What foods provide calcium?
Many foods have some calcium. You can get enough calcium by eating a variety of foods including milk, cheese, and yogurt; vegetables like kale, broccoli, and Chinese cabbage; and canned sardines and salmon with soft bones that you eat.
Calcium is added to some breakfast cereals, fruit juices, soy and rice beverages, and tofu (check the product labels).
What kinds of calcium dietary supplements are available?
Many multivitamin-mineral supplements have calcium. You can also buy calcium alone or together with vitamin D. If your supplement has calcium carbonate, you should take it with food. Calcium citrate costs more but you can take it on an empty stomach, and people older than 50 can absorb it more easily.
To absorb the most calcium from a supplement, don’t take more than 500 mg at once. So, for example, if you take 1,000 mg of calcium a day, split the dose in two and take them at separate times.
Calcium pills can cause gas, bloating, or constipation. If these occur, take smaller amounts at different times of the day, take the pills with meals, or try a different brand.
Am I getting enough calcium?
Most women, older men, and many other people don’t get enough calcium from food. After menopause especially, women need calcium and vitamin D to help keep their bones strong. Calcium-rich foods and supplements can help women get enough calcium.
Other people who might not get enough calcium include (1) vegetarians who avoid dairy foods, (2) people who are lactose intolerant (drinking milk upsets their stomach), (3) people with eating disorders, and (4) women who exercise so much that they stop having a monthly period. These people might need to take calcium supplements.
What happens if I don't get enough calcium?
Usually nothing obvious happens in the short run if you don’t get enough calcium. But over many years, not getting the amount of calcium you need can weaken your bones and make them break more easily.
What are some effects of calcium on health?
Scientists are studying calcium to see how it affects health. Here are a few examples of what this research has shown.
As people get older, their bones can become weak and break easily (a condition called osteoporosis). Foods and supplements with both calcium and vitamin D can help keep bones healthy. Talk to your health care provider about how much calcium and vitamin D you need to prevent or treat osteoporosis.
High blood pressure
Getting recommended amounts of calcium may lower blood pressure. If your blood pressure is high, eat plenty of low-fat and fat-free dairy products, vegetables, and fruits.
Scientists are studying whether recommended amounts of calcium might lower the chance of getting cancer of the colon and rectum. It’s too early to tell whether calcium intakes affect the risk of cancer.
Most kidney stones are not caused by too much or too little calcium. To reduce the risk of kidney stones, it's more important to drink enough liquids.
Can more calcium help you lose weight or body fat? Maybe, but the best studies so far have not shown that calcium helps much.
Can calcium be harmful?
In healthy children and adults, up to 2,500 mg of calcium a day is safe. High amounts of calcium in the blood can harm the kidneys, but this is almost always caused by diseases like cancer or taking very high amounts of vitamin D—not from calcium in foods or dietary supplements.
Are there any interactions with calcium that I should know about?
Some medicines (like some laxatives, antibiotics, and drugs to treat osteoporosis or thyroid disease) lower the amount of calcium the body absorbs. Other medicines (antacids with aluminum or magnesium, and mineral-oil laxatives) lower the amount of calcium in the body.