
The researchers hypothesized that a diet rich in omega-3s could lead to greater weight loss in obese individuals. To test this, they recruited 137 obese volunteers and divided them into two groups, each following a different diet designed for weight loss but containing the same total fat content with varying types of fats:
Both groups were instructed to avoid fish and seafood, which are rich in EPA and DHA, to isolate the effects of flaxseed-derived omega-3s from animal feed on human health.
The study’s findings were compelling in two key areas:
In fact, the amount of omega 3 in the red blood cell membranes of the experimental group increased significantly (the omega 3 fatty acid content of red blood cells is considered a tissue marker of the fatty acid composition of the diet). In addition, the levels of EPA and DHA, ALA-derived omega-3s contained in the flaxseed flour fed to the study animals, were maintained despite the very limited conversion of ALA to EPA and DHA in the body (0.5% for DHA) and in the absence of fish and seafood consumption.
The benefits of introducing flaxseed flour into animal and/or human diets are therefore clear.
In addition, the anthropometric parameters measured (weight, BMI, hip circumference), which had fallen in an equivalent manner for all participants during the study, ultimately evolved differently after the experiment. Approximately 5 months after the study (150 days later), the control group experienced significant weight gain, BMI and hip circumference increases, unlike the experimental group. This finding suggests that omega 3s have a real role to play in preventing weight regain in obese people.
The results relating to omega-3 levels in red blood cell membranes, but above all those relating to anthropometric parameters in this study, therefore revealed a novel role for omega-3 in inhibiting weight regain, or at least preventing it. It is also important to understand that, rather than omega-3s playing a specific role, this phenomenon is more a question of improving the omega-6/omega-3 ratio (by reducing omega-6 intake, which is often excessive, or by increasing omega-3 intake). These fatty acids are processed by the same enzyme in the body, and therefore compete with each other. Excessive intake of omega-6s means that their transformation, and therefore their availability, takes precedence over that of omega-3s. Consumption of omega-6s is nevertheless necessary, but their adipogenic properties (which promote the production of fatty tissue) explain the need to limit them.
The importance of balancing omega-6 and omega-3 fatty acids is further reinforced by the observation that the diet with a low omega-6/omega-3 ratio (optimal) also contained a significant proportion of saturated fats (a lipid type to limit) yet still led to significant weight loss. Cholesterol levels (total, HDL, LDL) remained similar among participants, emphasizing the priority of achieving the correct balance of polyunsaturated fatty acids. Saturated fat quantity may thus be secondary in determining weight outcomes.