Positive nutrition: shifting the focus from nutrients to diet for a healthy lifestyle

PURPOSE AND METHODS

This summary is based on a scientific symposium organized by the Mediterranean Diet Roundtable and the American Italian Food Coalition titled, 'Positive Nutrition: shifting focus from nutrients to diet for a healthy lifestyle.' It was held at the Embassy of Italy in Washington DC in September of 2022. The panel of experts discussed how science can inform policy, what insights may be gleaned from different countries' approaches to healthy eating and what principles of the Mediterranean diet will inform strategies for a healthy future. Recognizing that isolated actions have limited impact on the complex relationship between diet and obesity, the panel discussed the importance of a system approach. In particular, the panel emphasized that focusing on single ingredients, isolated food categories and narrow approaches to policy have had limited success across the globe.

RESULTS AND CONCLUSION

The panel agreed that there is a need for change of perspective that embraces complexity and emphasizes more positive nutrition messaging and policies.

LEVEL OF EVIDENCE

V, Opinions of respected authorities, based on descriptive studies, narrative reviews, clinical experience, or reports of expert committees.

Daily Almond Consumption Reduces Insulin Resistance and Serum Cholesterol Levels in Overweight Asian Indian Adults with Cardiometabolic Risk – A Randomized Controlled Trial

Objectives

The present study aimed to evaluate the efficacy of almonds consumption on insulin resistance, glycemia and lipid profile in overweight Asian Indian adults with cardiometabolic risks.

Methods

A parallel-arm open-labelled, randomized controlled trial was conducted on 184 adults with cardiometabolic risks (CMR) (92 in each group). Adults with CMR were identified using the harmonizing criteria which includes presence of minimum of 3 of the following conditions: raised blood pressure, dyslipidemia (raised triglycerides and lowered high-density lipoprotein cholesterol), impaired fasting glucose, and central obesity. The intervention group received 43g (1.5 oz) almonds/day for 12 weeks. The control group was instructed to follow their habitual diet except to exclude nuts in any form. The anthropometric, clinical, biochemical and dietary data of the participants were assessed periodically and their change from baseline were analysed using generalized linear model in SAS 9.4 version.

Results

The study was completed by 165 adults (response rate 82.5%). Their mean age was 40 years and waist circumference 97 ± 9.6 cm at baseline. Significant reductions [mean (95%CI)] in IR (−0.5(−1.0–0.0); P = 0.04), serum total cholesterol (−10.6 mg/dl (−17.8- −3.4); P = 0.004) and low-density lipoprotein cholesterol (−7.5 mg/dl (−14.2- −0.8); P = 0.03) were observed in the intervention group compared to the control group. Within the intervention group, significant reduction of 1% each for body weight, body mass index, waist circumference, 3% fasting glucose and 2% serum triglyceride were noted compared to baseline. Multiple 24hr dietary recall as a compliance marker revealed significant increase in total fat, MUFA, PUFA calories and dietary fibre with a propionate reduction in carbohydrate calories in the intervention group compared to control group.

Conclusions

Daily intake of 43g almonds reduced IR, total and LDL serum cholesterol in obese Asian Indians with CMR. Almond consumption also improved the overall quality of the diet.

Funding Sources

The present study was funded by Almond Board of California, Modesto, CA, USA.

Effects of whole peanut within an energy-restricted diet on inflammatory and oxidative processes in obese women: a randomized controlled trial

BACKGROUND

Peanut consumption has little effect on body weight, despite its high energy density and is associated with reduced cardiovascular disease risk. Based on previous research, we hypothesized that the consumption of whole peanut would be associated with greater improvements in body composition, lipid profile, and biomarkers of inflammation and oxidative stress.

METHODOLOGY

Twenty-four women with obesity [body mass index (BMI) > 30 kg m^-2 ], 33.1 ± 8.7 years old, were assigned to three groups and consumed 56 g of whole peanut (WP), skinned peanut (SP), and no peanut (NP) and consumed energy-restricted diets (250 kcal d^-1 less than their customary diet) for 8 weeks.

RESULTS

WP group lost an average of 3.2 kg, while SP group lost 2.6 kg and the NP group 1.8 kg. However, only the groups that consumed peanuts showed a significant reduction in BMI. WP group presented lower body weight, BMI, waist circumference, total lean mass, and total body fat than the SP group in the eighth week. There was a significant reduction in total cholesterol and low-density lipoprotein (LDL) after 4 weeks of intervention, which was maintained in week-8 for the WP and SP groups. In addition, there was an improvement in platelets and plasma homocysteine with WP group.

CONCLUSION

Our results suggest that the regular intake of the whole peanut as part of an energy-restricted diet showed health benefits since it enhanced body weight loss, besides improving body composition and reducing cholesterol, platelets, and homocysteine concentrations. © 2021 Society of Chemical Industry.

Almond Consumption Decreases Android Fat Mass Percentage in Adults With High Android Subcutaneous Adiposity but Does Not Change HbA1c

Objectives

The purpose of this study was to determine if the mixed evidence of almond consumption on HbA1c stems from testing people with different body fat distributions (BFD) associated with different risks of glucose intolerance.

