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.

The anticarcinogenic effect of conjugated linoleic acids (CLA) has been attributed to their antioxidant activity. Strong evidence is lacking, however, to substantiate that CLA is an antioxidant. The objective of this study was, therefore, to test whether CLA is an antioxidant or a prooxidant in canola oil. The oxidation was conducted at 90°C by monitoring oxygen uptake and changes in linoleic acid and α-linolenic acid. Free CLA and CLA methyl ester (CLAME) accelerated lipid oxidation in canola oil. The prooxidant activity of CLA and CLAME was dose-dependent at concentrations ranging from 0.1 to 1.0% in canola oil heated at 90°C. CLA-containing triacylglycerol, however, was neither an antioxidant nor a prooxidant. Under the present experimental conditions, CLA was not an antioxidant in fats and oil. JAOCS 73, 749-753 (1997).

Objective: To examine the serum fatty acid and lipid pro®les and dietary intake of Hong Kong Chinese omnivores and vegetarians with respect to cardiovascular health. Design: Random population survey strati®ed by age and sex. Subjects: One-hundred and ninety-four omnivore subjects (81 men, 113 women) age 25 ± 70 y, and 60 ovo-lactovegetarian adults (15 men, 45 women) age 30 ± 55 y. Measurements: Nutrient quantitation was by a food frequency method. Serum fatty acids were analysed by gas chromatography, and serum lipid by standard laboratory methods.

Contrary to current opinion, conjugated linoleic acids (CLA) as a mixture of several isomers have been previously shown to function as prooxidants in the form of free fatty acids and methyl esters in heated canola oil. Furthermore, CLA oxidizes considerably faster than linoleic acid. However, stability of CLA relative to other polyunsaturated fatty acids remains undetermined. The present study was therefore undertaken to examine the relative oxidation rate of CLA compared with that of linolenic acid (LNA), arachidonic acid (AA), and docosahexaenoic acid (DHA) in air at 90°C. CLA, both in the form of free fatty acids and triacylglycerols, were extremely unstable to the same extent as DHA, but they oxidized considerably faster than LNA and AA. The mechanism by which CLA were readily decomposed was probably due to formation of the unstable free-radical intermediate.

Tea, the most popular beverage worldwide, is consumed in three basic forms; green tea, black tea and oolong tea. Tea contains over 4,000 chemicals some of which are bioactive. In recent years there has been a mounting interest in understanding the cardiovascular and metabolic benefits of polyphenolic flavonoids in tea, which can be used as a supplement among patients. Diverse cardioprotective effects of consuming tea or tea polyphenols have been described on pathological conditions, e. g. hypertension, atherosclerosis, diabetics, hypercholesterolemia, obesity, and are attributed to antioxidative, anti-thrombogenic, anti-inflammatory, hypotensive and hypocholesterolemic properties of tea polyphenols. This review focuses on cardiovascular benefits of tea polyphenols based on in vitro and in vivo studies on experimental animal models and on studies of human subjects in four areas: (1) vasorelaxant effect; (2) protective effect against endothelial dysfunction; (3) antioxidant effect and (4) hypolipidemic effect. We will briefly discuss the effects of tea on atherosclerosis and hypertension.