Chromium (krô'mç-əm)

What Is It?

Chromium is an essential trace Mineral that the body needs to grow properly and remain healthy. It is necessary, among other things, for the breakdown of Protein , Fat , and carbohydrates.

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Health Benefits

Cardiovascular disease

Impaired glucose tolerance and type 2 diabetes are associated with adverse changes in lipid profiles and increased risk of cardiovascular diseases. Studies examining the effects of chromium supplementation on lipid profiles have been notable for their inconsistent results. While some studies have observed reductions in serum total cholesterol , LDL -cholesterol, and triglyceride levels or increases in HDL -cholesterol levels, others have observed no effect. Such inconsistent responses of lipid and lipoprotein levels to chromium supplementation may reflect differences in chromium nutritional status. It is possible that only those individuals with insufficient dietary intake of chromium will experience beneficial effects on lipid profiles after chromium supplementation.

Linus Pauling Institute

Impaired glucose tolerance and type 2 diabetes mellitus

Chromium is now generally recognized to play an important role in glucose and lipid metabolism. Chromium supplementation has the effect of normalizing blood sugar levels. Elevated blood sugar, or hyperglycemia, responds positively to chromium supplementation. Hyperglycemic patients given chromium after receiving a dose of glucose, or simple sugar, experienced a drop in blood sugar levels, while patients with low blood sugar, or hypoglycemia, experienced a normalization of their blood sugar levels after receiving chromium .

Chromium is believed to form an integral component of so-called glucose tolerance factor, a proposed metal-protein complex sometimes referred to as chromodulin. It is responsible for activating insulin receptor kinase, thereby increasing insulin sensitivity. High blood sugar is a damaging hallmark of diabetes. When cell membranes are sensitive to the presence of insulin, they are more receptive to insulin's efforts to usher glucose molecules out of the bloodstream and into cells, where glucose is then burned for energy.

Without adequate chromium , insulin evidently becomes ineffectual. As glucose piles up in the bloodstream, the pancreas produces ever-greater amounts of insulin, to little avail. In essence, chromium acts like a kind of doorman. While insulin escorts glucose to “doors” in the cell membrane, chromium (probably joined with protein fragments) rings the doorbell, and perhaps holds the door open by activating receptors, while insulin ushers its precious cargo into the cell. Without chromium's help, membrane portals simply fail to open. Blood sugar levels remain stable when adequate chromium is present.

Dr. Anderson is a nutritional research scientist with the US Department of Agriculture's Agricultural Research Service. For decades, he has studied chromium's role in glucose and lipid metabolism. As early as 1981, Dr. Anderson published a report declaring that chromium is essential for proper glucose and lipid metabolism. Furthermore, in 1986, Dr. Anderson noted, “The dietary chromium intake of most individuals is considerably less than the suggested safe and adequate intake.” He went on to note that our rampant consumption of refined sugar further depletes chromium stores. As sugar intake increases, more chromium is expended by the body in an effort to metabolize that sugar, resulting in a spiraling need for still more chromium .

Life Extension

In 12 out of 15 controlled studies of people with impaired glucose tolerance , chromium supplementation was found to improve some measure of glucose utilization or to have beneficial effects on blood lipid profiles. Impaired glucose tolerance refers to a metabolic state between normal glucose regulation and overt diabetes . Commonly, blood glucose levels are higher than normal but lower than those accepted as diagnostic for diabetes. Impaired glucose tolerance is associated with increased risk for cardiovascular diseases but is not associated with the other classic complications of diabetes. About 25% to 30% of individuals with impaired glucose tolerance eventually develop type 2 diabetes. Generally, chromium supplementation in a variety of forms, at doses of about 200 mcg/day for two to three months, has been found to be beneficial. The reasons for the variation or lack of effect in some studies are not clear, but chromium depletion is not the only known cause of impaired glucose tolerance. Additionally, the lack of an accurate measure of chromium nutritional status prevents researchers from identifying those individuals who are most likely to benefit from chromium supplementation. A recent meta-analysis of 15 randomized clinical trials reported that chromium had no effect on glucose or insulin concentrations in nondiabetic individuals.

Linus Pauling Institute

In people with type 2 diabetes, the pancreas secretes plenty of insulin in an effort to regulate blood sugar levels, but the body's cells don't respond to it. Researchers have found that a molecule called ''glucose tolerance factor'' (GTF) is critical for increasing the sensitivity of these cells to insulin. And GTF contains chromium.

