Diet is a modifiable risk factor for chronic disease and a potential modulator of telomere length (TL). The study aim was to investigate associations between diet quality and TL in Australian adults after a 12-week dietary intervention with an almond-enriched diet (AED). Participants (overweight/obese, 50–80 years) were randomised to an AED (n 62) or isoenergetic nut-free diet (NFD, n 62) for 12 weeks. Diet quality was assessed using a Dietary Guideline Index (DGI), applied to weighed food records, that consists of ten components reflecting adequacy, variety and quality of core food components and discretionary choices within the diet. TL was measured by quantitative PCR in samples of lymphocytes, neutrophils, and whole blood. There were no significant associations between DGI scores and TL at baseline. Diet quality improved with AED and decreased with NFD after 12 weeks (change from baseline AED + 9·8 %, NFD − 14·3 %; P < 0·001). TL increased in neutrophils (+9·6 bp, P = 0·009) and decreased in whole blood, to a trivial extent (–12·1 bp, P = 0·001), and was unchanged in lymphocytes. Changes did not differ between intervention groups. There were no significant relationships between changes in diet quality scores and changes in lymphocyte, neutrophil or whole blood TL. The inclusion of almonds in the diet improved diet quality scores but had no impact on TL mid-age to older Australian adults. Future studies should investigate the impact of more substantial dietary changes over longer periods of time.

This study compared the longer-term effects of a very low-carbohydrate, high-fat diet with a high-carbohydrate, low-fat diet on cognitive performance in individuals with type 2 diabetes (T2D). In total, 115 obese adults with T2D (sixty-six males, BMI: 34·6 (sd 4·3) kg/m2, age: 58 (sd 7) years, HbA1c: 7·3 (sd 1·1) %, diabetes duration: 8 (sd 6) years) were randomised to consume either an energy-restricted, very low-carbohydrate, low-saturated-fat (LC) diet or an energy-matched high unrefined carbohydrate, low-fat (HC) diet with supervised aerobic/resistance exercise (60 min, 3 d/week) for 52 weeks. Body weight, HbA1c and cognitive performance assessing perceptual speed, reasoning speed, reasoning ability, working memory, verbal fluency, processing speed, short-term memory, inhibition and memory scanning speed were assessed before and after intervention. No differences in the changes in cognitive test performance scores between the diet groups were observed for any of the cognitive function outcomes assessed (P≥0·24 time×diet). Percentage reduction in body weight correlated with improvements with perceptual speed performance. In obese adults with T2D, both LC and HC weight-loss diets combined with exercise training had similar effects on cognitive performance. This suggests that an LC diet integrated within a lifestyle modification programme can be used as a strategy for weight and diabetes management without the concern of negatively affecting cognitive function.

Nuts are rich in many nutrients that can benefit multiple cardiometabolic functions, including arterial compliance, blood pressure, inflammation, glucoregulation and endothelial vasodilatation. Impaired vasodilatation may contribute to impaired cognitive performance due to poor cerebral perfusion. The present narrative review examines associations between nut consumption, vascular health and cognitive function. It includes a systematic search which identified seventy-one epidemiological or intervention studies in which effects of chronic nut consumption on blood pressure, glucoregulation, endothelial vasodilator function, arterial compliance, inflammatory biomarkers and cognitive performance were evaluated. Weighted mean changes were estimated where data were available; they indicate that nut consumption reduces blood pressure and improves glucoregulation, endothelial vasodilator function and inflammation, whilst a limited number of studies suggest that nut consumption may also improve cognitive performance. Further clinical trials are warranted to explore relationships between nut consumption, endothelial function and cognitive function.

Protein hydrolysates provide a rich source of protein which is useful in situations where excess protein is needed, such as during repair of tissue damage. The consumption of protein hydrolysates has been shown to result in more rapid uptake of amino acids compared with whole proteins or free-form amino acid mixtures and some peptides in hydrolysates exhibit biological activity. Early studies showed that protein hydrolysates are more effectively utilised than intact proteins or amino acids. In addition, they promote a strong insulinotropic effect, which reduces protein breakdown and enhances muscle and tissue uptake of branched-chain amino acids. These effects contribute to benefits of protein hydrolysates for enhancing repair of tissue damage caused by surgery, ulcers, burns and muscle-damaging exercise. While there is evidence that protein hydrolysates may be useful for facilitating tissue repair, additional research is needed to further examine various roles of protein hydrolysates in this process.

