Journal: The British journal of nutrition
Demand for organic foods is partially driven by consumers' perceptions that they are more nutritious. However, scientific opinion is divided on whether there are significant nutritional differences between organic and non-organic foods, and two recent reviews have concluded that there are no differences. In the present study, we carried out meta-analyses based on 343 peer-reviewed publications that indicate statistically significant and meaningful differences in composition between organic and non-organic crops/crop-based foods. Most importantly, the concentrations of a range of antioxidants such as polyphenolics were found to be substantially higher in organic crops/crop-based foods, with those of phenolic acids, flavanones, stilbenes, flavones, flavonols and anthocyanins being an estimated 19 (95 % CI 5, 33) %, 69 (95 % CI 13, 125) %, 28 (95 % CI 12, 44) %, 26 (95 % CI 3, 48) %, 50 (95 % CI 28, 72) % and 51 (95 % CI 17, 86) % higher, respectively. Many of these compounds have previously been linked to a reduced risk of chronic diseases, including CVD and neurodegenerative diseases and certain cancers, in dietary intervention and epidemiological studies. Additionally, the frequency of occurrence of pesticide residues was found to be four times higher in conventional crops, which also contained significantly higher concentrations of the toxic metal Cd. Significant differences were also detected for some other (e.g. minerals and vitamins) compounds. There is evidence that higher antioxidant concentrations and lower Cd concentrations are linked to specific agronomic practices (e.g. non-use of mineral N and P fertilisers, respectively) prescribed in organic farming systems. In conclusion, organic crops, on average, have higher concentrations of antioxidants, lower concentrations of Cd and a lower incidence of pesticide residues than the non-organic comparators across regions and production seasons.
Cocoa flavanol (CF) intake improves endothelial function in patients with cardiovascular risk factors and disease. We investigated the effects of CF on surrogate markers of cardiovascular health in low risk, healthy, middle-aged individuals without history, signs or symptoms of CVD. In a 1-month, open-label, one-armed pilot study, bi-daily ingestion of 450 mg of CF led to a time-dependent increase in endothelial function (measured as flow-mediated vasodilation (FMD)) that plateaued after 2 weeks. Subsequently, in a randomised, controlled, double-masked, parallel-group dietary intervention trial (Clinicaltrials.gov: NCT01799005), 100 healthy, middle-aged (35���60 years) men and women consumed either the CF-containing drink (450 mg) or a nutrient-matched CF-free control bi-daily for 1 month. The primary end point was FMD. Secondary end points included plasma lipids and blood pressure, thus enabling the calculation of Framingham Risk Scores and pulse wave velocity. At 1 month, CF increased FMD over control by 1��2 % (95 % CI 1��0, 1��4 %). CF decreased systolic and diastolic blood pressure by 4��4 mmHg (95 % CI 7��9, 0��9 mmHg) and 3��9 mmHg (95 % CI 6��7, 0��9 mmHg), pulse wave velocity by 0��4 m/s (95 % CI 0��8, 0��04 m/s), total cholesterol by 0��20 mmol/l (95 % CI 0��39, 0��01 mmol/l) and LDL-cholesterol by 0��17 mmol/l (95 % CI 0��32, 0��02 mmol/l), whereas HDL-cholesterol increased by 0��10 mmol/l (95 % CI 0��04, 0��17 mmol/l). By applying the Framingham Risk Score, CF predicted a significant lowering of 10-year risk for CHD, myocardial infarction, CVD, death from CHD and CVD. In healthy individuals, regular CF intake improved accredited cardiovascular surrogates of cardiovascular risk, demonstrating that dietary flavanols have the potential to maintain cardiovascular health even in low-risk subjects.
