Research Focus

Dr. Taylor’s research program investigates how dietary compounds may be beneficial for the prevention and management of metabolic syndrome characteristics (obesity, insulin resistance, dyslipidemia, hypertension, inflammation and hepatic steatosis), prediabetes and the early stages of cardiovascular disease as well as established type 2 diabetes and cardiovascular disease. She has been investigating the roles of dietary fatty acids (omega-3 fatty acids, monounsaturated fatty acids, conjugated linoleic acid (CLA)), zinc, and bioactive compounds found in plants/agricultural crops. She has several research collaborations investigating potential beneficial effects of Manitoba crops including oilseeds (canola, flax), pulses (beans, peas, lentils, chickpeas), and buckwheat. Her research investigates the basic science/metabolic aspects of dietary interventions in animal models of disease. She has also been a principal investigator or co-investigator for clinical trials investigating the effects of canola oil or pulses (beans, peas, lentils) in individuals with peripheral artery disease or metabolic syndrome. Current/future clinical trials are comparing plant and fish oil sources of omega-3 fatty acids in the context of obesity-mediated inflammation in females, and protein sources (pea, whey) for maintenance of muscle mass and function during weight loss in both males and females. A multi-disciplinary team approach is important for these projects and she provides the nutrition expertise.

The overarching goal of the research program is to understand how dietary compounds modulate their metabolic effects at the molecular and cellular levels and how this relates to functional effects at the whole-body level. Given that obesity is a key factor in the development of type 2 diabetes and cardiovascular disease, we are investigating adipocyte dysfunction as a critical underlying mechanism. In obesity, adipocytes (fat cells) are enlarged, insulin-resistant and produce more pro-inflammatory and fewer anti-inflammatory adipokines. These adipokines (molecules produced by adipose tissue) are released into the circulation and impact metabolism and function in various other tissues including the liver, skeletal muscle, and vascular tissue (blood vessels). We are interested in how dietary interventions can improve adipocyte function, for example, by reducing adipocyte size, increasing insulin sensitivity, altering the balance of adipokines to be less pro-inflammatory and more anti-inflammatory, and consequently improving the function of adipose and other tissues as demonstrated by reductions in hepatic steatosis and less arterial stiffness. Interestingly, we have shown that some dietary interventions can improve these characteristics of adipocyte function without a decrease in adipose mass, indicating that body weight or adipose mass alone are not the best indicators of adipose tissue function.

Why is this work important?

This research is important to further our understanding of how dietary components affect metabolism in the body and their roles in chronic disease prevention and management. Much of the research on dietary fats has focused on cardiovascular disease and less is known about their effects on obesity and on insulin resistance and inflammation. Nutrients such as dietary fats have established functions and defined deficiency disease, and in the last few years, we are just beginning to identify other bioactive compounds in the diet that promote health and to define their functions. These bioactive compounds are present in various plants and agricultural crops. Nutrients and bioactive compounds can target the same pathways as pharmaceutical compounds, and despite much lower concentrations in the diet compared to pharmaceutical compounds, continuous low-level exposure in the diet likely contributes to health and disease prevention. Another goal of our research is to isolate and identify novel bioactive compounds in buckwheat and pulses which are responsible for blood-glucose-lowering and improvement of blood vessel health, respectively.

Given the current obesity rates and incidence of chronic diseases, a two-pronged approach is needed to understand how dietary intervention can be used to prevent disease and to delay the progression of established disease. Thus, research with animal models allows us to explore both prevention and treatment designs. In humans, diabetes and cardiovascular disease develop over many decades. We have obtained non-invasive instruments to directly assess blood vessel function (i.e. arterial stiffness) and are applying this novel methodology to detecting early-stage vascular disease as well as monitoring the effects of dietary intervention on blood vessel function acutely in healthy individuals and chronically in individuals with early or established vascular disease. To date, our results are demonstrating that diet modification can have positive effects on blood vessel function in individuals with the established vascular disease despite already receiving the best medical management in terms of medications and surgical procedures.

What techniques and equipment are used in this laboratory?

The techniques and equipment used in animal and human studies are both distinct and complementary. Observations in the human studies can be investigated further at a mechanistic level by dietary intervention in an animal model, and results from animal studies can be applied to the design and assessment of responses in the human studies.

The animal models are chosen to represent human disease and include both genetic and diet-induced models that exhibit obesity and characteristics of metabolic syndrome, type 2 diabetes or cardiovascular disease/hypertension.

