Boning Up On Calcium
Building Your Calcium Bank

By Patty Kirk, R.D., L.D.

For just a minute think of your bones as a tightly knit sweater. Dr. Sydney L. Bonnick, M.D., medical director of the Institute for Women's Health at Texas Women's University uses this analogy to describe osteoporosis, meaning "porous bones." 

From a distance, a sweater looks like a solid mass, but up close you can see an intricate system of interwoven fibers. When osteoporosis takes hold, it is as if the sweater is being unraveled, with the help of a few moths. The fibers loosen and pull apart, and holes form within the structure. This gradual weakening of the bone is what eventually leads to fractures.

The prevalence figures from the National Osteoporosis Foundation estimate 44 million men and women aged 50 and older have either low bone mass or osteoporosis. By the year 2020, that number will climb to an estimated 61 million if bone health does not become a top priority. Osteoporosis is usually preventable for most people. Currently, there are treatments for osteoporosis, but no cure.

No matter what your age, it is never too late to invest in your bone health. Adolescence is the prime time to build strong bones, and calcium is the key. Calcium is also needed to support many of our body's functions like managing blood pressure or maintaining heart beat. You can think of your bones as a bank account. The more calcium you deposit when you are young, the more you will have to draw from later in life. Your body will withdraw or take out the calcium banked in your bones if inadequate amounts are not included in your diet. As we age, if the bank is continuously overdrawn, bones can gradually become weak and fragile. Consider the adolescent years, your 20s and early 30s as your optimal window of opportunity to build your calcium bank account. Between the ages of 35 to 45, calcium withdrawals can increase. After 45 or menopause, bone loss accelerates due to a decrease in estrogen, and the need for calcium intake increases.

Since your skeletal calcium bank has to last through old age, we must make frequent deposits. The National Academy of Sciences advises women to consume between 1000 and 1300 milligrams of calcium a day. An expert panel representing the National Institutes of Health recommends calcium-rich foods, such as dairy products, as the preferred source of calcium. The rule of thumb is to focus on food first to get your calcium. A gold standard for getting calcium in your diet is milk. Milk not only supplies calcium, but also vitamin D, which helps your body absorb the calcium in food. You need the vitamin D and calcium partnership to keep your bones healthy. One-cup of nonfat milk or yogurt supplies approximately 300 milligrams of calcium. If you are lactose intolerant, use lactose-free milk as an alternative, such as Lactaid or Dairy Ease. These sources are also full of calcium. The inclusion of low-fat cheese to your diet can contribute 200 milligrams of calcium per ounce. And, for those of you who do not consume adequate amounts of dairy products daily, you still have the opportunity to include many calcium-rich foods in your diet due to fortification. Many foods that usually contain no calcium have been fortified to include this important mineral, which makes it easy to meet your calcium needs for the day. For example, one cup of calcium fortified orange juice, grapefruit juice, or V8 juice will have 300-400 milligrams of calcium. And, fortified soymilk, tofu, and cereals can also boost your calcium account. To evaluate whether a food contains calcium, start by reading food labels. If the food contains a 20 percent or greater amount of calcium per serving, it is considered a "high" or "excellent" source. The 20 percent translates to 200 milligrams of calcium per serving and a product with 30 percent equals 300 milligrams of calcium.

Besides getting calcium from food sources, you may be thinking about supplements. If you do not include dairy products or calcium fortified foods in your diet routinely, you probably are coming up short on your calcium needs. A supplement can be included for insurance. Calcium citrate or calcium carbonate supplements are your best choices. It is important to note the difference between these two supplement choices when it comes to food. Calcium carbonate supplements need to be taken with food because gastric acid is needed for the absorption of this form of calcium. Whereas, calcium citrate does not need this acidity and can be taken on an empty stomach. Another important factor is the body's ability to absorb calcium. Vitamin D helps to enhance calcium uptake into the bone. You can obtain vitamin D from fortified, nonfat milk and it is also produced in the body when exposed to ten minutes of sunlight per day. Some conditions that may limit vitamin D production include smoking, dark skin, living in northern areas with limited sunlight, and being homebound. Without adequate vitamin D, calcium absorption is reduced, which can lead to a loss of bone mass and weakening of skeletal structure. For convenience, you may want to choose a calcium supplement that contains vitamin D. However, if you are taking a multivitamin that already contains 400 IU of vitamin D, you do not need to take the additional vitamin D. An important factor to remember when taking a calcium supplement is that your body can only absorb 500 milligrams of calcium at one time. So Therefore, you need to divide your pills over several hours to obtain maximum benefit from supplementation.

To help close the calcium gap…

· Top cereal with milk or nonfat yogurt
· Make hot cereal with milk instead of water
· Melt low-fat cheese on whole wheat toast
· Make a fruit smoothie with frozen fruit and nonfat milk or yogurt
· Top a steaming, hot baked potato with nonfat yogurt or light 2 percent

  shredded cheese
· Make a cheese sauce with heated nonfat milk and 2 percent shredded

  cheese. Drizzle over steamed vegetables
· Make soups with milk instead of water
· Try a steaming cup of hot chocolate made with milk as a dessert or

  snack
· For a break have an iced mocha or latte instead of black coffee. A

  12-ounce drink can add 300 milligrams of calcium

Aside from calcium, here are some additional tips that will help you build your bones and keep them strong:

1.  Get moving: Regular weight-bearing activity helps stimulate bone

     formation. This type of activity includes walking, jogging, aerobic

    dancing, tennis, weight lifting and strength training. Even though

    swimming and biking are great forms of exercise, they do not build

    bones. Look for ways to increase steps in your everyday activities

    such as parking further away in the parking lot or taking the stairs. 

2. Avoid smoking: Although the connection between smoking and

    decreased bone density is not completely understood, there is a

    correlation between smoking and osteoporosis. 

3. Practice Moderation: Too much protein, alcohol, and sodium can

    adversely affect calcium absorption.


Bottom Line:
You never outgrow your need for calcium. In order for your bones to provide you with the support you need for a lifetime, you must support them by including ample calcium-containing foods as part of your daily diet, performing regular weight-bearing exercise and physical activity, and leading a healthy lifestyle.

References:
1. National Dairy Council, Thinking About Calcium? Find it in Food First. 1997.
2. National Dairy Council, Banking On Beautiful Bones. 1998.