Fat-free is clearly preferred. Why waste calories on putting 2 percent milk in your coffee? Soy milk is not an ideal choice, either, because it is not a complete protein, as milk is, has extra calories, and does not give you as much calcium.

Keep milk cold at the back of the refrigerator, at 35º-40ºF, not on a door shelf. Each 5ºF rise in temperature shortens milk's shelf life because of bacterial growth.

The sad fact is that teens are drinking half as much milk as they did thirty years ago. Milk has been replaced with newfangled drinks including designer bottled waters, exotic juices, iced teas, and soy beverages. But the saddest fact of all is the replacement of milk with carbonated sweetened beverages. When milk is replaced with carbonated beverages, the result is a loss from the diet of protein, calcium, magnesium, and vitamins A and D. There is an almost linear relationship between the rise in consumption of carbonated drinks and obesity in teens. Teenagers need to build bone mass that will last for a lifetime. Because of this, we have to look for new and creative ways to get the calcium we need every day. Space your intake of calcium during the day and also take a calcium supplement as an insurance policy.

Which Calcium Supplement Is Best?

Supplemental calcium comes in two forms: calcium carbonate and calcium citrate. Calcium carbonate must be taken with meals. This is also the type of calcium found in TUMS. By consuming this indigestion remedy, you are giving your bone density a boost. Calcium citrate may be taken any time -- with or without food. I recommend that my patients take at bedtime a supplement of calcium citrate containing vitamin D.

Even if you receive your calcium requirement from food, I recommend adding a calcium supplement just to insure adequate intake. If you have trouble swallowing calcium tablets, as many people do, try another form of calcium. TUMS and calcium chews are popular, and easy for most people to consume. They contain calcium carbonate and must be taken with food for the calcium to be digested. Calcium citrate can be taken with or without food. Make sure that your calcium supplement also contains vitamin D, for optimal absorption.

You need to be aware of the amount of elemental calcium any supplement contains. The term "elemental calcium" refers to the amount of calcium in a supplement that is available for your body to absorb. Most calcium supplements list on the label the amount of elemental calcium. Some brands list only the total weight -- in milligrams (mg) -- of each tablet. This is the weight of the calcium, plus whatever may be bound to it -- such as carbonate, citrate, lactate, or gluconate. For calcium, the % Daily Value (DV) is based on 1,000 mg of elemental calcium, so every 10 percent in the Daily Value column represents 100 mg of elemental calcium (0.10 x 1,000 mg = 100 mg). For example, if a calcium supplement has 60 percent Daily Value, it contains 600 mg of elemental calcium (0.60 x 1,000 mg = 600 mg). It is also important to note the serving size -- the number of tablets you must take to get the % DV listed on the label.

When choosing a calcium supplement, check the label for the abbreviation USP. The best supplements meet the voluntary standards of the U.S. Pharmacopeia (USP) for quality, purity, and tablet disintegration or dissolution. Generic brands of calcium supplements are often cheaper than name brands. However, they may not meet voluntary standards for tablet disintegration. In other words, they may dissolve more slowly, which decreases their effectiveness. Avoid calcium supplements that contain bone meal or dolomite, as these may also contain toxic substances, such as lead, mercury, and arsenic. Check the label for "no added sugar." Chelated calcium tablets tend to be more expensive and really do not have any advantage over other types of calcium. Coral calcium is also marketed as superior calcium, which has not been proven.

Many of my patients love Viactiv Calcium Soft Chews -- chewy little squares that taste like Kraft caramels and come in several dessertlike flavors. Although they are very sweet, two squares contain 100 percent of the Daily Value of calcium and include vitamins D and K. Each VIACTIV Calcium Soft Chew contains 500 mg of elemental calcium from 1,250 mg of calcium carbonate. (www.viactiv.com)

Calcium and Blood Pressure

Glimmerings of this important relationship began in 1982, when Dr. David A. McCarron noted that a diet low in dairy products increased a person's chance of developing high blood pressure. A study of the entire population of the United States confirmed his hypothesis and revealed that the people who ate the least amount of dairy products had the highest blood pressures. In fact, the normal diet of the majority of United States doesn't meet the minimal requirement for adequate calcium. This led to a 1997 clinical trial, Dietary Approaches to Stop Hypertension, or the DASH trial, which showed that blood pressure could be lowered by a diet high in fruits, vegetables, and low-fat dairy products. While fruits and vegetables lowered the blood pressure somewhat, it was the addition of dairy products that made the difference. The importance of maintaining an optimal blood pressure cannot be overstated. High blood pressure stresses the heart, strains the arteries, and increases the risk of heart attack and stroke. How remarkable that we can lower the risk for these terrible consequences simply by adding dairy products to our diets! I am constantly surprised that my patients who have high blood pressure have not been told anything about this relationship by their primary care physicians.

If you have high blood pressure, you should have a minimum of one dairy product at each meal. This can be easily accomplished by adding a glass of skim milk, 2 ounces of low-fat cheese, or a 6-ounce container of low-fat yogurt at each meal. This can be as vital as your taking your medication.

