Genetic Variation and Nutrition

Advances in genetics and molecular biology indicate that susceptibility to chronicdiseases such as coronary artery disease(CAD),hypertension,diabetes,obesity,osteopo-rosis,alcoholism,cancer,etc,to a great extentis genetically determined.Studies have shown that 50% of the variance in plasma cholesterol concentration is genetically deter-mined,whereas 30% -60% of the variance in blood pressure is genetically determined.For fibrinogen,and independent fisk factor for CAD,15%-50% of the variance is genetically determined.In the U.K.population the variance for the fibrinogen level is 15% whereas in the Hawaiian population, the variance is 50%, indicating significant differences between populations.Among Australians, 75% of the variance in bone density is found to be genetically determined.Genetic variation influences the response to diet.For example, individuals with ApoE4 have higher cholesterol levels and a higher risk of CAD than those with ApoE3.Additional studies show that women of the ApoE3/2 phenotype stand to benefit the least from a high polyunsaturated:saturate(P:S) diet because of reduction in the more'protective' high density lipoprotein cholesterol(HDL-C), whereas men of the ApoE4/3 phenotype showed the greatest improvement in the LDL/HDL ratio.Therefore a general recommendation to increase the polyunsaturated content of the diet in order to decrease the risk for CAD is not appropriate for women with ApoE3/2 phenotype.Thus, specific information is needed to define the optimal diet for an individual.