New research by a BYU molecular biologist conﬁrms obesity’s genetic link and may help us to understand why some individuals gain weight more easily than others.
Mark Rowe, chair of BYU’s Department of Food Science and Nutrition, has identiﬁed two genetic markers that correlate to differences in metabolism.
“It is widely known that our genes contribute some portion of our potential for obesity or thinness. The most important aspect of this work is its demonstration that individuals can inherit differences in speciﬁc genes that will determine, in part, their metabolic rate and potentially contribute to weight gain,” says Rowe, who recently presented his ﬁndings at the Experimental Biology meetings in Atlanta, Ga.
While researchers had previously identiﬁed 13 maternally inherited (mitochondrial) genes that affect how the body uses and stores energy, Rowe’s study is the ﬁrst to pinpoint markers on those genes that correspond to differences in metabolic rate.
Of the two genetic markers, Rowe found that one speciﬁc marker on the ND-1 gene had a strong correlation to higher metabolic rate. Low metabolic rate, where the body uses energy efficiently and stores leftover energy as fat, is considered a risk factor for weight gain.
In the study group, the difference between the resting metabolic rates of those with and without the ND-1 genetic marker was an average of 40 Calories (40 kcal) per day.
“So theoretically, if these two individuals ate the same diet, the difference (in metabolic rates) could account for a weight difference of ﬁve pounds per year or 50 pounds per decade,” he says.
The study was conducted among a group of 245 Pima Indians, a population with a 75-percent obesity rate. The population, which also has a high incidence of obesity-related illnesses such as heart disease and diabetes, is widely studied because of its severe health problems.
Rowe’s study is being duplicated in other groups to see if the markers are constant across populations.
“We have found one important difference in one population,” Rowe says of the discovery of the ND-1 marker. “There are assuredly others in other populations.”
Genetic inheritance, Rowe says, is just one factor that can impact whether a person is fat or thin. While researchers are just beginning to understand the connections between genetics and weight gain, Rowe is hopeful that such information might one day help individuals to assess their health risks.
“The goal of this kind of research is to identify people who are at risk and then give them genetically intelligent nutritional counseling. The whole idea is to help people understand more about themselves and how their individual nutrition may affect their health later in life.”
Genetically intelligent nutritional counseling, he says, may include providing information about dietary choices and encouraging at-risk individuals to watch caloric intake and to exercise regularly.
“Obesity is one of the very serious problems that is faced by the American population. So it’s important for us as scientists and nutritionists to determine what is causing obesity in as many ways as we can,” he says.
—Julie H. Walker