Calcium in diet
Calcium is the most plentiful mineral found in the human body. The teeth and bones contain the most calcium. Nerve cells, body tissues, blood, and other body fluids contain the rest of the calcium.
Calcium is one of the most important minerals for the human body. It helps form and maintain healthy teeth and bones. A proper level of calcium in the body over a lifetime can help prevent osteoporosis.
Calcium helps your body with:
- Building strong bones and teeth
- Clotting blood
- Sending and receiving nerve signals
- Squeezing and relaxing muscles
- Releasing hormones and other chemicals
- Keeping a normal heartbeat
CALCIUM AND DAIRY PRODUCTS
Many foods contain calcium, but dairy products are the best source. Milk and dairy products such as yogurt, cheeses, and buttermilk contain a form of calcium that your body can easily absorb.
Whole milk (4% fat) is recommended for children ages 1 to 2. Most adults and children over age 2 should drink low-fat (2% or 1%) milk or skim milk and other dairy products. Removing the fat will not lower the amount of calcium in a dairy product.
- Yogurt, most cheeses, and buttermilk are excellent sources of calcium and come in low-fat or fat-free versions.
- Milk is also a good source of phosphorus and magnesium, which help the body absorb and use calcium.
- Vitamin D is needed to help your body use calcium. Milk is fortified with vitamin D for this reason.
OTHER SOURCES OF CALCIUM
Other sources of calcium that can help meet your body’s calcium needs include:
- Green leafy vegetables such as broccoli, collards, kale, mustard greens, turnip greens, and bok choy or Chinese cabbage
- Salmon and sardines canned with their soft bones
- Almonds, Brazil nuts, sunflower seeds, tahini, and dried beans
- Blackstrap molasses
Calcium is often added to food products. These include foods such as orange juice, soy milk, tofu, ready-to-eat cereals, and breads. These are a very good source of calcium for people who do not eat a lot of dairy products.
Ways to make sure you get enough calcium in your diet:
- Cook foods in a small amount of water for the shortest possible time to keep more calcium in the foods you eat. (This means steaming or sautéing to cook instead of boiling foods.)
- Be careful about the other foods you eat with calcium-rich foods. Certain fibers, such as wheat bran, and foods with oxalic acid (spinach and rhubarb) can bind with calcium and prevent it from being absorbed. This is why leafy greens are not considered an adequate source of calcium by themselves, because your body is unable to utilize much of the calcium they contain. People on a vegan diet need to be sure to also include soy products and fortified products in order to get enough calcium.
Calcium is also found in many multivitamin-mineral supplements. The amount varies, depending on the supplement. Dietary supplements may contain only calcium, or calcium with other nutrients such as vitamin D. Check the label on the Supplement Facts panel of the package to determine the amount of calcium in the supplement. Calcium absorption is best when taken in amounts of no more than 500 mg at a time.
Two commonly available forms of calcium dietary supplements include calcium citrate and calcium carbonate.
- Calcium citrate is the more expensive form of the supplement. It is taken up well by the body on a full or empty stomach.
- Calcium carbonate is less expensive. It is absorbed better by the body if taken with food. Calcium carbonate is found in over-the-counter antacid products such as Rolaids or Tums. Each chew or pill usually provides 200 to 400 mg of calcium. Check the label for the exact amount.
Other types of calcium in supplements and foods include calcium lactate, calcium gluconate, and calcium phosphate.
Increased calcium for a limited period of time does not normally cause side effects. However, receiving higher amounts of calcium over a long period of time raises the risk for kidney stones in some people.
Those who do not receive enough calcium over a long period of time can develop osteoporosis (thinning of bone tissue and loss of bone density over time). Other disorders are also possible.
People with lactose intolerance have trouble digesting lactose, the sugar in milk. For this reason, they are often at risk for calcium deficiency. However, over-the-counter products are available that make it easier to digest lactose. You can also buy lactose-free milk at most grocery stores. Most people who do not suffer from severe lactose-intolerance are still able to digest hard cheeses and yogurt.
Tell your health care provider about any dietary supplements and medicines you take. Your provider can tell you if those dietary supplements might interact or interfere with your prescription or over-the-counter medicines. In addition, some medicines might interfere with how your body absorbs calcium.
The preferred source of calcium is calcium-rich foods such as dairy products. Some people will need to take a calcium supplement. How much calcium you need depends on your age and sex. Other factors, such as pregnancy and illnesses, are also important.
Recommendations for calcium, as well as other nutrients, are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board at the National Academies of Sciences, Engineering, and Medicine. DRI is a term for a set of reference intakes that are used to plan and assess the nutrient intakes of healthy people. These values, which vary by age and sex, include:
- Recommended Dietary Allowance (RDA): The average daily level of intake that is enough to meet the nutrient needs of nearly all (97% to 98%) healthy people. An RDA is an intake level based on scientific research evidence.
- Adequate Intake (AI): This level is established when there is not enough scientific research evidence to develop an RDA. It is set at a level that is thought to ensure enough nutrition.