Marcia is a forty-seven-year-old divorced mother of two teenage sons who works as a museum curator. She was referred to me by her primary care doctor for weight reduction. When I first met Marcia, she was five foot three and weighed 160 pounds. Her cholesterol and blood pressure were elevated and she took medication for both of these conditions. On the positive side, she had a commitment to exercise and swam three times per week for the last twenty-five years. However, Marcia's diet was sadly deficient in the foods that she needed to control her blood pressure and cholesterol. Her typical breakfast was coffee and a croissant with butter, lunch was a sandwich, and dinner was often her sons' leftover pizza. These foods were the worst possible choices for someone with her health problems. In revamping Marcia's life, I suggested that she start a walk-run program, which she readily committed to. There is greater weight loss with walking or running than with swimming. For food, I suggested that she begin her day with a vegetable omelet and a glass of skim milk. For a midmorning snack, she had some plain yogurt and fresh berries. (This reminded her of the summer she spent in France, where she began each morning with fresh raspberries and yogurt.) Lunch was a fruit salad with low-fat cottage cheese. I pointed out to Marcia that it was in her best interests to encourage her housekeeper to stop indulging her sons' pizza cravings, and to have her prepare a wholesome meal for them instead. Her housekeeper began preparing grilled fish or chicken with fresh herbs, two vegetables, and a salad for dinner. She set aside a portion of the meal for Marcia, who had a glass of skim milk with dinner and a calcium supplement prior to retiring.

The changes Marcia experienced were truly remarkable. She became a devoted runner, lost 40 pounds, and no longer required medication to control her blood pressure or cholesterol. Her health problems had been totally resolved by dietary changes. Even her sex life improved. She proudly showed me a bikini she had purchased for a vacation to France with her new boyfriend!

Calcium and Cancer Risk Reduction

Population studies indicate that a diet high in calcium lowers the risk for colon cancer. In both the Nurses Health Study, which included 88,000 women, and the Health Professionals Follow-up Study, with 47,300 men, people with the highest calcium intakes had the lowest rates of colon cancer. There was an inverse risk of colon cancer, meaning that the more calcium consumed, the lower the risk for cancer. The way that calcium reduces colon cancer is by binding digestive acids that could potentially harm the cells of the colon lining. The cells of the colon are susceptible to damage by fatty acids and bile (produced by the body to digest dietary fat). If they are subjected to these acids on a regular basis (as is the case with a high-fat diet), the cells proliferate and polyps form. Colonic polyps are precancerous tissue. They are not cancers but, allowed to grow, may evolve into cancer. (This is why it is important for everyone to have a colonoscopy after fifty. As we age, the colon cells are more apt to form polyps. These are easily removed during a colonoscopy before they have a chance to become cancerous.) When digestive acids are bound to calcium, they are inactivated and rendered incapable of damaging the colon cells. Furthermore, when people prone to developing polyps consume high amounts of calcium, formation of polyps is reduced.

If you have had colon cancer or colonic polyps, or have a family history of colon cancer, it is wise to lower the amount of fat in your diet and increase your calcium intake. The best way to do this is by incorporating low-fat dairy products and adding a calcium supplement.

Calcium and Weight Loss

Even more intriguing than the association of a reduction in blood pressure and cancer risk with calcium is the association of calcium with weight loss. The relation between calcium and body weight was first noted more than twenty years ago in the National Health and Nutrition Examination Survey. This study of the nutritional habits of the entire United States reported that the slimmest people had the highest intakes of calcium. Since there was no known mechanism for how calcium kept people thin, the finding was written off as pure chance. When the study was repeated ten years later, it was found that not only did the slimmest people have the highest calcium intakes, but the heaviest people had the lowest calcium intakes! Now, this got researchers' attention: Perhaps there could be a connection between calcium and weight.

A study at the University of Tennessee found that when fat cells were exposed to a calcium-rich environment, they broke down fat much more rapidly than when they were in a calcium-depleted environments. That was a very interesting finding but it was done in a Petri dish, not in human clinical trials. The reasons for the cells behaving in this manner are believed to date back to our prehistoric origins. In ancient times, our diets had much more calcium, due to the consumption of nuts, tubers, and roots grown in calcium-rich soil. Examination of the skeletons of prehistoric man shows bones with high amounts of calcium. Some researchers estimate the ancient diet had two to three times the calcium consumed today. In light of this, it may be that the body may respond to a low calcium intake as a state of starvation, causing it to hold on to fat stores more closely. Of course, this is all speculative.

What about real people and calcium? Can calcium really help them lose weight? In 2004, a published study showed that this was indeed the case. This weight-loss study, also from the University of Tennessee, divided overweight subjects into three groups. Each group was restricted by the same amount of calories, and the proportions of fat, carbohydrate, and protein were the same for each group. But they differed in the amount of calcium in their diets: One group had 1,200 to 1,300 mg of dairy (food-derived) calcium per day, another had 800 mg of supplemental calcium per day, and the third received no additional calcium. What do you suppose happened? The group that received 1,200 mg of dairy calcium lost 70 percent more weight than did the calcium-depleted group! And the group that consumed dairy products lost more weight than the group that got the same amount of calcium from supplements.

This tells us two very important things:

1. Calcium can help us lose weight.
2. There may be an as yet undiscovered factor in dairy foods that works with calcium to aid in fat breakdown.

Copyright © 2006 Jana Klauer, M.D.

Author

Jana Klauer, M.D., is on the medical advisory board at Equinox in New York City. She was also a research fellow at the New York Obesity Research Center of St. Luke's-Roosevelt Hospital and is actively involved in clinical research on obesity. She is in private practice in New York City, where she lives.

For more information, please visit www.janaklauermd.com .