Life Extension Magazine August 2004
Chromium: An Element Essential to Health
By Dale Kiefer
|LE Magazine August 2004|
|Chromium: An Element Essential to Health|
By Dale Kiefer
Chromium, the metallic element once believed to be toxic, is in fact essential to health. In the mid-twentieth century, scientists put laboratory rats on a diet devoid of chromium. The unfortunate rodents quickly developed glucose intolerance, a condition that often precedes the development of type II diabetes in humans. Researchers then switched the animals’ feed to brewer’s yeast—a rich, natural source of chromium—and the rats’ health promptly returned to normal.
Regulating Glucose and Lipid Metabolism
Chromium is believed to form an integral component of so-called glucose tolerance factor, a proposed metal-protein complex sometimes referred to as chromodulin.25 It is responsible for activating insulin receptor kinase, thereby increasing insulin sensitivity.24 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.
Chromium occurs in two chemical forms, called trivalent and hexavalent. The hexavalent form is usually a byproduct of the metallurgy industry (for example, chrome automobile parts). It may indeed be toxic if inhaled. Although it is not recommended for ingestion, when the hexavalent form is consumed orally it is quickly converted into the harmless, bioavailable trivalent form. Chromium intended for dietary supplementation is always trivalent. In contrast to hexavalent chromium, trivalent chromium is an essential micronutrient that is exceptionally well tolerated.1-25
Are We Starved for Chromium?
Unfortunately, some physicians are unconvinced that chromium is a necessary, helpful supplement. Their reticence is likely due to the existence of some small studies that used chromium doses that were too small to provide an effect, or studies that suffered from simple defects in design. That, at least, is the opinion of one of the world’s leading chromium researchers, Dr. Richard Anderson.
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.22 Furthermore, in 1986, Dr. Anderson noted, “The dietary chromium intake of most individuals is considerably less than the suggested safe and adequate intake.”23 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.20-24
Although modern multivitamins often contain at least trace amounts of chromium, inferential evidence suggests that many of us are nevertheless deficient in this crucial element. In Thailand recently, scientists measured the chromium present in gallstones and bile from patients in three Asian cities. They concluded that patients from Bangkok had consumed higher levels of chromium than their counterparts in the other locales. Since gallstones may take many months or years to form, they provide an intriguing snapshot of long-term trace metal status. Bangkok residents had lower levels of total cholesterol, triglycerides, and hemoglobin A1C (an indicator of uncontrolled blood sugar) than Asians with consistently lower intakes of dietary chromium.29
Of course, not every patient presents with gallstones. Moreover, there is currently no reliable method of assessing an individual’s chromium level. Increased loss can be monitored in the urine, but adequacy of chromium in the bloodstream must be inferred. Some scientists are convinced that the need for chromium increases as glucose intolerance and diabetes develop. It is believed that intense exercise, pregnancy, and traumatic injury also increase the body’s demand for chromium.4
Dr. Anderson writes, “Insufficient dietary chromium is associated with maturity-onset diabetes and/or cardiovascular diseases.” This alarming pronouncement takes on still greater significance in light of his observation that “Dietary chromium intake in the US and other developed countries is roughly half of the minimum suggested intake of 50 micrograms.”21 Scientists, including Dr. Anderson and his colleagues, are actively seeking to understand precisely how chromium renders assistance. It is clear, however, that chromium, regardless of the details of its activity, enhances insulin’s activity, and is crucial to normal glucose and lipid metabolism.
Given the alarming rise in cases of insulin resistance and diabetes in the US, it may be prudent to increase one’s level of chromium to stave off symptoms of metabolic syndrome, such as increased glucose intolerance, excess weight gain, elevated blood lipids (cholesterol and triglycerides), and low levels of high-density lipoprotein (HDL) cholesterol. All of these parameters are potentially harmful if left untreated.30-34
Positive Effects on Cholesterol, Fat Loss
Whole grains and mushrooms contain trace amounts of chromium, but only if they are grown in soil containing the mineral. Similarly, seafood and some meats may contain chromium, but only if the source animals ate foods containing chromium. Brewer’s yeast is the only food source rich in this essential nutrient. Unfortunately, brewer’s yeast lacks a certain appeal as a dietary source, particularly when you consider that chromium stores must be replenished frequently. That is why many experts recommend daily chromium supplements.
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.”36
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, researchers 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.16
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.16
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 individuals 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.33 Thus, controlling blood sugar may actually put the brakes on the aging process, and should be an essential component of any life-extension strategy.