Dietary Reference Intakes for calcium:
- 0 to 6 months: 200 milligrams per day (mg/day)
- 7 to 12 months: 260 mg/day
Children and adolescents (RDA):
- Age 1 to 3: 700 mg/day
- Age 4 to 8: 1,000 mg/day
- Age 9 to 18: 1,300 mg/day
- Age 19 to 50: 1,000 mg/day
- Age 51 to 70: Men – 1,000 mg/day; Women – 1,200 mg/day
- Over age 71: 1,200 mg/day
Pregnancy and breastfeeding (RDA):
- Age 14 to 18: 1,300 mg/day
- Age 19 to 50: 1,000 mg/day
Up to 2,500 to 3,000 mg a day of calcium from dietary sources and supplements appears to be safe for children and adolescents, and 2,000 to 2,500 mg a day appears to be safe for adults.
The following list can help you determine roughly how much calcium you are getting from food:
- 8-ounce (240 milliliter) glass of milk = 300 mg of calcium
- 8 ounce (240 milliliter) glass of calcium-fortified soy milk = 300 mg calcium
- 1.5 ounces (42 grams) of cheese = 300 mg of calcium
- 6 ounces (168 grams) of yogurt = 300 mg of calcium
- 3 ounces (84 grams) of sardines with bones = 300 mg of calcium
- ½ cup (82 grams) of cooked turnip greens = 100 mg of calcium
- ¼ cup (23 grams) of almonds = 100 mg of calcium
- 1 cup (70 grams) of shredded bok choy = 74 mg of calcium
Vitamin D is needed to help the body absorb calcium. When choosing a calcium supplement, look for one that also contains vitamin D.
Calcium is a mineral in your body that is also found in many foods. Most of the calcium in your body is in your bones and teeth. There is also calcium in your blood, muscles, other body tissues, and the fluid between your cells.
Path to improved health
You need calcium to keep your bones and teeth healthy and strong throughout your life. Your body also uses calcium to:
- Help blood vessels and muscles work properly.
- Help release hormones and enzymes that keep your body working properly.
- Help your nerves carry messages throughout your body.
- Help control important nutrients, such as magnesium, phosphorus, and potassium.
Your body can’t make more calcium. So it’s important for you to provide it with the calcium it needs. The amount of calcium you need each day depends on your age, your sex, and other factors. For example, vitamin D improves calcium absorption. Alcohol reduces calcium absorption. Doctors recommend:
- Children ages 0-6 months: 200 milligrams (mg) per day.
- Children ages 6-12 months: 260 mg per day.
- Children ages 1-3: 700 mg per day
- Children ages 4-8: 1,000 mg per day
- Children ages 9-18: 1,300 mg per day
- Adults ages 19-50: 1,000 mg per day
- Adult men ages 51-70: 1,000 mg per day
- Adult women ages 51-70: 1,200 mg per day
- Adults ages 71 and older: 1,200 mg per day.
It’s best to spread your calcium throughout the day. Eat calcium-rich foods at every meal rather than all at once. Be sure to get enough vitamin D each day to help your body absorb the calcium.
Nonfat and low-fat dairy products (yogurt, cheese, and milk) are good sources of calcium. Vegetable sources of calcium include dried beans, kale, spinach, and collard greens. Animal sources of calcium include fish with soft bones, such as sardines and salmon. For example, 2 ounces of nonfat American cheese has 447 mg of calcium. One cup of skim milk has 299 mg of calcium. And 3 ounces of pink salmon has 183 mg of calcium. Some foods may be fortified with calcium (orange juice, bread, pasta, dry breakfast cereal, and dairy substitutes).
If you’re not getting enough calcium from dietary sources, talk to your doctor about a calcium supplement. Depending on your age, sex, overall health, and other factors, your doctor might recommend that you take a calcium supplement. Also, your doctor can tell you if a calcium supplement will affect any medical conditions you have. He or she will need to know about any prescription or over-the-counter (OTC) medicines, or other dietary supplements you are taking. Calcium supplements can affect the way certain medicines work. For example, calcium supplements can interfere with blood pressure and synthetic thyroid medicines, bisphosphonates, and antibiotics. Other supplements, such as iron, can affect how the body absorbs, uses, or gets rid of medicines or supplements.
There are 2 main types of calcium supplements: calcium carbonate and calcium citrate. Both types are available without a prescription. Over-the-counter calcium supplements are available in tablet, chewable, liquid, and powder form. Other types of calcium include calcium gluconate and calcium lactate. These contain less elemental calcium than calcium carbonate and calcium citrate.
If a supplement is right for you, your doctor will help you decide which one to take. He or she will also explain what amount of calcium to take each day and how to take the supplement. For example, calcium carbonate should be taken with meals to avoid possible unpleasant health effects (also called adverse effects). Taking it with meals helps your body to better absorb it. Calcium citrate can be taken on an empty stomach.
Things to consider
If your body doesn’t get enough calcium and vitamin D to support important functions, it takes calcium from your bones. This is called losing bone mass. Losing bone mass makes the inside of your bones become weak and porous. This puts you at risk for the bone disease osteoporosis.
Certain populations are at higher risk for low calcium levels, including:
- Postmenopausal women.
- People who have lactose intolerance and avoid dairy products.
- Women who have an eating disorder (for example, anorexia).
- People who do not eat animal, fish, or dairy products (vegans).
- People who take certain medicines for osteoporosis.
- People who have parathyroid disorders, inflammatory bowel disease, or liver or kidney disease.