Making Sense of Calcium
By Dr. Sherry Ross
Is calcium supplementation right for you? When people think about calcium levels in our body, most people think of what can go wrong: osteoporosis, hip fractures and bone and teeth weakness. It may be surprising to learn that over 98% of calcium in our body is stored and found in our bones. When other organ systems need calcium, it is released from the bones and distributed where it is needed. If too much calcium is removed from bones this creates bone loss, which can ultimately cause osteoporosis.
Most healthy people can skip calcium supplements unless they have a history of fractures, osteoporosis or vitamin D deficiency. The Institute of Medicine’s 2011 Report “Dietary Reference Intakes for Calcium and Vitamin D” found that most people get adequate amounts, with the exception of growing girls ages 9 to 18, who have higher requirements. This report also found that a number of postmenopausal women who took calcium supplements to protect against osteoporosis are probably receiving too much. The exception would be for those people over the age of 65 who are at risk for falls.
Scientists have discovered recently that taking high amounts of supplemental calcium can have side effects and cause health problems. A recent study by the U.S. Preventive Services Task Force now reports that taking calcium and vitamin D supplements does not reduce the risk of fractures in postmenopausal women. The findings of their investigation showed that taking up to 1,000mg a day of calcium supplements and up to 400 IU of vitamin D a day did nothing to prevent fractures in healthy people. It also showed that this amount of calcium could increase your risk of kidney stones. Additionally, there was insufficient evidence to recommend for or against the use of calcium supplements in premenopausal women and men.
Emerging research also suggests that calcium supplementation increases a person’s risk of heart attack. A 12-year study of close to 400,000 women and men, 50 to 71 years old, showed a 37% increase risk of heart disease death among the men, (and not the women), who took more than 1,000mg of calcium supplements a day. It’s important to note that when calcium was consumed from food sources, the hazardous cardiovascular event did not occur. Further research is needed to understand the cause of this dangerous side effect of calcium supplements for men.
In the United States, it has been estimated that the dietary intake of elemental calcium varies between 750 to 850 mg in women. Elemental calcium refers to the actual amount of calcium in a supplement. Ideally a woman wants to consume 1000 to 1200 mg of calcium per day. The best source of calcium is from food. If you drink one glass of milk or eat one cup of yogurt you would receive 300 mg of calcium. Adding a couple servings of fruit and green leafy vegetables would easily complete your daily calcium requirements.
Examples of dietary calcium:
- Plain low-fat yogurt, 8 ounces – 415 mg of calcium
- Mozzarella, part skim milk, 1.5 ounces – 333 mg of calcium
- Yogurt with fruit, 8 ounces – 384 mg of calcium
- Milk, nonfat, 8 ounces – 299 mg of calcium
- Milk, 2% low-fat, 1 cup – 293 mg of calcium
- Orange Juice, calcium-fortified, 6 ounces – 261 mg of calcium
- Cheddar cheese, 1.5 ounces – 307 mg of calcium
- Low-fat cottage cheese, 1 cup – 206 mg of calcium
- Kale, raw, chopped, 1 cup – 100 mg of calcium
- Ice cream, vanilla, ½ cup – 84 mg of calcium
- Chinese cabbage, bok choi, raw, shredded, 1 cup – 74 mg of calcium
- Broccoli, raw, ½ cup – 21 mg of calcium
Calcium is found as a dietary supplement in 2 forms. Calcium carbonate, the less expensive form, is found in antacids such as Tums, and is best absorbed when taken with food. 40% of calcium carbonate contains elemental calcium which is the active form of calcium. Calcium citrate, the more expensive form, can be easily absorbed on an empty or full stomach. Only 20% of calcium citrate contains elemental calcium. You need to consume twice as much, but it is easier to absorb. It is important to understand this concept when purchasing over the counter supplemental calcium. The serving size on the supplement panel will reflect the amount of elemental calcium that you are receiving so it’s important to understand exactly what you are taking and in what amounts. Side effects of supplemental calcium include intestinal bloating, gas and constipation.
There is growing evidence that for most healthy people your daily intake of calcium should come from food sources. Women need to learn the best ways to consume 1000 to 1200 mg of calcium per day to meet the recommended daily allowance. Until further research can be done to understand all the potential health risks, the use of calcium supplements are discouraged unless absolutely necessary. Consult with your health care provider to ensure you are consuming appropriate amounts of calcium from your diet and if you are a candidate for supplements.