Methods

A 6-month RCT in 134 adults was conducted. Participants were randomly assigned to the almond or control treatment based on their BFD. Those in the almond group consumed 0.75 oz of almonds with their breakfast and as their afternoon snack (1.5 oz almonds/day) every day, and were instructed not to consume any other nuts. Those in the control treatment continued their habitual breakfast and afternoon snack routines, but were instructed not to consume any nuts. At 0 and 6 months, body composition was measured and blood samples were collected for analyses of HbA1c, glycemia and lipemia. Appetite and dietary intake data were recorded at 0, 2, 4, and 6 months and a blood sample was obtained for compliance testing. Body weight was measured every two weeks. An intention-to-treat linear mixed model analysis was performed with Bonferroni pairwise comparisons on diet quality, energy intake, HbA1c, and body composition change values.

Results

Incorporating almonds into the diet increased total diet quality by 8.3 ± 2.1% over the intervention (P = 0.001). Participants consuming almonds ingested 195 ± 87 kcals/day more than participants in the control group (P = 0.027), but this did not result in differences in body weight (P > 0.3). The almond, high android subcutaneous adiposity (SAT) group had a greater reduction in android fat mass % (P = 0.038), preserved android lean mass % (P = 0.042), and tended to decrease android VAT mass (P = 0.079) compared to those in the control, high SAT group. There were no differences of HbA1c between groups (P > 0.05).

Conclusions

Incorporating 1.5-oz of almonds into the diet improves diet quality without promoting positive energy balance and weight gain. Long-term consumption of almonds may also improve android composition in those with high android SAT. However, testing people with different BFD does not account for the mixed evidence on almond consumption and HbA1c.

Funding Sources

This study was funded by the Almond Board of California.

Fatty Acids Taste Intensity Ratings Before and After Sour Taste Adaptation

Objectives

Recent research indicates that the taste quality of fatty acids, called ‘Oleogustus’, differs from the traditionally accepted five basic tastes. However, the actual quality of the sensation has not been characterized. One question is whether there is a sour component because very short-chain fatty acids, like acetic acid, the sour tastant in vinegar, is structurally a fatty acid. The present study investigated the quality sensation of fatty acids of graded chain length.

Methods

Sensory stimuli were acetic acid, butyric acid, hexanoic acid, octanoic acid, decanoic acid, lauric acid, oleic acid, and linoleic acid emulsions and palmitic acid, stearic acid powder. The intensity of the samples before and after expectorating was measured. Next, participants repeatedly sipped, held for 5 seconds, and expectorated a sour solution (0.09% w/w) and rated the intensity on a gLMS until the intensity was lower than “weak”. After adaption to the sour solution, the intensity of the sample was measured before and after expectorating. Participants recorded the quality of each sample.

Results

The intensity of acetic acid was significantly lower after adaptation (P < 0.04) that before adaptation and a similar trend was noted for butyric acid. The other fatty acids were not affected by adaptation. The intensities of all liquid samples except the octanoic acid solution showed a significant difference between before and after expectorating the samples. The intensities of acetic, butyric and hexanoic acids were lower after expectorating the samples than the intensities before expectorating the samples (P < 0.05) while the intensities of decanoic acid, lauric acid, oleic acid, and linoleic acid (P < 0.05) were lower after expectorating. There was no significant difference in intensity of the palmitic acid solution and the intensity of the stearic acid solution between before and after expectorating.

Conclusions

The results showed that fatty acids with chain lengths great than 4 have a unique taste other than the sourness. In addition, short-chain fatty acid solutions had higher intensity before expectorating the solutions while the medium- and long-chain fatty acid solutions had higher intensity after expectorating solutions, indicating that there is a different persistence time for fatty acid directly related to chain-length.

Funding Sources

This study has no sponsors.

The Effects of Long Term Almond Consumption in Adults with Different Body Fat Distributions on Anthropometric Characteristics and HbA1c

Objectives

The purpose of this study was to determine if the mixed evidence of almond consumption on long term glycemic control stems from testing people with different body fat distributions.

Methods

A 6-month randomized controlled trial in 118 adults was conducted. Participants were randomly assigned to the almond or control group based on their body fat distribution. Those in the almond group consumed 0.75 oz of almonds with their breakfast and as their afternoon snack (1.5 oz almonds/day) every day, and were instructed not to consume any other nuts or nut products. Those in the control group continued their habitual breakfast and afternoon snack routines, but were instructed not to consume any nuts or nut products. Anthropometric characteristics, HbA1c, and glycemic and lipemic responses to a meal tolerance test were collected at baseline and 6 months. Appetite and dietary intake data were collected at baseline, 2, 4, and 6 months as was a blood sample for compliance testing. Body weight was measured every two weeks. A preliminary linear mixed model analysis on the anthropometric characteristics and HbA1c change values and pairwise comparisons with Bonferroni correction for significant main effects was performed.

Results

Preliminary results indicate that there was a trend towards a difference in visceral adipose tissue (VAT) mass with the almond group losing more VAT mass compared to the control group in those with high truncal subcutaneous adipose tissue (SAT) (P = 0.054). Additionally, there was a significant difference in change of VAT mass between the high SAT and high VAT (P = 0.02) and high gluteal-femoral adipose tissue (P = 0.41) control groups. There were no significant differences in any other anthropometric variables or HbA1c.

Conclusions

Preliminary results indicate that while almond consumption may decrease VAT mass in those with high SAT, testing people with different body fat distributions may not be why there is mixed evidence on almond consumption on long term glycemic control.

