Glucose tolerance factor chromium, more commonly called chromium GTF, is a mineral that is frequently used in bodybuilding, athletic and weight-loss supplements. However, the jury is still out on how effective this supplement is when used for these purposes. If you want to increase your intake of chromium GTF foods or take supplements containing this ingredient, check with a doctor first — especially if you take medicine or have a health condition.
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Chromium enhances the action of insulin, your body's fat storage hormone. Insulin also is needed to metabolize carbohydrates, fat and protein in your body. The naturally-occurring form of chromium is called dinicotinic-acid glutathione complex, or GTF chromium. GTF is different from simple chromium compounds because it is more easily absorbed by your body and safer than other forms, notes John Bertram Vincent in "The Nutritional Biochemistry of Chromium."
In 1957, researchers found that a compound in brewers' yeast prevented an age-related decline in rats' ability to maintain normal levels of glucose, or sugar, in their blood. Two years later, chromium was flagged as the active ingredient in this so-called "glucose tolerance factor." In fact, naturally-occurring GTF is most abundant in brewer's yeast, though it comprises less than 2 percent of the available chromium in this food. Researchers in the 1960s found that chromium could correct glucose intolerance and insulin resistance in animals that were deficient in the mineral, according to the Office of Dietary Supplements. Actual chromium deficiency in humans is rare, but chromium is added to intravenous solutions at hospitals routinely to prevent signs of diabetes that can occur due to a deficiency.
Companies that sell GTF chromium supplements tell buyers that the pills will curb carbohydrate and sugar cravings, otherwise suppress the appetite and promote weight loss while increasing energy. Many companies sell chromium GTF as a single-ingredient supplement. Other manufacturers sell it as an active ingredient in formulations. Meanwhile, scientific evidence to support the effects of chromium supplements on blood lipid levels in people remained mixed. A review of 24 studies on whether chromium supplements can increase lean muscle and reduce body fat found no significant benefits. The studies focused on the form of the mineral called chromium picolinate rather than chromium GTF, however.
If you are sensitive to caffeine, have certain health conditions or take certain medicines, taking chromium GTF is not a good idea. Many of the supplements that feature chromium GTF combine it with caffeine. This can cause side effects like irritability and nervousness. If you have high blood pressure, other cardiovascular ailments, hypoglycemia or diabetes, it may not be safe for you to consume chromium GTF. It also can interact with antidepressants, beta-blockers, insulin, H2 blockers, proton-pump inhibitors, corticosteroids, non-steroidal anti-inflammatory medications and other medicines.
Chromium was still not a well-understood mineral as of 2010. Its mechanisms of action in your body are still not well defined. Likewise, the amount you need for optimal health hasn't been pinpointed. The chromium content of foods needs to be more thoroughly evaluated, as does chromium's bioavailability, or the ability of your body to absorb and use it. It is difficult to determine what the true typical dietary intake of chromium actually is because its content in foods is substantially affected by manufacturing and agricultural processes as well as contamination with chromium from the environment.