Archive for July, 2014

Diabetes, Obesity and Genetics

Friday, July 18th, 2014

Doctors and researchers have found that obesity and diabetes are connected. People who are obese are at high risk for developing Type 2 diabetes (also known as “insulin-resistant” or “adult-onset” diabetes), particularly if a close family member is affected with diabetes. Therefore, it becomes very important to maintain a healthy body weight throughout your life in order to protect yourself from developing a chronic disease like diabetes. Researchers have also determined that only a slight predisposition for obesity is inherited. For example, the best way for children to avoid being overweight is to eat a diet that is balanced and is low in fat. This diet should consist of lots of fresh fruits and vegetables. Snacks like chips, cookies, ice cream, and soft drinks should be limited or eliminated. This may require a lifestyle change in a person’s life. It is very important that all children become involved in physical activities on a daily basis. Too many children spend their free time in front of computers, television, and video games, and this results in a growing number of kids who are obese and who will likely suffer medical consequences of obesity as adults. In order to become a diabetic, two factors need to be present. First, you need to inherit a predisposition to the disease, and second, the environment must trigger a response in your body. Your genes alone are not enough. This has already been shown in studies of groups of identical twins: when one of a pair of twins develops diabetes, there is only a slightly increased chance that the other sibling will develop the disease. Because identical twins are genetically similar, the environment of the individual might play a role in the development of diabetes. However, because both genetics and the environment are shared by family members, we recognize that people with a family history for diabetes have a greater risk for developing the disease. Another factor are epigenetic marks that change with diet and the environment. Molecular biology has shown the genetic and epigenetic basis for the development of both diseases. In recent years, expanded knowledge of the human genome has led to the development of new tools that facilitate the simultaneous analysis of thousands of genes for complex diseases. Researchers now rely on such tools in their search to uncover the gene networks associated to conditions such as diabetes and obesity. Today, geneticists use a number of forward approaches (for example, approaches that seek to find the genetic basis of a phenotype) in their efforts to understand how gene networks may contribute to these diseases. One such method is the genome-wide association study or GWAS; this high-throughput approach allows geneticists to scan the entire human genome in an unbiased manner, using statistical methods to determine associations between chromosomal loci and a given phenotype. For example, a recent genome-wide association study has reproducibly associated variants within introns of the gene FTO with increased risk for obesity and type 2 diabetes (for more information see “Obesity-associated variants within FTO form long-range functional connections with IRX3” by Smemo et al). Mutations in introns (noncoding regions) of the gene FTO have been widely investigated after genome-wide association studies revealed a strong link between FTO and diabetes. Yet, overexpressing or deleting FTO in animal models affects whole body mass and composition, not just fat, and experiments have failed to show that these obesity-linked introns affect the function of the FTO gene itself. Diabetes and obesity are directly involved since body fat and metabolism are strongly connected. This study showed that not just proteins are associated to obesity, but also non-coding regions such as enhancers and introns. Conformational changes in the DNA and epigenetics (mostly linked to diet and environmental exposure) might be the answer to better understand both diseases. However, until we completely uncover the mysteries of the genetics of metabolism, the best choice is to eat healthy and live well, independent on genetic predisposition and background. Like they say; you are what you eat. So, eat well and exercise.