Recent Studies Debate Chromium Safety

Recent Studies Debate Chromium Safety

PURCHASE, N.Y.The safety ofchromium has been the topic of debate in several studies conducted worldwide. InSeptember, Nutrition 21 (www.nutrition21.com), a bioscience firm that develops chromiumbased nutritional products, released a statement in response to a studyconducted at the University of Sydney questioning the safety of chromium (Cr).The study, published in the September issue of the AngewandteChemie International Edition (43, 34:4504-07, 2004)(www.angewandte.org) states elite athletes who take large amounts of chromiumdietary supplements to boost performance may be unwittingly putting themselvesat risk of cancer.

According to the Sydney study, chromium(III) used insupplements could be converted by naturally occurring oxidization in the bodyinto different forms of chromium; chromium(V) and chromium(VI). Both types ofchromium are toxic and are well established as substances responsible for thedevelopment of human cancers, according to the study.

In light of our new findings, the safety of chromium(III)compounds as nutritional supplements or drugs should be re-examined verycarefully, particularly for heavy users of the supplements such as eliteathletes, said Peter Lay, Ph.D., co-author of the study and ARC ProfessorialFellow from the Centre for Heavy Metals Research at the University of SydneysSchool of Chemistry.

However, according to the Nutrition 21 statement, the studysfindings contradict the Food and Drug Administration (FDA) and the U.S. Food and Nutrition Boards (FNB) recognition of chromium asan essential trace mineral with a recommended daily value of 120 mcg for goodhealth.

Trivalent chromium, the form of chromium found in food andsupplements, is considered one of the least toxic nutrients, according toRichard Anderson, Ph.D., CNS, FACN, lead researcher with the U.S.

Department of Agriculture (USDA) Nutrient Requirements &Functions Laboratory, Beltsville Human Nutrition Research Center. Theoverwhelming preponderance of scientific evidence indicates that chromiumpicolinate is a safe and beneficial nutritional supplement, Anderson added.

John Hathcock, Ph.D., vice president of international affairsat the Council for Responsible Nutrition, agreed. The safety of chromiumpicolinate is apparent when the vast array of peer-reviewed literature onchromium picolinate is considered, including genotoxic assays, longterm studiesin rats and clinical studies with human subjects, he said.

The National Academies Food and Nutrition Board DietaryReference Intake (DRI) committee that reviewed chromium found little evidence of carcinogenicity in humans or animals after oralconsumption of chromium(III). The report concluded that no adverse effectshave been convincingly associated with excess intakes of chromium from food orsupplements

However, according to Lay, the newer chromium supplements thathave been found by others to be the most active in animal studies, such as Crpropionate, were the most easily oxidized by the enzymes. Moreover, neither Crpicolinate nor Cr propionate inhibited the phosphatase enzymes believed to beresponsible for the anti-diabetic effects of chromium, whereas the chromium(VI)and chromium(V) oxidation products were strong inhibitors of these enzymes in invitro studies by the same mechanism that is well established for the vanadiumdietary supplements and anti-diabetic agents that are currently in humanclinical trials.

There are now three pieces of compelling evidence from thein vitro studies of the reactions of enzymes with the dietary supplements thatstrongly suggests that it is the resulting chromium(VI) and chromium(V) speciesthat interfere in our metabolism, Lay said These are: (1) the supplementsare oxidized by human enzymes to chromium(VI); (2) these oxidation products areactive against the enzymes that are likely to be responsible for theanti-diabetic activity, whereas the supplements themselves are not; and (3) themost active supplements in animal models are also the most easily oxidized. Eventhe presence of an excess concentration of natural antioxidants for chromium(VI)(above those present in the body) the effect on the phosphatase enzymes is notreduced, showing that the chromium(VI) reacts more rapidly with these enzymesthan the antioxidants.

The implications are potentially profound and warrant furtherinvestigation particularly for the cases indicated, he added. This isespecially the case since the latency time for chromium-induced cancers is often10 to 40 years meaning that any potential consequences for the users healthwould not be showing up yet, he said.

Later in September, a review of recent studies on the safetyof chromium picolinate was presented at a Centers for Disease Control andPrevention (CDC) conference on metal toxicity and carcinogenesis. Ronald S.

Slesinski, Ph.D., DABT, president-elect of the Regulatory& Safety Specialty Section of the Society of Toxicology, presented a reviewof recent scientific evidence confirming the safety of chromium picolinate foruse as a nutritional supplement.

Slesinski addressed findings from two previous laboratorystudies alleging adverse effects on hamster cells exposed to chromiumpicolinate. The new studies conducted under International Guidelines, showedthat comparative or higher doses of Chromax® (manufactured by Nutrition 21)chromium picolinate produced no adverse effects in these same tests, saidSlesinski. Chromax chromium picolinate has never been shown to be mutagenicin animals or to produce damage to genetic material (DNA) in humans wheningested, at any dose. Research studies conducted by the USDA, NTP and atindependent testing laboratories, show no evidence of genetic toxicity. Thesafety research overwhelmingly confirms that Chromax chromium picolinate is asafe nutritional supplement, Slesinski said.