No science is needed to conclude consumers like (or love) sweet things; however, science is needed to determine what causes varying perceptions of sweetness. A new study published in Twin Research and Human Genetics suggests a single set of genes affects a person’s perception of sweet taste, regardless of whether the sweetener is a natural sugar or a non-caloric sugar substitute (July 17, 2015).
Researchers tested 243 pairs of monozygotic (MZ), aka identical, twins, 452 pairs of dizygotic (DZ), aka fraternal, twins, and 511 unpaired individuals. Each person tasted and then rated the intensity of four sweet solutions: fructose and glucose—natural sweeteners—aspartame and neohesperidine dihydrochalcone (NHDC)—non-caloric artificial sweeteners. Studying twin pairs allowed the researchers to determine how much influence the twins’ shared genetics contributed to their perception of sweet taste intensity.
Perceived intensity for all sweeteners decreased with age (2 to 5 percent per year), Males rated aspartame slightly stronger than females (7 percent). The researchers found similar heritabilities for sugars and high-potency sweeteners; all were in the modest range. Multivariate modeling showed a common genetic factor accounted for more than 75 percent of the genetic variance in the four sweeteners, suggesting individual differences in perceived sweet intensity, which are partly due to genetic factors, may be attributed to a single set of genes. This study provided evidence of the shared genetic pathways between the perception of sugars and high-potency sweeteners.
“Even though almost everyone—consumers, physicians and public health officials—wants to decrease the amount of sugar in our diets, right now we have no tool that has the sensory equivalence of sugar," said study author Danielle Reed, a behavioral geneticist at Monell. “However, if we can understand why some people have weaker sweetness perception, we might be able to adjust this attribute so we could reduce the amount of sugar in foods."