Although the mechanisms are not well understood, omega-3 fatty acids are well studied for a variety of health benefits. Upon analysis, scientists discovered one of the chief ways omega-3s confer benefits is by impacting adult human metabolism on a variety of levels. Many of the studies discuss increased "lipid oxidation," which is simply the scientific terminology for burning fat cells faster. Enhanced lipid oxidation hasn't been observed in children; however, fat burning is only one of one of many ways omega-3s can help you become healthier.
Adolescent Metabolism
Childhood obesity is a growing public health problem prompting researchers reporting in the May 2011 issue of the "Journal of Nutrition and Metabolism" to investigate if omega-3s could speed up fat burning during the pubertal growth spurt. They enrolled 78 slightly overweight boys between the ages of 13 and 15 and randomly assigned them to consume 1.1 g of either omega-3 oils or placebo every day for 16 weeks. The omega-3 group did not lose any more weight than did the placebo group. The researchers offered no explanation, except to note that both groups lost some weight attributed to cutting sugar intake.
Young Adult Metabolism
In the May 2009 issue of "Public Health and Nutrition," a group of Icelandic researchers published a study involving 324 overweight Europeans between the ages of 20 and 40 in a dietary study aimed at promoting fish consumption for general health benefits. For eight weeks the subjects ate meals with varying levels of fish and had their blood tested for omega-3 levels to prove compliance. An unexpected result was weight loss among those with the highest omega-3 levels. These subjects lost an average of 8 percent body weight, attributed to omega-3s' fat-burning properties.
Ghrelin Metabolism
A March 2009 issue of the "European Journal of Nutrition" reports on the Icelandic study above from a different perspective. They sought to determine if omega-3s impact leptin and ghrelin, which are hormones responsible for regulating weight. Leptin signals the brain to burn calories and reduce appetite. Ghrelin signals the brain to slow metabolism and increase appetite. The researchers found that leptin levels decreased while ghrelin levels increased in those who lost weight. To explain the apparent contradiction, the researchers suggested that omega-3s impair ghrelin metabolism by replacing it on receptor cells and blocking its signals to the brain.
Elderly Muscle Metabolism
The February 2011 issue of the "American Journal of Clinical Nutrition" reports good news for people aged 65 and over. Noting that omega-3s stimulate protein metabolism in animal experiments, the researchers hoped to find the same benefit in humans. Sixteen elderly adults were randomly assigned to receive 2.3 g of either omega-3 or placebo every day for eight weeks. At the end of the trial, the omega-3 group had built significantly more muscle as a result of increased amino acids and insulin availability. Amino acids are the building blocks of muscle protein and insulin moves amino acids into muscle cells.
References
- "Journal of Nutrition and Metabolism"; The Effect of Dietary Fish Oil in Addition to Lifestyle Counselling on Lipid Oxidation and Body Composition in Slightly Overweight Teenage Boys; Maiken Pedersen et al.; May 2011
- "Public Health and Nutrition"; Fish Consumption Among Young Overweight European Adults and Compliance to Varying Seafood Content in Four Weight Loss Intervention Diets; Inga Thorsdottir et al.; May 2009
- "European Journal of Nutrition"; Effects of Seafood Consumption and Weight Loss on Fasting Leptin and Ghrelin Concentrations in Overweight and Obese European Young Adults; Alfons Ramel et al.; March 2009
- "American Journal of Clinical Nutrition"; Dietary Omega-3 Fatty Acid Supplementation Increases the Rate of Muscle Protein Synthesis in Older Adults: a Randomized Controlled Trial; Gordon Smith et al.; February 2011
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