Prospective study of nut consumption; long-term weight change; and obesity risk in women
BACKGROUND: Data concerning the long-term association between nut consumption and weight change in a free-living population are sparse. OBJECTIVE: The objective was to determine the relation between nut consumption and long-term weight change. DESIGN: The participants were 51;188 women in the Nurses' Health Study II aged 20-45 y; who had no cardiovascular disease; diabetes; or cancer. We prospectively evaluated the dietary intake of nuts and subsequent weight changes from 1991 to 1999. RESULTS: Women who reported eating nuts > or =2 times/wk had slightly less mean (+/- SE) weight gain (5.04 +/- 0.12 kg) than did women who rarely ate nuts (5.55 +/- 0.04 kg) (P for trend < 0.001). For the same comparison; when total nut consumption was subdivided into peanuts and tree nuts; the results were similar (ie; less weight gain in women eating either peanuts or tree nuts > or =2 times/wk). The results were similar in normal-weight; overweight; and obese participants. In multivariate analyses in which lifestyle and other dietary factors were controlled for; we found that greater nut consumption (> or =2 times/wk compared with never/almost never) was associated with a slightly lower risk of obesity (hazard ratio: 0.77; 95% CI: 0.57; 1.02; P for trend = 0.003). CONCLUSIONS: Higher nut consumption was not associated with greater body weight gain during 8 y of follow-up in healthy middle-aged women. Instead; it was associated with a slightly lower risk of weight gain and obesity. The results of this study suggest that incorporating nuts into diets does not lead to greater weight gain and may help weight control.
Mastication of almonds: effects of lipid bioaccessibility; appetite; and hormone response
BACKGROUND: Epidemiologic and clinical data indicate that nuts can be incorporated into the diet without compromising body weight. This has been attributed to strong satiety properties; increased resting energy expenditure; and limited lipid bioaccessibility. OBJECTIVE: The role of mastication was explored because of evidence that the availability of nut lipids is largely dependent on the mechanical fracture of their cell walls. DESIGN: In a randomized; 3-arm; crossover study; 13 healthy adults (body mass index; in kg/m(2): 23.1 +/- 0.4) chewed 55 g almonds 10; 25; or 40 times. Blood was collected and appetite was monitored during the following 3 h. Over the next 4 d; all foods were provided; including 55 g almonds; which were consumed under the same chewing conditions. Complete fecal samples were collected. RESULTS: Hunger was acutely suppressed below baseline (P < 0.05); and fullness was elevated above baseline longer (P < 0.05) after 40 chews than after 25 chews. Two hours after consumption; fullness levels were significantly lower and hunger levels were significantly higher after 25 chews than after 10 and 40 chews (P < 0.05). Initial postingestive glucagon-like peptide-1 concentrations were significantly lower after 25 chews than after 40 chews (P < 0.05); and insulin concentrations declined more rapidly after 25 and 40 chews than after 10 chews (both P < 0.05). Fecal fat excretion was significantly higher after 10 chews than after 25 and 40 chews (both P < 0.05). All participants had higher fecal energy losses after 10 and 25 chews than after 40 chews (P < 0.005). CONCLUSION: The results indicate important differences in appetitive and physiologic responses to masticating nuts and likely other foods and nutrients.
Food patterns measured by factor analysis and anthropometric changes in adults
BACKGROUND: Sixty-five percent of US adults are overweight; and 31% of these adults are obese. Obesity results from weight gains over time; however; dietary determinants of weight gain remain controversial. OBJECTIVE: Our objective was to examine whether food patterns derived from exploratory factor analysis are related to anthropometric changes. We hypothesized that we would derive a healthy food pattern and that it would predict smaller changes in body mass index (BMI; in kg/m(2)) and waist circumference (in cm) than would other food patterns in models adjusted for baseline anthropometric measures. DESIGN: The subjects were 459 healthy men and women participating in the Baltimore Longitudinal Study of Aging. Diet was assessed by using 7-d dietary records; from which 40 food groups were formed and entered into a factor analysis. RESULTS: Six food patterns were derived. Factor 1 (reduced-fat dairy products; fruit; and fiber) was most strongly associated with fiber (r = 0.39) and loaded heavily on reduced-fat dairy products; cereal; and fruit and loaded moderately on fruit juice; nonwhite bread; nuts and seeds; whole grains; and beans and legumes. In a multivariate-adjusted model in which the highest and lowest quintiles were compared; factor 1 was inversely associated with annual change in BMI (beta = -0.51; 95% CI: -0.82; -0.20; P < 0.05; P for trend < 0.01) in women and inversely associated with annual change in waist circumference (beta = -1.06 cm; 95% CI: -1.88; -0.24 cm; P < 0.05; P for trend = 0.04) in both sexes. CONCLUSION: Our results suggest that a pattern rich in reduced-fat dairy products and high-fiber foods may lead to smaller gains in BMI in women and smaller gains in waist circumference in both women and men.
The lipid messenger OEA links dietary fat intake to satiety
The association between fat consumption and obesity underscores the need to identify physiological signals that control fat intake. Previous studies have shown that feeding stimulates small-intestinal mucosal cells to produce the lipid messenger oleoylethanolamide (OEA) which; when administered as a drug; decreases meal frequency by engaging peroxisome proliferator-activated receptors-alpha (PPAR-alpha). Here; we report that duodenal infusion of fat stimulates OEA mobilization in the proximal small intestine; whereas infusion of protein or carbohydrate does not. OEA production utilizes dietary oleic acid as a substrate and is disrupted in mutant mice lacking the membrane fatty-acid transporter CD36. Targeted disruption of CD36 or PPAR-alpha abrogates the satiety response induced by fat. The results suggest that activation of small-intestinal OEA mobilization; enabled by CD36-mediated uptake of dietary oleic acid; serves as a molecular sensor linking fat ingestion to satiety.
The effect of Korean pine nut oil on in vitro CCK release; on appetite sensations and on gut hormones in post-menopausal overweight women
Appetite suppressants may be one strategy in the fight against obesity. This study evaluated whether Korean pine nut free fatty acids (FFA) and triglycerides (TG) work as an appetite suppressant. Korean pine nut FFA were evaluated in STC-1 cell culture for their ability to increase cholecystokinin (CCK-8) secretion vs. several other dietary fatty acids from Italian stone pine nut fatty acids; oleic acid; linoleic acid; alpha-linolenic acid; and capric acid used as a control. At 50 muM concentration; Korean pine nut FFA produced the greatest amount of CCK-8 release (493 pg/ml) relative to the other fatty acids and control (46 pg/ml). A randomized; placebo-controlled; double-blind cross-over trial including 18 overweight post-menopausal women was performed. Subjects received capsules with 3 g Korean pine (Pinus koraiensis) nut FFA; 3 g pine nut TG or 3 g placebo (olive oil) in combination with a light breakfast. At 0; 30; 60; 90; 120; 180 and 240 minutes the gut hormones cholecystokinin (CCK-8); glucagon like peptide-1 (GLP-1); peptide YY (PYY) and ghrelin; and appetite sensations were measured. A wash-out period of one week separated each intervention day.CCK-8 was higher 30 min after pine nut FFA and 60 min after pine nut TG when compared to placebo (p < 0.01). GLP-1 was higher 60 min after pine nut FFA compared to placebo (p < 0.01). Over a period of 4 hours the total amount of plasma CCK-8 was 60% higher after pine nut FFA and 22% higher after pine nut TG than after placebo (p < 0.01). For GLP-1 this difference was 25% after pine nut FFA (P < 0.05). Ghrelin and PYY levels were not different between groups. The appetite sensation "prospective food intake" was 36% lower after pine nut FFA relative to placebo (P < 0.05).This study suggests that Korean pine nut may work as an appetite suppressant through an increasing effect on satiety hormones and a reduced prospective food intake.
