by Deborah McInerney, MS, RD, CDN
In the past few years, more companies have begun adding calcium to packaged food and beverages. Maybe you’ve seen orange juice with calcium. You’ll also see calcium in cereals; in breakfast, granola, and sports bars; and in waffles, hot-chocolate mix, and even water. You may also notice that all types of milk (cow, soy, and rice) are higher in calcium per serving than they used to be, with amounts up to 500 mg of calcium per 8 ounces of liquid. It has never been easier to consume calcium-rich foods throughout the day, whether the calcium is naturally occurring or the food has been fortified with calcium.
Vitamin D up close. Often referred to as the “sunshine vitamin,” vitamin D is made in the skin through exposure to direct sunlight and is also present in some foods. Vitamin D helps your body absorb calcium. Although many people are able to get enough vitamin D through sunlight and food, some do not and need to take supplements. For example, older people and people with certain gastrointestinal disorders may have a reduced ability to absorb vitamin D from food. People who are housebound and those who live in northern latitudes during winter months may be vitamin D–deficient because of reduced exposure to the sun. Sunscreen, sun-protective clothing, cloudiness, and window glass that blocks sun can also prevent people from getting enough sun. (When wearing sunscreen, however, you can get enough sun as long as some part of your body gets about 10–15 minutes of sun 2–3 times a week.)
If you are concerned about how much vitamin D you get, make sure to consume some foods rich in vitamin D. These include fortified milk, fortified cereals, eggs, and fatty fish (mackerel, salmon, sardines).
Calcium and vitamin D supplements. If you’re not able to get enough calcium and vitamin D from food, think about supplements. The two most common forms of supplemental calcium in pill form are calcium citrate and calcium carbonate. Calcium citrate may be taken any time because it doesn’t require stomach acid for absorption. Calcium carbonate is more common than calcium citrate, but it needs stomach acid to be dissolved and absorbed and so is best taken with food. As we age, our stomachs produce less acid, making it more difficult to absorb calcium carbonate. Calcium citrate might be a better option for older adults. Whichever calcium supplement you choose to take, chances are it will also have vitamin D in it. If you don’t like or are unable to swallow pills, there are also calcium chews and liquid calcium. Just make sure you find a form you are able to tolerate and will actually take — there’s no sense buying one that sits in the cabinet.
When taking a calcium/vitamin D supplement, start slowly and drink plenty of fluids because calcium can cause constipation. It’s a good idea to start with 500 mg of calcium a day for a week to make sure you tolerate it without difficulty. If all goes well, increase the daily amount. Your body absorbs only about 500 mg of calcium at one time, so for your bones to get the maximum benefit, you should spread calcium sources (both foods and supplements) throughout the day.
There are many supplement brands on the market today. How are you supposed to choose a reputable one? Because supplements are considered a category of food, the U.S. Food and Drug Administration (FDA) does not regulate them. In other words, they are considered safe until proven otherwise. When choosing calcium supplements, avoid those made from oyster shell, dolomite, and bonemeal — they may contain lead or toxic metals. Look for the USP (United States Pharmacopeia) or NF (National Formulary) symbol on the label. These symbols indicate that the supplement has been tested to make sure it contains the ingredients listed on the label, that it is free of lead and other metals, and that it will dissolve in your stomach. To test a supplement’s dissolvability, you can simply drop it into a glass of clear vinegar, which is about as acidic as your stomach. Stir occasionally; if the pill disintegrates within 30 minutes, it should do so in your stomach as well.
Remember that too much of anything isn’t good for you. It is possible to consume too much calcium or vitamin D, though the danger is greater from excessive supplementation than from food. When taking supplemental calcium, do not exceed 2,000 mg a day or 2,500 mg from food and supplements combined. More than that may make it harder for your body to absorb zinc, iron, and magnesium. In any case, it is unlikely that you’d get extra benefit from taking more than 1,500 mg of calcium a day.
Vitamin D is a fat-soluble vitamin and is therefore stored with fat in the body. It can be toxic for infants up to 12 months of age to get more than 1,000 IU of vitamin D a day, or for all others (including pregnant and breast-feeding women) to get more than 2,000 IU. High levels of vitamin D in the body can lead to nausea, vomiting, poor appetite, constipation, weakness, weight loss, a confused mental state, and heart rhythm abnormalities. Always check with your doctor before taking a supplement — do not self-medicate!
Last Reviewed on June 18, 2010
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