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We sought to examine the effects of daily consumption of macadamia nuts on body weight and composition, plasma lipids and glycaemic parameters in a free-living environment in overweight and obese adults at elevated cardiometabolic risk. Utilising a randomised cross-over design, thirty-five adults with abdominal obesity consumed their usual diet plus macadamia nuts (~15 % of daily calories) for 8 weeks (intervention) and their usual diet without nuts for 8 weeks (control), with a 2-week washout. Body composition was determined by bioelectrical impedance; dietary intake was assessed with 24-h dietary recalls. Consumption of macadamia nuts led to increased total fat and MUFA intake while SFA intake was unaltered. With mixed model regression analysis, no significant changes in mean weight, BMI, waist circumference, percent body fat or glycaemic parameters, and non-significant reductions in plasma total cholesterol of 2⋅1 % (−4⋅3 mg/dl; 95 % CI −14⋅8, 6⋅1) and low-density lipoprotein (LDL-C) of 4 % (−4⋅7 mg/dl; 95 % CI −14⋅3, 4⋅8) were observed. Cholesterol-lowering effects were modified by adiposity: greater lipid lowering occurred in those with overweight v. obesity, and in those with less than the median percent body fat. Daily consumption of macadamia nuts does not lead to gains in weight or body fat under free-living conditions in overweight or obese adults; non-significant cholesterol lowering occurred without altering saturated fat intake of similar magnitude to cholesterol lowering seen with other nuts.
n-3 index, the erythrocyte proportion of the EPA + DHA fatty acids is a clinical marker of age-related disease risk. It is unclear whether regular intake of α-linolenic acid (ALA), a plant-derived n-3 polyunsaturated fatty acid, raises n-3 index in older adults. Of the 356 participants at the Loma Linda, CA centre from the original study, a randomly selected subset (n 192) was included for this secondary analysis (mostly Caucasian women, mean age 69 years). Participants were assigned to either the walnut (15 % of daily energy from walnuts) or the control group (usual diet, no walnuts) for 2 years. Erythrocyte fatty acids were determined at baseline and 1-year following intervention. No differences were observed for erythrocyte EPA, but erythrocyte DHA decreased albeit modestly in the walnut group (–0·125 %) and slightly improved in the control group (0·17 %). The change in n-3 index between the walnut and control groups was significantly different only among fish consumers (those who ate fish ≥ once/month). Longitudinal analyses combining both groups showed significant inverse association between the 1-year changes of the n-3 index and fasting plasma TAG (ß = −10), total cholesterol (ß = −5·59) and plasma glucose (ß = −0·27). Consuming ALA-rich walnuts failed to improve n-3 index in elders. A direct source of EPA/DHA may be needed to achieve desirable n-3 index, as it is inversely associated with cardiometabolic risk. Nevertheless, incorporating walnuts as part of heart healthy diets is still encouraged.
Eggs contain important compounds related to enhanced cognition, but it is not clear if egg consumption, as a whole, has a direct impact on memory decline in older adults. This study aimed to determine whether egg intake levels predict the rate of memory decline in healthy older adults after sociodemographic and dietary controls. We conducted a secondary analysis of data from 470 participants, age 50 and over, from the Biospsychosocial Religion and Health Study. Participants completed a food frequency questionnaire, which was used to calculate egg intake and divide participants into Low (<23 g/week, about half an egg), Intermediate (24–63 g/week, half to 1½ eggs) and High (≥63 g/week, about two or more eggs) tertiles. Participants were administered the California Verbal Learning Test – 2nd Edition (CVLT-II) Short Form in 2006–2007, and 294 of them were again tested in 2010–2011. Using linear mixed model analysis, no significant cross-sectional differences were observed in CVLT-II performance between egg intake levels after controlling for age, sex, race, education, body mass index, cardiovascular risk, depression and intake of meat, fish, dairy and fruits/vegetables. Longitudinally, the Intermediate egg group exhibited significantly slower rates of decline on the CVLT-II compared to the Low egg group. The High egg group also exhibited slower rates of decline, but not statistically significant. Thus, limited consumption of eggs (about 1 egg/week) was associated with slower memory decline in late life compared to consuming little to no eggs, but a dose-response effect was not clearly evident. This study may help explain discrepancies in previous research that did not control for other dietary intakes and risk factors.
How food is produced and consumed has consequences for ecosystems, such as resource use and greenhouse gas (GHG) emission among others. The Mediterranean diet (MedDiet) was proposed as a sustainable dietary model, due to its nutritional, environmental, economic and sociocultural dimensions. However, further evidence is needed. Thus, our objective was to evaluate the impact on resource (land, water and energy) use and GHG emission of better adherence to the MedDiet in a Mediterranean Spanish cohort.
