Dietary Omega-6/Omega-3 Polyunsaturated Fatty Acid (PUFA) and Omega-3 Are Associated With General and Abdominal Obesity in Adults: UK National Diet and Nutritional Survey

Introduction The link between dietary fats and obesity is still controversial, as in Western diets the percentage of energy from total fat has decreased while the intake of omega-6 has increased, and omega-3 decreased. These changes have corresponded with a significant increase in the prevalence of obesity. Objective This study aims to examine the association of percentages of energy intake (EI) from omega-3 and omega-6 and Σω-6/Σω-3 ratio with BMI and two proxy indicators of central obesity (waist circumference [WC], waist-to-height ratio [WHtR]) and relative fat mass (RFM) estimator of whole-body fat. Design A representative sample of 3,733 adults was used from the UK National Diet and Nutrition Survey Rolling Programme (2008/09-2018/19). An estimated four-day food record was used to calculate dietary intake. Regression models were used to verify the association of omega-3 and omega-6 and quintiles of Σω-6/ Σω-3 ratio with general and abdominal obesity with adjustment for important confounders. A p-value of <0.05 represented statistical significance. Results The findings of this study show that the average ratio of Σω-6/Σω-3 was 5.5:1 ± 2. There was a significant association between the ratio of Σω-6/Σω-3 and BMI, WC, WHtR and RFM. However, the percentage of total EI from total fat was only significant with BMI, while the percentage of EI from omega-3 was negatively associated with WC, WHtR and RFM. No association was found between the percentage of EI from omega-6 and general or abdominal obesity. Conclusion The effect of Σω-6/Σω-3 may be largely driven by a deficiency in the intake of omega-3. Omega-6 and omega-3 should be listed as such in national surveys instead of polyunsaturated fatty acid (PUFA). Meeting recommended levels of omega-3 and lowering Σω-6/Σω-3 are imperative to establish healthier dietary patterns and prevent obesity.