What chromium does
Chromium appears to help insulin move sugar from your blood into your cells, although its exact role is still being researched.
How much
Adults need only around 25–35 µg a day. Deficiency is extremely rare.
Plant sources
Whole grains, broccoli, green beans, potatoes, nuts, apples and spices. Refined grains lose much of their chromium.
A note
Chromium supplements are sometimes marketed for weight loss or blood sugar, but the evidence is weak. A varied whole-food diet provides what you need.