Table 2.

Factors that affect outcomes in Obesity studies leading to conflicting results in clinical intervention trials (Modified from Reference [19]).

- Determination of the composition of the background diet in terms of omega-6 and omega-3 fatty acids and inflammatory markers i.e., US, UK and Northern European countries have the highest amount of LA + AA in their diets, which competes with omega-3 PUFAs; they also have the lowest amount of vegetable and fruit intake, which are needed for optimal absorption of omega-3 PUFA from supplements

- Background inflammation

- Some studies are using fish and others omega-3 supplements; studies show that a continuous daily intake of omega-3 supplements leads to higher concentrations in the blood than eating fish two times/week

- Variation in the dose of omega-3 fatty acids

- Variation in the number of subjects

- Variation in the severity of disease

- Variation in the pharmacologic treatment

- Genetic variants predisposing to Obesity

- Dietary intake by means of questionnaires instead of actual measurements of omega-3 PUFAs in the red blood cell membrane phospholipids or plasma is a major problem that leads to conflicting results

- Length of intervention

- Genetic variants in the metabolism of omega-6 and omega-3 fatty acids