Funding Sources

This research is funded by the Almond Board of California.

Systematic Review and Meta-analysis of the Effect of Portion Size and Ingestive Frequency on Energy Intake and Body Weight Among Adults in Randomized Controlled Trials (P08-007-19)

Objectives

Total energy intake is the product of portion size (PS), the energy content of an ingestive event, and ingestive frequency (IF), the number of ingestive events per unit time. An alteration in either portion size or ingestive frequency, that is not compensated by the other, must result in a change in energy intake and, if maintained over time, body weight. The primary objective of this meta-analysis was to assess the independent effects of PS and IF on dietary energy intake and body weight among healthy adults in randomized controlled trials.

Methods

8,614 articles (duplicates removed) published through 2018 with no date restriction were identified with PubMed, Web of Science, Cochrane, and CINAHL databases. The articles were divided among ten researchers and each article was screened for eligibility by two to three independent reviewers. Exclusion criteria included: populations <19 y and >65 y, unhealthy, assessment <24 h in duration, and controlled feeding trials. Studies investigating the effect of IF or PS on body weight were at least 4 weeks in duration. Eleven articles (IF = 3, PS = 8) met the inclusion criteria. There were not enough articles to assess the effect of PS on body weight.

Results

There was significant heterogeneity in the effect sizes among all comparisons (I2 = >50%). Consuming smaller portion sizes was associated with lower 24 h energy intake [–135 kcal (–249, –21), n = 15; WMD (95% CI), n = comparisons]. In contrast, IF was not associated with a difference in 24 h energy intake [–103 kcal (–230, 24), n = 5], but was positively related to body weight in trials ≥6 wk duration [0.40 kg (0.70, 0.11), n = 4].

Conclusions

Results from RCTs support that greater PS but not IF is associated with higher daily energy consumption. However, IF is positively associated with increased body weight over time.

Funding Sources

NA

Potato product form impacts in vitro starch digestibility and glucose transport but only modestly impacts 24 h blood glucose response in humans

Potatoes are rich in phenolic compounds which have been reported to impact starch digestion and intestinal glucose transport in model systems through phenolic–starch interactions.

Higher plasma lipopolysaccharide concentrations are associated with less favorable phenotype in overweight/obese men

PURPOSE

Lipopolysaccharide (LPS) from the outer membrane of gram-negative bacteria might be an inflammation trigger in adipose tissue. It has recently been proposed that there is a link between adipose tissue distribution and blood LPS. However, the number of studies on this topic is scarce, and further investigation in humans is required. In this study, we explored the association between plasma LPS concentrations and body fat distribution, as well as the biochemical parameters that may indicate the presence of metabolic disorders.

METHODS

Sixty-seven young adult men with body mass index of 26-35 kg/m(2) were evaluated. Anthropometry, body composition and body fat distribution, blood pressure, energy expenditure, physical activity level, dietary intake, and biochemical parameters were assessed.

RESULTS

Men with median plasma LPS ≥ 0.9 EU/mL presented higher sagittal abdominal diameter, trunk fat percentage, and android fat percentage, and mass, insulin and alanine aminotransferase concentrations, homeostasis model assessment of insulin resistance (HOMA-IR), and beta cell dysfunction (HOMA-B) than those with lower plasma LPS. LPS correlated positively with the trunk fat percentage, and android fat percentage, and mass, insulin, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase concentrations, as well as HOMA-IR and HOMA-B.

CONCLUSION

Our results suggest that a higher plasma LPS concentration is associated with a less favorable phenotype as characterized by higher central adiposity, higher values of HOMA-IR, and beta cell function impairment in overweight/obese men.

Food environment and obesity

OBJECTIVE

The food environment plays an important and often dominant role in food choice, eating patterns, and ultimately, energy intake. The Obesity Society and the American Society for Nutrition jointly sponsored a series of reviews on topics of interest to both memberships. The goal was to consider the state of understanding on selected issues related to the food environment and obesity and to identify key knowledge gaps.

RESULTS

The first article (not necessarily of importance) targeted energy density (ED) and focuses on the role of ED in the regulation of energy intake and body weight. It offers recommendations for prioritizing research. The second article addresses economic factors and examines food and beverage purchases as a function of price changes. It concludes that targeted food taxes and subsidies alone are unlikely to substantially affect obesity. The third article concerns sweetened beverages and points out the difficulty in establishing the strength of the association between intake of sugar-sweetened beverages and weight gain and obesity. In the fourth article, the contributions of palatability and variety to eating behavior and weight are reviewed. Article five explores the influence of portion size on energy intake and weight management. It finds that consumers generally tend to eat proportionally more as portion size increases. The sixth article focuses on the efficacy and effectiveness of eating frequency manipulations for body weight management and finds that such manipulations have consistently yielded null results. Finally, article seven identifies several limitations of the existing literature regarding neighborhood access to healthy foods.

CONCLUSIONS

This series of reviews addresses important questions regarding the contribution of the food environment to obesity. Independent of physiological/genetic determinants, factors such as ED, cost, food form, palatability, variety, portion size, eating frequency, and access to healthy food are each evaluated for their role in the etiology of obesity and metabolic health. This series of reviews also identifies important gaps in knowledge.

