Best Sources of Calcium in Food

Milk, yogurt, and cheese are some of the best sources of calcium in food and are the major food bestower of this nutrient to people in the US.¹

Best sources of calcium (non dairy) in vegetables include, Chinese cabbage, kale, and broccoli.²

Grains do not contain a high amount of calcium, unless they are fortified; however, grains contribute calcium to the diet because they do contain small amounts of calcium and people consume them often.³ Foods fortified with calcium include many fruit juices and drinks, tofu, and cereals. Selected sources of calcium in food are listed in Table 2.

Table 2: Selected Sources of Calcium in Food^4 5 6

* DV = Daily Value. DVs were developed by the U.S. Food and Drug Administration to help consumers compare the nutrient contents among products within the context of a total daily diet. The DV for calcium is 1,000 mg for adults and children aged 4 and older. Foods providing 20% of more of the DV are considered to be high sources of a nutrient, but foods providing lower percentages of the DV also contribute to a healthful diet.

The U.S. Department of Agriculture’s Nutrient Database Web site http://www.nal.usda.gov/fnic/foodcomp/search lists the nutrient content of many foods. It also provides a comprehensive list of foods containing calcium at http://www.nal.usda.gov/fnic/foodcomp/Data/SR20/nutrlist/sr20a301.pdf.

** Calcium content varies slightly by fat content; the more fat, the less calcium the food contains.

*** Calcium content is for tofu processed with a calcium salt. Tofu processed with other salts does not provide significant amounts of calcium.

In its food guidance system, MyPyramid, the U.S. Department of Agriculture recommends that persons aged 9 years and older eat 3 cups of foods from the milk group per day.⁷ A cup is equal to 1 cup (8 ounces) of milk, 1 cup of yogurt, 1.5 ounces of natural cheese (such as Cheddar), or 2 ounces of processed cheese (such as American).

Dietary Supplements: Best Form Calcium Absorption

The two main forms of calcium in supplements are carbonate and citrate. Calcium carbonate is more commonly available and is both inexpensive and convenient. Both the carbonate and citrate forms are similarly well absorbed, but individuals with reduced levels of stomach acid can absorb calcium citrate more easily.

Other calcium forms in supplements or fortified foods include gluconate, lactate, and phosphate. Calcium citrate malate is a well-absorbed form of calcium found in some fortified juices.⁸ The body absorbs calcium carbonate most efficiently when the supplement is consumed with food, whereas the body can absorb calcium citrate equally effectively when the supplement is taken with or without food.⁹

Calcium supplements contain varying amounts of elemental calcium. For example, calcium carbonate is 40% calcium by weight, whereas calcium citrate is 21% calcium.

The percentage of calcium absorbed depends on the total amount of elemental calcium consumed at one time; as the amount increases, the percentage absorption decreases. Absorption is highest in doses ≤500 mg. So, for example, one who takes 1,000 mg/day of calcium from supplements might split the dose and take 500 mg at two separate times during the day.

Some individuals who take calcium supplements might experience gas, bloating, constipation, or a combination of these symptoms. Such symptoms can often be resolved by spreading out the calcium dose throughout the day, taking the supplement with meals, or changing the brand of supplement used.

Supplements & Healthful Diets: What is in the Food Pyramid?

According to the 2005 Dietary Guidelines for Americans, "nutrient needs should be met primarily through consuming foods." Foods provide an array of nutrients and other compounds that may have beneficial effects on health. In certain cases, fortified foods and dietary supplements may be useful sources of one or more nutrients that otherwise might be consumed in less than recommended amounts. However, dietary supplements, while recommended in some cases, cannot replace a healthful diet."

The Dietary Guidelines for Americans describe a healthy diet as one that:

• Emphasizes a variety of fruits, vegetables, whole grains, and fat-free or low-fat milk and milk products: Many dairy products, such as milk, cheese, and yogurt, are rich sources of calcium. Some vegetables provide significant amounts of calcium, as do some fortified cereals and juices.
• Includes lean meats, poultry, fish, beans, eggs, and nuts.
• Tofu made with calcium salts is a good source of calcium, as are canned sardines and salmon with soft bones.
• Is low in saturated fats, trans fats, cholesterol, salt (sodium), and added sugars. Low- and nonfat dairy products provide amounts of calcium that are roughly similar to the amounts in their full-fat versions.
• Stays within your daily calorie needs.

For more information about building a healthful diet, refer to the Dietary Guidelines for Americans and the U.S. Department of Agriculture's food guidance system, MyPyramid.

Medicines

Because of its ability to neutralize stomach acid, calcium carbonate is found in some over-the-counter antacid products, such as Tums® and Rolaids®. Depending on its strength, each chewable pill or softchew provides 200 to 400 mg of calcium. As noted above, calcium carbonate is an acceptable form of supplemental calcium, especially for individuals who have normal levels of stomach acid.