Marva Sweeney-Nixon, PhD

Marva Sweeney-Nixon, PhD


Blueberries – a hyperberry for hypertension (PDF)


Dr. Marva Irene Sweeney-Nixon is an Associate Professor in the Department of Biology at UPEI and a member of the Atlantic Canada Network on Bioactive Compounds (ACNBC). After completing a Ph.D. in Pharmacology from Dalhousie University, she accepted an MRC-funded post-doctoral research fellowship to work at the University of London (St. George’s Hospital and Royal Free Hospital Schools of Medicine, London, England) from 1989-1993. Before coming to UPEI in 1997, she was an Assistant Professor in the Department of Physiology, University of Saskatchewan, and Principal Investigator in the Saskatchewan Stroke Research Center, Royal University Hospital, Saskatoon.
Her research focuses on health effects of blueberries and cranberries, specifically related to cardiovascular health and inflammation, in collaboration with scientists at UPEI, other universities in Canada, US and Australia, and Canadian government labs. She held a 3 year Research Professorship in Nutrisciences and Health from the Louis Levesque Foundation, 2005-2008, as part of her research into the effects of food (berries) on cardiovascular health. She is the author of 32 peer-reviewed publications, 7 book chapters or monographs, and 41 conference proceedings, and has assisted in the invention of 11 pre-commercial functional food products.
Dr. Sweeney’s research program aims to determine whether ‘bioactive’ compounds are beneficial to cardiovascular disease, a leading cause of death of Canadians. The extracts that interest her most derive from Vaccinium species (lowbush blueberry [V. angustifolium], American cranberry [V. macrocarpon]), or other flavonoid-rich species (e.g. pomegranates). Major risk factors for cardiovascular diseases are the clusters of disorders that make up metabolic syndrome, including hypertension (high blood pressure), abdominal obesity, hypercholestolemia (elevated blood cholesterol) leading to atherosclerosis (‘hardening of the arteries’ and abnormal glucose metabolism with insulin resistance, a precursor of diabetes.

The main research question is evaluating whether dietary flavonoids lower the risk and severity of stroke, hypertension, atherosclerosis, and insulin resistance, and is interested in determining mechanisms. These cardiovascular and metabolic disorders all involve oxidative stress and/or inflammation to some degree, as part of their pathology. Thus, a central hypothesis of her research is that flavonoids from blueberries and cranberries mitigate the effects of oxidative stress and inflammation in animals and humans at risk of cardiovascular disease or metabolic syndrome.

There are 2 general experimental approaches that I take to evaluate the development and severity of cardiovascular disease: 1) feed whole or isolated extracts of blueberries and cranberries to various animal disease models, and then monitor several specific biomarkers of disease or 2) add isolated compounds including mixtures directly to animal or human cells grown in tissue culture; these cells are usually manipulated in some ways to simulate a cardiovascular disease.