Comparison of the effect of rapeseed oil or amaranth seed oil supplementation on weight loss, body composition, and changes in the metabolic profile of obese patients following 3-week body mass reduction program: a randomized clinical trial

Background: Amaranth seed oil (ASO) and rapeseed oil (RSO) are functional foods that display antioxidant and hepatoprotective properties. These oils are also known to lower glucose and cholesterol levels. The current study compared the effects exerted by RSO and ASO on weight loss and metabolic parameters during a 3-week body mass reduction program.

Methods: Eighty-one obese subjects (BMI > 30 kg/m²), aged 25-70 years, were enrolled in a 3-week body mass reduction program based on a calorie-restricted diet and physical activity. Participants were randomly categorized into an AO group (administered 20 mL/d of ASO), a RO group (administered 20 mL/d of RSO), and a C group (control; untreated). Anthropometric and metabolic parameters were measured at baseline and endpoint.

Results: Significant decreases in weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), fat mass (FM), lean body mass (LBM), visceral fat mass (VFM), and total body water (TBW%) were observed in all groups (P < 0.05). No significant improvements were observed in the clinical parameters of group C. Fasting insulin (Δ - 5.9, and Δ - 5.7) and homeostatic model assessment of insulin resistance (HOMA-IR) (Δ - 1.1 and Δ - 0.5) were decreased in both RO and AO groups, respectively. Fasting glucose (Δ -8.5; P = 0.034), total cholesterol (Δ -14.6; P = 0.032), non-HDL cholesterol (Δ 15.9; P = 0.010), TG/HDL ratio (Δ -0.6; P = 0.032), LDL cholesterol (Δ -12.3; P = 0.042), and triglycerides (Δ -6.5; P = 0.000) were significantly improved in the AO group, compared to the RO group.

Conclusions: The 3-week body mass reduction intervention caused a significant reduction in the weight, BMI, WC, HC, FM, and VFM of all groups. Except for HOMA-IR, there were no statistical differences between the clinical parameters of all groups. However, a trend toward improved insulin levels and HDL% was noticeable in AO and RO. Therapies involving edible oils with high nutritional value, such as RSO and ASO, show potential for improving metabolic measurements during body mass reduction programs. Thus, obese patients undertaking weight reduction programs may benefit from RSO and ASO supplementation.

Trial registration: retrospectively registered, DRKS00017708.

Keywords: Amaranth seed oil; Body composition; Metabolic profile; Rapeseed oil; Weight loss.