Depressive symptoms may increase the risk of progressing from mild cognitive impairment (MCI) to dementia. Consumption of n-3 PUFA may alleviate both cognitive decline and depression. The aim of the present study was to investigate the benefits of supplementing a diet with n-3 PUFA, DHA and EPA, for depressive symptoms, quality of life (QOL) and cognition in elderly people with MCI. We conducted a 6-month double-blind, randomised controlled trial. A total of fifty people aged >65 years with MCI were allocated to receive a supplement rich in EPA (1·67 g EPA+0·16 g DHA/d; n 17), DHA (1·55 g DHA+0·40 g EPA/d; n 18) or the n-6 PUFA linoleic acid (LA; 2·2 g/d; n 15). Treatment allocation was by minimisation based on age, sex and depressive symptoms (Geriatric Depression Scale, GDS). Physiological and cognitive assessments, questionnaires and fatty acid composition of erythrocytes were obtained at baseline and 6 months (completers: n 40; EPA n 13, DHA n 16, LA n 11). Compared with the LA group, GDS scores improved in the EPA (P = 0·04) and DHA (P = 0·01) groups and verbal fluency (Initial Letter Fluency) in the DHA group (P = 0·04). Improved GDS scores were correlated with increased DHA plus EPA (r 0·39, P = 0·02). Improved self-reported physical health was associated with increased DHA. There were no treatment effects on other cognitive or QOL parameters. Increased intakes of DHA and EPA benefited mental health in older people with MCI. Increasing n-3 PUFA intakes may reduce depressive symptoms and the risk of progressing to dementia. This needs to be investigated in larger, depressed samples with MCI.

In healthy older subjects, the glycaemic response to carbohydrate-containing meals is dependent on gastric emptying and intestinal absorption; when the latter is slowed, the magnitude of the rise in glucose is attenuated. The oligosaccharide α-cyclodextrin has been reported to diminish the glycaemic response to starch in young adults; this effect has been attributed to the inhibition of pancreatic amylase. We examined the effects of α-cyclodextrin on gastric emptying of, and the glycaemic and insulinaemic responses to, oral sucrose in healthy older subjects; as sucrose is hydrolysed by intestinal disaccharides, any effect(s) of α-cyclodextrin would not be attributable to amylase inhibition. A total of ten subjects (seven males and three females, age 68–76 years) were studied on 2 d. Gastric emptying, blood glucose and serum insulin were measured after ingestion of a 300 ml drink containing 100 g sucrose, labelled with 99mTc-sulphur colloid, with or without 10 g α-cyclodextrin. Gastric emptying was slowed slightly by α-cyclodextrin; this effect was evident between 135 and 195 min and was associated with a slight increase (P < 0·05) in distal stomach retention. After α-cyclodextrin, blood glucose was slightly less (P < 0·05) at 60 min, and serum insulin was less (P < 0·0005) at 90 and 120 min. There was no difference in the incremental areas under the curve (iAUC) for blood glucose, but there was a trend for the iAUC for serum insulin to be lower (P = 0·09) after α-cyclodextrin. We conclude that in a dose of 10 g, α-cyclodextrin has modest effects to slow gastric emptying of, and modify the glycaemic and insulinaemic responses to, oral sucrose, probably due to delayed intestinal carbohydrate absorption.

