DNA link to sugar impact risk for heart disease and diabetes

September 30, 2013 Sophie Langley

Genes in mitochondria, the powerhouses that turn sugar into energy in human cells, shape a persons risk for heart disease and diabetes, according to a study from researchers at the University of Alabama at Birmingham (UAB).

The findings may have implications for diet-planning and the ongoing debates surrounding added sugars in foods and beverages.

Researchers said the findings, published in the Biochemical Journal 8 August 2013, may explain why some people get sick and others do not despite having the same traditional risk factors like ageing, obesity and smoking.

Research in recent years has shown that miscues in mitochondrial energy production create too many particles called oxidants and free radicals that cause cells to self-destruct as part of heart disease, diabetes and cancer.

Having been in this field for decades, I remember when mitochondrial DNA variations were thought to play a role only in the rarest of genetic syndromes, said Scott Ballinger, PhD, Professor in the Division of Molecular and Cellular Pathology at the UAB School of Medicine and corresponding study author. Today there is a growing consensus that variation in mitochondrial DNA alone make a substantial contribution to each persons risk for heart disease, and ours is the first study to directly confirm it in a living mammal, he said.

Evolution of mitochondria in humans

The UAB study reflects the theory that humans ancient one-celled ancestors swallowed the bacterial forebears of what are now mitochondria. These gave their hosts the ability to convert sugar from food into about 15 times as much cellular energy as the hosts could by using oxygen. As the evolutionary process continued, the mitochondria became permanent sub-compartments of human cells.

Each human cell has two genomes, the long stretches of DNA that encode the blueprint for the human body: one set inherited from both parents in a central nucleus, and a separate, smaller set in each mitochondrion. The mitochondria genes are inherited from a childs mother.

Researchers have struggled to genetically engineer mice that would enable them to separate the impact of one gene set from the other, making the theory that mitochondria DNA shape disease risk difficult to prove. Additionally, the human nuclear genome contains more than 30,000 genes, compared to just 13 energy-related genes in the mitochondria.

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DNA link to sugar impact risk for heart disease and diabetes