Fitness Forum: Calcium fights obesity, cancer

The Herald-Sun
Jun 3, 2003 : 10:46 am ET

Other than preventing osteoporosis, what are some other benefits of dietary calcium?

Selena Sullivan of the Durham County Health Department replies: Calcium, a mineral used for building and maintaining strong bones and teeth, is also involved with muscle contraction, heart rhythm regulation, nerve impulse transmission, blood clotting, and the maintenance of cell membranes. Recent studies and new information have identified calcium and dairy products (milk, cheese and yogurt) as potentially powerful allies in the fight against overweight and obesity, hypertension and colon cancer.

A relationship between calcium intake and body weight has been observed in clinical studies. Individuals who consumed higher levels of calcium and dairy products tended to have less body fat. The most significant impact was seen at the highest level of calcium intake. Overweight adults on a reduced-calorie, higher calcium (1,200-1,300 milligrams/day) eating plan lost more weight than those on a reduced-calorie, lower-calcium (400-500 milligrams/day) plan. Weight loss was greatest with lowfat or nonfat dairy versus regular fat (whole milk) dairy products or calcium supplements.

A diet low in calcium, according to researchers, can increase your risk for high blood pressure. During calcium shortage, the body releases a hormone called calcitriol, which acts on the smooth muscle walls of arteries, constricting them and thus elevating your blood pressure. Given this, calcium intake may be almost as important to blood pressure as sodium intake.

The recommended daily intake for calcium is 1,000 to 1,300 milligrams for most adults. An 8-ounce serving of milk provides about 300 milligrams of calcium. For more information on calcium, visit www.nationaldairycouncil.org.

I understand that following the DASH diet can help lower blood pressure. I am confused. Is this diet related to Mrs. Dash, the salt-free seasoning blends?

Selena Sullivan replies: DASH stands for "Dietary Approaches to Stop Hypertension," a National Heart, Lung and Blood Institute-supported study. The DASH eating plan, rich in fruit, vegetables and lowfat dairy products, significantly lowers blood pressure, especially when combined with a reduced or lower sodium intake (1,500 milligrams a day), physical activity and smoking cessation. For more information on DASH, visit www.nhlbi.nih.gov/health/public/heart/hbp/dash/ or call (301) 592-8573.

The DASH diet bears no relationship to the "Mrs. Dash seasoning blends," products of Alberto-Culver USA Inc. However, the confusion is understandable since the seasoning blends are "salt-free" and often recommended to those on sodium or salt restriction.

Is it true that eating foods high in calcium can cause kidney stones?

Selena Sullivan replies: Kidney stones are tiny pebbles that form in the kidney and upon lodging in the urinary tube can cause intense pain. Most kidney stones consist of calcium plus oxalate, a substance found in fruit, vegetables and grains. Some individuals are at higher risk for forming kidney stones and may have been advised to avoid calcium-rich foods. However, two recent large-scale studies indicate that dietary calcium may actually reduce the risk of kidney stones. Calcium in the diet blocks the absorption of oxalates from food. Therefore, now, people with a history of kidney stones may be counseled to cut back on oxalate-rich foods, such as beans, beets, greens, rhubarb, chocolate and nuts while consuming adequate dietary calcium. Any dietary modifications should be individualized based on the type and cause of stone formation. Consult your healthcare provider.

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Selena Sullivan, MS,RD,LDN,CFCS, is the Community Nutrition Team Leader at the Durham County Health Department. She can be reached at 560-7791.