We analysed the dietary pattern of participants through a validated FFQ. The outcomes were land use, water and energy consumption and GHG emission according to MedDiet adherence. The specific environmental footprints of food item production and processing were obtained from different available life-cycle assessments.
Spanish university graduates.
Participants (n 20 363) in the Seguimiento Universidad de Navarra (SUN) cohort.
Better adherence to the MedDiet was associated with lower land use (−0·71 (95 % CI −0·76, −0·66) m2/d), water consumption (−58·88 (95 % CI −90·12, −27·64) litres/d), energy consumption (−0·86 (95 % CI −1·01, −0·70) MJ/d) and GHG emission (−0·73 (95 % CI −0·78, −0·69) kg CO2e/d). A statistically significant linear trend (P<0·05) was observed in all these analyses.
In this Mediterranean cohort, better adherence to the MedDiet was an eco-friendly option according to resource consumption and GHG emission.
Older adults tend to require fewer energy content and higher levels of nutrients to promote and maintain optimal health. Regrettably, dietary variety and quality are known to decline with advancing age. We conducted a 2-year prospective, randomised, dietary intervention trial where we asked free-living elderly subjects (63–79 years) on self-selected habitual diets to incorporate walnuts daily into their diet (15 % energy). We then compared their nutrient intake with that of a similar group of concurrent participants on self-selected habitual diets but abstaining from walnut consumption (control). No recipes or advice on use of nuts were provided. Dietary intake was assessed by multiple unannounced 24-h telephone dietary recalls. On average, walnut supplement consumption was 43 g/d or 1171·5 kJ (281 kcal). The mean daily energy intake was 954 kJ (228 kcal) higher in the walnut group than in the control group (P<0·001). Compared with control, participants in the walnut group reported significantly higher intake of total protein, vegetable protein, total PUFA and n-3 and n-6 PUFA; and significantly lower intake of total carbohydrate, animal protein, SFA, and Na. An estimated 19 % of total energy and 25 % of total fat from other food sources was displaced. Displacement of MUFA and total PUFA was 21 and 16 %, respectively. Thus adding a daily supplement of walnuts to an ad libitum diet of older adults can induce favourable modifications to the nutrient profile in a way that addresses declining nutrient intake associated with aging.
The vegetarian dietary pattern is traditionally a plant-based diet that includes fruits, vegetables, cereals, legumes, nuts, vegetable oils, soya, and possibly dairy products and/or eggs. Vegetarians and other populations who follow a plant-based dietary pattern enjoy longevity. Specifically, vegetarian dietary patterns have been associated with a lower risk for developing IHD, type 2 diabetes, hypertension, specific cancers, lower all-cause mortality and reduction in cause-specific mortality. The prevalence of the metabolic syndrome (MetS) in the USA is approximately 20 % and is currently increasing in developing countries in line with the obesity epidemic. The health care costs associated with the MetS are on a magnitude of 1·6 overall compared with healthy individuals, which makes it an important public health problem. Current evidence from several cross-sectional and case–control studies shows an association between consumption of a vegetarian dietary pattern and a reduced prevalence or risk of developing the MetS. There is a need for further research to be conducted, particularly prospective cohort studies to evaluate the effect of vegetarian dietary patterns on reducing the incidence of the MetS and, clinical trials should be designed to explore vegetarian dietary patterns for the reversal of the MetS in high-risk populations. This research could contribute to reduce the societal and economic burdens associated with the disorder.
To compare the use of water, energy, pesticides and fertilizer to produce commodities for two dietary patterns that vary in the content of plant and animal products.
A unique analysis using ‘real-world’ data was performed, in contrast to previous analyses which applied simulated data. Consumption data from the Adventist Health Study were used to identify two dietary patterns with a markedly different consumption of several plant and animal products. State agricultural data were collected and applied to commodity production statistics. Indices were created to allow a comparison of the resource requirements for each dietary pattern.
The diet containing more animal products required an additional 10 252 litres of water, 9910 kJ of energy, 186 g of fertilizer and 6 g of pesticides per week in comparison to the diet containing less animal products. The greatest contribution to the difference came from the consumption of animal products, particularly beef.
Consuming a more plant-based diet could to an extent alleviate the negative environmental impacts related to food production. As a method to feed ourselves more sustainably, behavioural adjustments appear to be a very important tool.
To investigate the resource efficiency and environmental impacts of producing one kilogram of edible protein from two plant- and three animal-protein sources.
Primary source data were collected and applied to commodity production statistics to calculate the indices required to compare the environmental impact of producing 1 kg of edible protein from kidney beans, almonds, eggs, chicken and beef. Inputs included land and water for raising animals and growing animal feed, total fuel, and total fertilizer and pesticide for growing the plant commodities and animal feed. Animal waste generated was computed for the animal commodities.
Desk-based study at the Department of Nutrition and Department of Occupational and Environmental Health, Loma Linda University.