Morning coffee is a common remedy following disrupted sleep yet each factor can independently impair glucose tolerance and insulin sensitivity in healthy adults. Remarkably, the combined effects of sleep fragmentation and coffee on glucose control upon waking per se have never been investigated.In a randomised cross-over design, 29 adults (Mean ± SD; age: 21 ± 1 years, BMI: 24.4 ± 3.3 kg·m-2) underwent three oral glucose tolerance tests (OGTT). One following a habitual night of sleep (Control; in bed, lights-off trying to sleep ~2300-0700 h) the others following a night of sleep fragmentation (as Control but waking hourly for 5 min), once with and once without morning coffee ~1 h after waking (~300 mg caffeine as black coffee 30 min prior to OGTT).Peak plasma glucose and insulin concentrations were unaffected by sleep quality but were higher following coffee consumption (Mean [normalised confidence interval] for Control, Fragmented, and Fragmented+Coffee, respectively; Glucose: 8.20 [7.93-8.47] mmol∙L-1versus 8.23 [7.96-8.50] mmol∙L-1versus 8.96 [8.70-9.22] mmol.L-1; Insulin: 265 [247-283] pmol∙L-1; and 235 [218-253] pmol∙L-1; and 310 [284-337] pmol∙L-1). Likewise, iAUC for plasma glucose was higher in the Fragmented+Coffee trial compared to Fragmented.Whilst sleep fragmentation did not alter glycaemic or insulinaemic responses to morning glucose ingestion, if a strong caffeinated coffee is consumed then a reduction in glucose tolerance can be expected.
Diets rich in fruits and vegetables (FV), which contain (poly)phenols, protect against age-related inflammation and chronic diseases. T-lymphocytes contribute to systemic cytokine production and are modulated by FV intake. Little is known about the relative potency of different (poly)phenols in modulating cytokine release by lymphocytes. We compared thirty-one (poly)phenols and six (poly)phenol mixtures for effects on pro-inflammatory cytokine release by Jurkat T-lymphocytes. Test compounds were incubated with Jurkat cells for 48 h at 1 and 30 µm, with or without phorbol ester treatment at 24 h to induce cytokine release. Three test compounds that reduced cytokine release were further incubated with primary lymphocytes at 0·2 and 1 µm for 24 h, with lipopolysaccharide added at 5 h. Cytokine release was measured, and generation of H2O2 by test compounds was determined to assess any potential correlations with cytokine release. A number of (poly)phenols significantly altered cytokine release from Jurkat cells (P<0·05), but H2O2 generation did not correlate with cytokine release. Resveratrol, isorhamnetin, curcumin, vanillic acid and specific (poly)phenol mixtures reduced pro-inflammatory cytokine release from T-lymphocytes, and there was evidence for interaction between (poly)phenols to further modulate cytokine release. The release of interferon-γ induced protein 10 by primary lymphocytes was significantly reduced following treatment with 1 µm isorhamnetin (P<0·05). These results suggest that (poly)phenols derived from onions, turmeric, red grapes, green tea and açai berries may help reduce the release of pro-inflammatory mediators in people at risk of chronic inflammation.
Demand for organic milk is partially driven by consumer perceptions that it is more nutritious. However, there is still considerable uncertainty over whether the use of organic production standards affects milk quality. Here we report results of meta-analyses based on 170 published studies comparing the nutrient content of organic and conventional bovine milk. There were no significant differences in total SFA and MUFA concentrations between organic and conventional milk. However, concentrations of total PUFA and n-3 PUFA were significantly higher in organic milk, by an estimated 7 (95 % CI ���1, 15) % and 56 (95 % CI 38, 74) %, respectively. Concentrations of ��-linolenic acid (ALA), very long-chain n-3 fatty acids (EPA+DPA+DHA) and conjugated linoleic acid were also significantly higher in organic milk, by an 69 (95 % CI 53, 84) %, 57 (95 % CI 27, 87) % and 41 (95 % CI 14, 68) %, respectively. As there were no significant differences in total n-6 PUFA and linoleic acid (LA) concentrations, the n-6:n-3 and LA:ALA ratios were lower in organic milk, by an estimated 71 (95 % CI ���122, ���20) % and 93 (95 % CI ���116, ���70) %. It is concluded that organic bovine milk has a more desirable fatty acid composition than conventional milk. Meta-analyses also showed that organic milk has significantly higher ��-tocopherol and Fe, but lower I and Se concentrations. Redundancy analysis of data from a large cross-European milk quality survey indicates that the higher grazing/conserved forage intakes in organic systems were the main reason for milk composition differences.
