Research suggests that omega-3 fatty acids promote health benefits, such as reduced breast cancer risk. But few studies have examined the effect of omega-3s on skeletal muscle cells.
“What is so special about these types of fats that actually make them beneficial rather than harmful?” asks Chris Gerling, a master’s student in the Department of Human Health and Nutritional Sciences. To answer that question, he’s studying the effects of omega-3 supplements on skeletal muscles. His preliminary results suggest that supplementation boosts fat metabolism.
Although a low-fat diet is considered healthy, not all fats are created equal. Some fats are actually good for you – in moderation. Fatty acids are important building blocks in the membranes that surround cells and their organelles.
Researchers believe that taking omega-3 supplements can improve the function of these membranes by altering their structural characteristics. “The theory is that when these omega-3s get into the cell membrane,” says Gerling, “they can affect protein function within those membranes. I want to find out how these omega-3s affect protein function within a muscle cell in terms of energy production.”
Gerling is focusing on the external plasma membrane and the membrane that surrounds the mitochondria, which convert nutrients into usable energy. He’s trying to find out whether omega-3s are incorporated into these membranes and how this may affect the proteins involved in cellular metabolism.
The study involved recreationally active men between 18 and 30. They weren’t allowed to participate if they were already supplementing their diet with omega-3 fatty acids, which tend to linger in the body. “Even after you stop taking them, there appears to be prolonged effects,” says Gerling. “I wanted their omega-3 status to be as low as possible.”
The participants took three grams of omega-3 supplements per day – specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) – for 12 weeks. Current guidelines recommend taking between 0.3 and 0.5 grams, but Gerling says, “Our omega-3 intake isn’t anywhere close to what it should be.” Dietary sources include fatty fish and fortified foods such as eggs and milk.
The participants visited the lab four times before they started taking the supplements and four times after. A maximal oxygen uptake (VO2 max) test determined their body’s maximum capacity to take in and use oxygen. The test involved breathing into a mouthpiece while riding a stationary bicycle for about 10 minutes as the resistance was gradually increased. “We know how much oxygen that’s in the air,” says Gerling, “and we measure how much oxygen that they expire into the mouthpiece to calculate how much they’re actually using.”
Participants also rode a stationary bike for an hour at 60 per cent of their VO2 max, which is considered optimal for fat oxidation. “That’s when you burn the most fat,” says Gerling. The researchers measured their heart rate and collected blood samples every 15 minutes, and sampled oxygen and carbon dioxide every 20 minutes. They used those gas measurements to calculate fat and carbohydrate use during exercise and to see whether the supplements increased fat oxidation.
Participants also underwent muscle biopsies so researchers could examine plasma and mitochondrial membrane proteins involved in energy production. Gerling is especially interested in fat transporter proteins because their amounts could be boosted by omega-3s. “We’re also looking at the composition of the membranes to see if the omega-3 composition is actually different pre- and post-supplementation, and how this may correlate with any changes in protein content or function. If there’s any increase of omega-3s in the membrane, that would indicate a potential positive effect.”