Effects of lupin-enriched foods on body composition and cardiovascular disease risk factors: a 12-month randomized controlled weight loss trial.

BACKGROUND: Regular consumption of diets with increased protein or fibre intakes may benefit body weight and composition and cardiovascular disease risk factors. Lupin flour is a novel food ingredient high in protein and fibre. OBJECTIVE: To investigate the effects of a lupin-enriched diet, during and following energy restriction, on body weight and composition and cardiovascular disease risk factors in overweight individuals. DESIGN: Participants (n = 131) were recruited to a 12-month parallel-design trial. They were randomly assigned to consume lupin-enriched foods or matching high-carbohydrate control foods. All participants underwent 3 months of weight loss, 1 month of weight stabilization and 8 months of weight maintenance. Body weight and composition and cardiovascular disease risk factors were assessed at baseline, 4 and 12 months. RESULTS: Lupin, relative to control, did not significantly influence (mean difference (95% CI)) weight loss at 4 months (0.1 kg (-1.2, 1.4)) and 12 months (-0.6 kg (-2.0, 0.8)), maintenance of weight loss from 4 to 12 months (-0.7 kg (-1.83, 0.48)) or measures of body fat and fat-free mass. Relative to control, 24-h ambulatory systolic (-1.3 mm Hg (-2.4, -0.3), P = 0.016) and diastolic (-1.0 mm Hg (-1.9, -0.2), P = 0.021) blood pressures were lower at 12 months but not at 4 months; fasting insulin concentrations and homeostasis model assessment (HOMA) scores were significantly lower at 4 months (-1.2 mU l(-1) (-1.3, -1.1), P = 0.004 and -0.6 units (-1.0, -0.19), P = 0.004) and 12 months (-1.3 mU l(-1) (-1.4, -1.1), P < 0.001 and -0.7 units (-1.1, -0.24), P = 0.002). CONCLUSIONS: A diet higher in protein and fibre derived from lupin-enriched foods does not enhance weight loss or improve the maintenance of weight loss. However, such a diet may provide cardiovascular health benefits in terms of insulin sensitivity and blood pressure.

Effects of increasing dietary protein and fibre intake with lupin on body weight and composition and blood lipids in overweight men and women.

BACKGROUND: Lupin kernel flour (LKF) is a novel food ingredient that is high in protein and fibre. We have previously shown that partial substitution of refined wheat-derived carbohydrate in bread with protein and fibre from LKF can reduce appetite and energy intake acutely. In addition, several studies have suggested that lupin may reduce cholesterol concentrations and benefit glucose and insulin metabolism. AIM: The aim of this study was to investigate the effects on body weight and composition and blood lipids, glucose and insulin of an ad libitum LKF-enriched diet higher in dietary protein and fibre. SUBJECTS AND METHODS: A total of 88 overweight and obese men and women were recruited for a 16-week parallel-design randomized controlled trial. Participants replaced 15-20% of their usual daily energy intake with white bread (control) or LKF-enriched bread (lupin) in an ad libitum diet. Measurements of body weight and composition, and fasting blood biochemical measurements were performed at baseline and 16 weeks. The primary analysis included 74 participants (37 per group) who completed the intervention. RESULTS: At baseline, mean (+/-s.d.) body mass index and total cholesterol were 30.6+/-3.5 kg m(-2) and 5.37+/-0.94 mmol l(-1), respectively. Estimated (mean between-group difference (95% confidence interval)) protein (13.7 (2.28, 25.0) g per day) and fibre (12.5 (8.79, 16.2) g per day) intakes were higher during the intervention with lupin than with control. For lupin relative to control, the net effects on body weight (-0.4 (-1.3, 0.6) kg), fat mass (-0.5 (-1.1, 0.2) kg) and percentage (-0.5 (-1.1, 0.1)%), plasma leptin (-1.66 (-4.91, 1.59) ng ml(-1)) and adiponectin (0.20 (-0.73, 1.13) mg l(-1), as well as serum total cholesterol (-0.08 (-0.38, 0.22) mmol l(-1)), triglycerides (0.09 (-0.10, 0.21) mmol l(-1)), glucose (0.10 (-0.11, 0.30) mmol l(-1)) and insulin (0.40 (-1.20, 2.00) mU l(-1)) were not significant. CONCLUSIONS: This study does not support the proposal that an ad libitum diet enriched in LKF resulting in moderate changes in both protein and fibre intakes can benefit body weight and composition or fasting blood lipids, glucose and insulin concentrations in overweight men and women with mildly elevated total cholesterol concentrations.