Obesity, the metabolic syndrome, and type 2 diabetes in developing countries: role of dietary fats and oils

Abstract

Developing countries are undergoing rapid nutrition transition concurrent with increases in obesity, the metabolic syndrome, and type 2 diabetes mellitus (T2DM). From a healthy traditional high-fiber, low-fat, low-calorie diet, a shift is occurring toward increasing consumption of calorie-dense foods containing refined carbohydrates, fats, red meats, and low fiber. Data show an increase in the supply of animal fats and increased intake of saturated fatty acid (SFAs) (obtained from coconut oil, palm oil, and ghee [clarified butter]) in many developing countries, particularly in South Asia and South-East Asia. In some South Asian populations, particularly among vegetarians, intake of n-3 polyunsaturated fatty acids (PUFAs) (obtained from flaxseed, mustard, and canola oils) and long-chain (LC) n-3 PUFAs (obtained from fish and fish oils) is low. Further, the effect of supplementation of n-3 PUFAs on metabolic risk factors and insulin resistance, except for demonstrated benefit in terms of decreased triglycerides, needs further investigation among South Asians. Data also show that intake of monounsaturated fatty acids (MUFAs) ranged from 4.7% to 16.4%en in developing countries, and supplementing it from olive, canola, mustard, groundnut, and rice bran oils may reduce metabolic risk. In addition, in some developing countries, intake of n-6 PUFAs (obtained from sunflower, safflower, corn, soybean, and sesame oils) and trans-fatty acids (TFAs) is increasing. These data show imbalanced consumption of fats and oils in developing countries, which may have potentially deleterious metabolic and glycemic consequences, although more research is needed. In view of the rapid rise of T2DM in developing countries, more aggressive public health awareness programs coupled with governmental action and clear country-specific guidelines are required, so as to promote widespread use of healthy oils, thus curbing intake of SFAs and TFAs, and increasing intake of n-3 PUFAs and MUFAs. Such actions would contribute to decelerating further escalation of "epidemics" of obesity, the metabolic syndrome, and T2DM in developing countries.