Childhood malnutrition is associated with a reduction in the total melanin content of scalp hair

Abstract

Childhood malnutrition is known to be associated with visible lightening of hair colour (hypochromotrichia). Nevertheless, no systematic investigations have been carried out to determine the biochemical basis of this change. We used an HPLC method to measure melanins in the scalp hair of thirteen Jamaican children, diagnosed as having primary malnutrition, during various stages of their treatment and after recovery. During treatment for malnutrition, a progressive decrease in total melanin content along the hair shaft from tip to root (root:tip ratio: 0·62 (sd 0·31)) was observed. This ratio was significantly different (P = 0·003) from the ratio observed among children sampled several months after discharge from hospital (0·93 (sd 0·23)) and among normal control children (0·97 (sd 0·12)). Thus, it appears that a decrease in melanin content is associated with periods of malnutrition. The low root:tip ratio during malnutrition presumably arises because the tips reflect prior hair growth during ‘normal’ nutrition and the roots reflect hair growth during malnutrition; a return of the root:tip ratio to that seen among controls reflects ‘recovery’ from malnutrition. It is possible that reduced intake or availability of tyrosine, a key substrate in melanin synthesis, may play a role in the reduction of hair melanin content during periods of malnutrition. The precise mechanisms by which melanin content is reduced, and the role of aromatic amino acid availability in hair colour change and other features of childhood malnutrition remain to be explored.

Diversity of human hair pigmentation as studied by chemical analysis of eumelanin and pheomelanin

“…Nevertheless, no systemic studies had been carried out to determine the biochemical basis of this change. Therefore, we measured melanin contents in hair of 13 Jamaican children diagnosed as having primary malnutrition 73 . Melanin content decreased progressively along the hair shaft from the tip to the root with a root/tip ratio of 0.62, which was significantly different from the ratio observed among children sampled several months after discharge from the hospital (0.93) and among normal control children (0.97).…”

An update on the honesty of melanin‐based color signals in birds

“…Prominent studies within the last decade have been performed on domestic cats, showing that variation in dietary amino acids can change melanin composition and color of the coat (Anderson et al., 2002; Morris et al., 2002). A very recent study in a malnourished population of human children also showed that growing dark hair requires adequate nourishment (perhaps dietary tyrosine; McKenzie et al., 2007).…”

Sexual Dimorphism in Melanin Pigmentation, Feather Coloration and Its Heritability in the Barn Swallow (Hirundo rustica)

“…Indeed, while there is plenty of evidence of parent-offspring resemblance in melanin-based coloration, only very few studies have been able to partition genetic and environmental causes of such resemblance ([42], see [3]). Moreover, there is both correlative and experimental evidence that nutritional condition including availability of cysteine at the level of melanosomes [28], [43], variation in food abundance [14], parasitism [13] and individual variation in androgens profile [44] can affect melanogenesis.…”