Research issues: the food environment and obesity

"Research Issues: The Food Environment and Obesity" is an article series commissioned by the American Society for Nutrition and The Obesity Society in an attempt to consider the state of understanding on this topic and identify key knowledge gaps. Roberts and Karl focus on the role of energy density in the regulation of energy intake and body weight and offer recommendations for prioritizing research. Finkelstein et al examine food and beverage purchases as a function of price changes and conclude that targeted food taxes and subsidies alone are unlikely to substantially affect obesity. Pereira points out the difficulty in establishing the strength of the association between intake of sugar-sweetened beverages and weight gain and obesity. Johnson and Wardle review the effects of palatability and variety on eating behavior and weight. Livingstone and Pourshahidi examine the impact of portion size manipulations on energy intake and weight management and find that consumers generally tend to eat proportionally more as portion size increases. Kant focuses on the efficacy and effectiveness of eating frequency manipulation for body weight management and finds that such manipulation has consistently yielded null results. Finally, Gordon-Larsen identifies several limitations of the existing literature regarding neighborhood access to healthy foods.

Effect of a high-fat meal containing conventional or high-oleic peanuts on post-prandial lipopolysaccharide concentrations in overweight/obese men

BACKGROUND

An increased plasma lipopolysaccharide (LPS) concentration may favour metabolic disorders such as insulin resistance. The meal composition influences plasma LPS concentrations. The present study aimed to investigate the effect of the acute consumption of a high-fat meal (49% of energy from fat) containing conventional or high-oleic peanuts on post-prandial LPS concentrations and its relationship with lipaemia and insulinaemia in overweight and obese men.

METHODS

The test meal consisted of a shake containing conventional peanuts (CVP; n = 21), high-oleic peanuts (HOP; n = 23) or a control biscuit (CT; n = 21). Blood samples were collected in the fasting state and 1, 2 and 3 h post-prandially. LPS, insulin, lipids and glucose concentrations were assessed.

RESULTS

LPS concentrations were lower in CVP [mean (SE) 0.7 (0.5) EU mL(-1) ] and HOP [1.0 (0.9) EU mL(-1) ] groups compared to CT [1.6 (1.2) EU mL(-1) ] at 3 h post-prandially. Triacylglycerol and insulin concentrations increased in all groups. Triacylglycerol started to increase only after 2 h in the CVP and HOP groups. LPS correlated positively with triacylglycerol. Insulin returned to basal concentrations at 3 h only in the CVP and HOP groups.

CONCLUSIONS

The acute consumption of peanuts delayed the increase in serum triacylglycerol and favoured the quicker return of insulin to basal concentrations, especially in the CVP group. Our results suggest that the consumption of conventional or high-oleic peanuts may help to reduce the risk of endotoxaemia and metabolic disorders.

High-oleic peanuts: new perspective to attenuate glucose homeostasis disruption and inflammation related obesity

OBJECTIVE

To evaluate the effects of acute and daily consumption of high-oleic peanuts (HOP) on inflammation and glucose homeostasis in overweight/obese men.

METHODS

In a 4-week randomized clinical trial, males with body mass index of 29.8 ± 2.3 kg/m(2) and aged 18-50 years were assigned to the groups: control (CT, n = 22); conventional peanuts (CVP, n = 22); or HOP (n = 21). They followed a hypocaloric-diet with or without 56 g/day of CVP or HOP. Main outcomes were changes in fasting blood biomarkers and postprandial insulin, glucose, tumor necrosis factor-alfa (TNF-α), and interleukin-10 (IL-10) responses after acute peanut intake.

RESULTS

At baseline, HOP showed significantly lower postprandial responses of glucose, insulin, and TNF-α than CVP and CT. Changes in fasting blood biomarkers did not differ between groups after the 4-week intervention. However, within groups, total cholesterol decreased in CT, and all groups reduced High-density lipoprotein (HDL-c). Triglycerides were reduced in HOP and CVP. IL-10 increased significantly in all groups while only the CT and CVP showed increased TNF-α after intervention.

CONCLUSION

Acute high-oleic peanut consumption leads to stronger moderation of postprandial glucose, insulin, and TNF-α concentrations than CVP and control meal intake. Whether daily intake of high-oleic peanuts has additional benefits to CVP remains uncertain.

Die Schwingungsspektren von MoO3, WO2Cl2 und WO3 im festen Zustand /Solid State Vibrational Spectra of MoO3, WO2Cl2 and WO3

The Raman and infrared spectra of MoO3, WO2Cl2 and WO3 have been measured. The application of the method of factor group analysis leads to the assignment of the observed frequencies to terminal or bridging metal-oxygen bonds. The observed frequencies depend on the length or type (terminal or bridging) of a bond and on the coordination number of the metal atom.

Die Schwingungsspektren von MoO3.2 H2O und MoO2Cl2 · H2O / Vibrational Spectra of MoO3 · 2 H2O and MoO2Cl2 · H2O

The Raman and infrared spectra of MoO3·2 H2O and MoO2Cl2 · H2O have been assigned based on the known crystal structures of these compounds. In the region of the Mo-O-stretching frequencies the spectra of ΜοO3·2Η2O and MoO2Cl2 or WO2Cl2 are very similar. The same is valid for MoO2Cl2H2O compared with MoO3. The frequency νas (Mo-O - Mo) depends highly on the ratio of the bond lengths of the two bridge bonds.

