Starve a Bear, Feed a Heart Attack

Black bears pull off some metabolic marvels in their sleep, as I wrote in this column not too long ago. If their tricks of recycling calcium and urea while they hibernate could be transferred to human beings, we'd be a healthier and longer-lived species.

A friend drew my attention to a report about the metabolic functioning of another kind of bear. From this research, it looks as if the message in the bear's blood might translate into human benefit fairly quickly.

In this case, the bears of interest are the sea-going terrors of the whole High Arctic, polar bears. If polar bears were people, they'd be frequently scolded by dietitians. Those big white bears pudge up on blubber. They gorge on fat. When they catch a seal, they usually chow down on its hide and the layer of fat under the skin. Often enough, they leave the lean portions of the carcass for birds and foxes to scavenge.

When they can't catch nice fat seals, polar bears dine infrequently or not at all. These bears are more carnivorous than their cousins to the south---berries don't have much appeal. Roots and sprouts rank even lower on their food-preference lists. (Besides, they're not often found on the sea ice.)

Going by the human model, it's easy to predict that a happily feeding polar bear, with an ideal diet (from the bear's point of view) approaching 100 percent animal fat, would have terrifically high levels of blood cholesterol. Easy, but incorrect. An environmental physiologist at the University of Iowa, G. Edgar Folk, Jr., reports that a fat-fed polar bear has splendidly healthy blood.

In fact, blood taken from bears during the seal-free season showed levels of cholesterol nearly 25 percent higher than blood taken while the bears had plenty of seal blubber to eat. The level of triglycerides, another fatty substance implicated in clogging arteries, is nearly 50 percent higher while the bears are fasting than while they're feeding,

What a well-fed bear's blood does have is plenty of omega-3 fatty acid---10 times more than in a fasting bear. Studies with human volunteers have shown that omega-3 fatty acids in the diet reduce cholesterol in the blood stream. That finding delighted fishermen, because fish oil is a great source of omega-3 fatty acids.

The bears don't eat fish, but seals do. Physiologist Folk thinks the bears are benefiting from the seals' fish-oily diet. His contention apparently has been supported by another study of the causes of death for 8000 Canadian Inuit. Heart disease in this population is only one-fourth that of the Canadian population as a whole. The proportion of fat in their diet is much higher than for other Canadians, but most of it is fat from oily fish or blubber.

I suspect this research will cause some delight in Kotzebue, Barrow, and other coastal points. But, even if blubber is as good for you as wise elders have always claimed, I don't think we'll be finding muktuk next to the bean sprouts in the health-food stores anytime soon.

The research on polar bears' bloodstreams may lead to better health for human arteries in other ways. Fatty fish such as salmon should become more popular menu items---good news indeed for Alaska's fisherfolk. And we may find more experiments attempting to incorporate omega-3 fatty acids into our diets by feeding them to other things we like to eat---or at least some of us terrestrially centered omnivores hope so. I look forward to the day when well-marbled steaks and greasy hamburgers loaded with omega-3 fatty acids appear next to the bean sprouts on the health-food shelves!