Five Questions With: Dr. Simin Liu

"We now know that tens to hundreds of genes, if not more, affect diverse biological functions and pose predispositions to both diseases."

Dr. Simin Liu is a professor at Brown University and epidemiologist whose work unites molecular genetics, nutrition, physiology and clinical medicine. He earned his medical degree from Jinan University in China and his master of public health and doctoral degrees in both epidemiology and nutrition from Harvard University. He recently was awarded $500,000 in research funds from the American Heart Association to study gene-diet interactions in cardiovascular disease and type 2 diabetes among diverse ethnic groups.

PBN: What do we already know about different ways that diet and genes affect the likelihood of a person contracting cardiovascular disease and type 2 diabetes across different ethnic groups?
LIU:
We now know that tens to hundreds of genes, if not more, affect diverse biological functions and pose predispositions to both diseases. We also know that high caloric diets that are characterized by low intake of fruits and vegetables and high intake of red meats, and lack of physical activity play important roles in both diseases. Findings from gene-diet studies, although limited and not entirely consistent across populations, indicate that some specific gene-diet interactions influence the risk of type 2 diabetes or cardiovascular disease. Our own research supports the notion that although there are shared mechanisms between ethnic groups, there are likely ethnic differences in both genetic and biochemical pathways leading to these disorders.

PBN: Between genetic predisposition to type 2 diabetes and genetic predisposition to cardiovascular disease which condition is more difficult to avoid entirely through careful adherence to diet?
LIU
: It is difficult to distinguish the effect of dietary interventions on these cardio-metabolic disorders. The two vascular metabolic diseases – type 2 diabetes and cardiovascular are closely related. It is safe to say that on average at the population level the incidence of both diseases can be significantly reduced should the dietary causes be reduced. However, it remains challenging to directly translate these observations from population studies into a precise prediction of an individual’s future risk of developing the specific disease. First, clinical effectiveness of specific dietary interventions on affecting risk of these complex diseases has not been measured consistently to allow for accurate comparisons. Second, the genetic risk components of both diseases are highly complex and involve many biological processes. Some disease-related processes such as cholesterol and glucose metabolism may be more responsive to dietary control but others may not. While these two diseases do share similar dietary and biochemical risk factors, not all individuals have the same types of dietary, genetic, and biochemical risks. It is indeed challenging to accurately map out each individual’s risk profile for these diseases.

PBN: Should individuals with a genetic predisposition to type 2 diabetes and cardiovascular disease consider taking medication before developing any symptoms?
LIU:
Thinking within the therapeutic paradigm of personalized medicine, it is indeed tempting to ask such a question. However, the state of the art science is such that medications are designed to focus on a specific molecular target that may have other off-target effects for a specific disorder of interest. As such, we need to carefully weigh the balance of risks and benefits for an individual as medications may or may not provide benefits. Depending on his/her risk profile, for example, an individual whose lipids levels are in the normal range may not benefit from taking cholesterol-lowering drugs even if this person carries some genetic predisposition to heart disease. From the preventive perspective, it is certainly far more desirable to adopt a healthy lifestyle (e.g. engage in physical activity regularly and eat a healthy diet).

- Advertisement -

PBN: How do you obtain the relevant genetic material for study?
LIU:
Genetic materials are mainly extracted from blood samples that were obtained when these participants were enrolled in the Women’s Health Initiative, Framingham Heart Study, and the Jackson Heart Study and gave their consent to genetic studies.

PBN: To what extent does computing power inform the genome research competition game – are you in a constant quest to obtain more computing power to advance your research?
LIU:
To advance our research in integrative genomics, computing power does play an important role. We are indeed in a constant quest for more computing units, relevant data storage and queries that are managed by highly skilled statistical analysts.

No posts to display