Milk and other dairy products are the major dietary sources of calcium — the most abundant mineral in the body. Calcium is necessary for building and maintaining healthy bones and teeth and also helps regulate heartbeat, nerve function, hormone secretion and blood clotting.
Dairy products are also excellent sources of zinc, phosphorus, magnesium, complete protein, B vitamins and vitamins A and D. Lack of adequate calcium has been associated with an increased risk of osteoporosis as well as hypertension, high cholesterol, premenstrual syndrome, colon cancer and obesity.
Osteoporosis is the most common calcium-related disease, affecting millions of women and some men. It is characterized by thinning of bone tissue. One out of two women are at risk for developing bone fractures from osteoporosis after menopause — especially those who are fair-skinned and blond, petite and small boned, underweight or have experienced anorexia nervosa are lactose intolerant or sedentary.
Smoking, alcohol and caffeine also increase osteoporosis risk. Calcium and vitamin D intake, estrogen replacement therapy and weight-bearing exercise may all help slow loss of bone as women enter menopause, but the best way to prevent osteoporosis is to eat plenty of calcium-rich foods beginning in childhood and continuing throughout life.
Calcium continuously is being taken out of skeletal tissues for different bodily functions and must be replaced daily through the diet. Research has shown that more calcium is stored between the ages of 11 and 16 than at any other time.
Even when peak bone mass occurs about the age of 30, it is important for women to consume adequate amounts of calcium to maintain bone mass until menopause or age 50. That is when more calcium begins to be taken out of bones than can be replenished, causing bone loss and osteoporosis.
Inadequate intake of calcium is usually a result of eating too few servings of low-fat dairy products. Dietary Reference Intakes from the National Academy of Science recommend anywhere from 1,000 to 1,300 milligrams of calcium a day for adolescents and adults depending on age and sex.
Most people can get adequate calcium from three to four servings of low-fat dairy products and calcium-fortified foods a day. Post-menopausal women not on hormone replacement therapy would need to eat one more serving daily.
One serving (8 ounce glass) of low-fat milk or buttermilk has 300 milligrams of calcium, and you can count these foods as equivalent: 1 cup low-fat yogurt, 2 ounces of most cheeses, 1/2 cup of nonfat dry milk powder, 3 ounces of canned sardines or pink salmon with bones, 1 cup of tofu or 8 ounces of calcium-fortified orange juice.
You may add nonfat dry milk to soups, casseroles, puddings or baked products to increase the calcium content. You can make double-strength milk by blending 1/3 to 1/2 cups nonfat dry milk to every cup of liquid milk without altering the taste.
Dark green leafy vegetables, dried fruits like figs, dried beans, nuts and seeds also contain good amounts of calcium.
One of the most exciting areas of calcium research is that of weight management. Evidence is building that suggests that at least 1,000 milligrams of calcium from milk and dairy products combined with a reduced-calorie diet can result in a reduction of body fat in children and adults.
Dairy foods seem to provide much more weight loss and body fat than supplementary sources of calcium. The anti-obesity effect of dietary calcium has been shown in cellular research as well as animal studies, human epidemiological studies and clinical trials.
One unexpected finding in some studies has been that more than 50 percent of total fat lost was from the abdominal region.
Central obesity — an apple shape that is common in men and post-menopausal women — is a risk factor for metabolic syndrome, which includes heart disease, hypertension, insulin resistance — a precursor for type 2 diabetes.
Research has shown that other components in dairy products besides calcium work synergistically with calcium to accelerate fat burning, making them more effective than supplements.
The National Institute of Child Health and Human Development refers to osteoporosis as a “pediatric disease with adult consequences.” Only about 10 to 25 percent of children and adolescents are meeting their calcium requirements. Replacing milk and dairy products with sweetened beverages lowers calcium intake in children and adolescents.
Two of the best activities at any age are weight-bearing exercise and strength training. Research suggests that this helps build stronger and denser bones in children and teens.
In fact, some studies have shown that prepubescent children who exercised developed bones that were twice as dense as those without exercise. Exercise throughout life promotes bone health and slows bone loss even after menopause.
Thirty to 50 million Americans are lactose intolerant, according to the American Dietetic Association. This means that they cannot digest the carbohydrate in milk called lactose. Individuals experience varying degrees of intolerance to lactose and may have a range of symptoms after eating dairy products. Lactose intolerance is easily managed, especially with the help of a registered dietitian.
Calcium supplementation may be necessary for those with lactose intolerance or others who do not eat enough dairy products to meet daily calcium requirements.
Here are some tips in choosing the supplement best for you:
–Choose known brand names that have the United States Pharmacopeia (USP) symbol.
–Avoid calcium from unpurified products without the USP symbol.
–To test absorption, place a tablet in a small amount of warm water for 30 minutes. If it doesn’t dissolve, it will probably not dissolve in the stomach. Chewable and liquid supplements dissolve well.
–Calcium is best absorbed by the body if taken several times a day in amounts of 500 milligrams.
–Calcium carbonate is best absorbed when taken with food.
–Calcium citrate can be taken any time.
–Calcium supplements can cause gas or constipation, so increase supplements slowly.
–Ask your physician if your calcium supplement can cause an interaction with other medication.
For more resources, visit www.thealabamabaptist.org
Editor’s Note — Pat Hart Terry, Ph.D., is chairman of the department of nutrition and dietetics at Samford University in Birmingham and a registered dietitian.
Share with others: