Effects of peanut processing on body weight and fasting plasma lipids.

Peanuts and peanut butter are commonly consumed as a snack, meal component and ingredient in various commercial products. Their consumption is associated with reduced CVD risk and they pose little threat to positive energy balance. However, questions have arisen as to whether product form (e.g. whole nut v. butter) and processing properties (e.g. roasting and adding flavours) may compromise their positive health effects. The present study investigated the effects of peanut form and processing on two CVD risk factors: fasting plasma lipids and body weight. One hundred and eighteen adults (forty-seven males and seventy-one females; age 29.2 (sd 8.4) years; BMI 30.0 (sd 4.5) kg/m2) from Brazil, Ghana and the United States were randomised to consume 56 g of raw unsalted (n 23), roasted unsalted (n 24), roasted salted (n 23) or honey roasted (n 24) peanuts, or peanut butter (n 24) daily for 4 weeks. Peanut form and processing did not differentially affect body weight or fasting plasma lipid responses in the total sample. However, HDL-cholesterol increased significantly at the group level, and total cholesterol, LDL-cholesterol and TAG concentrations decreased significantly in individuals classified as having elevated fasting plasma lipids compared with those with normal fasting plasma lipids. These observations suggest that the processing attributes assessed in this trial do not compromise the lipid-lowering effects of peanuts, and do not negatively impact body weight. Further studies are warranted to determine the effects of form and processing on other health risk factors.

Regular peanut consumption improves plasma lipid levels in healthy Ghanaians.

OBJECTIVE: To determine whether the daily intake of 2,092 kJ (500 kcal) from peanuts will improve the lipid profiles and diet quality of healthy Ghanaians. DESIGN: A 30-week, randomized, cross-over trial study was conducted with healthy adults. METHOD: There were three treatment arms: Treatment 1 (T1), subjects were provided 2,092 kJ/day (500 kcal/day) peanuts to incorporate into their daily diet for 8 weeks at any time and in any form they chose; Treatment 2 (T2), subjects were provided 2,092 kJ/day (500 kcal/day) peanuts and were instructed to consume them in addition to their customary daily diet for 3 weeks; Treatment 3 (T3), substitution of 2,092 kJ/day fat, with energy from peanuts. Total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol and triglyceride were measured at baseline, week 4 and week 8 (T1 and T3) or at baseline and week 3 (T2). Three-day dietary intake records were kept during each treatment. RESULTS: There was significant decrease in total cholesterol (7.2%) and triacylglycerol (20.0%) after T1. However, individually, high-density lipoprotein-cholesterol and low-density lipoprotein-cholesterol levels did not change significantly. Total fat intake increased by 9%, due to elevations of monounsaturated fatty acid of 60% and polyunsaturated fatty acid of 50%. Similar non-significant trends were observed during T2 and T3. CONCLUSION: The results suggest that regular consumption of peanuts lowers the total cholesterol and triacylglycerol concentrations among healthy Ghanaians. Regular consumption of peanuts should therefore be encouraged.

Effects of peanut oil load on energy expenditure, body composition, lipid profile, and appetite in lean and overweight adults.

OBJECTIVE: We evaluated the effects of peanut oil intake on appetite, energy expenditure, body composition, and lipid profile in lean and overweight adults. METHODS: In a parallel-arm, long-term feeding trial, lean and overweight participants received a daily peanut oil load in a milk shake equivalent to 30% of their resting energy expenditure for 8 wk. Forty-eight adults (24 lean and 24 overweight, 12 male and 12 female in each group) completed the protocol. Anthropometric indices, appetite, dietary intake, energy expenditure, and plasma lipids were monitored. RESULTS: Energy intake increased significantly in the overweight but not in the lean participants. A statistically significant body weight gain (median 2.35 kg) was also observed among the overweight subjects, although this corresponded to only 43% of the theoretical weight gain. Among overweight subjects, high-density lipoprotein cholesterol increased significantly and low-density lipoprotein cholesterol decreased at week 4, but neither concentration was significantly different from baseline at week 8. Similar, but less marked, changes were observed in lean subjects. Resting energy expenditure was 5% greater (P < 0.01) in the overweight group, but no significant difference was observed in the lean subjects. No marked differences of appetite were observed over time in either group or between overweight and lean participants. CONCLUSION: These data indicate that ingestion of peanut oil elicits a weaker compensatory dietary response among overweight compared with lean individuals. Body weight increased, albeit less than theoretically predicted. The weaker effect of whole nuts on body weight reported in previous studies suggests components other than oil may be responsible.