Applied nutritional investigationEffects of peanut oil load on energy expenditure, body composition, lipid profile, and appetite in lean and overweight adults
Introduction
Cardiovascular disease, diabetes, and high blood pressure will account for 75% of all deaths in developing nations by the year 2020, according to the World Health Organization [1]. Obesity is a risk factor for these disorders [2] and its prevalence has increased markedly over the past 25 y [3]. The prevention and management of overweight/obesity is a public health priority because it is expected to decrease the occurrence and complications of comorbidities.
Dietary guidance aimed at prevention of weight gain frequently includes a limitation on consumption of energy-dense foods in an attempt to limit total caloric intake. Despite their high energy density, inclusion of nuts in the diet is not associated with body weight gain [4], [5], [6], [7], [8], [9], [10]. Several factors may account for this observation. The high satiety value of nuts and noted inefficiencies in nut energy absorption may result in reduced total energy intake and fat bioaccessibility [11], [12], [13], [14]. Monounsaturated fatty acids (MUFAs) and protein content of peanuts may increase resting metabolic rate and diet-induced thermogenesis (DIT) [10], [15], [16]. This would decrease energy deposition in the body.
The fatty acid composition of nuts may also have beneficial effects on blood lipid profiles. Substitution of dietary saturated fatty acids (SFAs) with MUFAs leads to increased high-density lipoprotein (HDL) cholesterol and decreased low-density lipoprotein (LDL) cholesterol, triacylglycerol (TAG), lipid oxidation, and LDL susceptibility to oxidation [5], [17], [18]. Dietary MUFA has also been shown to elicit a smaller postprandial lipemic response [19] with lower chylomicron remnant concentration [20]. Addition of peanuts or other MUFA-rich nuts to the diet significantly improves the blood lipid profile [6], [21].
The effects of peanut oil on satiety are not well characterized. Studies in rats have shown that unsaturated fats, which comprise approximately 40% [22] of a peanut’s energy content, elicit stronger satiety effects than do saturated fats [23]. This suggests that substitution of dietary saturated fat with peanuts could aid in appetite management. However, limited evidence has failed to support a stronger effect of peanut oil on appetite than other fat sources [24], [25]. It is not clear whether the lean and overweight differ in appetitive responses to dietary challenges, especially for high-energy density foods, such as nuts and peanuts. Therefore, the present study evaluated the effects of peanut oil (high in MUFAs) on appetite, body weight, energy expenditure, body composition, and lipid profile in lean and overweight individuals.
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Subjects
Forty-eight healthy, non-smoking men (n = 24) and women (n = 24) 18 to 50 y of age completed the study (Table 1). Fifty percent of participants were lean (body mass index <25 kg/m2) and 50% were overweight (body mass index 25–30 kg/m2). The 24 overweight subjects were recruited in the Universidade Federal de Viçosa (Viçosa, Brazil) and the 24 lean subjects were recruited from Purdue University (West Lafayette, IN, USA), the Food Research Institute (Accra, Ghana), and Universidade Federal de
Dietary assessment
Energy and nutrient intakes of lean and overweight subjects are listed in Table 1. Median energy intake of the lean participants tended to be higher during weeks 4 and 8 compared with baseline, but not significantly. Lean participants compensated for 66% of the oil load. In contrast, energy intake was significantly higher than baseline in the overweight group at weeks 4 and 8. This group had a very weak compensatory dietary response (4%). For lean and overweight participants, dietary fat was
Discussion
Epidemiologic studies and clinical interventions have shown that nut consumption is associated with stable or lower body weight [4], [5], [10], [19], [34], [35]. The present study indicates that peanut oil ingestion, at a level of 30% of REE, leads to a significant increase in body weight (∼2.4 kg) among overweight individuals. The increment is attributable largely to increased fat mass. The mean change for the lean participants was slightly larger (∼2.6 kg) but, due to greater variance, was
Conclusion
Data support beneficial effects of peanuts on lipid profiles and a limited effect on energy balance. The influence of peanut fatty acid composition was hypothesized to explain it, but data failed to support this view. These data also showed differential responses of lean and overweight individuals to peanut oil ingestion.
Acknowledgments
The authors thank Amy Devitt for thoughtful suggestions and editing.
References (48)
Defining overweight and obesitywhat are the issues?
Am J Clin Nutr
(2000)- et al.
High-monounsaturated fatty acid diets lower both plasma cholesterol and triacylglycerol concentrations
Am J Clin Nutr
(1999) - et al.
Walnuts lower serum cholesterol in Japanese men and women
J Nutr
(2000) - et al.
Pecans lower low-density lipoprotein cholesterol in people with normal lipid levels
J Am Diet Assoc
(2000) - et al.
Effects of diets enriched in almonds on insulin action and serum lipids in adults with normal glucose tolerance in type 2 diabetes
Am J Clin Nutr
(2002) - et al.
The effect of intestinal infusion of long-chain fatty acids on food intake in humans
Gastroenterology
(2000) - et al.
Role of cell walls in the bioaccessibility of lipids in almond seeds
Am J Clin Nutr
(2004) - et al.
Thermic effect of feeding carbohydrate, fat, protein and mixed meals in lean and obese subjects
Am J Clin Nutr
(1985) - et al.
Lowering dietary saturated fat and total fat reduces the oxidative susceptibility of LDL in healthy men and women
J Nutr
(2000) - et al.
Low-fat and high-monounsaturated fatty acid diets decrease plasma cholesterol ester transfer protein concentrations in young, healthy, normolipemic men
Am J Clin Nutr
(2000)
Assessment of fat-free mass using bioelectrical impedance measurements of the human body
Am J Nutr
The validity of appetite ratings beliefs
Appetite
A satiety quotienta formulation to access the satiating effect of food
Appetite
Effects of walnut consumption on plasma fatty acids and lipoprotein in combined hyperlipidemia
Am J Clin Nutr
Partial replacement of saturated fatty acids with almonds on plasma cholesterol and lipoproteins
Am J Clin Nutr
Fuel partitioning and food intake
Am J Clin Nutr
A changing role for dietary monounsaturated fatty acids
J Am Diet Assoc
Increasing prevalence of overweight among US adultsthe National Health and Nutrition Examination Surveys 1960 to 1991
JAMA
A possible protective effect of nut consumption on risk of coronary heart diseasethe Adventist Health Study
Arch Intern Med
Effect on body weight of a free 76 kilojoule (320 calorie) daily supplement of almonds for six months
J Am Coll Nutr
Effects of chronic peanuts consumption on energy balance and hedonics
Int J Obes Relat Metab Disord
Effects of food attributes on hunger and food intake
Int J Obes Relat Metab Disord
Comparison of the effects on satiety and eating behavior of infusion of lipids into the different regions of the small intestine
Gut
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This work was supported by USAID Prime Agreement No. LAG-G-00-96-00013-00 under the University of Georgia Subcontract No. RC710-013/4092094 (Peanut CRSP).