Chromium is a mineral that humans require in trace amounts, although its mechanisms of action in the body and the amounts needed for optimal health are not well defined. It is found primarily in two forms: 1) trivalent (chromium 3+), which is biologically active and found in food, and 2) hexavalent (chromium 6+), a toxic form that results from industrial pollution. This fact sheet focuses exclusively on trivalent (3+) chromium.

Chromium is known to enhance the action of insulin [1-3], a hormone critical to the metabolism and storage of carbohydrate, fat, and protein in the body [4]. In 1957, a compound in brewers' yeast was found to prevent an age-related decline in the ability of rats to maintain normal levels of sugar (glucose) in their blood [3]. Chromium was identified as the active ingredient in this so-called "glucose tolerance factor" in 1959 [5].

Chromium also appears to be directly involved in carbohydrate, fat, and protein metabolism [1-2,6-11], but more research is needed to determine the full range of its roles in the body. The challenges to meeting this goal include:

    Defining the types of individuals who respond to chromium supplementation;
    Evaluating the chromium content of foods and its bioavailability;
    Determining if a clinically relevant chromium-deficiency state exists in humans due to inadequate dietary intakes; and
    Developing valid and reliable measures of chromium status [9].

Table of Contents

    Chromium: What is it?
    What foods provide chromium?
    What are recommended intakes of chromium?
    What affects chromium levels in the body?
    When can a chromium deficiency occur?
    Who may need extra chromium?
    What are some current issues and controversies about chromium?
    What are the health risks of too much chromium?
    Chromium and medication interactions
    Supplemental sources of chromium
    Chromium and Healthful Diets
    References
    Disclaimer

What foods provide chromium?

Chromium is widely distributed in the food supply, but most foods provide only small amounts (less than 2 micrograms [mcg] per serving). Meat and whole-grain products, as well as some fruits, vegetables, and spices are relatively good sources [12]. In contrast, foods high in simple sugars (like sucrose and fructose) are low in chromium [13].

Dietary intakes of chromium cannot be reliably determined because the content of the mineral in foods is substantially affected by agricultural and manufacturing processes and perhaps by contamination with chromium when the foods are analyzed [10,12,14]. Therefore, Table 1, and food-composition databases generally, provide approximate values of chromium in foods that should only serve as a guide.
Table 1: Selected food sources of chromium [12,15-16] Food     Chromium (mcg)
Broccoli, ½ cup     11
Grape juice, 1 cup     8
English muffin, whole wheat, 1     4
Potatoes, mashed, 1 cup     3
Garlic, dried, 1 teaspoon     3
Basil, dried, 1 tablespoon     2
Beef cubes, 3 ounces     2
Orange juice, 1 cup     2
Turkey breast, 3 ounces     2
Whole wheat bread, 2 slices     2
Red wine, 5 ounces     1–13
Apple, unpeeled, 1 medium     1
Banana, 1 medium     1
Green beans, ½ cup     1
What are recommended intakes of chromium?

Recommended chromium intakes are provided in the Dietary Reference Intakes (DRIs) developed by the Institute of Medicine of the National Academy of Sciences [14]. Dietary Reference Intakes is the general term for a set of reference values to plan and assess the nutrient intakes of healthy people. These values include the Recommended Dietary Allowance (RDA) and the Adequate Intake (AI). The RDA is the average daily intake that meets a nutrient requirement of nearly all (97 to 98%) healthy individuals [14]. An AI is established when there is insufficient research to establish an RDA; it is generally set at a level that healthy people typically consume.

In 1989, the National Academy of Sciences established an "estimated safe and adequate daily dietary intake" range for chromium. For adults and adolescents that range was 50 to 200 mcg [17]. In 2001, DRIs for chromium were established. The research base was insufficient to establish RDAs, so AIs were developed based on average intakes of chromium from food as found in several studies [14]. Chromium AIs are provided in Table 2.
Table 2: Adequate Intakes (AIs) for chromium [14] Age     Infants and children
(mcg/day)     Males
(mcg/day)     Females
(mcg/day)     Pregnancy
(mcg/day)     Lactation
(mcg/day)
0 to 6 months    0.2                   
7 to 12 months    5.5                   
1 to 3 years    11                   
4 to 8 years    15                   
9 to 13 years         25    21         
14 to 18 years         35    24    29    44
19 to 50 years         35    25    30    45
>50 years         30    20         

mcg = micrograms

Adult women in the United States consume about 23 to 29 mcg of chromium per day from food, which meets their AIs unless they're pregnant or lactating. In contrast, adult men average 39 to 54 mcg per day, which exceeds their AIs [14].

