Calcium: Not just for bones anymore! - Yale-New Haven Hospital Nutrition Advisor

Not just for bones anymore!

Think of all of the reasons it is important to have calcium in your diet. The first thing that came to mind was probably your bones. Not only does this mineral aid in bone formation, it also plays a role in muscle and heart contraction, blood clotting and nerve transmission. Even more exciting is that recent studies suggest the calcium in dairy products may help in weight loss.

Calcium and weight gain or loss
Studies have shown the inverse relationship between body weight and calcium, meaning that a low calcium diet may actually promote weight gain.

Studies done on mice demonstrated this connection. When calories were restricted, greater fat loss was observed in the group of mice consuming a high calcium diet versus a low calcium diet because calcium may help in the breakdown of fat.

A low calcium diet stimulated fat stores and fastened weight gain, but a high calcium diet increased fat usage and slowed fat formation. The mice consuming the low calcium diet also had a lower body core temperature compared to the group on a high calcium diet resulting in increased fat storage.

Another study on women and bone health also revealed that “women who consumed lower amounts of calcium gained an average of nearly a pound a year by mid-life.” On the other hand, women who ate at least three servings of milk, cheese or yogurt daily experienced slight weight loss. These studies also suggested that dairy sources of calcium are more effective in weight and fat loss than fortified calcium food or supplements. Just another reason to include low-fat dairy products in your diet.

What's the connection?
Just how does calcium help in weight reduction? A possible rationale for the relationship between body weight and calcium is the effect calcium has on the body's energy metabolism.

When your calcium levels are low, a hormone called parathyroid hormone (PTH) and vitamin D increase in response to the low level of calcium. High levels of PTH and vitamin D are also seen during food shortage. In this starvation mode, your body will absorb and store more energy for later use.

Therefore, if your calcium levels are consistently low, the elevated levels of PTH and vitamin D may trick your body into thinking you are starving. As a result, you may store more energy in the form of fat and gain more weight.

Now that you have just learned one more benefit of eating calcium, the next step is getting enough calcium in your diet to meet your need.

How much calcium should you eat?
Aim for three servings of low-fat dairy foods a day. A serving equals one cup of milk or yogurt or one ounce of cheese. If dairy products don't agree with you, other calcium-rich foods include lactose-reduced products, dark green vegetables (such as broccoli and kale), Chinese cabbage and the edible bones of fish, like canned salmon.

If you are unable to meet your needs with these foods, try calcium-fortified products, like cereals and juices or consider taking a calcium supplement.

How much calcium do I need?

Life Stage	Dietary Reference Intakes (mg/day)
Infants
Birth—l6 months	210
7 months—1year	270
Children
1—3 years	500
4—8 years	800
Males
9—18 years	1,300
19—50 years	1,000
1,200
> 70 years	1,200
Females *
9—18	1,300
19—50 years	1,000
50—70 years	1,200
> 70 years	1,200
Pregnancy/Lactation	1,000

Take-home message
The bottom line is that calcium is important and not just for bones! So, be sure to aim for three servings of calcium-rich foods a day!

The Yale-New Haven Nutrition Advisor is created by registered dietitians and dietetic interns who staff the Nutrition Clinic at Yale-New Haven Hospital. For information, contact the Nutrition InfoLine at (203) 688-2422.

For more information on this topic, you could visit:

Calcium intake and body weight, Journal of Clinical Endocrinology & Metabolism, vol. 85, no. 12, 2000.
Mechanisms of dairy modulation of adiposity, Journal of Nutrition, vol. 133, January 2003.
Normalizing calcium intake: Projected population effects for body weight, Journal of Nutrition, vol. 133, January 2003.
Optimal calcium intake, Consensus Development Conference Statement, National Institutes of Health, June 6-8, 1994.
Test your calcium IQ, Association of Reproductive Health Professionals, November 5, 2002.
Press release: Fighting the battle of the bulge with a 1-2-3 punch, The National Dairy Council, March/April 2003.

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Last revised:March 10, 2005 (jj)