Electrolyte profile of Malaysian mothers' milk.

The influence of socioeconomic status (ethnicity, income, and parity) on electrolyte composition (sodium and potassium) in human milk is little known. The authors have thus quantitatively analyzed approximately 700 samples of milk (1-90 days postpartum) obtained from healthy Malaysian mothers (Malay, Chinese, and Indians) of full-term infants. Results show that the mean concentration (mmol/1) of sodium is highest 48.2 +/- 1.7; mean +/- SEM) in the Malaysian mothers' colostrum and this value decreased by 30% in their transitional milk and remained constant throughout subsequent days of lactation. Ethnically, it is found that the level of sodium in colostrum of Malay and Chinese mothers was similar but the Indian mothers' colostrum showed apparently higher value (52.7 +/- 3.4 mmpl/1) that is statistically insignificant. The transitional milk of all 3 ethnic groups studied exhibited similar levels of sodium. On subsequent days of lactation (mature milk) the Malay mothers exhibited the lowest concentration (25.9 +/- 2.6 mmol/1) of sodium that is significantly (p .05) different from that of Chinese and Indian mothers. Income and parity do not significantly affect the sodium level in Malaysian mothers' milk during all stages of lactation studied. The level of potassium, however, did not change significantly with days of lactation. Like sodium, potassium too was not influenced by income and parity.