Dr Gopinadhan (Gopi) Paliyath

Fruit consumption for cancer prevention
Researcher hones in on fruit as a functional food for disease prevention

Fruits such as grapes, blueberries, elderberries and blackberries are rich in polyphenols – a component that contributes to the colour of fruits and vegetables. Polyphenols are known to have several physiological and biochemical effects in the human body that may contribute to positive health effects. In particular, a University of Guelph researcher is finding polyphenols influence calcium signalling processes in cancer cells, which provides a key benefit in cancer prevention.

Prof. Gopi Paliyath, Department of Plant Agriculture, is studying the physiology and biochemistry of fruits and vegetables and their roles in preventing or reducing cancer. In particular, he’s exploring the health-related benefits of consuming fruit high in polyphenols. He’s found that polyphenols interfere with calcium release and sequestration, a highly regulated process in normal cells. Several forms of cancer, including breast cancer, show abnormal calcium signalling processes and may involve the calcium-binding protein called calmodulin, as well as several other proteins and enzymes regulated by calcium and calmodulin.

“It is possible that consumption of fruits high in polyphenols may provide a threshold level of polyphenols within the body that may prevent the formation of cancer cells through their antioxidant function, as well as destroy any cancer cells formed by affecting their metabolism,” says Paliyath.

Paliyath says polyphenols have antioxidant properties that are important for cancer prevention. These antioxidant properties help detoxify free radicals – molecules that are regularly produced during the body’s metabolism that are harmful to cells – and prevent mutations in the genetic material.

Through his current research with grapes and Merlot wine, Paliyath has found that grape polyphenols can also interfere with the calcium balance in breast cancer cells. When breast cancer cells were treated with polyphenols extracted from the wine, the cellular calcium concentration was disrupted. Normally, calcium levels are low in cells, but after adding the polyphenols, the levels increased rapidly. Paliyath found that the excess calcium may be taken up by mitochondria (energy centres in cells), which resulted in the loss of mitochondrial function and triggered the cells to self-destruct. This finding is particularly important in cancer research because cancer cells appear to be extremely susceptible to polyphenol treatment.

“Normal cells do not respond to polyphenols as cancer cells do,” says Paliyath. “For some reason, polyphenols selectively influence the metabolism of cancer cells causing their death.”

Paliyath’s interest in health and cancer research arose after observing that apples contained a natural calmodulin inhibitor while doing postdoctoral work at Washington State University in the U.S. He has since focused more than 20 years of study and research on the biochemistry of fruits and vegetables, particularly looking at their role as functional foods in disease prevention.

In future research, Paliyath plans to study the relationship between fruit and vegetable consumption and estrogen and testosterone metabolism. He is interested in understanding how the foods affect the metabolism of steroid hormones that may affect the development of prostate cancer and breast cancer. He is also interested in learning more about the bioavailability of polyphenols to determine what form is most readily absorbed, its metabolism, how it is retained in the tissue and how to incorporate higher levels of polyphenols in fruits, vegetables and their processed products.

Paliyath has a Master’s degree in Botany from the University of Calicut in India. He also has a PhD in Biochemistry from the Indian Institute of Science and did postdoctoral work at Washington State University and the University of Waterloo before joining the University of Guelph.

Paliyath’s research is supported by the Natural Sciences and Engineering Research Council, the Ontario Ministry of Agriculture, Food and Rural Affairs, the University of Guelph’s Food System Biotechnology Centre and several industry organizations.

Written by Lindsay Brown, SPARK University of Guelph’s student research writing program

For further information, please contact Dr Gopinadhan (Gopi) Paliyath using the Email contact form or by phone at 519 824-4120 ext 54856