Regular intake of high-oleic peanuts improves fat oxidation and body composition in overweight/obese men pursuing a energy-restricted diet

OBJECTIVE

Evaluate the effect of high-oleic and conventional peanuts within a hypocaloric-diet on energy metabolism and body composition.

METHODS

This 4-week randomized clinical trial included males with BMI of 29.7 ± 2.4 kg m(-2) and aged between 18 and 50 years. Participants were assigned to the groups: control (CT, n = 22) that followed a hypocaloric-diet; conventional peanuts (CVP, n = 22) or high-oleic peanuts (HOP, n = 21) that received the hypocaloric-diet including (not adding) 56 g day(-1) of peanuts. Glucose, fat oxidation, and body fatness and lean mass were the main outcomes.

RESULTS

Body weight and composition did not differ between groups. However, within group total body fat (kg) reduced with CVP and HOP, with a significant decrease in body fat percentage in HOP. While total lean mass (kg) decreased in CT, total lean mass (%) increased in HOP. Truncal lean mass decreased in the CT. At baseline, HOP had greater postprandial fat oxidation than the CVP. After 4-weeks, fasting fat oxidation increased in CVP and HOP. Fat oxidation increased in CT and HOP during the 200 min after meal intake compared to the fasting condition.

CONCLUSION

Regular peanut consumption, especially the high-oleic type, within a hypocaloric-diet increased fat oxidation and reduced body fatness in overweigh and obese men.

Effect of chronic consumption of almonds on body weight in healthy humans

Small changes of diet may reduce CVD risk. One example is the inclusion of nuts. They are rich in fibre, unsaturated fatty acids and phytonutrients. However, their fat content and energy density raise concerns that chronic consumption will promote weight gain. Randomised intervention studies are required to evaluate whether this concern is well founded. This study's aim was to determine if the inclusion of a 1440 kJ serving of almonds in the daily diet results in positive energy balance, and body composition change. During a 23-week cross-over design study, participants were required to consume almonds for 10 weeks and were provided no advice on how to include them in their diet. For another 10 weeks (order counter-balanced), participants followed their customary diet and there was a 3-week washout between. The study group consisted of twenty women. Potential mechanisms of energy dissipation were measured. Ten weeks of daily almond consumption did not cause a change in body weight. This was predominantly due to compensation for the energy contained in the almonds through reduced food intake from other sources. Moreover, inefficiency in the absorption of energy from almonds was documented (P < 0·05). No changes in resting metabolic rate, thermic effect of food or total energy expenditure were noted. A daily 1440 kJ serving of almonds, sufficient to provide beneficial effects on cardiovascular risk factors, may be included in the diet with limited risk of weight gain. Whether this can be generalised to other high-fat energy dense foods warrants evaluation.

Financial incentive for diet recall accuracy does not affect reported energy intake or number of underreporters in a sample of overweight females

Underreporting of energy intake in diet recalls is common, especially among obese individuals. Incentives have been used to ameliorate the problem, but are typically provided without efficacy assessment. The present study sought to determine whether financial incentives decrease underreporting in diet recalls. Three groups were used to assess incentive timing effects in this parallel group crossover study. One group received a $50 bonus for accurate diet recalls on the first two of four recalls. Accuracy was purportedly verified by salivary analysis. Another group received the $50 bonus for the last two recalls. A third group received no incentive. Mean energy intake during the first two visits was compared to mean energy intake during the last two visits to assess differences resulting from the incentive. Underreporters were identified using a Goldberg cutoff and energy intake <76% of estimated energy expenditure. Energy intake did not differ within or between groups at any time, and the number of underreporters was not associated with group at any time. Overall, the incentive was ineffective in this small, homogeneous sample. Future studies should assess different forms of incentives, other study populations, and the probability of incentives causing undereating.

Fluid calories and energy balance: The good, the bad, and the uncertain

Energy-yielding fluids are a large and growing proportion of daily energy intake. The specific form and nutrient composition of fluids may hold divergent implications for energy balance. Ethanol elicits a weak compensatory dietary response, resulting in positive energy balance. However, its impact on body weight is unclear, possibly due to metabolic inefficiencies. In contrast, the weak dietary compensation for clear beverages containing other energy sources is associated with weight gain. How these beverages elude satiety mechanisms has not been studied. Soups hold higher satiating value, at least in part, due to cognitive factors. Nutrient dense beverages have been used successfully in meal replacement regimens for weight management, but due to their relatively weak satiety value, are widely consumed for weight gain and as nutrient supplements. A better understanding of the role of fluid calories in the diet is needed to improve dietary guidelines.

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.

Crystallization and preliminary X-ray diffraction studies of two thermostable alpha-galactosidases from glycoside hydrolase family 36

alpha-Galactosidases from thermophilic organisms have gained interest owing to their applications in the sugar industry. The alpha-galactosidases AgaA, AgaB and AgaA A355E mutant from Geobacillus stearothermophilus have been overexpressed in Escherichia coli. Crystals of AgaB and AgaA A355E have been obtained by the vapour-diffusion method and synchrotron data have been collected to 2.0 and 2.8 A resolution, respectively. Crystals of AgaB belong to space group I222 or I2(1)2(1)2(1), with unit-cell parameters a = 87.5, b = 113.3, c = 161.6 A. Crystals of AgaA A355E belong to space group P3(1)21 or P3(2)21, with unit-cell parameters a = b = 150.1, c = 233.2 A.

