The short version
Chromium is one of the few minerals the government's own advisory board has openly second-guessed. For years the working assumption was that it is essential to normal insulin action, then newer evidence undercut even that.
Primary source 01 / 05
it is not an essential mineral because an absence or deficiency of chromium does not produce abnormalities that can be reversed with the addition of chromium
Europe's food safety regulator went further.
Primary source 02 / 05
no convincing evidence shows that chromium is an essential nutrient and, therefore, setting chromium intake recommendations would be inappropriate
Deficiency essentially doesn't happen
Whatever chromium turns out to do, going without it in a normal diet has not been shown to cause a problem in anyone healthy.
Primary source 03 / 05
Chromium deficiency has not been reported in healthy populations, and no definitive deficiency symptoms have been established
The handful of case reports once cited as proof of deficiency came from patients on long-term intravenous feeding in the 1970s and 80s, and modern reviewers concluded those studies never measured the chromium levels involved closely enough to prove deficiency caused the symptoms. There is no diet, vegan or otherwise, linked to a documented chromium shortfall.
The supplement claim outruns the evidence
None of that has slowed the market for chromium picolinate, sold on the promise of better blood sugar and easier weight loss. FDA's own required label language shows how thin the backing actually is.
Primary source 04 / 05
One small study suggests that chromium picolinate may reduce the risk of insulin resistance, and therefore possibly may reduce the risk of type 2 diabetes. FDA concludes, however, that the existence of such a relationship between chromium picolinate and either insulin resistance or type 2 diabetes is highly uncertain
The clinical trial record backs up that skepticism. A 2019 meta-analysis of 21 weight-loss trials found chromium supplements produced 0.75 kg more weight loss than placebo, a real but tiny difference, and a Cochrane review reached a similar verdict on the whole body of evidence.
Primary source 05 / 05
the effect of chromium supplementation on body weight is of debatable clinical relevance and the overall quality of the evidence is low
The American Diabetes Association has twice declined to recommend chromium supplements for people with diabetes, most recently in 2015, citing insufficient evidence. None of this touches diet itself: there is no reported chromium shortfall from eating a plant-based diet to fix, and the supplement bottle does not deliver what its marketing implies.