Almonds vs. complex carbohydrates in a weight reduction program
OBJECTIVE: To evaluate the effect of an almond-enriched (high monounsaturated fat; MUFA) or complex carbohydrate-enriched (high carbohydrate) formula-based low-calorie diet (LCD) on anthropometric; body composition and metabolic parameters in a weight reduction program. DESIGN: A randomized; prospective 24-week trial in a free-living population evaluating two distinct macronutrient interventions on obesity and metabolic syndrome-related parameters during weight reduction. SUBJECTS: In total; 65 overweight and obese adults (age: 27-79 y; body mass index (BMI): 27-55 kg/m(2)). INTERVENTION: A formula-based LCD enriched with 84 g/day of almonds (almond-LCD; 39% total fat; 25% MUFA and 32% carbohydrate as percent of dietary energy) or self-selected complex carbohydrates (CHO-LCD; 18% total fat; 5% MUFA and 53% carbohydrate as percent of dietary energy) featuring equivalent calories and protein. MAIN OUTCOME MEASUREMENTS: Various anthropometric; body composition and metabolic parameters at baseline; during and after 24 weeks of dietary intervention. RESULTS: LCD supplementation with almonds; in contrast to complex carbohydrates; was associated with greater reductions in weight/BMI (-18 vs -11%); waist circumference (WC) (-14 vs -9%); fat mass (FM) (-30 vs -20%); total body water (-8 vs -1%) and systolic blood pressure (-11 vs 0%); P=0.0001-0.05. A 62% greater reduction in weight/BMI; 50% greater reduction in WC and 56% greater reduction in FM were observed in the almond-LCD as compared to the CHO-LCD intervention. Ketone levels increased only in the almond-LCD group (+260 vs 0%; P<0.02). High-density lipoprotein cholesterol (HDL-C) increased in the CHO-LCD group and decreased in the almond-LCD group (+15 vs -6%; P=0.05). Glucose; insulin; diastolic blood pressure; total cholesterol; triglycerides; low-density lipoprotein cholesterol (LDL-C) and LDL-C to HDL-C ratio decreased significantly to a similar extent in both dietary interventions. Homeostasis model analysis of insulin resistance (HOMA-IR) decreased in both study groups over time (almond-LCD: -66% and CHO-LCD: -35%; P<0.0001). Among subjects with type 2 diabetes; diabetes medication reductions were sustained or further reduced in a greater proportion of almond-LCD as compared to CHO-LCD subjects (96 vs 50%; respectively) [correction]. CONCLUSION: Our findings suggest that an almond-enriched LCD improves a preponderance of the abnormalities associated with the metabolic syndrome. Both dietary interventions were effective in decreasing body weight beyond the weight loss observed during long-term pharmacological interventions; however; the almond-LCD group experienced a sustained and greater weight reduction for the duration of the 24-week intervention. Almond supplementation of a formula-based LCD is a novel alternative to self-selected complex carbohydrates and has a potential role in reducing the public health implications of obesity.
An Indian experiment with nutritional modulation in acute myocardial infarction
In a randomized; single-blind intervention trial; 406 patients 24 to 48 hours after acute myocardial infarction (AMI) were assigned to either diet A (204 patients; group A) or B (202 patients; group B) for 6 weeks. At entry to the study; mean age; male sex; risk factors; complications; possible and definite AMI; and drug therapy were comparable between the 2 groups. Dietary adherence to intervention and control diets was checked by questionnaire; and drug therapy by tablet count. Group A received significantly lower calories; a higher percentage of calories from complex carbohydrates; vegetable/fish proteins; polyunsaturated fatty acids; and a higher polyunsaturated/saturated fat ratio diet than did group B (higher total calories and saturated fatty acids). Group A also received less dietary cholesterol; salt and caffeine; and higher soluble dietary fiber; vitamins and minerals than did group B. After 6 weeks; group A had a significant decrease in mean serum total (-20.5 vs -8.6 mg/dl) and low-density lipoprotein (-16.6 vs -6.4 mg/dl) cholesterols; and triglycerides (-15.5 vs -7.6 mg/dl); with no decrease in high-density lipoprotein cholesterol (-1.5 vs -1.3 mg/dl) compared with the initial levels and changes in group B. Group A also had a greater decrease in mean body weight (3.4 vs 1.3 kg) than that of group B.
