Chromium, the basis:
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.
Functions:
Chromium is known to enhance the action of insulin, 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, 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.
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. 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 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
Foods that are good sources of chromium include liver, kidney, yeast products, wholegrain cereal, nuts and legumes.
Most people get enough chromium from food.
What symptoms and disorders Chromium deficiency may cause:
Deficiencies are more common in both the elderly and the young, especially teenagers on poor diets.
Tissue levels of chromium tend to decrease with age, which may be a factor in the increase of adult-onset diabetes, a disease whose incidence rose more than sixfold during the second half of the 20th century. This increase may also mirror the loss of chromium from our diets because of soil deficiency and the refinement of foods. Much of the chromium in whole grains and sugarcane is lost in making refined flour (40% loss) and white sugar (93% loss). In addition, there is some evidence that refined flour and sugar deplete even more chromium from the body.
Reduced absorption related to aging, diets that are stressful to the digestive system, and the modern refined diet all contribute to chromium deficiency. Higher fat intake also may inhibit chromium absorption. If chromium is as important as we think it is to blood sugar metabolism, its deficiency may be in part responsible, along with the refined and processed diet, for increasing diabetes mellitus rates.
People who eat a diet high in sugar and refined foods are more at risk for not getting enough chromium. Sugar increases chromium loss and refined foods are very low in chromium. Athletes may also have increased chromium loss through exercise.
Milk and other high-phosphorus foods tend to bind with chromium in the gut to make chromium phosphates that travel through the intestines and are not absorbed.
Signs and Symptoms:
Even mild deficiencies of chromium can produce symptoms other than problems in blood sugar metabolism, such as anxiety or fatigue. Abnormal cholesterol metabolism and increased progress of atherosclerosis are associated with chromium deficiency, and deficiency may also cause decreased growth in young people and slower healing time after injuries or surgery.
Chromium deficiency can resemble diabetes.
Problems related to excessive doses:
Side effects.
Chromium seems to have few side effects. There have been some reports of chromium causing occasional irregular heartbeats, sleep disturbances and allergic reactions. Chromium may increase the risk of kidney or liver damage. If you have kidney or liver disease, do not take chromium without talking to your GP first.Interactions.
Since chromium may affect blood sugar levels, it is crucial that anyone taking diabetes medications - like insulin - only use chromium under medical supervision.Chromium may also interact with medicines like antacids, acid reflux drugs, corticosteroids, beta-blockers, insulin and NSAID painkillers. These interactions may cause the chromium to be poorly absorbed or amplify the effect of of the medication being taken.
Risks.
Pregnant and breastfeeding women should not take chromium supplements. For children, consult your child’s GP. Some experts recommend that no one should take more than 200mcg/day without medical advice. Doses of over 1,000mcg/day may be dangerous, though some experts place the figure much higher. There is a theoretical risk that it could increase the risk of cancer, so don’t use chromium in high doses without talking to your doctor first.Chromium dose
For labelling purposes, the European Union’s Recommended Daily Allowance (EU RDA) for chromium has been set at 40mcg per day for adults.
Many people get more chromium than that. However, no one knows exactly how much more is safe.
The UK Expert Group on Vitamins and Minerals report on safe upper limits suggests that intakes of chromium of up to 10mg (10,000mcg) per person per day would be expected to be without adverse health effects.
Excessive doses of chromium may actually worsen insulin sensitivity.
Top tip:
To Avoid Deficiency and Maintain a Good Intake of Chromium:• Avoid sugar and sugar products, soda pops, candy, and presweetened breakfast cereals.
• Avoid refined, white flour products, such as white breads and crackers.
• Use whole wheat products, wheat germ, and/or brewer's yeast.
• Eat whole foods.