To produce 1 kg of protein from kidney beans required approximately eighteen times less land, ten times less water, nine times less fuel, twelve times less fertilizer and ten times less pesticide in comparison to producing 1 kg of protein from beef. Compared with producing 1 kg of protein from chicken and eggs, beef generated five to six times more waste (manure) to produce 1 kg of protein.
The substitution of beef with beans in meal patterns will significantly reduce the environmental footprint worldwide and should also be encouraged to reduce the prevalence of non-communicable chronic diseases. Societies must work together to change the perception that red meat (e.g. beef) is the mainstay of an affluent and healthy diet.
Vegetarian dietary patterns have been reported to be associated with a number of favourable health outcomes in epidemiological studies, including the Adventist Health Study 2 (AHS-2). Such dietary patterns may vary and need further characterisation regarding foods consumed. The aims of the present study were to characterise and compare the food consumption patterns of several vegetarian and non-vegetarian diets. Dietary intake was measured using an FFQ among more than 89 000 members of the AHS-2 cohort. Vegetarian dietary patterns were defined a priori, based on the absence of certain animal foods in the diet. Foods were categorised into fifty-eight minor food groups comprising seventeen major food groups. The adjusted mean consumption of each food group for the vegetarian dietary patterns was compared with that for the non-vegetarian dietary pattern. Mean consumption was found to differ significantly across the dietary patterns for all food groups. Increased consumption of many plant foods including fruits, vegetables, avocados, non-fried potatoes, whole grains, legumes, soya foods, nuts and seeds was observed among vegetarians. Conversely, reduced consumption of meats, dairy products, eggs, refined grains, added fats, sweets, snack foods and non-water beverages was observed among vegetarians. Thus, although vegetarian dietary patterns in the AHS-2 have been defined based on the absence of animal foods in the diet, they differ greatly with respect to the consumption of many other food groups. These differences in food consumption patterns may be important in helping to explain the association of vegetarian diets with several important health outcomes.
Walnuts contain a number of potentially neuroprotective compounds like vitamin E, folate, melatonin, several antioxidative polyphenols and significant amounts of n-3 α-linolenic fatty acid. The present study sought to determine the effect of walnuts on verbal and non-verbal reasoning, memory and mood. A total of sixty-four college students were randomly assigned to two treatment sequences in a crossover fashion: walnuts–placebo or placebo–walnuts. Baseline data were collected for non-verbal reasoning, verbal reasoning, memory and mood states. Data were collected again after 8 weeks of intervention. After 6 weeks of washout, the intervention groups followed the diets in reverse order. Data were collected once more at the end of the 8-week intervention period. No significant increases were detected for mood, non-verbal reasoning or memory on the walnut-supplemented diet. However, inferential verbal reasoning increased significantly by 11·2 %, indicating a medium effect size (P = 0·009; d = 0·567). In young, healthy, normal adults, walnuts do not appear to improve memory, mood or non-verbal reasoning abilities. However, walnuts may have the ability to increase inferential reasoning.
To assess race-specific validity of food and food group intakes measured using an FFQ.
Calibration study participants were randomly selected from the Adventist Health Study-2 (AHS-2) cohort by church, and then by subject-within-church. Intakes of forty-seven foods and food groups were assessed using an FFQ and then compared with intake estimates measured using six 24 h dietary recalls (24HDR). We used two approaches to assess the validity of the questionnaire: (i) cross-classification by quartile and (ii) de-attenuated correlation coefficients.
Seventh-day Adventist church members geographically spread throughout the USA and Canada.
Members of the AHS-2 calibration study (550 whites and 461 blacks).
The proportion of participants with exact quartile agreement in the FFQ and 24HDR averaged 46 % (range: 29–87 %) in whites and 44 % (range: 25–88 %) in blacks. The proportion of quartile gross misclassification ranged from 1 % to 11 % in whites and from 1 % to 15 % in blacks. De-attenuated validity correlations averaged 0·59 in whites and 0·48 in blacks. Of the forty-seven foods and food groups, forty-three in whites and thirty-three in blacks had validity correlations >0·4.
The AHS-2 questionnaire has good validity for most foods in both races; however, validity correlations tend to be higher in whites than in blacks.
To validate a 204-item quantitative FFQ for measurement of nutrient intake in the Adventist Health Study-2 (AHS-2).
Calibration study participants were randomly selected from the AHS-2 cohort by church, and then subject-within-church. Each participant provided two sets of three weighted 24 h dietary recalls and a 204-item FFQ. Race-specific correlation coefficients (r), corrected for attenuation from within-person variation in the recalls, were calculated for selected energy-adjusted macro- and micronutrients.
Adult members of the AHS-2 cohort geographically spread throughout the USA and Canada.
Calibration study participants included 461 blacks of American and Caribbean origin and 550 whites.
Calibration study subjects represented the total cohort very well with respect to demographic variables. Approximately 33 % were males. Whites were older, had higher education and lower BMI compared with blacks. Across fifty-one variables, average deattenuated energy-adjusted validity correlations were 0·60 in whites and 0·52 in blacks. Individual components of protein had validity ranging from 0·40 to 0·68 in blacks and from 0·63 to 0·85 in whites; for total fat and fatty acids, validity ranged from 0·43 to 0·75 in blacks and from 0·46 to 0·77 in whites. Of the eighteen micronutrients assessed, sixteen in blacks and sixteen in whites had deattenuated energy-adjusted correlations ≥0·4, averaging 0·60 and 0·53 in whites and blacks, respectively.
With few exceptions validity coefficients were moderate to high for macronutrients, fatty acids, vitamins, minerals and fibre. We expect to successfully use these data for measurement error correction in analyses of diet and disease risk.
Frequent consumption of nuts lowers the risk of CHD. While lowering blood lipids is one of the mechanisms for cardioprotection, the present study sought to determine whether monounsaturated fat-rich almonds also influence other CHD risk factors such as inflammation and haemostasis. This was a randomised, controlled, crossover feeding study with twenty-five healthy adults (eleven men; fourteen women), age 22–53 years. Following a 2 week run-in phase (34 % energy from fat), subjects were assigned in random order to three diets for 4 weeks each: a heart-healthy control diet with no nuts ( < 30 % energy from fat), low-almond diet and high-almond diet (10 % or 20 % isoenergetic replacement of control diet with almonds, respectively). Serum E-selectin was significantly lower on the high-almond diet compared with the control diet. E-selectin decreased as the percentage of energy from almonds increased (P < 0·0001). C-reactive protein (CRP) was lower in both the almond diets compared with the control diet. A clear dose response was not observed for either E-selectin or CRP. There was no effect of diet on IL-6 or fibrinogen. Tissue plasminogen activator antigen was significantly lower on the control and high-almond diets compared with the low-almond diet, although the values were within normal range. In conclusion, consumption of almonds influenced a few but not all of the markers of inflammation and haemostasis. A clear dose response was not observed for any of the markers studied.
To validate a 171-item semi-quantitative food-frequency questionnaire (FFQ) for measurement of nutrient intake in an intervention trial based on walnut supplementation.
Design and setting
Free-living adults from Southern California were randomly assigned to either an intervention (walnut-supplemented) or a control diet. The prescribed 6-month intervention was ≥ 28 g of walnuts per day for the walnut-supplemented group and ≤ 2 g of walnuts per day for the control group. Participants provided at least six 24-hour dietary recalls and completed a self-administered FFQ.
Eighty-seven adults aged 30–72 years (48 females, 39 males).
Our findings from validation (by correlation with six diet recall measures) of the measurement of 32 nutrients by the FFQ are as follows. We found significant positive correlations (corrected for measurement error) between the FFQ and diet recalls for total energy (r = 0.34), total carbohydrate (r = 0.42), vegetable protein (r = 0.43), total fat (r = 0.51), polyunsaturated fat (r = 0.77), total fibre (r = 0.60), linoleic acid (r = 0.78) and α-linolenic acid (r = 0.79) – the last nutrient being an excellent nutrient biomarker of the intervention (walnut supplementation). Significant positive correlations were also found for vitamin C (r = 0.96) and certain minerals (r = 0.46–0.80 for calcium, phosphorus, magnesium, iron and potassium). Uncorrected correlations were also high (r>0.40) for retinol, β-carotene, folate and alcohol. Both diet recalls and FFQ showed a similar significant difference in α-linolenic acid content between the walnut-supplemented and control diets.
The FFQ demonstrated good relative validity in the estimation intake of some of the major nutrients in a dietary intervention trial and was a particularly valid estimate of an important nutrient biomarker of walnut supplementation.
To specify the principles, definition and dimensions of the new nutrition science.
To identify nutrition, with its application in food and nutrition policy, as a science with great width and breadth of vision and scope, in order that it can fully contribute to the preservation, maintenance, development and sustenance of life on Earth.
A brief overview shows that current conventional nutrition is defined as a biological science, although its governing and guiding principles are implicit only, and no generally agreed definition is evident. Following are agreements on the principles, definition and dimensions of the new nutrition science, made by the authors as participants at a workshop on this theme held on 5–8 April 2005 at the Schloss Rauischholzhausen, Justus-Liebig University, Giessen, Germany.
Nutrition science as here specified will retain its current [classical] identity as a biological science, within a broader and integrated conceptual framework, and will also be confirmed as a social and environmental science. As such it will be concerned with personal and population health, and with planetary health – the welfare and future of the whole physical and living world of which humans are a part.