By AMERICAN HEART ASSOCIATION NEWS
Understanding the complex interplay of heredity, diet and microbes may one day lead to diets that prevent and treat cardiovascular disease.
According to a new scientific statement published Tuesday by the American Heart Association, cracking the connection between genes and diet could lead to future heart disease treatments.
“It’s not entirely what you eat, it’s in part the genes your parents gave you in terms of how you respond,” said endocrinologist Robert H. Eckel, M.D., a professor of medicine at the University of Colorado who was not involved in the statement.
The emerging field in this area, known as nutrigenomics, is extremely complex, according to lead author Jane Ferguson, Ph.D., assistant professor of medicine at Vanderbilt University School of Medicine in Nashville, Tennessee.
“The idea is that different people may respond differently to different diets based on their genetic background,” she said. “Some people will metabolize their diets differently from others, based on their genetic profiles.”
Of many environmental factors that affect a person’s risk of cardiovascular disease, diet is one of the most important, according to the statement.
“The ultimate goal would be that [the information] be used for a personalized diet or drug,” Ferguson said. “We need to do a lot more research before we can take this into the clinic.”
When food enters the body, gut bacteria help metabolize it and break it down into a large number of component parts including macronutrients such as fats and carbohydrates, as well as micronutrients and other metabolites, Ferguson said. These are absorbed from the intestine into the bloodstream, where they interact with cells throughout the body, guided by receptors which may differ depending on an individual’s DNA.
Every individual has his or her own unique DNA sequence which forms genes that provide the instructions to the body about how to respond to the environment, metabolize food, and react to pollutants and germs. A complete “owner’s manual” of all these instructions is present in all 100 trillion cells in the human body, although Ferguson said not all are activated at once.
Nutrigenomics researchers are identifying actual inherited, genetic differences and outside factors that affect how genes express themselves, according to the statement.
Gut bacteria, dietary fats, proteins, and electrolytes such as sodium, magnesium and calcium may all play different roles in how genes and diet affect people and alter the development of cardiovascular disease and vice-versa, Eckel said.
Gut bacteria are part of the microbiome, a collection of genetic materials from bacteria, fungi, viruses and protozoa that live in and outside the body. Alterations in the microbiome can potentially contribute to obesity and the development of heart disease and diabetes.
According to Ferguson, early studies looked at how a single gene interacted with various nutrients, including those affecting obesity. Some that were investigated were the genetic roots of celiac disease and lactose intolerance.
“Rarely, several genes can cause severe obesity,” Eckel said.
Today, technology has advanced to the point that researchers are using huge databases to evaluate how “to look at millions of variants across the genome at the same time,” Ferguson said. What used to take years, now we can look at it in a day, she said.
This “big picture” approach could better identify the complex interactions responsible for putting some people at higher risk for developing cardiovascular disease and help lead to eventual diet or drug-based treatments.
Despite the progress, research isn’t ready for prime time yet.
Ferguson cautions that there’s no existing data that proves that DNA-based personalized diets can improve cardiovascular health or promote weight loss, although there are companies advertising these diets to the general public.
Additional genetic research and nutrition information will help reveal how diet, genetics and the microbiome affect risk.
Nutrigenomics has the potential to allow earlier intervention to help people live healthier lives, Ferguson said. “If we can gather all this information and understand what’s happening we can potentially advise them before they develop disease.”
“The science is poised for discovery and intervention,” said Eckel, but applying research to patients may be decades away. “We need to allow science to mature so we can make more specific recommendations for cardiovascular disease, cancer and diabetes prevention.”