The average amount of chromium in the breast milk of healthy, well-nourished mothers is 0.24 mcg per quart, so infants exclusively fed breast milk obtain about 0.2 mcg (based on an estimated consumption of 0.82 quarts per day) [14]. Infant formula provides about 0.5 mcg of chromium per quart [18]. No studies have compared how well infants absorb and utilize chromium from human milk and formula [10,14].
What affects chromium levels in the body?

Absorption of chromium from the intestinal tract is low, ranging from less than 0.4% to 2.5% of the amount consumed [19-25], and the remainder is excreted in the feces [1,23]. Enhancing the mineral's absorption are vitamin C (found in fruits and vegetables and their juices) and the B vitamin niacin (found in meats, poultry, fish, and grain products) [26]. Absorbed chromium is stored in the liver, spleen, soft tissue, and bone [27].

The body's chromium content may be reduced under several conditions. Diets high in simple sugars (comprising more than 35% of calories) can increase chromium excretion in the urine [13]. Infection, acute exercise, pregnancy and lactation, and stressful states (such as physical trauma) increase chromium losses and can lead to deficiency, especially if chromium intakes are already low [28-29].
When can a chromium deficiency occur?

In the 1960s, chromium was found to correct glucose intolerance and insulin resistance in deficient animals, two indicators that the body is failing to properly control blood-sugar levels and which are precursors of type 2 diabetes [1]. However, reports of actual chromium deficiency in humans are rare. Three hospitalized patients who were fed intravenously showed signs of diabetes (including weight loss, neuropathy, and impaired glucose tolerance) until chromium was added to their feeding solution. The chromium, added at doses of 150 to 250 mcg/day for up to two weeks, corrected their diabetes symptoms [7,30-31]. Chromium is now routinely added to intravenous solutions.
Who may need extra chromium?

There are reports of significant age-related decreases in the chromium concentrations of hair, sweat and blood [32], which might suggest that older people are more vulnerable to chromium depletion than younger adults [14]. One cannot be sure, however, as chromium status is difficult to determine [33]. That's because blood, urine, and hair levels do not necessarily reflect body stores [9,14]. Furthermore, no chromium-specific enzyme or other biochemical marker has been found to reliably assess a person's chromium status [9,34].

There is considerable interest in the possibility that supplemental chromium may help to treat impaired glucose tolerance and type 2 diabetes, but the research to date is inconclusive. No large, randomized, controlled clinical trials testing this hypothesis have been reported in the United States [14]. Nevertheless, this is an active area of research.
What are some current issues and controversies about chromium?

Chromium has long been of interest for its possible connection to various health conditions. Among the most active areas of chromium research are its use in supplement form to treat diabetes, lower blood lipid levels, promote weight loss, and improve body composition.

Type 2 diabetes and glucose intolerance
In type 2 diabetes, the pancreas is usually producing enough insulin but, for unknown reasons, the body cannot use the insulin effectively. The disease typically occurs, in part, because the cells comprising muscle and other tissues become resistant to insulin's action, especially among the obese. Insulin permits the entry of glucose into most cells, where this sugar is used for energy, stored in the liver and muscles (as glycogen), and converted to fat when present in excess. Insulin resistance leads to higher than normal levels of glucose in the blood (hyperglycemia).

Chromium deficiency impairs the body's ability to use glucose to meet its energy needs and raises insulin requirements. It has therefore been suggested that chromium supplements might help to control type 2 diabetes or the glucose and insulin responses in persons at high risk of developing the disease. A review of randomized controlled clinical trials evaluated this hypothesis [35]. This meta-analysis assessed the effects of chromium supplements on three markers of diabetes in the blood: glucose, insulin, and glycated hemoglobin (which provides a measure of long-term glucose levels; also known as hemoglobin A1C). It summarized data from 15 trials on 618 participants, of which 425 were in good health or had impaired glucose tolerance and 193 had type 2 diabetes. Chromium supplementation had no effect on glucose or insulin concentrations in subjects without diabetes nor did it reduce these levels in subjects with diabetes, except in one study. However, that study, conducted in China (in which 155 subjects with diabetes were given either 200 or 1,000 mcg/day of chromium or a placebo) might simply show the benefits of supplementation in a chromium-deficient population.

