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April 1, 2011
Omega-3 fatty acids protect against the development of obesity-related disease
An article published online on March 23, 2011 in the European Journal of Clinical Nutrition reveals a protective effect for high omega-3 fatty acid intake against the development of diseases related to obesity, including cardiovascular disease and diabetes.
For the current study, Zeina Makhoul, PhD and her colleagues at Fred Hutchinson Cancer Research Center, in collaboration with the Center for Alaska Native Health Research at the University of Alaska-Fairbanks, evaluated data from 330 Yup’ik Eskimos. Omega-3 fatty acid intake among the Yup'iks averages twenty times higher than most Americans.
Triglycerides, glucose, insulin, leptin and C-reactive protein (CRP, a marker of inflammation) were measured in the participants' blood samples, and dietary questionnaire responses were analyzed for the intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from such sources as salmon, sardines and other fatty fish. Among subjects with lower blood levels of EPA and DHA, having a high body mass index was correlated with high triglycerides and C-reactive protein, both of which are associated with an increased risk of cardiovascular disease and possibly diabetes. "These results mimic those found in populations living in the Lower 48 who have similarly low blood levels of EPA and DHA," senior author Alan Kristal, DrPH reported. "However, the new finding was that obesity did not increase these risk factors among study participants with high blood levels of omega-3 fats."
"Because Yup'ik Eskimos have a traditional diet that includes large amounts of fatty fish and have a prevalence of overweight or obesity that is similar to that of the general U.S. population, this offered a unique opportunity to study whether omega-3 fats change the association between obesity and chronic disease risk," stated Dr Makhoul, who is a postdoctoral researcher in the Cancer Prevention Program of the Public Health Sciences Division at the Fred Hutchinson Center. "Interestingly, we found that obese persons with high blood levels of omega-3 fats had triglyceride and CRP concentrations that did not differ from those of normal-weight persons. It appeared that high intakes of omega-3-rich seafood protected Yup'ik Eskimos from some of the harmful effects of obesity."
Although the prevalence of being overweight among the study population is similar to that of most Americans, their rate of diabetes is only half as high. "While genetic, lifestyle and dietary factors may account for this difference, it is reasonable to ask, based on our findings, whether the lower prevalence of diabetes in this population might be attributed, at least in part, to their high consumption of omega-3-rich fish," Dr Makhoul speculated.
The researchers recommend that a clinical trial be conducted to help confirm whether increased omega-3 fatty acids reduce obesity's effect on triglycerides and inflammation. "If the results of such a trial were positive, it would strongly suggest that omega-3 fats could help prevent obesity-related diseases such as heart disease and diabetes," Dr Makhoul concluded.
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The risk of death from all causes, including cardiovascular disease and cancer, increases with rising obesity in both men and women in all age groups, and the risk associated with a high BMI is greater for whites than for blacks (Calle et al 1999).
Obesity increases the risk of developing metabolic syndrome and coronary heart disease (Shirai 2004); type 2 diabetes (Mensah et al 2004); osteoarthritis of major load-bearing joints, such as the knee (Felson et al 1997); hypertension (high blood pressure); sleep apnea (periods of suspended breathing during sleep) (Wolk et al 2003); and gall bladder disease (Petroni 2000).
The International Agency for Research on Cancer has classified obesity as a critical causal risk factor for cancers of the colon, breast (postmenopausal women), endometrium, kidney (renal cell), and esophagus (adenocarcinoma) (Calle et al 2004).
A study reported in the Journal of the American Medical Association suggests that obesity causes 111,909 deaths annually (Flegal et al 2005), while epidemiological evidence shows that a lower body weight is associated with lower mortality risk (Stevens 2000). In the well-known Framingham Heart Study, risk of death increased by 1 percent for each extra pound (0.45 kg) of weight between age 30 and 42 and increased by 2 percent between age 50 and 62 (Solomon et al 1997; Kopelman 2000).
Essential fatty acids (omega-3) found in fish oils promote thermogenesis, the process by which foods are converted to heat. Because of this, the body burns calories instead of converting them into fat for storage (McCarty 1994). Another benefit of essential fatty acids is to make cell membranes more sensitive to the effects of insulin (Storlien et al 1986, 1987, 1996; Borkman et al 1993; Vessby et al 1994; Pan et al 1995).
Eating fish is an excellent way to promote weight loss. Many people also choose to take essential fatty acid supplements that are high in EPA and DHA extracted from fish oils. Consuming cold-water fish (e.g., salmon, herring, and mackerel) and fish oil supplements favorably influences hormone-like substances in the body known as prostaglandins, specifically PgE1, conferring a protective effect against chronic inflammation and vascular disease, common in overweight individuals (Maachi et al 2004).
Life Extension Magazine® April, 2011 Issue Now Online!
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