Breast milk fatty acid composition: a comparative study between Hong Kong and Chongqing Chinese

The fatty acids of milk samples obtained from 51 Hong Kong Chinese and 33 Chongqing Chinese (Si Chuan Province, China) were analyzed by gas-liquid chromatography. Compared with those of published data for Canadian and other Western countries, the Chinese milk from both Hong Kong and Chongqing contained higher levels of longer-chain polyunsaturated fatty acids, particularly docosahexaenoic acid (22:6n-3) and arachidonic acid (20:4n-6). In contrast, the content of trans fatty acids in the Chinese milk was lower compared with those for Canadian and other Western countries. Longitudinally, the concentrations of 22:6n-3 and 20:4n-6 gradually decreased when lactation progressed from colostrum (week 1) to mature (week 6). Over the same interval, linoleic acid (18:2n-6) remained unchanged in Chongqing Chinese but significantly increased in Hong Kong Chinese. Unlike 18:2n-6, linolenic acid (18:3n-3) increased in Chongqing Chinese but remained unchanged in Hong Kong Chinese throughout the study. The total milk fat also increased with the duration of lactation. In addition, the milk of Chongqing Chinese had higher total milk fat than that of Hong Kong Chinese and Canadians. The content of erucic acid (22:1n-9) increased with the progression of lactation in Chongqing Chinese, indicating that there was a switch in dietary consumption from fats of animal origin to rapeseed oil when lactation reached week 6. The present study showed that Hong Kong and Chongqing Chinese had a different fatty acid profile in many ways, which largely reflected a different dietary habit and life-style in these two places.