the data suggest that real dairy products achieve greater suppression of calcitriol and calcium in adipocytes, with a consequent reduction in the efficiency of energy utilization. But other research suggests that mega-doses of vitamin D taken with calcium carbonate may achieve the same results.

Although vitamin D is classified as a vitamin, it is more properly characterized as a steroid hormone that regulates specific gene expression. The biologically active form of vitamin D, calcitriol (1,25-dihydroxy vitamin D3), functions primarily to regulate calcium and phosphorous homeostasis. But according to a 1999 study, the 200 IU daily recommendation for adults (400 IU for children) is not sufficient to attain a high enough calcitriol level for proper calcium absorption.

In a May 1999 review article, published in the American Journal of Clinical Nutrition, Reinhold Vieth of Mount Sinai Hospital in Toronto, took exception to the current government recommendations for vitamin D, stating that they have led to an epidemic of osteoporosis. In addition, vitamin D supplementation has been found to prevent some cancers, and slow the progression of osteoarthritis, multiple sclerosis, and hypertension. And vitamin D deficiency is linked to the development of seasonal affective disorder (SAD). 2, 4, 6

The purpose of vitamin D supplementation is to correct for the lack of sunlight exposure in modern society. While our ancient ancestors received full body surface exposure to the sun almost daily, modern humans cover all but about 5 percent of their skin surface. To make matters worse, many of us live in high latitudes where sun exposure would never be sufficient, and others spend too much time indoors to get enough vitamin D from natural sources. 9

The modern recommendation for vitamin D was set to prevent diseases like rickets and osteomalacia. In most of North America, vitamin D availability is sufficient to prevent these diseases, but the mere absence of clinical rickets can hardly be considered an adequate definition of either health or vitamin D sufficiency. Despite a greater understanding of how vitamin D works, the vitamin D recommendation continues to be equated to the absence of rickets and osteomalacia. But the tide has started to turn. "The shift away from this approach is reflected, for example, in the tripling of the vitamin D recommendation for the elderly in the most recent dietary reference intakes from the Food and Nutrition Board of the Institute of Medicine, arguably the largest increase in the history of dietary recommendations." 3, 5

There is now a consensus that serum 25-hydroxyvitamin D (25-OH-D) concentration is the proper indicator of vitamin D sufficiency in humans. Concentrations of 20-25 nmol/L indicate severe D deficiency, leading to rickets and osteomalacia. Concentrations between 25-40 nmol/L reflect marginal deficiency, a situation common in countries north of the US. Marginal concentrations of 25-OH-D are associated with mildly elevated parathyroid hormones and diminished calcitriol concentrations, 9 in other words, the inability to properly metabolize calcium.

Vieth suggests that the daily vitamin D requirement from all sources should be 4,000 IU, 200 percent over the current daily recommendation.

Vitamin D toxicity?

A reason for limiting the daily intake of vitamin D, a fat soluble vitamin, is the potential for buildup in tissues and vitamin D toxicity. As 25-OH-D concentrations rise above 220 nmol/L hypercalcemia, excess calcium in the blood, becomes evident. Hypercalcemia can cause dehydration, weakness, loss of appetite, constipation, and even coma. The condition has been reported in individuals with 20-OH-D concentrations as low as 140 nmol/L, although such reports are rare.

The National Academy of Sciences indicated in 1989 that the toxic dose of vitamin D can be as low as "five times the RDA". This recommendation has been carried forward to the latest set of revisions to the RDA in which the upper intake level was set at 2000 IU. 3 Vieth says, the reported cases of vitamin D toxicity are poorly substantiated, and the outcome of these unfounded vitamin toxicity fears is higher rates of osteoporosis and arteriosclerosis. 9 While the actual supplementation of vitamin D needs to be adjusted for the amount of sun exposure a person gets, the current adult DRI of 200 IU is woefully inadequate, and Vieth's recommendation of 4,000 IU (from all sources) is well lower than the 10,000 IU the Institute of Medicine set as the lowest daily dose that might cause toxicity.

Back to dietary calcium and weight loss.

So why has dietary calcium from dairy been found to work better in studies? Simple. Most milk products are fortified with vitamin D. And while you would have to drink 2 1/2 quarts of milk to get 1,0000 IU, calcium supplements contain no vitamin D. Fatty fish, like salmon and tuna, egg yolks, liver, cheese, butter, vegetables, 21 nuts and beans contain natural vitamin D. But the major natural source of vitamin D is sunlight, which explains why most people need supplementation in order to maintain sufficient levels for calcium metabolism.