Overall, the value of chromium supplements for diabetes is inconclusive and controversial [36]. Randomized controlled clinical trials in well-defined, at-risk populations where dietary intakes are known are necessary to determine the effects of chromium on markers of diabetes [35]. The American Diabetes Association states that there is insufficient evidence to support the routine use of chromium to improve glycemic control in people with diabetes [37]. It further notes that there is no clear scientific evidence that vitamin and mineral supplementation benefits people with diabetes who do not have underlying nutritional deficiencies.

Lipid metabolism
The effects of chromium supplementation on blood lipid levels in humans are also inconclusive [1,8,38]. In some studies, 150 to 1,000 mcg/day has decreased total and low-density-lipoprotein (LDL or "bad") cholesterol and triglyceride levels and increased concentrations of apolipoprotein A (a component of high-density-lipoprotein cholesterol known as HDL or "good" cholesterol) in subjects with atherosclerosis or elevated cholesterol or among those taking a beta-blocker drug [39-41]. These findings are consistent with the results of earlier studies [42-45].

However, chromium supplements have shown no favorable effects on blood lipids in other studies [46-51]. The mixed research findings may be due to difficulties in determining the chromium status of subjects at the start of the trials and the researchers' failure to control for dietary factors that influence blood lipid levels [9-10].

Body weight and composition
Chromium supplements are sometimes claimed to reduce body fat and increase lean (muscle) mass. Yet a recent review of 24 studies that examined the effects of 200 to 1,000 mcg/day of chromium (in the form of chromium picolinate) on body mass or composition found no significant benefits [11]. Another recent review of randomized, controlled clinical trials did find supplements of chromium picolinate to help with weight loss when compared wtth placebos, but the differences were small and of debatable clinical relevance [52]. In several studies, chromium's effects on body weight and composition may be called into question because the researchers failed to adequately control for the participants' food intakes. Furthermore, most studies included only a small number of subjects and were of short duration [36].
What are the health risks of too much chromium?

Few serious adverse effects have been linked to high intakes of chromium, so the Institute of Medicine has not established a Tolerable Upper Intake Level (UL) for this mineral [10,14]. A UL is the maximum daily intake of a nutrient that is unlikely to cause adverse health effects. It is one of the values (together with the RDA and AI) that comprise the Dietary Reference Intakes (DRIs) for each nutrient.
Chromium and medication interactions

Certain medications may interact with chromium, especially when taken on a regular basis (see Table 3). Before taking dietary supplements, check with your doctor or other qualified healthcare provider, especially if you take prescription or over-the-counter medications.
Table 3: Interactions between chromium and medications [14,53-55] Medications     Nature of interaction

    Antacids
    Corticosteroids
    H2 blockers (such as cimetidine, famotidine, nizatidine, and rantidine)
    Proton-pump inhibitors (such as omeprazole, lansoprazole, rabeprazole, pantoprazole, and esomeprazole)

    These medications alter stomach acidity and may impair chromium absorption or enhance excretion

    Beta-blockers (such as atenolol or propanolol)
    Corticosteroids
    Insulin
    Nicotinic acid
    Nonsteroidal anti-inflammatory drugs (NSAIDS)
    Prostaglandin inhibitors (such as ibuprofen, indomethacin, naproxen, piroxicam, and aspirin)

    These medications may have their effects enhanced if taken together with chromium or they may increase chromium absorption
Supplemental sources of chromium

Chromium is a widely used supplement. Estimated sales to consumers were $85 million in 2002, representing 5.6% of the total mineral-supplement market [56]. Chromium is sold as a single-ingredient supplement as well as in combination formulas, particularly those marketed for weight loss and performance enhancement. Supplement doses typically range from 50 to 200 mcg.

The safety and efficacy of chromium supplements need more investigation. Please consult with a doctor or other trained healthcare professional before taking any dietary supplements.

