Researchers found that the apolipoprotein A-II gene (APOA2) is associated with proportions of fat, carbohydrates, and proteins in the diet, along with total calories and, therefore, with BMI.
The scientists analyzed genetic alleles in the APOA2 promoter. The alleles of the APOA2 promoter, T and C, form combinations; TT, TC, and CC. Of more than 1,000 study participants, approximately 85% had the common TT and TC genotypes, whereas 15% of participants had the CC genotype. “Both men and women with the CC genotype had a statistically significant higher intake of fat than people with the TT and TC genotypes,” says Jose Ordovas, Ph.D., director of the nutrition and genomics laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. “People with the CC genotype also consumed an average of 200 more calories per day and were nearly two times more likely to be obese, as compared to those with the two more common alleles.”
In addition to preference for dietary fat, the researchers found evidence that the APOA2 gene influences preferences for proteins and carbohydrates. People with the CC genotype consumed higher absolute amounts of proteins and lower absolute amounts of carbohydrates than those with the TT and TC genotypes.
Researchers measured participants’ weight, height, and waist and hip circumference, along with blood lipid levels both before and after a high-fat meal.
The researchers did not find an association between any alleles of APOA2 and blood lipid levels, including triglycerides, total cholesterol, or LDL or HDL cholesterol. People with the CC genotype, however, did have greater amounts of small HDL cholesterol particles as compared to larger HDL cholesterol particles in their blood after eating the high-fat meal than did people with at least one T allele. Small HDL cholesterol particles are more of a risk factor for cardiovascular disease than are larger HDL particles.
These results are published in the June issue of Clinical Chemistry.