Calcium is an important mineral with several essential functions in the body. Not only is it important for maintaining healthy bones and teeth, but it is also needed for muscle, blood vessel, and nerve function as well as hormone secretion.
Many people fall short of meeting the daily recommendations for calcium. In particular, teenage girls, women over age 50, and men and women over age 70 seem to be at higher risk for calcium deficiency. The daily recommendation for calcium intake in men and women ages 19-50 is 1,000 mg per day. Women over age 50 and both men and women over age 70 have higher recommendations, at 1,200 mg per day.
In general, it is better for our bodies to get calcium from foods, as it can be more easily absorbed this way. The best food sources of absorbable calcium are dairy products–things like low-fat milk, yogurt and cheese. But other foods can be fortified with calcium as well, like soy and almond milks, tofu, orange juice, breads and breakfast cereals. Additionally, calcium can be found in leafy green vegetables like broccoli, kale and spinach; however, the calcium in these types of vegetables is not as easily absorbed by the body.
Daily calcium recommendations can be met by eating 3 servings of dairy per day, as each dairy serving contains about 300 mg calcium. One serving of dairy is equal to 1 cup of milk, 6-8 oz yogurt or 1-1.5 oz cheese. Similarly, one serving of a calcium fortified product like almond or soy milk contains about 300 mg, depending on the product.
If you are finding it difficult to meet calcium requirements through your food, you might want to look into supplementation. The calcium in supplements comes in two main forms: 1) calcium carbonate, and 2) calcium citrate. Both forms are well-absorbed. However, in those with reduced levels of stomach acid, calcium citrate is more easily absorbed. Additionally, calcium citrate can be absorbed when taken with or without food, whereas calcium carbonate is more easily absorbed when taken with food.
To get the best calcium absorption from a supplement, you want to make sure that your supplement has no more than 500 mg of calcium per serving. So, if you were taking 1,000 mg of calcium per day, you would want to split that and take two 500 mg servings at different times in the day. Also, using a calcium supplement that includes vitamin D improves absorption, as vitamin D and calcium work closely together in the body. Some calcium supplements might also include magnesium, which is another important mineral in bone health.
There are a few things to watch out for, as these can increase our excretion of calcium, or in other words, make the body get rid of calcium instead of absorbing it:
- Meal plans high in sodium (try and keep sodium at recommended levels of less than 2,300 mg per day)
- Meal plans high in protein (follow the plate method for eating–1/2 plate fruits and vegetables, 1/4 plate whole grains and 1/4 plate lean proteins)
- High alcohol intake (moderation is one drink or less per day for women and two drinks or less per day for men)
- High caffeine intake (moderation is about 300 mg or less per day–see Emily’s recent blog post on Caffeine–click this link)
A word of caution for those using calcium supplements: excessive or too much calcium can cause health problems. High intake of calcium from supplements (not food) has been show to increase risk for kidney stones. If you are prone to kidney stones, you may want to check with your doctor before taking a calcium supplement. Calcium supplementation may also interfere with some medications.
Rachel Andrew MPH, RD, CD