Serum selenium levels in individuals on PKU diets

Abstract

Serum selenium levels in 73 patients with phenylketonuria were significantly lower than in controls. The phenylketonuric and hyperphenylalaninaemic individuals taking the non-supplemented amino acid mixture generally had lower levels: 36% were below the normal range as defined by our laboratory, compared with 19% in the supplemented group. The low levels were present even in those on diet, who had a greater phenylalanine tolerance — that is, a tolerance for more than 9×50 mg phenylalanine exchanges per day, in other words a higher intake of natural protein. Individuals on long-term synthetic diets may be at risk for selenium deficiency even on selenium supplements. In areas where the soil may be low in selenium, the deficiency may be aggravated. Long-term low levels may impair health but the required amount of selenium supplementation remains uncertain.