    Articles.
  1. Ambrozy SL, et al. Effects of dietary calcium on blood pressure, vascular reactivity and vascular smooth muscle calcium efflux rate in Zucker rats. (medline) Am J Hypertens. 1991 Jul;4(7 Pt 1):592-6.
  2. Compson JE. Vitamin D deficiency: time for action. Evidence supports routine supplementation for elderly people and others at risk. (medline) (editorial) BMJ 1998 Nov 28;317(7171):1466-7.
  3. Food and Nutrition Board, Institute of Medicine. Dietary reference intakes for calcium, phosphorus, magnesium, vitamin D, and fluoride. (text) National Academy Press, 1999.
  4. Garland CF, et al. Calcium and vitamin D. Their potential roles in colon and breast cancer prevention. (medline) Ann N Y Acad Sci. 1999;889:107-19. Review.
  5. Heaney RP. Lessons for nutritional science from vitamin D. (medline) (editorial) Am J Clin Nutr. 1999 May;69(5):825-6.
  6. Landsdowne AT, et al. Vitamin D3 enhances mood in healthy subjects during winter. (medline) Psychopharmacology (Berl). 1998 Feb;135(4):319-23.
  7. Levy J, et al. Role of cellular calcium metabolism in abnormal glucose metabolism and diabetic hypertension. (medline) Am J Med. 1989 Dec 8;87(6A):7S-16S. Review.
  8. Shi H, et al. Role of the sulfonylurea receptor in regulating human adipocyte metabolism. (medline) FASEB J. 1999 Oct;13(13):1833-8.
  9. Vieth R. Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety. (medline) (article) Am J Clin Nutr. 1999 May;69(5):842-56. Review.
  10. Xue B, et al. The agouti gene product inhibits lipolysis in human adipocytes via Ca 2 - dependent mechanism. (medline) FASEB J. 1998 Oct;12(13):1391-6.
  11. Zemel MB, et al. Regulation of adiposity by dietary calcium. (medline) FASEB J. 2000 Jun;14(9):1132-8.
  12. Zemel MB, et al. Nutritional and endocrine modulation of intracellular calcium: implications in obesity, insulin resistance and hypertension. (medline) Mol Cell Biochem. 1998 Nov;188(1-2):129-36. Review.
  13. Zemel MB, et al. Agouti regulation of intracellular calcium: Role in the insulin resistance of viable yellow mice. (medline) (article) Proc Natl Acad Sci U S A. 1995 May 23;92(11):4733-7.
  14. Zemel MB, et al. Impaired calcium metabolism associated with hypertension in Zucker obese rats. (medline) Metabolism. 1990 Jul;39(7):704-8.

    15. Abstracts.
  15. Causey KR, et al. Effects of 1,25-dihydroxyvitamin D (1,25-D) on adipocyte differentiation. The University of Tennessee, Knoxville, TN 37996. (abstract) Experimental Biology 2000.
  16. Shi H, et al. Effects of dietary calcium on adipocyte lipid metabolism and body weight regulation in energy-restricted mice. The University of Tennessee, Knoxville, TN 37996. Experimental Biology 2000.
  17. Shi H, et al. Role of intracellular calcium in human adipocyte differentiation. (abstract) Obes Res 1999 Nov:7: 50. (Suppl. 1: abstr. O83)
  18. Teegarden D, et al. Calcium intake relates to change in body weight in young women. (abstract) Experimental Biology 1999.
  19. Xue B, et al. Agouti regulates in vivo expression and activity of human adipose tissue fatty acid synthase. (abstract) Obes Res 1999 Nov:7: 50. (Suppl. 1: abstr. O82)
  20. Xue B, et al. Mechanism of intracellular calcium inhibition of lipolysis in human adipocytes. The University of Tennessee, Knoxville, TN 37996. Experimental Biology 2000.

    21. Mainstream articles and press releases.
  21. Are you SAD this winter? Toronto Sun article, January 18, 1999.
  22. Black women may need more vitamin D in winter. USDA Agricultural Research Service press release, August 18, 1998.
  23. Drink this! New study finds lowfat milk may help reduce obesity risk. National Dairy Council press release, May 25, 2000.
  24. Study finds lowfat milk may reduce obesity risk. National Dairy Council press release, November 17, 1999.
  25. UT study shows lowfat milk slows weight gain. University of Tennessee press release, November 18, 1999. (Real audio interview)
  26. Vitamin D deficiency may increase risk of hip fracture in older women. NIH press release, April 27, 1999.
  27. Vitamin D picture could be sunnier for elders. USDA Agricultural Research Service press release, July 8, 1998.
  28. Vitamin D supplements should be taken during winter months. Mt. Sinai Hospital (Toronto) press release, December 21, 1998.

header

Home|Subscribe|Archives|Drug info|Contact|Media & Links|Site index|FAQs|Doctors/meetings|Admin

Obesity-news is a publication of Hirsch Communications. An on-line subscription is $104.00 per year, payable in advance by check, money order, American Express, Discover, VISA or Mastercard. Subscribing is simple using our secure on-line subscription form. Obesity-news also accepts fax orders at 703/960-7462 and mail orders at PO Box 19316, Alexandria, VA 22320-0316. Copyright 1997-2008, all rights reserved.

IMPORTANT: All information in this publication is believed to be accurate and true. Publisher is not liable for omissions or inaccuracies. Information in this newsletter is for educational purposes only and should not be construed as medical advice, or be used in lieu of consultation with a health care provider.