This study investigated metabolic, endocrine, appetite, and mood responses to a maximal eating occasion in fourteen men (mean ±SD: age 28 ±5 y, body mass 77.2 ±6.6 kg, body mass index 24.2 ±2.2 kg·m-2) who completed two trials in a randomised crossover design. On each occasion participants ate a homogenous mixed-macronutrient meal (pizza). On one occasion, they ate until ‘comfortably full’ (ad libitum) and on the other until they ‘could not eat another bite’ (maximal). Mean [95% CI] energy intake was double in the maximal (13,024 [10964, 15084] kJ; 3113 [2620,3605] kcal) compared with the ad libitum trial (6627 [5708,7547] kJ; 1584 [1364,1804] kcal). Serum insulin iAUC increased ~1.5-fold in the maximal compared with ad libitum trial (mean [95% CI] ad libitum 51.1 [33.3,69.0] nmol·L-1·4 h, maximal 78.8 [55.0,102.6] nmol·L-1·4 h, p < 0.01), but glucose iAUC did not differ between trials (ad libitum 94.3 [30.3,158.2] mmol·L-1·4 h, maximal 126.5 [76.9,176.0] mmol·L-1·4 h, p = 0.19). TAG iAUC was ~1.5-fold greater in the maximal versus ad libitum trial (ad libitum 98.6 [69.9,127.2] mmol·L-1·4 h, maximal 146.4 [88.6,204.1] mmol·L-1·4 h, p < 0.01). Total GLP-1, GIP, and PYY iAUC were greater in the maximal compared with ad libitum trial (p < 0.05). Total ghrelin concentrations decreased to a similar extent, but AUC was slightly lower in the maximal versus ad libitum trial (p = 0.02). There were marked differences on appetite and mood between trials, most notably maximal eating caused a prolonged increase in lethargy. Healthy men have capacity to eat twice the calories required to achieve comfortable fullness at a single meal. Postprandial glycaemia is well-regulated following initial overeating, with elevated postprandial insulinaemia likely contributing.
Demand for organic meat is partially driven by consumer perceptions that organic foods are more nutritious than non-organic foods. However, there have been no systematic reviews comparing specifically the nutrient content of organic and conventionally produced meat. In this study, we report results of a meta-analysis based on sixty-seven published studies comparing the composition of organic and non-organic meat products. For many nutritionally relevant compounds (e.g. minerals, antioxidants and most individual fatty acids (FA)), the evidence base was too weak for meaningful meta-analyses. However, significant differences in FA profiles were detected when data from all livestock species were pooled. Concentrations of SFA and MUFA were similar or slightly lower, respectively, in organic compared with conventional meat. Larger differences were detected for total PUFA and n-3 PUFA, which were an estimated 23 (95 % CI 11, 35) % and 47 (95 % CI 10, 84) % higher in organic meat, respectively. However, for these and many other composition parameters, for which meta-analyses found significant differences, heterogeneity was high, and this could be explained by differences between animal species/meat types. Evidence from controlled experimental studies indicates that the high grazing/forage-based diets prescribed under organic farming standards may be the main reason for differences in FA profiles. Further studies are required to enable meta-analyses for a wider range of parameters (e.g. antioxidant, vitamin and mineral concentrations) and to improve both precision and consistency of results for FA profiles for all species. Potential impacts of composition differences on human health are discussed.