Efeitos dos óleos de amendoim, açafrão e oliva na composição corporal, metabolismo energético, perfil lipídico e ingestão alimentar de indivíduos eutróficos normolipidêmicos

OBJETIVOS: O presente trabalho visou avaliar os efeitos do consumo dos óleos de amendoim, açafrão e oliva no perfil lipídico, composição corporal, metabolismo energético e ingestão alimentar em indivíduos eutróficos normolipidêmicos. MÉTODOS: Foram selecionados 32 indivíduos, divididos aleatoriamente em quatro grupos, tendo quatro mulheres e quatro homens em cada grupo, com idade entre 18 e 50 anos. Foi oferecido um milk shake aos voluntários no desjejum, veiculando uma quantidade equivalente a 30% da sua energia basal na forma de óleo (amendoim, açafrão ou oliva), por um período de oito semanas, exceto para o grupo-controle, que não recebeu o shake. Foram realizadas avaliações dos valores de colesterol total e frações, triacilgliceróis, composição corporal, taxa de metabolismo basal, termogênese induzida pela dieta e ingestão alimentar dos indivíduos nas semanas basal, 4ª e 8ª. RESULTADOS: Não foi observada diferença significante no perfil lipídico e na saciedade, no entanto, o grupo que recebeu óleo de açafrão apresentou valores de lipídios plasmáticos mais reduzidos. A ingestão dos óleos levou ao aumento do ganho de peso, sendo que o óleo de oliva proporcionou maior circunferência do quadril. CONCLUSÃO: A adição dos óleos na dieta levou ao aumento da deposição de gordura corporal sem provocar alterações no perfil lipídico e ingestão dietética, ao contrário do relatado na literatura. O uso dos óleos em substituição a outros nutrientes energéticos da dieta, o maior número de voluntários e um período maior de intervenção devem ser investigados em estudos futuros.

Soup and satiety☆

Energy-yielding fluids generally have lower satiety value than solid foods. However, despite high water content, soups reportedly are satiating. The mechanisms contributing to this property have not been identified and were the focus of this study. A within-subject design, preload study was administered to 13 male and 18 female adults (23.7+/-0.9 years old) with a mean body mass index (BMI) of 23.0+/-0.7 kg/m2. At approximately weekly intervals, participants reported to the lab after an overnight fast and completed questionnaires on mood, appetite, psychological state, strength, and fine motor skills. After administration of motor tasks, participants consumed a 300-kcal preload in its entirety within 10 min. The test foods included isocaloric, solid, and liquefied versions of identical foods high in protein, fat, or carbohydrate. Single beverage and no-load responses were also tested. The same questionnaires and motor skills tests were completed at 15-min intervals for 1 h and at 30-min intervals for an additional 3 h after loading. Diet records were kept for the balance of the day. The soups led to reductions of hunger and increases of fullness that were comparable to the solid foods. The beverage had the weakest satiety effect. Daily energy intake tended to be lower on days of soup ingestion compared to the solid foods or no-load days and was highest with beverage consumption. Thus, these data support the high satiety value of soups. It is proposed that cognitive factors are likely responsible.

Cloning and characterization of genes from Agrobacterium sp. IP I-671 involved in hydantoin degradation

Cloning and sequencing of a 7.1 kb DNA fragment from Agrobacterium sp IP I-671 revealed seven open reading frames (ORFs) encoding D-hydantoinase, D-carbamoylase and putative hydantoin racemase, D-amino acid oxidase and NAD(P)H-flavin oxidoreductase. Two incomplete ORFs flanking the hydantoin utilization genes showed similarities to genes involved in transposition. Expression of the D-hydantoinase and D-carbamoylase gene in Escherichia coli gave mainly inactive protein concentrated in inclusion bodies, whereas homologous expression on an RSF1010 derivative increased hydantoinase and D-carbamoylase activity 2.5-fold and 10-fold, respectively, in this strain. Inactivation of the D-carbamoylase gene in Agrobacterium sp IP I-671 led to a complete loss of detectable carbamoylase activity whereas the low hydantoinase activity remaining after inactivation of the D-hydantoinase gene indicated the presence of a second hydantoinase-encoding gene. Two plasmids of 80 kb and 190 kb in size were identified by pulsed-field gel electrophoresis and the cloned hydantoin utilization genes were found to be localized on the 190 kb plasmid.

Organization of genes responsible for the stereospecific conversion of hydantoins to alpha-amino acids in Arthrobacter aurescens DSM 3747

Arthrobacter aurescens DSM 3747 hydrolyzes stereospecifically 5'-monosubstituted hydantoins to alpha-amino acids. The genes involved in hydantoin utilization (hyu) were isolated on an 8.7-kb DNA fragment, and by DNA sequence analysis eight ORFs were identified. The hyu gene cluster includes four genes: hyuP encoding a putative transport protein, the hydantoin racemase gene hyuA, the hydantoinase gene hyuH, and the carbamoylase gene hyuC. The four genes are transcribed in the same direction. Upstream of hyuP and in opposite orientation to the hyu genes, three ORFs were found showing similarities to cytochrome P450 monooxygenase (ORF1, incomplete), to membrane proteins (ORF2), and to ferredoxin (ORF3). ORF8 was found downstream of hyuC and again in opposite orientation to the hyu genes. The gene product of ORF8 displayed similarities to the LacI/GalR family of transcriptional regulators. Reverse transcriptase PCR experiments and Northern blot analysis revealed that the genes hyuPAHC are coexpressed in A. aurescens after induction with 3-N-CH3-IMH. The expression of the hyu operon was not regulated by the putative regulator ORF8 as shown by gene disruption and mobility-shift experiments.