Chromium supplements are available as chromium chloride, chromium nicotinate, chromium picolinate, high-chromium yeast, and chromium citrate. Chromium chloride in particular appears to have poor bioavailability [36]. However, given the limited data on chromium absorption in humans, it is not clear which forms are best to take.
Chromium and Healthful Diets

The federal government's 2010 Dietary Guidelines for Americans notes that "nutrients should come primarily from foods. Foods in nutrient-dense, mostly intact forms contain not only the essential vitamins and minerals that are often contained in nutrient supplements, but also dietary fiber and other naturally occurring substances that may have positive health effects. ...Dietary supplements...may be advantageous in specific situations to increase intake of a specific vitamin or mineral."

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

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

    Emphasizes a variety of fruits, vegetables, whole grains, and fat-free or low-fat milk and milk products.

        Whole grain products and certain fruits and vegetables like broccoli, potatoes, grape juice, and oranges are sources of chromium. Ready-to-eat bran cereals can also be a relatively good source of chromium.

    Includes lean meats, poultry, fish, beans, eggs, and nuts.

        Lean beef, oysters, eggs, and turkey are sources of chromium.

    Is low in saturated fats, trans fats, cholesterol, salt (sodium), and added sugars.
    Stays within your daily calorie needs.

References

    Mertz W. Chromium occurrence and function in biological systems. Physiol Rev 1969;49:163-239.
    Mertz W. Chromium in human nutrition: a review. J Nutr 1993;123:626-33.
    Mertz W. Interaction of chromium with insulin: a progress report. Nutr Rev 1998;56:174-7.
    Porte Jr. D, Sherwin RS, Baron A (editors). Ellengerg & Rifkin's Diabetes Mellitus, 6th Edition. McGraw-Hill, New York, 2003.
    Schwarz K, Mertz W. Chromium(III) and the glucose tolerance factor. Arch Biochem Biophys 1959;85:292-5.

What is vitamin D and what does it do?

Vitamin D is a nutrient found in some foods that is needed for health and to maintain strong bones. It does so by helping the body absorb calcium (one of bone's main building blocks) from food and supplements. People who get too little vitamin D may develop soft, thin, and brittle bones, a condition known as rickets in children and osteomalacia in adults.

Vitamin D is important to the body in many other ways as well. Muscles need it to move, for example, nerves need it to carry messages between the brain and every body part, and the immune system needs vitamin D to fight off invading bacteria and viruses. Together with calcium, vitamin D also helps protect older adults from osteoporosis. Vitamin D is found in cells throughout the body.
Table of Contents

    What is vitamin D and what does it do?
    How much vitamin D do I need?
    What foods provide vitamin D?
    Can I get vitamin D from the sun?
    What kinds of vitamin D dietary supplements are available?
    Am I getting enough vitamin D?
    What happens if I don't get enough vitamin D?
    What are some effects of vitamin D on health?
    Can vitamin D be harmful?
    Are there any interactions with vitamin D that I should know about?
    Vitamin D and healthful eating
    Where can I find out more about vitamin D?
    Disclaimer

How much vitamin D do I need?

The amount of vitamin D you need each day depends on your age. Average daily recommended amounts from the Food and Nutrition Board (a national group of experts) for different ages are listed below in International Units (IU):
Life Stage     Recommended Amount
Birth to 12 months    400 IU
Children 1–13 years    600 IU
Teens 14–18 years    600 IU
Adults 19–70 years    600 IU
Adults 71 years and older    800 IU
Pregnant and breastfeeding women    600 IU
What foods provide vitamin D?

Very few foods naturally have vitamin D. Fortified foods provide most of the vitamin D in American diets.

    Fatty fish such as salmon, tuna, and mackerel are among the best sources.
    Beef liver, cheese, and egg yolks provide small amounts.
    Mushrooms provide some vitamin D. In some mushrooms that are newly available in stores, the vitamin D content is being boosted by exposing these mushrooms to ultraviolet light.
    Almost all of the U.S. milk supply is fortified with 400 IU of vitamin D per quart. But foods made from milk, like cheese and ice cream, are usually not fortified.
    Vitamin D is added to many breakfast cereals and to some brands of orange juice, yogurt, margarine, and soy beverages; check the labels.

Can I get vitamin D from the sun?

The body makes vitamin D when skin is directly exposed to the sun, and most people meet at least some of their vitamin D needs this way. Skin exposed to sunshine indoors through a window will not produce vitamin D. Cloudy days, shade, and having dark-colored skin also cut down on the amount of vitamin D the skin makes.

