Abstract
Background: Obesity has been associated with several major health compromising risk factors, including high blood cholesterol, insulin resistance and hypertension, giving increased risk of developing cardiovascular diseases (CVD), metabolic syndrome (MetS) and type 2 diabetes (T2D). A group of obese individuals, metabolically healthy (MH) obese, appear to be more resistant to the development of metabolic disturbances normally associated with obesity. In contrast, metabolically unhealthy (MU) normal weight, are individuals who develop metabolic disturbances usually associated with obesity, despite a body mass index (BM) within the normal range. Metabolic disturbances may affect fatty acid metabolism and desaturase activity. Exploring fatty acid profile and desaturase activity in MH and MU individuals might contribute to understand why individuals within the same BMI group have different metabolic profiles. Aim: The overall aim was to explore fatty acid profile in blood and estimated desaturase activity in MH and MU individuals. Method and sample: This cross-sectional study used participants and data from the The Vascular lifestyle-Intervention and Screening in phArmacies (VISA) study. Participants were first categorized as MH (n=150) and MU (n=52), and further stratified by BMI into six groups, MH and MU normal weight, overweight and obese. Fatty acid product to precursor ratios were used to estimate activity of SCD (C16:1n7/C16:0 and C18:1n9/C18:0), D6D (C18:3n6/C18:2n6 and 20:3n6/18:2n6) and D5D (C20:4n6/C20:3n6). Results: The MU had significantly higher levels of C14:0, C16:0, C16:1n7, C18:1n9, total monounsaturated fatty acids (MUFA), C18:3n3 and SCD, and significantly lower levels of C18:0, C18:2n6, C20:4n6, C20:5n3, C22:5n3, C22:6n3, total polyunsaturated fatty acids (PUFA), total n6 fatty acids and D5D compared to the MH. Many of these differences remained when the two groups were further stratified by BMI, particularly among the overweight and obese subjects. Levels of physical activity were higher in MH than MU. Conclusions: Levels of SFAs (except C18:0) and MUFAs and estimated SCD activity were higher in MU subjects, while levels of most PUFAs and D5D appeared to be higher in MH subjects. These differences were maintained when stratified into BMI subgroups. More studies are needed to confirm if changes in fatty acid profile and desaturase activity may influence metabolic profile.