Although breakfast consumption is widely considered to be an important component of a healthy lifestyle, few UK studies have examined differences in nutrient intakes between breakfast consumers and breakfast skippers among children and adolescents. We investigated associations between breakfast skipping in 4-18-year-olds and their nutrient intakes using data from the UK’s National Diet and Nutrition Survey Rolling Programme. Dietary data were derived from 4-d estimated food diaries of 802 children aged 4-10 years and 884 children aged 11-18 years (1686 in total). Daily nutrient intakes of children with different breakfast habits were compared by one-way ANCOVA adjusting for relevant covariates (sex, age, ethnicity, equivalised household income and BMI). Within-person analysis was carried out on children with an irregular breakfast habit (n 879) comparing nutrient intakes on breakfast days with those on non-breakfast days using repeated measures ANCOVA. We observed that the overall nutritional profile of the children in terms of fibre and micronutrient intake was superior in frequent breakfast consumers (micronutrients: folate, Ca, Fe and I (P<0·01)) and, for the 4-10 years age group, on breakfast days (micronutrients: folate, vitamin C, Ca and I (P<0·01)). Also, significantly higher proportions of breakfast-consuming children met their reference nutrient intakes of folate, vitamin C, Ca, Fe and I compared with breakfast skippers (χ 2 analysis, P<0·001). Our study adds to the body of data linking breakfast consumption with higher quality dietary intake in school-age children, supporting the promotion of breakfast as an important element of a healthy dietary pattern in children.
There is strong evidence indicating that elevated plasma total homocysteine (tHcy) levels are a major independent biomarker and/or a contributor to chronic conditions, such as CVD. A deficiency of vitamin B12 can elevate homocysteine. Vegetarians are a group of the population who are potentially at greater risk of vitamin B12 deficiency than omnivores. This is the first systematic review and meta-analysis to appraise a range of studies that compared the homocysteine and vitamin B12 levels of vegetarians and omnivores. The search methods employed identified 443 entries, from which, by screening using set inclusion and exclusion criteria, six eligible cohort case studies and eleven cross-sectional studies from 1999 to 2010 were revealed, which compared concentrations of plasma tHcy and serum vitamin B12 of omnivores, lactovegetarians or lacto-ovovegetarians and vegans. Of the identified seventeen studies (3230 participants), only two studies reported that vegan concentrations of plasma tHcy and serum vitamin B12 did not differ from omnivores. The present study confirmed that an inverse relationship exists between plasma tHcy and serum vitamin B12, from which it can be concluded that the usual dietary source of vitamin B12 is animal products and those who choose to omit or restrict these products are destined to become vitamin B12 deficient. At present, the available supplement, which is usually used for fortification of food, is the unreliable cyanocobalamin. A well-designed study is needed to investigate a reliable and suitable supplement to normalise the elevated plasma tHcy of a high majority of vegetarians. This would fill the gaps in the present nutritional scientific knowledge.
There is some evidence from studies in adults and limited evidence from studies in children that eating later in the day may increase the risk of overweight and obesity. In this cross-sectional study, we investigated associations between evening meal timing in children and their weight status and energy intake. Dietary data obtained from the UK’s National Diet and Nutrition Survey Rolling Programme (2008-2012) for 768 children aged 4-10 years and 852 children aged 11-18 years were analysed. We tested for an association between evening meal timing (consuming the evening meal before or after 20.00 hours) and risk of overweight and/or obesity, adjusting for relevant confounding variables. We also explored whether evening meal timing was associated with overall nutrient intake. We found no association between evening meal timing and risk of obesity or risk of overweight and obesity combined in either the 4-10 years age group (obesity: OR 1·43; 95 % CI 0·49, 4·13; obesity and overweight combined: OR 1·33; 95 % CI 0·53, 3·33) or the 11-18 years age group (obesity: OR 0·50; 95 % CI 0·24, 1·02; obesity and overweight combined: OR 0·83; 95 % CI 0·50, 1·38), split by sex or as combined. No significant associations were found between evening meal timing and energy intake, and no clear patterns in variation of nutrient intakes with evening meal times were identified. In conclusion, we found no evidence that, for children aged 4-18 years in the UK, eating the evening meal after 20.00 hours was associated with excess weight or increased energy intake.