However, despite the importance of the sun to vitamin D synthesis, it is prudent to limit exposure of skin to sunlight in order to lower the risk for skin cancer. When out in the sun for more than a few minutes, wear protective clothing and apply sunscreen with an SPF (sun protection factor) of 8 or more. Tanning beds also cause the skin to make vitamin D, but pose similar risks for skin cancer.

People who avoid the sun or who cover their bodies with sunscreen or clothing should include good sources of vitamin D in their diets or take a supplement. Recommended intakes of vitamin D are set on the assumption of little sun exposure.
What kinds of vitamin D dietary supplements are available?

Vitamin D is found in supplements (and fortified foods) in two different forms: D2 (ergocalciferol) and D3 (cholecalciferol). Both increase vitamin D in the blood.
Am I getting enough vitamin D?

Because vitamin D can come from sun, food, and supplements, the best measure of one's vitamin D status is blood levels of a form known as 25-hydroxyvitamin D. Levels are described in either nanomoles per liter (nmol/L) or nanograms per milliliter (ng/mL), where 1 nmol/L = 0.4 ng/mL.

In general, levels below 30 nmol/L (12 ng/mL) are too low for bone or overall health, and levels above 125 nmol/L (50 ng/mL) are probably too high. Levels of 50 nmol/L or above (20 ng/mL or above) are sufficient for most people.

By these measures, some Americans are vitamin D deficient and almost no one has levels that are too high. In general, young people have higher blood levels of 25-hydroxyvitamin D than older people and males have higher levels than females. By race, non-Hispanic blacks tend to have the lowest levels and non-Hispanic whites the highest. The majority of Americans have blood levels lower than 75 nmol/L (30 ng/mL).

Certain other groups may not get enough vitamin D:

    Breastfed infants, since human milk is a poor source of the nutrient. Breastfed infants should be given a supplement of 400 IU of vitamin D each day.
    Older adults, since their skin doesn't make vitamin D when exposed to sunlight as efficiently as when they were young, and their kidneys are less able to convert vitamin D to its active form.
    People with dark skin, because their skin has less ability to produce vitamin D from the sun.
    People with disorders such as Crohn's disease or celiac disease who don't handle fat properly, because vitamin D needs fat to be absorbed.
    Obese people, because their body fat binds to some vitamin D and prevents it from getting into the blood.

What happens if I don't get enough vitamin D?

People can become deficient in vitamin D because they don't consume enough or absorb enough from food, their exposure to sunlight is limited, or their kidneys cannot convert vitamin D to its active form in the body. In children, vitamin D deficiency causes rickets, where the bones become soft and bend. It's a rare disease but still occurs, especially among African American infants and children. In adults, vitamin D deficiency leads to osteomalacia, causing bone pain and muscle weakness.
What are some effects of vitamin D on health?

Vitamin D is being studied for its possible connections to several diseases and medical problems, including diabetes, hypertension, and autoimmune conditions such as multiple sclerosis. Two of them discussed below are bone disorders and some types of cancer.

Bone disorders
As they get older, millions of people (mostly women, but men too) develop, or are at risk of, osteoporosis, where bones become fragile and may fracture if one falls. It is one consequence of not getting enough calcium and vitamin D over the long term. Supplements of both vitamin D3 (at 700–800 IU/day) and calcium (500–1,200 mg/day) have been shown to reduce the risk of bone loss and fractures in elderly people aged 62–85 years. Men and women should talk with their health care providers about their needs for vitamin D (and calcium) as part of an overall plan to prevent or treat osteoporosis.

Cancer
Some studies suggest that vitamin D may protect against colon cancer and perhaps even cancers of the prostate and breast. But higher levels of vitamin D in the blood have also been linked to higher rates of pancreatic cancer. At this time, it's too early to say whether low vitamin D status increases cancer risk and whether higher levels protect or even increase risk in some people.
Can vitamin D be harmful?

Yes, when amounts in the blood become too high. Signs of toxicity include nausea, vomiting, poor appetite, constipation, weakness, and weight loss. And by raising blood levels of calcium, too much vitamin D can cause confusion, disorientation, and problems with heart rhythm. Excess vitamin D can also damage the kidneys.