Impaired endothelial vasodilatation may contribute to the exaggerated blood pressure (BP) responses to exercise in individuals who are overweight/obese. The present study investigated whether consumption of cocoa flavanols, which improve endothelium-dependent flow-mediated dilatation (FMD), can modify BP responsiveness to exercise. Twenty-one volunteers (eight females and thirteen males, 54·9 (se 2·2) years, BMI 31·6 (se 0·8) kg/m2, systolic BP 134 (se 2) mmHg, diastolic BP (DBP) 87 (se 2) mmHg) were randomised to consume single servings of either a high-flavanol (HF, 701 mg) or a low-flavanol (LF, 22 mg) cocoa beverage in a double-blind, cross-over design with 3–7-d washout between treatments. Two hours after cocoa consumption, FMD was measured, followed by continuous beat-to-beat assessment (Finapres™) of BP before and during 10 min of cycling at 75 % of age-predicted maximum heart rate. Averaged data from two assessments on each type of beverage were compared by analysis of covariance using pre-exercise BP as the covariate. Pre-exercise BP was similar after taking LF and HF (153 (se 3)/88 (se 3) v. 153 (se 4)/87 (se 2) mmHg, respectively, P>0·05). However, the BP response to exercise (area under BP curve) was attenuated by HF compared with LF. BP increases were 68 % lower for DBP (P = 0·03) and 14 % lower for mean BP (P = 0·05). FMD measurements were higher after taking HF than after taking LF (6·1 (se 0·6) % v. 3·4 (se 0·5) %, P < 0·001). By facilitating vasodilation and attenuating exercise-induced increases in BP, cocoa flavanols may decrease cardiovascular risk and enhance the cardiovascular benefits of moderate intensity exercise in at-risk individuals.

Heart rate (HR) variability and large arterial compliance can be improved using fish oils. DHA, a component of fish oil, has cardiovascular health benefits, but its effect on HR variability (HRV) and arterial compliance is yet to be quantified. Sixty-seven overweight or obese adults (thirty-six males and thirty-one females; 53 (sem 2) year; BMI 31·7 (sem 1·1) kg/m2) were randomly allocated to consume either 6 g/d sunola oil (control; n 17), fish oil (260 mg DHA+60 mg EPA per g) at doses of 2 g/d (n 16), 4 g/d (n 17) or 6 g/d (n 17). Blood pressure, HR and compliance of large and small arteries were measured while supine at baseline and after 12 weeks in all participants, and HRV was assessed in a subgroup of forty-six participants. There was no effect of fish oil on blood pressure, small artery compliance or HR. However, the low frequency:high frequency ratio of HRV decreased with increasing doses of fish oil (r − 0·34, P = 0·02), while large artery compliance increased (r 0·34, P = 0·006). Moreover, the changes in these biomarkers were significantly correlated (r − 0·31, P = 0·04) and may reflect fish oil-induced improvements in arterial function and cardiac autonomic regulation.

Females perform better in certain memory-related tasks than males. Sex differences in cognitive performance may be attributable to differences in circulating oestrogen acting on oestrogen β receptors (ERβ) which are prevalent in brain regions such as the hippocampus, frontal lobe and cortex that mediate cognitive functions. Since soya isoflavones are known to activate ERβ, chronic isoflavone supplementation in males may improve cognitive performance in memory-related tasks. A 12-week double-blind, placebo-controlled cross-over trial was conducted in thirty-four healthy men to investigate the effect of isoflavone supplementation on cognitive function. Volunteers were randomised to take four capsules/d containing soya isoflavones (116 mg isoflavone equivalents/d: 68 mg daidzein, 12 mg genistein, 36 mg glycitin) or placebo for 6 weeks, and the alternate treatment during the following 6 weeks. Assessments of memory (verbal episodic, auditory and working), executive function (planning, attention, mental flexibility) and visual-spatial processing were performed at baseline and after each treatment period. Isoflavone supplementation significantly improved spatial working memory (P = 0·01), a test in which females consistently perform better than males. Compared with placebo supplementation, there were 18 % fewer attempts (P = 0·01), 23 % fewer errors (P = 0·02) and 17 % less time (P = 0·03) required to correctly identify the requisite information. Isoflavones did not affect auditory and episodic memory (Paired Associate Learning, Rey's Auditory Verbal Learning Task, Backward Digit Span and Letter-Number Sequencing), executive function (Trail Making and Initial Letter Fluency Task) or visual-spatial processing (Mental Rotation Task). Isoflavone supplementation in healthy males may enhance cognitive processes which appear dependent on oestrogen activation.

