Archive

Research Area: Body Weight/Satiety

Lifestyle counseling and supplementation with flaxseed or walnuts influence the management of metabolic syndrome.

Wu, H., A. Pan, Z. Yu, Q. Qi, L. Lu, G. Zhang, D. Yu, G. Zong, Y. Zhou, X. Chen, L. Tang, Y. Feng, H. Zhou, X. Chen, H. Li,W. Demark-Wahnefried, F.B. Hu, X. Lin, 2010. Lifestyle counseling and supplementation with flaxseed or walnuts influence the management of metabolic syndrome. J. Nutr. 140(11):1937-42. .

A healthy lifestyle may ameliorate metabolic syndrome (MetS); however, it remains unclear if incorporating nuts or seeds into lifestyle counseling (LC) has additional benefit. A 3-arm, randomized, controlled trial was conducted among 283 participants screened for MetS using the updated National Cholesterol Education Program Adult Treatment Panel III criteria for Asian Americans. Participants were assigned to a LC on the AHA guidelines, LC + flaxseed (30 g/d) (LCF), or LC + walnuts (30 g/d) (LCW) group. After the 12-wk intervention, the prevalence of MetS decreased significantly in all groups: -16.9% (LC), -20.2% (LCF), and -16.0% (LCW). The reversion rate of MetS, i.e. those no longer meeting the MetS criteria at 12 wk, was not significantly different among groups (LC group, 21.1%; LCF group, 26.6%; and LCW group, 25.5%). However, the reversion rate of central obesity was higher in the LCF (19.2%; P = 0.008) and LCW (16.0%; P = 0.04) groups than in the LC group (6.3%). Most of the metabolic variables (weight, waist circumference, serum glucose, total cholesterol, LDL cholesterol, apolipoprotein (Apo) B, ApoE, and blood pressure) were significantly reduced from baseline in all 3 groups. However, the severity of MetS, presented as the mean count of MetS components, was significantly reduced in the LCW group compared with the LC group among participants with confirmed MetS at baseline (P = 0.045). Our results suggest that a low-intensity lifestyle education program is effective in MetS management. Flaxseed and walnut supplementation may ameliorate central obesity. Further studies with larger sample sizes and of longer duration are needed to examine the role of these foods in the prevention and management of MetS.

Nuts and healthy body weight maintenance mechanisms

Mattes, R.D., M.L. Dreher, 2010. Nuts and healthy body weight maintenance mechanisms. Asia Pac J Clin Nutr. 19(1):137-141.

Nuts are rich sources of multiple nutrients and phytochemicals associated with health benefits, including reduced cardiovascular disease risk. This has prompted recommendations to increase their consumption. However, they are also high in fat and are energy dense. The associations between these properties, positive energy balance and body weight raise questions about such recommendations. Numerous epidemiological and clinical studies show that nuts are not associated with weight gain. Mechanistic studies indicate this is largely attributable to the high satiety and low metabolizable energy (poor bioaccessibility leading to inefficient energy absorption) properties of nuts. Compensatory dietary responses account for 55-75% of the energy provided by nuts. Limited data suggest that routine nut consumption is associated with elevated resting energy expenditure and the thermogenic effect of feeding, resulting in dissipation of another portion of the energy they provide. Additionally, trials contrasting weight loss through regimens that include or exclude nuts indicate improved compliance and greater weight loss when nuts are permitted. Nuts may be included in the diet, in moderation, to enhance palatability, nutrient quality, and chronic disease risk reduction without compromising weight loss or maintenance.

A 3 years follow-up of a Mediterranean diet rich in virgin olive oil is associated with high plasma antioxidant capacity and reduced body weight gain.

Razquin, C., J.A. Martinez, M.A. Martinez-Gonzalez, M.T. Mitjavila, R. Estruch, A. Marti, 2009. A 3 years follow-up of a Mediterranean diet rich in virgin olive oil is associated with high plasma antioxidant capacity and reduced body weight gain. Eur J Clin Nutr.  63(12):1387-93.