If GTF does indeed increase insulin sensitivity, chromium supplements may have a role to play in normalizing blood sugar levels. Several double-blind clinical trials have borne this out. Some studies have even found that chromium supplements enable certain people with diabetes to decrease their dosage of diabetes medications. Taking the chromium with vitamin B3 (niacin) may enhance the chromium's effects.

And although not yet confirmed in clinical trials, chromium supplements may have a role to play in preventing excessive blood sugar drops in people without diabetes. Symptoms of low blood sugar (hypoglycemia), including headaches, fatigue, and irritability, may be less likely to occur as a result.

WholeHealthMD.com

Positive Effects on Cholesterol, Fat Loss

No less an authority that Dr. Richard Atkins, the founding father of the current low-carb revolution, called chromium “the most pivotal nutrient involved in sugar metabolism.” Dr. Atkins went on to point out “more than 90% of all Americans are deficient . . .” Besides normalizing glucose and insulin levels, supplemental chromium evidently lowers harmful total cholesterol and triglycerides, while raising beneficial HDL cholesterol. There is even evidence to suggest that chromium promotes fat loss and lean muscle mass retention.

Some notable studies have indicated an improvement in the ratio of body fat to lean muscle during and after chromium supplementation in humans. Dr. Anderson writes, “[ Chromium ] supplementation may be useful to direct . . . fat loss with the retention of lean body mass and to ameliorate many manifestations of aging.”

In an interview with Life Extension, Dr. Anderson scoffed at researchers who claim to have found no such effect. “Some of these studies are too short term to see any effect . . . they're poorly done studies,” says Dr. Anderson. He notes that a recent report, which analyzed all the available data on the issue of fat loss and lean muscle retention, concluded that chromium supplementation had no significant effect. “Insignificant weight losses?” asks Dr. Anderson. “They found a [0.3 to 0.8] kilo-per-month loss. That's about eight pounds per year. In five years that adds up to 40 pounds [of fat loss]. That's not insignificant. To say that's insignificant is bizarre.”

His incredulity is understandable. In one study of 20 overweight African-American women, research-ers found that “fat loss was significantly greater, and non-fat body mass loss significantly less, with chromium intake.” In this randomized, double-blind study, subjects took either 600 mcg of chromium nicotinate or placebo for two months. Groups were then switched for two months, without their knowledge. Those receiving chromium began taking placebo, and vice versa. All subjects also engaged in a modest diet and exercise regimen throughout the study period.

Perhaps the most intriguing aspect of this clinical trial was the finding that subjects on chromium lost fat but retained lean muscle, in contrast to those on placebo, who lost fat and muscle. Researchers also noted that during the placebo phase, fat loss was significantly less among women who received placebo first than among those who received chromium first, indicating a carryover effect from chromium supplementation. These women continued to lose proportionally more fat, even during the placebo phase. None of the women experienced significant adverse effects from taking 600 mcg of niacin-bound chromium .

Dr. Anderson is also skeptical about some scientists' claim that chromium does not affect glucose metabolism. “Those are usually people who haven't done much work in the field,” says Dr. Anderson. Citing one meta-analysis that claimed to find no significant effect, Dr. Anderson pointed to “many problems” with the design of the analysis. “Nobody is going to convince me there aren't any beneficial effects. Many of these are lousy studies; lots of them aren't giving enough [ chromium ]. . . they're too short term, or they use healthy normal subjects. You must have impaired glucose tolerance to see an effect. More than 30 studies have demonstrated an effect.”

In addition, the number of in-dividuals with impaired glucose tolerance is alarmingly high in the US and abroad, says Dr. Anderson. “People with impaired glucose handling, metabolic syndrome, and diabetes—you're talking about a very high percentage of the population. I'd say 25-35% is a very conservative estimate.” Metabolic syndrome, also known as Syndrome X, is a combination of medical conditions characterized by abnormal glucose metabolism, elevated insulin levels, excess weight and abdominal fat distribution, disturbances of normally healthy lipid levels, and high blood pressure—all of which are associated with the subsequent development of type II diabetes and cardiovascular disease.

While diabetes and cardiovascular disease are well-recognized threats to overall health, some researchers believe that elevated blood sugar—even absent these other conditions—contributes directly to aging. By interacting with proteins and nucleic acids, excess glucose molecules wreak havoc with tissue elasticity and normal function. Thus, controlling blood sugar may actually put the brakes on the aging process, and should be an essential component of any life-extension strategy.

Life Extension

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