The Queen of Fats: Why Omega-3s Were Removed from the Western Diet and What We Can Do to Replace Them

11. THE SPEED OF LIFE

ELEVEN THE SPEED OF LIFE The fire of life seems to burn brighter in some than others. D. S. MILLER, AMERICAN PHYSIOLOGIST READERS WITH A PHILOSOPHICAL BENT MAY ALREADY BE WONDERing why the fats of leaves and the fats of seeds would have such different effects on human health. They may already have hypothesized that the disparity has something to do with the fact that these fats are markers of the changing seasons—as good as, if not better than, light and temperature. Once incorporated into an animal’s cell membranes, they might help an animal prepare for the future: for periods of activity and reproduction, when the fats of leaves are abundant, and periods of hunkering down and survival, when the fats of seeds are more plentiful. These preparations could be accomplished and coordinated by signals of the different fatty acids (as eicosanoids) and by changes in the membranes themselves, since the membrane is the medium in which many enzymes and proteins work, the air in which they breathe. Not all the membranes would have to change with changes in seasons and food supply. Some might be protected from change, as it seems the membranes of the cells of the brain and nervous system are protected. Humans would have benefited from these seasonal changes in their membranes when 120 they were foraging animals, but we ran into trouble when the seasonal became permanent and we began eating high omega-6 diets year-round. This idea makes a great deal of sense, but it is just an idea, the germ of a hypothesis. It’s an idea that only became possible, though, as researchers have learned to distinguish between omega-6s and omega-3s, the two families of fats that humans and other animals cannot make from scratch. Until recently, most researchers grouped the two families together, calling them all polyunsaturated fatty acids, or PUFAs (pronounced poofas). Prior to the 1960s, few had the means to distinguish between them. Times have changed, though, and nature is giving up its secrets to those who know the names of these different fatty acids and who control for them in their experiments. Among these researchers is Lawrence Rudel at Wake Forest University School of Medicine, who found that omega-3 fatty acids, but not omega-6s, decrease atherosclerosis in his experimental animals by creating more fluid cholesterol droplets and increasing the rate of cholesterol hydrolysis and departure from cells (much as Ralph Holman has been suggesting since the 1950s). And Leonard Sauer and Robert Dauchy at the Bassett Research Institute in Cooperstown, N.Y., who find it easy to grow tumors in their experimental animals when those animals are being fed a diet rich in corn oil (linoleic acid), but almost impossible when the corn oil is replaced with fish oil. And Gregory Florant, who studies hibernation, and the cues that trigger it, in the yellow-bellied marmot, a relative of the common hamster and a denizen of Colorado, where Florant works. The role of fats in hibernation was a great puzzle to researchers when they grouped all the polyunsaturates together. No consistent pattern could be found in either the tissues of hibernating animals or the foods they ate. But as soon as Florant THE SPEED OF LIFE 121 FIGURE 7 Tumor growth. Human breast tumors were implanted in both these nude rats, but the tumor in the animal on the bottom is growing much faster than the one in the animal on the top. The only difference is their diet. Fifteen days after implantation, the top animal was switched from a 5% corn oil diet (the control) to a 5% omega-3 diet. Leonard Sauer and Robert Dauchy at the Bassett Research Institute in Cooperstown, N.Y., have run this same experiment using many different lines of human and rat tumors; each time, their results have been similar. If they start the rats out on a 5% omega-3 diet (rather than switching to it after 15 days), they can’t even get the implantations to take. Photo by and courtesy of Leonard Sauer and Robert Dauchy. distinguished between omega-3s and omega-6s, he saw a clear and very revealing pattern. When Florant fed his marmots a diet rich in linseed oil, a diet with an alpha linolenic content close to that of their natural summer diet, they did not go into hibernation when Florant put them in...