Diseases caused by vitamin deficiencies are rare in developed countries. However, researchers are finding that these essential nutritional components have the potential to prevent other types of diseases and conditions. Here's a look at a few more intriguing examples.
Calcium and Weight Loss
The connection between calcium and bone health is familiar. However, recent research by Michael Zemel, Ph.D., director of the Nutrition Institute at the University of Tennessee, Knoxville, shows that the calcium in milk plays a role in reducing obesity by regulating fat metabolism as well.
In a paper published last spring in the Journal of the American College of Nutrition, Zemel showed that an increase in dietary calcium significantly contributes to loss in fat and weight.1 In a clinical study, 32 people went on a diet. After six months, all the dieters lost weight, however, those that had consumed more dairy products lost an average of 19 pounds, compared with 11 pounds in the control group. Zemel theorizes that a high calcium diet suppresses calcitriol, a hormone that normally stimulates fat production in fat cells while suppressing fat burning.
Other studies support Zemel's findings. In the mid-1990's, Connie Weaver, Ph.D., and Dorothy Teegarden, Ph.D., researchers at Purdue University, West Lafayette, Ind., found that women between the ages of 18 and 31 who ate a diet rich in milk, cheese or yogurt lost weight or stayed stable.2
Their research suggests that women who consume calcium from dairy products or who consumed an average of 1,000mg per day showed an overall decrease in body weight as high as six to seven pounds. The women in the study who consumed less than 1,900 calories and at least 780mg of calcium either had no body fat increase or lost body mass over a two-year period. Women who ingested less than this amount of calcium gained body fat mass with the same number of calories.
In another study, Robert P. Heaney, M.D., professor of medicine at Creighton University Medical Center, Omaha, Neb., found a correlation in his data on women's calcium intake from years of bone studies and found that a higher calcium intake correlated with lower body weight in women of all ages.3 Each 300mg increment in calcium intake is associated with about two pounds less body fat in children and 3 to 6lbs lower body weight in adults.
Alzheimer's and Parkinson's
Although studies are not conclusive, researchers have examined the antioxidant vitamin E's role in the management of Alzheimer's and Parkinson's disease. Impairment of oxidative metabolism has been implicated as one factor responsible for pathological changes of these conditions.
A study at Harvard School of Public Health, Boston, on the effects of consuming vitamin E, vitamin C and carotenoids both from food and dietary supplements was published in Neurology last fall. The research examined the ability of these nutrients to reduce the risk of Parkinson's.4 Results showed that foods rich in vitamin E, such as nuts, contribute to reducing the risk of Parkinson's, while vitamin supplements alone had no effect. The researchers hypothesized that other bioactive components are also important.
Other new research suggests that a lack of iron may contribute to the decay of brain cells in Alzheimer's.5 Reducing the production of heme, the most common form of iron in cells, led to degeneration similar to that caused by aging and Alzheimer's disease. While the study does not prove that a lack of heme is the cause of Alzheimer's-related degeneration, it does provide a plausible mechanism.
Antioxidant and Eye Health
Antioxidant vitamins and zinc may reduce the risk of vision loss from AMD, according to recent studies. For high-risk patients, a dietary supplement of vitamins C, E and beta-carotene and/or zinc lowered the risk of progressing to an advanced stage of disease by about 25%, according to a study at Johns Hopkins' Wilmer Eye Institute, Baltimore, Md. The supplements also reduced the risk of vision loss by about 19%. Patients with intermediate AMD or advanced AMD in one eye but not the other were more likely to benefit from the treatment. Vitamin E also plays a role in using oxygen and in the prevention of cataracts caused by free radical damage. There are two current hypotheses on how antioxidants may benefit the eyes. Both of these involve the stabilization of free radicals formed by ultraviolet and blue light to maintain lens clarity and reduce the formation of deposits of extra cellular materials that cause macular degeneration.
In clinical studies involving vitamin E and diabetics, research has shown that high doses of vitamin E supplements can be effective in reducing blood vessel complications related to diabetes. Diabetics are at increased risk of developing a wide range of complications, including an eye disease called diabetic retinopathy, which can cause sight loss and blindness. The studies show that high doses of vitamin E can be effective in improving blood flow in the retina of the eye and the kidneys in patients with type I (juvenile onset) diabetes. Kidney function improved as well.
The popularity of specific vitamins and minerals will rise as researchers and consumers better understand their role beyond preventing basic nutritional deficiencies.
On the Web: VITAMINS & MINERALS
- www.PreparedFoods.com/archives/2002/2002_7/0702ns_eye.htm Article on ingredients for eye health in June 2002 issue of NutraSolutions
- http://ohioline.osu.edu/hyg-fact/5000/5554.html Ohio State University Extension Fact Sheet on vitamin E
- www.altdiabetes.com/Summary/VitE.htm Supplements and diabetes
- www.nlm.nih.gov/medlineplus/news/fullstory_9963.html Vitamin E and Parkinson's disease (National Library of Medicine)
- www.cchs.net/health/health-info/docs/2200/2244.asp?index=9197 Vitamin E's role in Parkinson's disease (Cleveland Clinic Health System
1 Zemel, M.B. 2002. Regulation of Adiposity and Obesity Risk by Dietary Calcium: Mechanisms and Implications. J Am Coll Nutr 21(2):146S.
2 Lin, Y-C, et al., 2000. Calcium intake relates to change in body weight in young women. J Am Coll Nutr, 19(6):754-760.
3 Heaney, R.P., et al., 2002. Calcium and Weight: Clinical Studies. J Am Coll Nutr 21(2):152S. www.am-coll-nutr.org/jacn/vol_21/no_2/pg152S.htm
4 Zhang, S.M., et al., 2002. Intakes of vitamins E and C, carotenoids, vitamin supplements, and PD risk. Neurology 59:1161-1169.
5 Atamna, H., et al., 2002. Heme deficiency may be a factor in the mitochondrial and neuronal decay of aging. Proc Nat Aca Sci 99(23): 14807-14812.