From the American Dairy Council’s “Got Milk?” ads to your doctor’s office people are talking about calcium. So what’s the buzz on calcium?
Why Do I Need Calcium?
We all know calcium is the essential mineral in bones and teeth but calcium also plays a vital role in many of the body’s functions like muscle contraction and relaxation, blood clotting and nerve conduction.
When the diet does not include enough calcium to support these functions the body draws on the reservoir in the skeleton to maintain adequate tissue levels. Longterm, an inadequate calcium intake can lead to a thinning of the bones called osteoporosis, which increases bone fracture risk. The marked disability and even death which could be attributed to hip fractures in the elderly caused researchers to wake up to importance of maintaining bone health at all ages.
How Much Calcium Do I Need?
Calcium requirements change depending on age and metabolic needs.
Most HBS students in their 20’s and 30’s need about 1000mg per day of calcium. Those students who drink alcohol, smoke cigarettes, or take corticosteroid medication, for arthritis or asthma, may need more.
Don’t Women Need More Calcium Than Men?
The requirements for daily calcium intake are the same for men and women. Women do tend to have smaller skeletons than men and calcium absorption in women is contingent on estrogen. After menopause, women can lose bone mass. It is thus very important that women achieve as high a bone mass as they can while they are young.
Pregnancy, breast -feeding, amenorrhea, and anorexia can also result in loss of calcium from the skeleton.
Are There Any Consequences for Men of a Low Calcium Intake?
Despite their larger skeletons and calcium reserves as many as 20% of older men have osteoporosis and so are at risk for hip or back fractures.
So How Do I Get Calcium?
Its usually best to get calcium from food in your diet. Dairy items are the most concentrated source of calcium with each glass of milk, cup of yogurt, (or ice cream!) providing about 300mg of calcium. Lowfat dairy has the same amount of calcium as whole milk versions. Most milk is fortified with Vitamin D which also helps with calcium absorption.
What If I Don’t Like Milk or Am Lactose Intolerant?
There are forms of lactose free milk available. There are also calcium fortified juices, breads, and cereals. Most tofu contains calcium as do some legumes, nuts, leafy greens, and broccoli.
What About Supplements?
Calcium supplements come in several forms such as calcium carbonate, calcium lactate and calcium citrate. They differ in cost and sometimes in gastrointestinal effects such as gas formation or constipation. All are better absorbed when taken at mealtimes. They come in 200mg to 500mg sizes. Five hundred is the largest dose to be taken at once. Calcium “chews” are popular as are some antacid preparations. Multivitamins usually have only 150-200mg of calcium and so are not adequate as a total day’s supply.
What Else?
Exercise which causes large muscles to pull on their attachments to bones promotes calcium deposition at these sites. Vitamin D and Magnesium are also needed for optimal calcium absorption. Even with calcium and exercise though, the body needs good overall nutrition to build healthy bone.
And finally…your mother was right. DRINK YOUR MILK!
