Chromium research from a distance: from 1959 to 1980.

More than 50 years of work have led to the recognition of trivalent chromium as an essential element. Shortly after its identification as an essential element in 1959, its interaction with insulin in vitro and in vivo was established, and the site of action identified as the insulin-sensitive cell membrane. Despite other early clinical successes with chromium supplementation, four major problems have influenced the rate of progress since then: 1) chromium analysis; 2) interaction of chromium with other dietary factors; 3) diagnosis of chromium status; and 4) other controversies, such as the carcinogenic potential of chromium (since disproved) and the lack of an effect on glucose tolerance even in chromium deficient organisms (now explained). These controversies have mostly dissipated as new knowledge integrated seemingly irreconcilable facts and opinions. It is now known that chromium may potentiate the action of insulin either by an effect on insulin dependent functions, or by maintaining these functions with less insulin, or by a combination of both. Despite much progress in the last 30 years, major challenges in chromium research remain, such as the development of practical methods for diagnosing chromium deficiency. Of several approaches for solving this problem, the most feasible might be to standardize the urinary chromium response following an insulinogenic challenge, such as an oral load of glucose or of glucose plus fructose (for maximal stimulation) with urine collection before and during the 2-hour test.