Calcium is the most abundant mineral in the body with about 99% in bones. Inadequate calcium can lead to weak bones. Weak bones are more likely to break if a person falls.
Older people are more likely to fall—each year about one in three will have a fall. Broken bones in older people, especially broken hip bones, can lead to serious complications, even death.
But weak bones are not just a problem in older people. The problem starts much earlier, even in teenage. That’s because teenage is when inadequate calcium will impair the development of strong healthy bones. It can be hard to catch up in subsequent years, so weak bones may continue through adulthood. Then later, menopause in women or andropause in men happens, starting the inevitable loss of bone. People with strong healthy bones will lose some bone mass, but not enough to worry about. People with already weak bones will lose bone mass, often enough to put them at real risk for bone fractures with even gentle falls.
Who May Have Trouble Getting Enough Dietary Calcium?
Vegetarians. Dairy products are a major source of dietary calcium. Vegetarians who avoid all animal products (vegans) are at risk. Not only that, some vegetables interfere with calcium absorption, which may be a further problem for vegetarians. Vegetarians need to seek out calcium diligently. Note that early studies suggesting vegetarian diets were better for bone health have since been refuted—they are not.
Lactose Intolerants. Some people are born with inability to digest lactose in dairy products. Others develop the inability with age. Those with lactose intolerance usually avoid dairy products. (For some, drinking milk with meals limits symptoms and is tolerable. Some yogurts with live [active] cultures may aid digestion. Lactose reduced or lactose-free milk is available.) People with lactose intolerance are excellent candidates for calcium diet supplements.
Malabsorption. People with intestinal diseases that retard absorption may need extra calcium.
Female Athletes. Exercise in women athletes may lead to amenorrhea (absence of menstrual periods). Amenorrhea often leads to decreased estrogen which may lead to decreased calcium absorption or to increased calcium loss.
People who have low stomach acid, or who take pills to reduce stomach acid, and rely on calcium carbonate diet supplements. Calcium carbonate is less well absorbed if taken on an empty stomach with low acid.
How Much Calcium is Enough?
Dietary Reference Intakes (DRIs) are reference values for nutrition. There are three levels of DRI. Recommended Dietary Allowances (RDA) are based on enough scientific data to establish recommendations for dietary intake by age group. Adequate Intakes (AIs) are not based on as much data, but are believed to meet the amount needed to maintain adequate nutrition. Tolerable Upper Limit (UL) levels are those beyond which bad effects are more likely to occur.
There is no RDA for calcium. The AI (adequate intake) from the Institute of Medicine, widely used in the US, is 1000 mg each day for adults 19 to 50 years old, and 1200 mg each day for those older. Because many older people do not absorb calcium as well, some authorities suggest 1500 mg a day for people over 50. On the other hand, many experts would limit the intake for men to 1200 due to a possible increased risk of prostate cancer from higher doses.
Foods That Provide More Calcium
Most people get most of their calcium from dairy products, at least in the US. Indeed, dairy products are the best source—an eight ounce glass of non-fat milk provides 300 mg of calcium; eight ounces of plain low fat yogurt provides over 400 mg.
Some breakfast cereals are calcium fortified, and some provide up to 1000 mg in one cup. Similarly, fortified orange juice or soy beverage are good calcium sources. The amount of calcium per serving is always printed on the label.
Grains and, surprisingly, cream cheese are poor sources.
About $1 billion is spent annually for calcium supplements. Facts about supplements are described elsewhere.
Source: National Institutes of Health
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