This is adapted from the book, Eat Smart, Play Hard, by RW USA Nutrition Editor Liz Applegate.
Chromium has been around the research block a few times. For years, the mineral was rumored to help burn body fat and build muscle size and strength, which appealed to those looking for a stronger, shapelier body. But before you sprint to the nearest nutrition depot, heres a look at the facts.
Chromium assists the hormone insulin in processing carbohydrates. Insulin also helps your body manufacture new proteins, a fact that supports the theory of chromium as a muscle builder.
Unfortunately, that theory just doesnt pan out. Much of the initial chromium craze was based on a slew of flawed studies showing that chromium supplementation (in the form of chromium picolinate) improved muscle gains during strength training. Yet in a well-designed study on football players, those who weight trained 4 days a week while taking 200 micrograms of chromium saw no increase in their muscle mass compared to a placebo group. But while most research has failed to support chromium for fat burning or muscle building, the supplement may show promise in another area: Research suggests that this supplement might be useful for boosting sprint performance.
Chromium is a trace mineral that helps your cells use carbohydrate for energy. Along with the hormone insulin, chromium acts like a key that unlocks cells, allowing sugar to enter. This explains why blood sugar levels improve in people with diabetes who are given extra chromium in their diets. Using this logic, it makes sense that an extra shot of chromium during exercise could help shuttle more carbohydrate into muscle cells for a boost of energy.
Researchers from the University of Dayton in Ohio put this theory to the test with a group of trained cyclists. On two separate occasions, cyclists worked out for an hour while they drank either a high-carbohydrate beverage similar to a sports drink or the same beverage with added chromium. They consumed about 60 grams of carbohydrate (240 calories) and about 200 micrograms of chromium (equivalent to the daily recommended intake).
At the end of the hour-long ride, cyclists pedaled as hard as they could for just under a minute. Researchers measured the amount of work performed during the sprint and found that the chromium-fortified drink boosted sprint performance by 7 percent over the plain carbohydrate drink. Blood sugar levels were also slightly lower in the cyclists who had used the chromium-fortified beverage, suggesting that more glucose had been used by the muscles. Lead researcher Mary Ellen Horn, R.D., notes, "Under these conditions, it appears that a modest chromium dose improves glucose uptake for use during a sprint effort."
My recommendation: You dont need to buy a supplement to increase your daily chromium intake; you get 50 to 60 micrograms of chromium from 1 cup of refried beans, two microbrewed beers, a cooked chicken breast, or 1 cup of peas.
To keep your chromium levels optimal (many endurance athletes do fall short of the recommended 50 to 200 micrograms), beware of eating too many refined foods, such as white bread and sweets, which are not only low in chromium but also may boost your need for it (to help process carbohydrates). Sticking with food sources instead of a supplement is both cheaper and safer. If you consume too much chromium (which can happen only if you supplement), you can hamper your absorption of iron and zinc.