The aim of this study was to analyze the influence of a Mediterranean dietary pattern on plasma total antioxidant capacity (TAC) after 3 years of intervention and the associations with adiposity indexes in a randomized dietary trial (PREDIMED trial) with high cardiovascular risk patients. 187 subjects were randomly selected from the PREDIMED-UNAV center after they completed 3-year intervention program. Participants were following a Mediterranean-style diet with high intake of virgin olive oil or high intake of nuts, or a conventional low-fat diet. Adiposity indexes were measured at baseline and at year 3. Plasma TAC was evaluated using a commercially available colorimetric assay kit. Plasma TAC in the control, olive oil and nuts groups was 2.01+/-0.15, 3.51+/-0.14 and 3.02+/-0.14 mM Trolox, respectively after adjusting for age and sex. The differences between the Mediterranean diet and control groups were statistically significant (P<0.001). Moreover higher levels of TAC were significantly associated with a reduction in body weight after 3 years of intervention among subjects allocated to the virgin olive oil group (B=-1.306; 95% CI=-2.439 to -0.173; P=0.025, after adjusting for age, sex and baseline body mass index). Mediterranean diet, especially rich in virgin olive oil, is associated with higher levels of plasma antioxidant capacity. Plasma TAC is related to a reduction in body weight after 3 years of intervention in a high cardiovascular risk population with a Mediterranean-style diet rich in virgin olive oil.

Mastication of almonds: effects of lipid bioaccessibility, appetite, and hormone response

Cassady, B.A., J.H. Hollis, A.D. Fulford, R.V. Considine, R.D. Mattes, 2009. Mastication of almonds: effects of lipid bioaccessibility, appetite, and hormone response. Am. J. Clin. Nutr. 89:794-800.

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/m2: 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. This trial was registered at clinicaltrials.gov as NCT00768417.

Prospective study of nut consumption, long-term weight change, and obesity risk in women

Bes-Rastrollo, M., N.M. Wedick, M.A. Martinez-Gonzalez, T.Y. Li, L. Sampson, F.B. Hu, 2009. Prospective study of nut consumption, long-term weight change, and obesity risk in women. Am J Clin Nutr 89:1-7.

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 _2 times/wk had a slightly less mean (6 SE) weight gain (5.04 6 0.12 kg) than did women who rarely ate nuts (5.55 6 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 (i.e., less weight gain in women eating either peanuts or tree nuts _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 (_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 ¼ 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.

Nuts and health outcomes: new epidemiologic evidence

Sabate’, J., Y. Ang, 2009. Nuts and health outcomes: new epidemiologic evidence. Am J Clin Nutr89(suppl):1643S-8S.

This article reviews recent epidemiologic evidence on nut intake and health outcomes. It focuses on studies in which nut consumption is directly assessed or when nuts are included in a dietary score or pattern. Epidemiologic studies have been remarkably consistent in showing an association between nut consumption and a reduced risk of coronary heart disease (CHD). Some evidence has emerged recently to suggest health-protective benefits of nuts other than CHD. Frequent nut intake probably reduces risk of diabetes mellitus among women, but its effects on men are unknown. Evidence on the anticarcinogenic effects of nuts is somewhat limited because studies in the past 2 decades have examined only 3 tumor sites, and the benefits appear to be manifested only in women. However, the protective benefits of frequent nut consumption on gallstone diseases are observed in both sexes. Long-term nut consumption is linked with lower body weight and lower risk of obesity and weight gain. A dietary pattern or score that includes nuts is consistently related with beneficial health outcomes, and this provides an indirect evidence of the salutary benefits of nut consumption. More longitudinal studies are needed to clarify the possible effects of nuts on diseases other than CHD.

Acute effects of three high-fat meals with different fat saturations on energy expenditure, substrate oxidation and satiety

Casas-Agustench, P., P. Lo’ pez-Uriarte, M. Bullo’, E. Ros, A. Go’ mez-Flores, J. Salas-Salvado’, 2009. Acute effects of three high-fat meals with different fat saturations on energy expenditure, substrate oxidation and satiety. Clinical Nutrition 28:39-45.

Background & aims: To compare the acute effects of three fatty meals with different fat quality on postprandial thermogenesis, substrate oxidation and satiety. Methods: Twenty-nine healthy men aged between 18 and 30 years participated in a randomized crossover trial comparing the thermogenic effects of three isocaloric meals: high in polyunsaturated fatty acids from walnuts, high in monounsaturated fatty acids from olive oil, and high in saturated fatty acids from fat-rich dairy products. Indirect calorimetry was used to determine resting metabolic rate, respiratory quotient, 5-h postprandial energy expenditure and substrate oxidation. Satiety was estimated by using visual analogue scales and measuring caloric intake in a subsequent ad libitum meal. Results: Five-h postprandial thermogenesis was higher by 28% after the high-polyunsaturated meal (p = 0.039) and by 23% higher after the high-monounsaturated meal (p = 0.035) compared with the high saturated meal. Fat oxidation rates increased nonsignificantly after the two meals rich in unsaturated fatty acids and decreased nonsignificantly after the high-saturated fatty acid meal. Postprandial respiratory quotient, protein and carbohydrate oxidation, and satiety measures were similar among meals. Conclusions: Fat quality determined the thermogenic response to a fatty meal but had no clear effects on substrate oxidation or satiety.

