Grizzlies show no clinical signs of disease following short-term consumption of saturated fats, but scientists question long-term health
By Natalie Sopinka, Communications Coordinator, Canadian Science Publishing
Campgrounds and cottages are getaways for humans. They are also locations where grizzly bears acquire appetites for human foods high in saturated fats—foods associated with many diseases. A new study published today in the Canadian Journal of Zoology found that, unlike humans, bears do not show symptoms of disease when fed foods high in saturated fats.
Researchers from Washington State University (WSU) fed adult bears one of two diets prior to hibernation: one of oats and salmon, high in “healthy” polyunsaturated fats, and one of beef and cheese, high in “unhealthy” saturated fats. From May to the end of October, the bears maintained their prescribed diet and then hibernated over winter. When they awoke in spring, it was time for a check-up.
Bears on a short-term high saturated fat diet got a relatively clean bill of health—their cholesterol and insulin levels were the same as the bears that ate the diet high in healthy fats. But what about a long-term diet? Evidence of mild inflammation and heart strain raised questions about long-term health.
“While grizzly bears were relatively resistant to developing severe metabolic imbalances or overt clinical disease due to a high saturated fat diet, it is important to note that this study occurred only over a single feeding season,” says Danielle Rivet, who led the study during her graduate studies at WSU. “The heart and inflammation abnormalities detected could manifest into objective symptoms of disease, such as insulin resistance, high cholesterol, or chronic hypertension, in bears relying heavily on garbage in dumpsters or bears in captive facilities over a longer term.”
In autumn, bears feed voraciously, building up body fat that they will metabolize and survive on throughout winter hibernation. Bears can accumulate 30 to 40 percent body fat, percentages considered obese or morbidly obese by human standards.
“Obesity as defined by human standards may be healthy or even necessary for this species to thrive and reproduce,” says Rivet. “But certain types of fats may be better or healthier than others for foraging bears.”
Rivet recommends that the availability of food waste in natural areas inhabited by bears should be eliminated for the health and safety of both bears and humans. Diets of captive bears should be carefully selected to avoid high saturated fat content, she added.
The article, “Systemic effects of a high saturated fat diet in grizzly bears (Ursus arctos horribilis)” by Danielle Rivet, Lynne Nelson, Chantal Vella, Heiko Jansen, and Charles Robbins was published today in the Canadian Journal of Zoology.