The Importance of Calcium

I just took the exam to become a Certified Specialist in Sports Dietetics (results to be mailed in up to 8 weeks!) and one thing that I had to study about quite a bit was the importance of calcium for female athletes. Involved in growth, maintenance, and repair of bone tissue, maintenance of blood calcium levels, regulation of muscle contraction, nerve conduction, and normal blood clotting, calcium is actually an important mineral for everyone. Inadequate intake of calcium and vitamin D increases the risk of low-bone mineral density, stress factures, and eventually osteoporosis. Female athletes are at greatest risk for deficiency but studies have shown that most people do not get enough calcium in their diets.

The best food sources of calcium are milk and milk products such as yogurt and cheese, oysters, small fish (with bones) such as sardines, tofu, beans, and green vegetables such as broccoli and turnip greens. If it is not possible to meet your calcium needs from food alone then a supplement is recommended. Most multivitamins do not contain a lot of calcium because calcium is a bulky mineral so you will want to look for a calcium supplment in addition to your multivitamin.

Recommended Intakes:
The Dietary Reference Intake (DRI) for calcium is the same for women and men.
< 18 yrs old - 1300 mg/day
19-50 yrs old - 1000 mg/day
>51 yrs old - 1200 mg/day
For those with disordered eating, amenorrhea, and/or risk for early osteoporosis it is recommend to to consume 1500 mg/day.

So how does that convert to food? Below is the calcium content of some high calcium foods.
1 cup milk = 300 mg
1.5 oz cheddar cheese = 306 mg
1 cup broccoli = 94 mg
3 oz sardines = 324 mg
1 cup kidney beans = 61 mg
1 cup nonfat yogurt = 488 mg

Choosing a Supplment:

• As always when using supplements, make sure you choose a supplement that is third party tested for quality and purity. Look for a little stamp that says "USP" or "GMP" on the label.
• Make sure your calcium supplement contains vitamin D in addition to calcium (400-800 IU) as vitamin D helps with calcium absportion.
• Spread your dose throughout the day for better absorption. For example, if your supplement contains 1000 mg of calcium divide it into two 500 mg doses.
• Most supplements will be calcium citrate or calcium carbonate. Calcium carbonate needs stomach acid to be broken down so you will want to take a calcium carbonate supplement with meals. Calcium citrate does not need this and can be taken anytime, although some people experience nausea when taking supplements on an empty stomach.