Got Calcium?

Continued from our Retreat & Renew Daily Tip.

It’s no secret that calcium does a body good. This essential mineral has always had a stellar reputation for its ability to keep bones and teeth healthy. But strong pearly whites and unbreakable bones are not calcium’s only claims to fame. In fact, there seems to be no end to calcium’s reputed health-benefits. This so-called miracle mineral is also being hailed for its potential to promote weight loss, prevent cancer, and control high blood pressure. Is calcium the new secret to keeping slim and trim and fighting disease?

Boning Up

Calcium is the most abundant mineral in your body and the majority of it is stored in your bones and teeth where it functions to support their structure. The rest is circulating throughout your body where it helps perform such important functions as muscle contraction, the transmission of nerve impulses, and the activation of hormones and enzymes that regulate energy release, digestion, and metabolism.

A constant level of calcium is maintained in your body so it can perform these vital processes, and when your diet does not provide enough, your body simply takes as much calcium as it needs from your bones. This is where the trouble begins. Numerous studies show that not consuming enough calcium can drain the bones, making them porous and weak, ultimately leading to osteoporosis.

Osteoporosis affects more than 10 million Americans, 80 percent of whom are women, making bones fragile and more likely to fracture. Another 34 million suffer from osteopenia (low bone mass), the predecessor to osteoporosis. The loss of bone density, a serious health problem in the United States, is responsible for 1.5 million fractures every year. While these brittle-bone breaks may seem like a threat only to older people, the sooner you fight off this preventable disease, the healthier you’ll be. And one of your best weapons against osteoporosis is a diet rich in calcium.

The Skinny

You’ve probably seen the ads in magazines and on TV pushing dairy as the new weight-loss superstar. According to the ads, loading up on calcium-rich cheese, milk, and yogurt will make it easier for you to shed unwanted pounds and burn fat. Three small studies are the fuel behind this dairy marketing bonanza. The studies show that calcium-rich dairy products may help obese individuals, following reduced-calorie diets, lose extra weight. The studies also link higher calcium intakes from dairy foods to lower body weights and to less weight gain over time.

So should dieters break out the milk and start guzzling? Well, not exactly. Despite all the buzz, the studies are just too small to draw conclusive results, and other recent scientific trials have found that higher intakes of dairy products had absolutely no effect on weight or fat mass. The discrepancy in these studies makes it clear that the calcium and weight loss link is complex and not well understood.

The bottom line: Despite an aggressive ad campaign, larger clinical trials are needed to better determine the effects of calcium and dairy products on body weight.

The Cancer Connection

Our understanding of the cancer-calcium connection is still in its infancy, but the research is rapidly expanding.

For pre-menopausal women, the news about breast cancer and calcium just keeps getting better. In the Nurses’ Health Study, pre-menopausal women with higher calcium consumption developed about 30 percent less breast cancer than those who consumed very little. And recently researchers revealed that an increased intake of vitamin D and calcium could reduce a pre-menopausal woman’s risk of developing breast cancer by reducing the density of tissue in her breasts. (Research has shown that women with dense breasts are more likely to be diagnosed with breast cancer than women whose breasts are less dense.) More long-term studies are needed, but the news so far is certainly encouraging.

There’s also strong evidence suggesting that calcium and low-fat dairy foods may protect against colorectal cancer, a deadly disease that ranks second to lung cancer as the leading cause of cancer deaths. Studies suggest that increased intakes of dietary (low-fat dairy) and supplemental calcium are associated with a decreased risk of colon cancer and may guard against growths that become malignant in those prone to colorectal cancer.

On the flip side, higher calcium intakes are associated with the development of prostate cancer. However, the risk only seems to rise if a man’s calcium consumption exceeds 2,000 milligrams daily the equivalent of more than 11/2 quarts of milk.

Milk and More

The amount of calcium you need each day depends on your age and stage in life.

Shoot for 1,000 milligrams a day if you’re 50 and younger or 1,200 milligrams per day if you’re over 50. Women who are pregnant or nursing should aim to consume 1,300 milligrams a day.

It’s best to get the calcium you need from food, and most folks know to head straight to the dairy case to find the richest sources. Low-fat milk is a good place to start and its added vitamin D helps your body absorb the calcium. Other dairy products such as cheese, yogurt, and ice cream are also loaded with calcium; unfortunately they’re also loaded with artery-clogging saturated fat. To get the most calcium bang for your buck (and your heart) stick with low-fat choices.

Dairy not your thing? Lactose intolerant? Vegan? No need to fret, as cow’s milk is certainly not the sole source of calcium. In fact, food manufacturers are tripping over themselves to stock  supermarket  shelves  with  calcium-fortified alternatives. Calcium is finding its way into cereal bowls not only through milk, but also through calcium-fortified cereals. And a cup of calcium-fortified orange juice or milk substitute (soy, almond, rice, etc.) will supply you with as much calcium as an equal amount of cow’s milk. Just keep in mind that the amount of calcium in fortified foods varies from brand to brand. You’re best bet is to investigate.   

A product’s calcium content will be listed on the label as a percent of the Daily Value (DV). Since the current DV for calcium is 1,000 milligrams, you need to multiply the percent DV by 10 to calculate the amount of calcium (in milligrams) in one serving. For example, orange juice with 35 percent of the DV for calcium would have 350 milligrams of calcium in one serving.

Tofu can also be a good source of calcium, but the amount of calcium depends on the coagulating agent used to make the tofu. Look at the ingredient list and choose tofu processed with calcium sulfate. Other calcium-rich food sources include such green, leafy vegetables as kale, collards, and mustard greens, as well as dried peas and beans, and soybeans (see Calcium Counts).

If you don’t eat foods high in calcium, or do not get enough calcium from your diet for any reason, supplements are the way to go. But don’t go overboard; doses at 2,000 milligrams a day or more may increase your risk of prostate cancer, and even higher doses (more than 2,500 milligrams daily) can lead to constipation, kidney stones, and in extreme cases, kidney failure.

Calcium Counts

Food Source                                            Calcium (milligrams)

Total cereal fortified with calcium (1 cup)             1,000

Nonfat plain yogurt (1 cup)                                    450

Tofu, processed with calcium sulfate (1/2  cup)     435

Soy milk fortified with calcium (1 cup)                    370

Orange juice fortified with calcium (1 cup)             350

Milk, skim or 1% low fat (1 cup)                             300

Cottage cheese, 1% low fat (1 cup)                     140

Collards (1/2  cup cooked)                                   135

Soybeans (1/2 cup cooked)                                130

Navy beans (1/2 cup cooked)                               65

Mustard greens (1/2 cup cooked)                         50   

Broccoli or kale (1/2 cup cooked)                          45

Pinto beans or chickpeas (1/2 cup cooked)          40

Sources: Manufacturers and USDA Nutrient Database for Standard Reference.

By H.K. Jones, R.D.