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 . 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 . Chromium was identified as the active ingredient in this so-called “glucose tolerance factor” in 1959 .
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:
- Recommended Dietary Allowance (RDA): Average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy individuals; often used to plan nutritionally adequate diets for individuals.
- Adequate Intake (AI): Intake at this level is assumed to ensure nutritional adequacy; established when evidence is insufficient to develop an RDA.
- Estimated Average Requirement (EAR): Average daily level of intake estimated to meet the requirements of 50% of healthy individuals; usually used to assess the nutrient intakes of groups of people and to plan nutritionally adequate diets for them; can also be used to assess the nutrient intakes of individuals.
- Tolerable Upper Intake Level (UL): Maximum daily intake unlikely to cause adverse health effects.
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 . In contrast, foods high in simple sugars (like sucrose and fructose) are low in chromium .
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]|
|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 . 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 . 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 . 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 . Chromium AIs are provided in Table 2.
|Table 2: Adequate Intakes (AIs) for chromium |
|Age||Infants and children|
|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|
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 .
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) . Infant formula provides about 0.5 mcg of chromium per quart . 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) . Absorbed chromium is stored in the liver, spleen, soft tissue, and bone .
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 . 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 . 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.