Dietary fats; teas; dairy; and nuts: potential functional foods for weight control?
Functional foods are similar to conventional foods in appearance; but they have benefits that extend beyond their basic nutritional properties. For example; functional foods have been studied for the prevention of osteoporosis; cancer; and cardiovascular disease. They have yet to be related to the prevention of obesity; although obesity is one of the major health problems today. The inclusion of foods or the replacement of habitual foods with others that may enhance energy expenditure (EE) or improve satiety may be a practical way to maintain a stable body weight or assist in achieving weight loss; such foods may act as functional foods in body weight control. Some foods that might be classified as functional foods for weight control because of their effects on EE and appetite-including medium-chain triacylglycerols; diacylglycerols; tea; milk; and nuts-are reviewed here. Only human studies reporting EE; appetite; or body weight are discussed. When studies of whole food items are unavailable; studies of nutraceuticals; the capsular equivalents of functional foods; are reviewed. To date; dietary fats seem to be most promising and have been the most extensively studied for their effects on body weight control. However; the weight loss observed is small and should be considered mostly as a measure to prevent weight gain. Carefully conducted clinical studies are needed to firmly ascertain the effect of tea; milk; and nuts on body weight maintenance; to assess their potential to assist in weight-loss efforts; and to ascertain dose-response relations and mechanisms of action for the 4 food types examined.
Nut consumption and body weight.
Frequent nut consumption is associated with lower rates of coronary artery disease (CAD). Also; nut-rich diets improve the serum lipid profile of participants in dietary intervention trials. However; nuts are fatty foods; and in theory their regular consumption may lead to body weight gain. Because obesity is a major public health problem and a risk factor for CAD; clinicians and policy makers ponder several questions. Will hypercholesterolemic patients advised to consume nuts gain weight? Is recommending increased nut consumption to the general population for CAD prevention sound public health advice? Epidemiologic studies indicate an inverse association between frequency of nut consumption and body mass index. In well-controlled nut-feeding trials; no changes in body weight were observed. Some studies on free-living subjects in which no constraints on body weight are imposed show a nonsignificant tendency to lower weight while subjects are on the nut diets. In another line of evidence; preliminary data indicate that subjects on nut-rich diets excrete more fat in stools. Further research is needed to study the effects of nut consumption on energy balance and body weight. In the meantime; the available cumulative data do not indicate that free-living people on self-selected diets including nuts frequently have a higher body mass index or a tendency to gain weight.
Does regular walnut consumption lead to weight gain?
Studies consistently show the beneficial effects of eating nuts; but as high-energy foods; their regular consumption may lead to weight gain. We tested if daily consumption of walnuts (approximately 12 % energy intake) for 6 months would modify body weight and body composition in free-living subjects. Ninety participants in a 12-month randomized cross-over trial were instructed to eat an allotted amount of walnuts (28-56 g) during the walnut-supplemented diet and not to eat them during the control diet; with no further instruction. Subjects were unaware that body weight was the main outcome. Dietary compliance was about 95 % and mean daily walnut consumption was 35 g during the walnut-supplemented diet. The walnut-supplemented diet resulted in greater daily energy intake (557 kJ (133 kcal)); which should theoretically have led to a weight gain of 3.1 kg over the 6-month period. For all participants; walnut supplementation increased weight (0.4 (se 0.1) kg); BMI (0.2 (se 0.1) kg/m(2)); fat mass (0.2 (se 0.1) kg) and lean mass (0.2 (se 0.1) kg). But; after adjusting for energy differences between the control and walnut-supplemented diets; no significant differences were observed in body weight or body composition parameters; except for BMI (0.1 (se 0.1) kg/m(2)). The weight gain from incorporating walnuts into the diet (control-->walnut sequence) was less than the weight loss from withdrawing walnuts from the diet (walnut-->control sequence). Our findings show that regular walnut intake resulted in weight gain much lower than expected and which became non-significant after controlling for differences in energy intake.