Production of recombinant alpha-galactosidases in Thermus thermophilus

A Thermus thermophilus selector strain for production of thermostable and thermoactive alpha-galactosidase was constructed. For this purpose, the native alpha-galactosidase gene (agaT) of T. thermophilus TH125 was inactivated to prevent background activity. In our first attempt, insertional mutagenesis of agaT by using a cassette carrying a kanamycin resistance gene led to bacterial inability to utilize melibiose (alpha-galactoside) and galactose as sole carbohydrate sources due to a polar effect of the insertional inactivation. A Gal(+) phenotype was assumed to be essential for growth on melibiose. In a Gal(-) background, accumulation of galactose or its metabolite derivatives produced from melibiose hydrolysis could interfere with the growth of the host strain harboring recombinant alpha-galactosidase. Moreover, the AgaT(-) strain had to be Km(s) for establishment of the plasmids containing alpha-galactosidase genes and the kanamycin resistance marker. Therefore, a suitable selector strain (AgaT(-) Gal(+) Km(s)) was generated by applying integration mutagenesis in combination with phenotypic selection. To produce heterologous alpha-galactosidase in T. thermophilus, the isogenes agaA and agaB of Bacillus stearothermophilus KVE36 were cloned into an Escherichia coli-Thermus shuttle vector. The region containing the E. coli plasmid sequence (pUC-derived vector) was deleted before transformation of T. thermophilus with the recombinant plasmids. As a result, transformation efficiency and plasmid stability were improved. However, growth on minimal agar medium containing melibiose was achieved only following random selection of the clones carrying a plasmid-based mutation that had promoted a higher copy number and greater stability of the plasmid.

The production of improved tissue-type plasminogen activator in Escherichia coli

Tissue-type plasminogen activator (t-PA) is a valuable thrombolytic agent because of its high affinity to fibrin. When produced in mammalian cell lines, it is glycosylated, a modification that is believed to promote its rapid clearance from the circulation. Bacteria such as Escherichia coli have been tested as alternative expression systems but were not able to express the cDNA of t-PA effectively. The coding sequence for t-PA revealed a significant proportion of AGA and AGG codons, which are rarely used in the coding sequences of E. coli. The argU and argW gene products of E. coli proved to be minor tRNA(arg) species, respectively decoding the very rare triplets AGA/AGG and AGG for arginine. Analysis of genomic fragments from E. coli for both tRNA(arg) genes revealed the presence of defective, cryptic prophages integrated within the impaired tRNA genes. Cloning and supplementation of the limiting tRNA genes argU and argW on helper plasmids improved the translation of the rare AGA and AGG codons. This augmentation improved bacterial growth and enhanced t-PA production in the form of inactive inclusion bodies. This dependence on augmentation of tRNA(arg4) or tRNA(arg5) for improved cell growth and expression was also observed for other genes with a high content of these rare arginine codons. Construction and production of nonglycosylated t-PA in inclusion bodies in E. coli along with improvement of the subsequent renaturation and purification procedures resulted in material comparable to that derived from CHO cells. Deletion of domain-encoding segments yielded various "muteins" of t-PA (e.g., reteplase [rPA]) that could be produced in and activated from the purified inclusion bodies analogously. Furthermore, it was shown that rPA has an extended half-life in the circulation because of its lack of glycosylation and impaired receptor binding capability. rPA was successfully used in various clinical studies. It is a new-generation thrombolytic agent with a longer half-life and can thus be administered more conveniently as a double bolus.

Cloning, nucleotide sequence and expression of a hydantoinase and carbamoylase gene from Arthrobacter aurescens DSM 3745 in Escherichia coli and comparison with the corresponding genes from Arthrobacter aurescens DSM 3747

The genes encoding hydantoinases (hyuH1) and carbamoylases (hyuC1) from Arthrobacter aurescens DSM 3745 and Arthrobacter aurescens DSM 3747 (hyuH2, hyuC2) were cloned in Escherichia coli and the nucleotide sequences determined. The hydantoinase genes comprised 1,377 base pairs and the carbamoylase genes 1,239 base pairs each. Both hydantoinases, as well as both carbamoylases, showed a high degree of nucleotide and amino acid sequence identity (96-98%). The hyuH and hyuC genes were expressed in E. coli under the control of the rhamnose promoter and the different specific activities obtained in E. coli crude extracts were compared to those produced by the original hosts. For purification the hyuH2 gene was expressed as a maltose-binding protein (MalE) and as an intein-chitin binding domain (CBD) fusion in E. coli. The expression of malE-hyuH2 resulted in the production of more soluble and active protein. With respect to temperature stability, optimal pH and optimal temperature, substrate and stereospecificity, the purified fusion enzyme exhibited properties similar to those of the wild-type enzyme.