The safe upper limit for vitamin D is 1,000 to 1,500 IU/day for infants, 2,500 to 3,000 IU/day for children 1-8 years, and 4,000 IU/day for children 9 years and older, adults, and pregnant and lactating teens and women. Vitamin D toxicity almost always occurs from overuse of supplements. Excessive sun exposure doesn't cause vitamin D poisoning because the body limits the amount of this vitamin it produces.
Are there any interactions with vitamin D that I should know about?

Like most dietary supplements, vitamin D may interact or interfere with other medicines or supplements you might be taking. Here are several examples:

    Prednisone and other corticosteroid medicines to reduce inflammation impair how the body handles vitamin D, which leads to lower calcium absorption and loss of bone over time.
    Both the weight-loss drug orlistat (brand names Xenical® and Alli®) and the cholesterol-lowering drug cholestyramine (brand names Questran®, LoCholest®, and Prevalite®) can reduce the absorption of vitamin D and other fat-soluble vitamins (A, E, and K).
    Both phenobarbital and phenytoin (brand name Dilantin®), used to prevent and control epileptic seizures, increase the breakdown of vitamin D and reduce calcium absorption.

Tell your doctor, pharmacist, and other health care providers about any dietary supplements and medicines you take. They can tell you if those dietary supplements might interact or interfere with your prescription or over-the-counter medicines, or if the medicines might interfere with how your body absorbs, uses, or breaks down nutrients.
Vitamin D and healthful eating

People should get most of their nutrients from food, advises the federal government's Dietary Guidelines for Americans. Foods contain vitamins, minerals, dietary fiber and other substances that benefit health. Dietary supplements might help in some situations to increase the intake of a specific vitamin or mineral. For more information on building a healthy diet, refer to the Dietary Guidelines for Americansexternal link icon and the U.S. Department of Agriculture's food guidance system, ChooseMyPlateexternal link icon.

Calcium is a mineral found in many foods. The body needs calcium to maintain strong bones and to carry out many important functions. Almost all calcium is stored in bones and teeth, where it supports their structure and hardness.

The body also needs calcium for muscles to move and for nerves to carry messages between the brain and every body part. In addition, calcium is used to help blood vessels move blood throughout the body and to help release hormones and enzymes that affect almost every function in the human body.
Table of Contents

    What is calcium and what does it do?
    How much calcium do I need?
    What foods provide calcium?
    What kinds of calcium dietary supplements are available?
    Am I getting enough calcium?
    What happens if I don't get enough calcium?
    What are some effects of calcium on health?
    Can calcium be harmful?
    Are there any interactions with calcium that I should know about?
    Calcium and healthful eating
    Where can I find out more about calcium?
    Disclaimer

How much calcium do I need?

The amount of calcium you need each day depends on your age. Average daily recommended amounts are listed below in milligrams (mg):
Life Stage     Recommended Amount
Birth to 6 months    200 mg
Infants 7–12 months    260 mg
Children 1–3 years    700 mg
Children 4–8 years    1,000 mg
Children 9–13 years    1,300 mg
Teens 14–18 years    1,300 mg
Adults 19–50 years    1,000 mg
Adult men 51–70 years    1,000 mg
Adult women 51–70 years    1,200 mg
Adults 71 years and older    1,200 mg
Pregnant and breastfeeding teens    1,300 mg
Pregnant and breastfeeding adults    1,000 mg
What foods provide calcium?

Calcium is found in many foods. You can get recommended amounts of calcium by eating a variety of foods, including the following:

    Milk, yogurt, and cheese are the main food sources of calcium for the majority of people in the United States.
    Kale, broccoli, and Chinese cabbage are fine vegetable sources of calcium.
    Fish with soft bones that you eat, such as canned sardines and salmon, are fine animal sources of calcium.
    Most grains (such as breads, pastas, and unfortified cereals), while not rich in calcium, add significant amounts of calcium to the diet because people eat them often or in large amounts.
    Calcium is added to some breakfast cereals, fruit juices, soy and rice beverages, and tofu. To find out whether these foods have calcium, check the product labels.

What kinds of calcium dietary supplements are available?

Calcium is found in many multivitamin-mineral supplements, though the amount varies by product. Dietary supplements that contain only calcium or calcium with other nutrients such as vitamin D are also available. Check the Supplement Facts label to determine the amount of calcium provided.