Walnut consumption increases satiation but has no effect on insulin resistance or the metabolic profile over a 4-day period

Brennan A.M., L.L. Sweeney, X. Liu, C.S. Mantzoros, 2009. Walnut consumption increases satiation but has no effect on insulin resistance or the metabolic profile over a 4-day period. Obesity. doi:10.1038/oby.2009.409

Obesity and diabetes have been associated with increased consumption of highly processed foods, and reduced consumption of whole grains and nuts. It has been proposed, mainly on the basis of observational studies, that nuts may provide superior satiation, may lead to reduced calorie consumption, and may decrease the risk of type 2 diabetes; but evidence from randomized, interventional studies is lacking. A total of 20 men and women with the metabolic syndrome participated in a randomized, double-blind, crossover study of walnut consumption. Subjects had two 4-day admissions to the clinical research center where they were fed an isocaloric diet. In addition, they consumed shakes for breakfast containing either walnuts or placebo (shakes were standardized for calories, carbohydrate, and fat content). Appetite, insulin resistance, and metabolic parameters were measured. We found an increased level of satiety (overall P value = 0.0079) and sense of fullness (P = 0.05) in pre-lunch questionnaires following the walnut breakfast as compared to the placebo breakfast, with the walnut effect achieving significance on day 3 and 4 (P = 0.02 and P = 0.03). We did not find any change in resting energy expenditure, hormones known to mediate satiety, or insulin resistance when comparing the walnut vs. placebo diet. Walnut consumption over 4 days increased satiety by day 3. Long-term studies are needed to confirm the physiologic role of walnuts, the duration of time needed for these effects to occur, and to elucidate the underlying mechanisms.

The effect of including a conventional snack (cereal bar) and a nonconventional snack (almonds) on hunger, eating frequency, dietary intake and body weight

Zaveri, S., S. Drummond, 2009. The effect of including a conventional snack (cereal bar) and a nonconventional snack (almonds) on hunger, eating frequency, dietary intake and body weight. J Hum Nutr Diet, 22:461-468.

Background: With the increasing prevalence of being overweight and obesity, dietary strategies to curb hunger levels and increase satiety at lower energy intakes are sought. The frequency of eating and type of snack may influence total energy intake. The present study aimed to assess the impact of providing either a conventional snack (cereal bar) or a nonconventional snack (almonds) on eating frequency, hunger rating, dietary intake, body weight and blood lipids. Methods: Forty-five healthy men (aged 25-50 years, body mass index = 25-35 kg m-2 were recruited and allocated to a control, cereal bar or almond snack group. Two packets of cereal bars and almonds were introduced for 12 weeks to the cereal bar group and the almond snack group, respectively. Dietary intakes and eating frequency were assessed by 4-day unweighed diet diaries; visual analogue scales were used to assess hunger ratings; and fasting blood parameters (i.e. glucose, insulin, total cholesterol, triglycerides, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol) were measured at baseline, 6 and 12 weeks. In addition, anthropometric measures (height, weight, skinfold thickness, waist and hip circumference) were measured at baseline, 6 and 12 weeks. Results: The present study found no significant change in the eating frequency within groups at 12 weeks. However, the almond snack group had a significantly higher eating frequency than the control group (P ≤ 0.05) and cereal bar group (P ≤ 0.01). This did not result in higher energy intake, body weight or percentage body fat in the almond snack group. Conclusion: The present study demonstrated that snacking on almonds, in comparison to cereal bars, promoted a higher eating frequency, but not a higher energy intake. Advice to snack on either almonds or cereal bars did not result in weight gain, suggesting that energy compensation took place.

The nutritional and health benefits of almonds: a healthy food choice

Richardson, D.P., A. Astrup, A. Cocaul, P. Ellis, 2009. The nutritional and health benefits of almonds: a healthy food choice. Food Science and Technology Bulletin: Functional Foods. 6(4):41-50.

Over the last decade, the research on the effects of almonds on reducing blood cholesterol levels and reduction of risk of heart disease has grown significantly. Emerging research on almonds also shows promising health benefits linked to body weight control and diabetes. Almonds naturally contain high levels of monounsaturated and polyunsaturated fatty acids, protein and dietary fiber, as well as a variety of essential nutrients including vitamin E and several trace elements. Almonds are very low in sodium and high in potassium, and they contain a range of phytoprotective constituents. The available evidence also indicates that weight gain may not be a concern when nuts are consumed in moderation, and that regular consumption of nuts can be recommended in the context of a healthy balanced diet.