Chromium

Chromium (in its trivalent form Cr³⁺, the dietary form) is a trace element present in tiny amounts. It was long considered necessary for insulin to work properly, via a molecule called “glucose tolerance factor”.

A fresh angle (the nutrient we doubt): a rare and interesting case, chromium’s “essential” status is now being questioned. Long classed as an essential trace element, it has been downgraded by some authorities (the European EFSA does not recognise a clearly established essential role). No chromium deficiency has been convincingly demonstrated in healthy humans eating normally.

It is a good example of the evolution of nutrition science: a nutrient once presented as important can be reconsidered as the evidence is refined. This calls for caution in the face of categorical claims.

Supplement marketing (chromium picolinate): despite these uncertainties, chromium (chromium picolinate) is sold as a supplement to “control blood sugar”, “reduce sugar cravings” and “help you lose weight”. The evidence for these effects is weak and inconsistent: most serious studies show no significant benefit in people who are not deficient. An example of a supplement oversold on fragile foundations.

In practice: a varied diet provides plenty of chromium (as trace amounts), found in many foods. There is no reason to supplement without evidence of a real need.

Sources: broccoli, meat, wholegrain cereals, nuts, green beans, brewer’s yeast, and traces just about everywhere.