The two main forms of calcium dietary supplements are carbonate and citrate. Calcium carbonate is inexpensive, but is absorbed best when taken with food. Some over-the-counter antacid products, such as Tums® and Rolaids®, contain calcium carbonate. Each pill or chew provides 200–400 mg of calcium. Calcium citrate, a more expensive form of the supplement, is absorbed well on an empty or a full stomach. In addition, people with low levels of stomach acid (a condition more common in people older than 50) absorb calcium citrate more easily than calcium carbonate. Other forms of calcium in supplements and fortified foods include gluconate, lactate, and phosphate.

Calcium absorption is best when a person consumes no more than 500 mg at one time. So a person who takes 1,000 mg/day of calcium from supplements, for example, should split the dose rather than take it all at once.

Calcium supplements may cause gas, bloating, and constipation in some people. If any of these symptoms occur, try spreading out the calcium dose throughout the day, taking the supplement with meals, or changing the supplement brand or calcium form you take.
Am I getting enough calcium?

Many people don't get recommended amounts of calcium from the foods they eat, including:

    Boys aged 9 to 13 years,
    Girls aged 9 to 18 years,
    Women older than 50 years,
    Men older than 70 years.

When total intakes from both food and supplements are considered, many people—particularly adolescent girls—still fall short of getting enough calcium, while some older women likely get more than the safe upper limit. See our Health Professional Fact Sheet on Calcium for more details.

Certain groups of people are more likely than others to have trouble getting enough calcium:

    Postmenopausal women because they experience greater bone loss and do not absorb calcium as well. Sufficient calcium intake from food, and supplements if needed, can slow the rate of bone loss.
    Women of childbearing age whose menstrual periods stop (amenorrhea) because they exercise heavily, eat too little, or both. They need sufficient calcium to cope with the resulting decreased calcium absorption, increased calcium losses in the urine, and slowdown in the formation of new bone.
    People with lactose intolerance cannot digest this natural sugar found in milk and experience symptoms like bloating, gas, and diarrhea when they drink more than small amounts at a time. They usually can eat other calcium-rich dairy products that are low in lactose, such as yogurt and many cheeses, and drink lactose-reduced or lactose-free milk.
    Vegans (vegetarians who eat no animal products) and ovo-vegetarians (vegetarians who eat eggs but no dairy products), because they avoid the dairy products that are a major source of calcium in other people's diets.

Many factors can affect the amount of calcium absorbed from the digestive tract, including:

    Age. Efficiency of calcium absorption decreases as people age. Recommended calcium intakes are higher for people over age 70.
    Vitamin D intake. This vitamin, present in some foods and produced in the body when skin is exposed to sunlight, increases calcium absorption.
    Other components in food. Both oxalic acid (in some vegetables and beans) and phytic acid (in whole grains) can reduce calcium absorption. People who eat a variety of foods don't have to consider these factors. They are accounted for in the calcium recommended intakes, which take absorption into account.

Many factors can also affect how much calcium the body eliminates in urine, feces, and sweat. These include consumption of alcohol- and caffeine-containing beverages as well as intake of other nutrients (protein, sodium, potassium, and phosphorus). In most people, these factors have little effect on calcium status.
What happens if I don't get enough calcium?

Insufficient intakes of calcium do not produce obvious symptoms in the short term because the body maintains calcium levels in the blood by taking it from bone. Over the long term, intakes of calcium below recommended levels have health consequences, such as causing low bone mass (osteopenia) and increasing the risks of osteoporosis and bone fractures.

Symptoms of serious calcium deficiency include numbness and tingling in the fingers, convulsions, and abnormal heart rhythms that can lead to death if not corrected. These symptoms occur almost always in people with serious health problems or who are undergoing certain medical treatments.
What are some effects of calcium on health?

Scientists are studying calcium to understand how it affects health. Here are several examples of what this research has shown:

Bone health and osteoporosis
Bones need plenty of calcium and vitamin D throughout childhood and adolescence to reach their peak strength and calcium content by about age 30. After that, bones slowly lose calcium, but people can help reduce these losses by getting recommended amounts of calcium throughout adulthood and by having a healthy, active lifestyle that includes weight-bearing physical activity (such as walking and running).