High-cell-density fermentation for production of L-N-carbamoylase using an expression system based on the Escherichia coli rhaBAD promoter

A high-cell-density fed-batch fermentation for the production of heterologous proteins in Escherichia coli was developed using the positively regulated Escherichia coli rhaBAD promoter. The expression system was improved by reducing of the amount of expensive L-rhamnose necessary for induction of the rhamnose promoter and by increasing the vector stability. Consumption of the inducer L-rhamnose was inhibited by inactivation of L-rhamnulose kinase encoding gene rhaB of Escherichia coli W3110, responsible for the first irreversible step in rhamnose catabolism. Plasmid instability caused by multimerization of the expression vector in the recombination-proficient W3110 was prevented by insertion of the multimer resolution site cer from the ColE1 plasmid into the vector. Fermentation experiments with the optimized system resulted in the production of 100 g x L(-1) cell dry weight and 3.8 g x L(-1) of recombinant L-N-carbamoylase, an enzyme, which is needed for the production of enantiomeric pure amino acids in a two-step reaction from hydantoins.

Development of an Escherichia coli whole cell biocatalyst for the production of L-amino acids

A whole cell biocatalyst for the enzymatic production of L-amino acids from hydantoins was created by coexpressing the genes encoding the L-hydantoinase, the L-N-carbamoylase and the hydantoin racemase from Arthrobacter aurescens in Escherichia coli. In order to construct a well balanced reaction system the enzymatic activity in the cells was varied by using vectors with different copy numbers for expression of the genes. Derivatives of pSC101, pACYC184 and pBR322 were employed for the various constructions and in one construct the hydantoinase gene was integrated into the E. coli chromosome. All constructs carried the E. coli rhamnose promoter system enabling gene expression control by transcriptional regulation. The productivity for L-tryptophan from the corresponding hydantoin was more than 6-fold higher than achieved with Arthrobacter aurescens.

Modulation of the regioselectivity of a Bacillus alpha-galactosidase by directed evolution

Alpha-galactosidase AgaB of Bacillus stearothermophilus was subjected to directed evolution in an effort to modify its regioselectivity. The wild-type enzyme displays a major 1,6 and minor 1,3 regioselectivity. We used random mutagenesis and staggered extension process (StEP) to obtain mutant enzymes displaying modified regioselectivity. We developed a screening procedure allowing first the elimination of AgaB mutants bearing the 1,6 regioselectivity and secondly the selection of those retaining a 1,3 regioselectivity. Our results show that, among the evolved enzymes that have lost most of their activity towards the 1,6 linkage both in hydrolysis and in synthesis, one (E901) has retained its 1,3 activity. However the transglycosylation level reached by this mutant is quite low versus that of the native enzyme. This work constitutes the first example of modification of glycosylhydrolase regioselectivity by directed evolution.

Comparison of verbal and pictorial measures of hunger during fasting in normal weight and obese subjects

OBJECTIVE

Friedman, Ulrich, and Mattes described a new pictorial instrument for assessing hunger wherein respondents outline areas on a drawing of a human figure to depict the location of their hunger sensations. The present study compared normal weight and obese individuals on the pictorial measure and on more traditional verbal hunger measures during a 22-hour fast.

RESEARCH METHODS AND PROCEDURES

The pictorial measure, along with 13 verbal items assessing hunger and hunger-related symptoms, was administered to 29 normal weight college students and 46 overweight clinic patients four times during a 22-hour fast. Factor analyses of verbal hunger items produced Hunger, Somatic Symptoms, and Stomach Symptoms factors. The pictorial measure was divided into peripheral (arms, legs, head) and central (trunk) body areas.

RESULTS

The increases in hunger during the fast were greater when measured using the pictorial as opposed to the verbal instrument. Correlations between and within the three verbal hunger measures and two pictorial measures were generally few in number and modest in size. The overall pattern of correlations suggested that the verbally based hunger measures more adequately reflected the experience of hunger in normal weight than in obese individuals. A significant interaction between weight status and assessment period was found for the pictorial measure, indicating that normal weight subjects experienced more bodily hunger than overweight subjects initially but experienced less hunger than obese subjects after a prolonged period of food deprivation.

DISCUSSION

Although more testing is needed, these results suggest that the pictorial hunger assessment provides information about the experience of hunger that could complement information provided by traditional verbally based hunger measures.

Comparative study of new alpha-galactosidases in transglycosylation reactions

We have studied the potential of several newly cloned alpha-galactosidases to catalyze the regioselective synthesis of disaccharides using 4-nitrophenylgalactoside as a donor. The kinetics of the reactions were followed by in situ NMR spectroscopy. The following thermophilic enzymes have been tested: Aga A and an isoenzyme Aga B obtained from the strain KVE39 and Aga 285 from the strain IT285 of Bacillus stearothermophilus; Aga T is an alpha-galactosidase from Thermus brockianus (strain IT360). Two other non-thermophilic alpha-galactosidases have also been evaluated: Aga 1 (Streptococcus mutans, strain Ingbritt) and Raf A (Escherichia coli, strain D1021). For all of the enzymes studied, high regioselectivity was observed leading to two (1 --> 6)-disaccharides: 4-nitrophenyl alpha-D-galactopyranosyl-(1--> 6)-alpha-D-galactopyranoside and methyl alpha-D-galactopyranosyl-(1--> 6)-alpha-D-galactopyranoside, which were obtained in 54% (Aga B) and 20% (Aga T) yields, respectively.