Chromium: is it essential, pharmacologically relevant, or toxic?

Area of Science:

• Nutritional biochemistry
• Trace element metabolism

Background:

• Chromium (trivalent ion) was proposed as essential for mammalian carbohydrate and lipid metabolism over 50 years ago.
• Evidence stemmed from rodent studies, total parenteral nutrition patients, and chromium absorption/transport research.
• Popularity as a supplement for weight loss and muscle gain surged, despite lack of identified biomolecules like glucose tolerance factor (GTF).

Purpose of the Study:

• To formally re-evaluate the essentiality of chromium.
• To address conflicting evidence regarding chromium's role in metabolism and its purported benefits.
• To review safety concerns and pharmacological effects of chromium(III).

Main Methods:

• Review of historical dietary studies in rodents.
• Analysis of studies involving patients on total parenteral nutrition.
• Examination of research on chromium absorption, transport, and proposed biomolecular interactions.
• Evaluation of safety and efficacy data from human and animal studies.

Main Results:

• Chromium supplementation has not shown beneficial effects on body mass or composition.
• Chromium(III) compounds are generally non-toxic and show pharmacological benefits in rodent models of insulin insensitivity.
• Human studies have not conclusively demonstrated beneficial effects of chromium supplementation.
• Proposed mechanisms for chromium's effects lack consistent supporting evidence.

Conclusions:

• Chromium's essentiality status requires re-evaluation, with evidence suggesting it should be removed from the list of essential trace elements.
• While chromium(III) exhibits potential pharmacological benefits in animal models, human evidence remains inconclusive.
• Further research is needed to clarify chromium's role in human health and metabolism.