Saturated fatty acid

Saturated fatty acid (SFA) is the fat acid without double bond. Generally, SFAs are regarded as the negative factor of human health, which is able to inhibit low density lipoprotein (LDL) metabolism and increase LDL, cholesterol and triglycerides concentrations in serum, resulting in increase in risks of coronary heart disease (CHD). In some developed countries, there is high incidence of CHD, which results in about 50% of all death each year. Dietary habit difference leads to the difference of rates of CHD in various countries. In Japan, low SFAs intake causes low rates of fatal myocardial infarction; whereas there is a close correlation between high SFAs intake and high rates of fatal myocardial infarction in USA and Finland. Legume seeds contain low SFAs content, increase level of which in daily diet can decrease the risk of CHD effectively (Steijns, 2008; Poliklinik, Eppendorf, & Germany, 2000).

Unsaturated fatty acids (UFAs)

Unsaturated fatty acids are divided two groups: monounsaturated fatty acids and polyunsaturated fatty acids, which are also thought to decrease risk of CHD.

Monaunsaturated fatty acid

Monounsaturated fatty acid (MUFA) is the fatty acid which contains only one double bond in fatty acid chain, compared with saturated fatty acid (SFA) has no double bond and polyunsaturated fatty acid (PUFA) has more than one double bond. Common dietary MUFAs include palmitoleic acid (16:1 n−7), cis-vaccenic acid (18:1 n−7) and oleic acid (18:1 n−9). Oleic acid is the fatty acid of 18 carbon-atoms chain with double bond occurring in the ninth carbon atom from the carboxyl end (another end of fatty acid is the methyl group). MUFAs are able to decrease LDL level in serum via increase of LDL receptor activity. Indeed, increase MUFAs intake can inhibit the synthesis of small very low density lipoprotein (VLDL) which can be hydrolyzed and leave VLDL remnant, resulting increase of LDL level in serum. In addition, increase intake of MUFAs can also decrease plasma cholesterol and triglycerides concentrations, inhibit thrombosis and atherosclerosis, and improve insulin sensitivity, resulting in decrease on blood pressure (Curb, Wergowske, Dobbs, Abbott, & Huang, 2000; Grund7,1987; Lopez-Miranda et al., 2006; Rasmussen et al., 2006; Vessby et al., 2001).

Polyunsaturated fatty acids

Polyunsaturated fatty acid (PUFA) is the fatty acid with more than one double bond.