Osteoporosis is a disease of the bones in older adults (especially women) in which the bones become porous, fragile, and more prone to fracture. Osteoporosis is a serious public health problem for more than 10 million adults over the age of 50 in the United States. Adequate calcium and vitamin D intakes as well as regular exercise are essential to keep bones healthy throughout life.

Cardiovascular Disease
Whether calcium affects the risk of cardiovascular disease is not clear. Some studies show that getting enough calcium might protect people from heart disease and stroke. But other studies show that some people who consume high amounts of calcium, particularly from supplements, might have an increased risk of heart disease. More research is needed in this area.

High blood pressure
Some studies have found that getting recommended intakes of calcium can reduce the risk of developing high blood pressure (hypertension). One large study in particular found that eating a diet high in fat-free and low-fat dairy products, vegetables, and fruits lowered blood pressure.

Cancer
Studies have examined whether calcium supplements or diets high in calcium might lower the risks of developing cancer of the colon or rectum or increase the risk of prostate cancer. The research to date provides no clear answers. Given that cancer develops over many years, longer term studies are needed.

Kidney stones
Most kidney stones are rich in calcium oxalate. Some studies have found that higher intakes of calcium from dietary supplements are linked to a greater risk of kidney stones, especially among older adults. But calcium from foods does not appear to cause kidney stones. For most people, other factors (such as not drinking enough fluids) probably have a larger effect on the risk of kidney stones than calcium intake.

Weight loss
Although several studies have shown that getting more calcium helps lower body weight or reduce weight gain over time, most studies have found that calcium—from foods or dietary supplements—has little if any effect on body weight and amount of body fat.
Can calcium be harmful?

Getting too much calcium can cause constipation. It might also interfere with the body's ability to absorb iron and zinc, but this effect is not well established. In adults, too much calcium (from dietary supplements but not food) might increase the risk of kidney stones. Some studies show that people who consume high amounts of calcium might have increased risks of prostate cancer and heart disease, but more research is needed to understand these possible links.

The safe upper limits for calcium are listed below. Most people do not get amounts above the upper limits from food alone; excess intakes usually come from the use of calcium supplements. Surveys show that some older women in the United States probably get amounts somewhat above the upper limit since the use of calcium supplements is common among these women.
Life Stage     Upper Safe Limit
Birth to 6 months    1,000 mg
Infants 7–12 months    1,500 mg
Children 1–8 years    2,500 mg
Children 9–18 years    3,000 mg
Adults 19–50 years    2,500 mg
Adults 51 years and older    2,000 mg
Pregnant and breastfeeding teens    3,000 mg
Pregnant and breastfeeding adults    2,500 mg
Are there any interactions with calcium that I should know about?

Calcium dietary supplements can interact or interfere with certain medicines that you take, and some medicines can lower or raise calcium levels in the body. Here are some examples:

    Calcium can reduce the absorption of these drugs when taken together:
        Bisphosphonates (to treat osteoporosis)
        Antibiotics of the fluoroquinolone and tetracycline families
        Levothyroxine (to treat low thyroid activity)
        Phenytoin (an anticonvulsant)
        Tiludronate disodium (to treat Paget's disease).
    Diuretics differ in their effects. Thiazide-type diuretics (such as Diuril® and Lozol®) reduce calcium excretion by the kidneys which in turn can raise blood calcium levels too high. But loop diuretics (such as Lasix® and Bumex®) increase calcium excretion and thereby lower blood calcium levels.
    Antacids containing aluminum or magnesium increase calcium loss in the urine.
    Mineral oil and stimulant laxatives reduce calcium absorption.
    Glucocorticoids (such as prednisone) can cause calcium depletion and eventually osteoporosis when people use them for months at a time.

Tell your doctor, pharmacist, and other health care providers about any dietary supplements and medicines you take. They can tell you if those dietary supplements might interact or interfere with your prescription or over-the-counter medicines or if the medicines might interfere with how your body absorbs, uses, or breaks down nutrients.
Calcium and healthful eating

People should get most of their nutrients from food, advises the federal government's Dietary Guidelines for Americans. Foods contain vitamins, minerals, dietary fiber and other substances that benefit health. Dietary supplements might help in some situations to increase the intake of a specific vitamin or mineral. For more information on building a healthy diet, refer to the Dietary Guidelines for Americansexternal link icon and the U.S. Department of Agriculture's food guidance system, ChooseMyPlateexternal link icon.