The assessments in the animal models range from the whole body to molecular levels, for example:

• in vivo functional assessments: body composition (EchoMRI-700TM Whole Body Quantitative Magnetic Resonance ), blood pressure (CODA Non-Invasive Blood Pressure System), arterial stiffness (Indus Instruments Doppler System for Pulse Wave), oral glucose tolerance testing, insulin tolerance testing, saphenous blood collections, metabolic cages for urine collection.
• inter-organ and cellular metabolism: immunohistochemistry and morphometry for pancreatic β-cell size, hepatic lipid droplet size, adipocyte size, macrophage/T-cell infiltration in adipose tissue.
• molecules and biomarkers in serum/urine/tissue: various spectrometric, biochemical, ELISA, electrochemiluminescence, and multiplex assays; gas chromatography for fatty acid profile; HPLC for bioactive compounds and metabolites; atomic absorption spectrophotometry for trace elements.
• Immunology and adipogenesis: phenotypic characterization of cell types in thymus, spleen, lymph nodes and the stromal vascular fraction from adipose tissue by flow cytometry; immune cell isolation, culture and cytokine production.
• molecular pathways and cell signalling: Western blotting, Real-Time PCR.

Most of the clinical studies are chronic (i.e. dietary intervention for several weeks) and a few have been acute (e.g. glycemic index testing or effects of a food item on satiety factors over a 2-3 hour period; vascular responses). For the chronic studies, food items containing the test ingredient (e.g. canola oil, pulses) are prepared, frozen in the required portion, and provided to participants to incorporate into their usual diet at home. For the comparison of plant and marine sources of omega-3 fatty acids, flaxseed oil containing alpha-linolenic acid (ALA) and docosahexaenoic acid (DHA)-rich fish oil have been provided in capsules. Depending on the study, participants are a) healthy, or b) have obesity-associated inflammation or c) have early-stage vascular disease and/or diabetes (i.e. managed by diet and not taking lipid-lowering or glucose-lowering medications), or d) have established cardiovascular disease (e.g. peripheral arterial disease) and/or type 2 diabetes. [Click on this link for studies currently recruiting participants]. Assessments in the clinical studies fall into the following categories:

• vascular function: blood pressure, ankle-brachial index and pulse wave velocity (VP-1000); pulse wave analysis and velocity (SphygmoCor Px/Vx); peripheral artery tonometry (Endo-PAT2000).
• glycemic response: glucose tolerance testing; advanced glycation end-products (AGE reader).
• cognitive function: various standardized cognition/memory tests.
• anthropometric: body mass index, waist circumference, body composition.
• circulating biomarkers and metabolite/bioactive profiles: various spectrometric, biochemical, ELISA , electrochemiluminescence, and multiplex assays; gas chromatography for fatty acid profile; HPLC for bioactive compounds and metabolites.
• food intake/background diet: food frequency questionnaire, 3-day food records.

About Dr. Carla Taylor

Dr. Taylor grew up on a mixed farm in southwestern Manitoba and has always been interested in the relationships between food and health. She completed her Bachelor’s degree in Human Ecology (Foods and Nutrition) at the University of Manitoba and her Ph.D. in Nutritional Sciences at the University of Guelph. Her Ph.D. dissertation investigated the effects of nutrition, and specifically zinc and copper deficiency and supplementation, on antioxidant defence. Her post-doctoral training was at the University of Michigan in Ann Arbor and the University of Washington in Seattle where she gained further expertise in antioxidant and immune defence systems. She accepted an Assistant Professor position in the Department of Human Nutritional Sciences at the University of Manitoba and moved back to Manitoba. She has been promoted to Full Professor and has held various administrative responsibilities in the Department including Acting Department Head, Associate Head, and Chair of the Undergraduate Committee. She has also served on grant selection committees for NSERC and CIHR. She is an Associate Editor for Lipids and has completed the maximum two terms as an Associate Editor for the British Journal of Nutrition.

Over the years, Dr. Taylor’s research program has evolved into metabolic nutrition – how the metabolism of nutrients and other dietary components can impact both prevention and management of chronic diseases such as obesity, type 2 diabetes and cardiovascular disease. This research focus complements the main undergraduate course she teaches on macronutrients (carbohydrates, lipids and proteins), their metabolism, and roles in various gastrointestinal diseases, type 1 and type 2 diabetes, cardiovascular disease, and renal disease. Dr. Taylor’s research has been recognized through two major awards: the International Life Sciences Institute Future Leader Award in Nutrition in 1996 and the Canadian Society of Nutritional Sciences – Centrum Foundation New Scientist Award in 2005.

In her free time, Dr. Taylor enjoys cooking, gardening, keeping fit (cardiovascular/weight training, tennis, cross-country skiing, golfing, hiking, etc.), being in the outdoors, and travelling in North America or wherever a conference may take her around the world.

For more information, contact:

Dr. Carla Taylor
Tel. (204) 258-1361
Fax. (204) 237-4018
ctaylor@sbrc.ca