Dietary Chromium: Health Effects and Toxicity
One of a number of lesser known minerals our body needs is a metallic element called chromium. Although it is needed only in tiny amounts, the latest research shows that it may have far reaching effects on our health. Chromium seems to play an important role in sugar and lipid metabolism. It balances both high and low blood glucose, controls sugar cravings and hunger, helps with fat loss, lowers bad cholesterol, slows the loss of calcium, helps to prevent glaucoma and even helps to build muscle when used in conjunction with exercise.
Chromium comes in two chemical forms – trivalent and hexavalent. Hexavalent chromium is a by-product of the metallurgic process used to make chrome for aerospace and automotive industries and it is extremely toxic and carcinogenic. Trivalent chromium is the one usable by the human body but its role in our metabolism is still controversial.
A tolerable upper intake level for chromium has not been established. Adequate intakes for chromium in mcg per day (micrograms not milligrams!) can be viewed in the table below.
|Age||Males (mcg per day)||Females (mcg per day)|
|Birth to 6 months||0.2||0.2|
|7 – 12 months||5.5||5.5|
|1 – 3 years||11||11|
|4 – 8 years||15||15|
|9 – 13 years||25||21|
|14 – 18 years||35||24, pregnant 29, lactating 44|
|19 – 50 years||35||25, pregnant 30, lactating 45|
|51 years and older||30||20|
The Role of Chromium in Human Metabolism
In order to fully understand the role of chromium in the human body, it is necessary to begin with the metabolic process. Through our metabolic process, carbohydrates eventually turn into simple sugar called glucose, the cellular fuel. Insulin is released by the pancreas and binds with glucose in the blood to be carried to the body’s cells. High amounts of sugar and bad fats in our diets, over-eating as well as genetic predisposition can cause semi-permeable cell walls to become insulin resistant. That means they no longer accept the insulin/glucose package needed for nourishment. The excess glucose in the bloodstream that is not accepted on a cellular level gets taken to the liver and is converted into fat.
And here is where chromium can play its role. Chromium is the key that unlocks the door to allow the insulin/glucose complex to enter the cell. It seems to make the cell membrane once again sensitive to insulin. With more glucose now available to fuel the body’s basic unit, the whole body will experience increased energy.
Potential Health Benefits of Chromium
Chromium is part of the chemical compound known as glucose tolerance factor (GTF) enhancing insulin activity. Therefore, the main health benefit associated with getting an adequate amount of chromium is efficient metabolism of sugars. Controlling blood glucose levels efficiently is necessary for preventing diabetes and lowering high blood pressure and thus preventing heart disease. As a result, this may also help to put the brakes on aging. Other beneficial effects associated with adequate intake of chromium include controlling healthy weight, preventing glaucoma, contributing to healthy bones and prevention of osteoporosis, and helping to build muscle.
Some experts think that chromium deficiency is rare though others suggest that nearly half of the people in the industrialized countries are deficient in chromium. Factors that may lead to such high rates of chromium deficiency include diets high in refined carbohydrates (especially wheat), refined sugars and fat. Moreover, diets high in milk may contribute to deficiency of chromium because milk binds with chromium in the gastrointestinal tract and prevents its absorption. Likewise, the regular use of antacids, h2 blockers, proton-pump inhibitors and corticosteroids decreases absorption of dietary chromium. Pregnancy, intense physical exercise and traumatic injuries may also increase the need for chromium.
Deficiency of chromium may lead to problems metabolizing carbohydrates and fats and result in diabetes, stunted growth in young children, and elevated blood pressure, glaucoma and accelerated atherosclerosis in adults.
Symptoms of chromium deficiency include fatigue, anxiety, insulin intolerance, weight gain and slow wound healing. Individuals lacking chromium may also develop other health problems related to the aforementioned medical conditions, especially diabetes.
Chromium is a heavy metal which may accumulate in the body if taken in excess. It has been associated with carcinogenic effects for a long time. However, dietary chromium rarely causes toxicity. Likewise, the use of dietary supplements that contain chromium has not been associated with chromium overdose. The most common cause of chromium toxicity is the exposure to industrial contaminants (e.g. chromate dust).
Symptoms of chromium toxicity include skin rash and ulcers, allergic and irritant dermatitis, respiratory irritation, asthma, bronchitis and sinusitis. Long-term exposure may cause kidney and liver damage, lung cancer and premature dementia.
Dietary Sources of Chromium
There are many foods that contain chromium but the amounts absorbed by the body are typically very low. Those foods include whole grains (especially buckwheat), cornmeal, wheat bran, wheat germ and rye bread. Also broccoli, beets, mushrooms, potatoes, molasses, apple skins, prunes, oranges, black pepper, garlic, basil and thyme contain chromium. In addition, dietary chromium can be found in animal products including calf liver, lean beef, oysters, chicken, eggs, turkey and cheese. However, brewers yeast has the most bio-available chromium. Drinking water, especially hard water, also contains chromium.
Supplemental chromium normally comes as picolinate, nicotinate, chloride or gluconate. Chromium picolinate is the more common form, whilst nicotinate has a smaller molecule which is absorbed more readily. However, not too many doctors would advise their patients to take chromium supplements.
Where to Get More Information: USDA