Dietary fish oil supplementation and regular physical activity can improve outcomes in patients with established CVD. Exercise has been shown to improve heart rate variability (HRV), a predictor of cardiac death, but whether fish oil benefits HRV is controversial. Obese adults at risk of future coronary disease have impaired HRV and may benefit from these interventions. We evaluated the effect of DHA-rich tuna fish oil supplementation with and without regular exercise on HRV in sedentary, overweight adults with risk factors for coronary disease. In a randomised, double-blind, parallel comparison, sixty-five volunteers consumed 6 g fish oil/d (DHA 1·56 g/d, EPA 0·36 g/d) or sunflower-seed oil (placebo) for 12 weeks. Half of each oil group also undertook regular moderate physical activity (3 d/week for 45 min, at 75 % of age-predicted maximal heart rate (HR)). Resting HR and the HR response to submaximal exercise were measured at weeks 0, 6 and 12. In forty-six subjects, HRV was also assessed by power spectrum analysis of 20 min electrocardiogram recordings taken supine at baseline and 12 weeks. Fish oil supplementation improved HRV by increasing high-frequency power, representing parasympathetic activity, compared with placebo (P = 0·01; oil ×  time interaction). It also reduced HR at rest and during submaximal exercise (P = 0·008; oil ×  time interaction). There were no significant fish oil ×  exercise interactions. Dietary supplementation with DHA-rich fish oil reduced HR and modulated HRV in keeping with an improved parasympathetic–sympathetic balance in overweight adults with risk factors for future coronary disease.

The long-chain (LC) n-3 PUFA content of pork, particularly DHA, can be increased by including 15 % PorcOmega® (a fortified tuna fishmeal product) in pig finisher diets. The aim of the present study was to see whether this enriched pork could deliver cardiovascular health benefits to consumers. In a double-blind intervention trial, thirty-three healthy adult volunteers (sixteen female and seventeen male) were randomised to consume either n-3-enriched or regular (control) pork (a selection of five fresh cuts totalling 1000 g/week) for 12 weeks. Fasting blood samples were collected every 4 weeks and analysed for serum lipids, maximally stimulated thromboxane production and erythrocyte fatty acid composition. The n-3-enriched pork provided subjects with 1·3 g LC n-3 PUFA per week. Erythrocyte DHA levels rose 15 % in the n-3 group and fell 5 % in the control group over 12 weeks (P = 0·001). Compared with the control group, serum TAG decreased to a greater extent in the n-3 group (P = 0·02) and serum thromboxane production increased to a lesser extent (P = 0·004). Changes in the latter were inversely associated with changes in incorporation of DHA into erythrocytes (r − 0·54; P < 0·05). Thus the modest increases in LC n-3 PUFA intake resulting from regular consumption of enriched pork can improve cardiovascular risk factors.

Consumption of long-chain n-3 PUFA, particularly DHA, has been shown to improve cardiovascular risk factors but the intake required to achieve benefits is unclear. We sought to determine the relationship between DHA intake, increases in erythrocyte DHA content and changes in blood lipids. A total of sixty-seven subjects (thirty-six male, thirty-one female, mean age 53 years) with fasting serum TAG ≥ 1·1 mmol/l and BMI>25 kg/m2 completed a 12-week, randomized, double-blind, placebo-controlled parallel intervention. Subjects consumed 2, 4 or 6 g/d of DHA-rich fish oil (26 % DHA, 6 % EPA) or a placebo (Sunola oil). Fasting blood lipid concentrations and fatty acid profiles in erythrocyte membranes were assessed at baseline and after 6 and 12 weeks. For every 1 g/d increase in DHA intake, there was a 23 % reduction in TAG (mean baseline concentration 1·9 (sem 0·1) mmol/l), 4·4 % increase in HDL-cholesterol and 7·1 % increase in LDL-cholesterol. Erythrocyte DHA content increased in proportion to the dose of DHA consumed (r 0·72, P < 0·001) and the increase after 12 weeks was linearly related to reductions in TAG (r − 0·38, P < 0·01) and increases in total cholesterol (r 0·39, P < 0·01), LDL-cholesterol (r 0·33, P < 0·01) and HDL-cholesterol (r 0·30, P = 0·02). The close association between incorporation of DHA in erythrocytes and its effects on serum lipids highlights the importance of erythrocyte DHA as an indicator of cardiovascular health status.

CVD is associated with a cellular inflammatory/immune response. n-3 PUFA and moderate aerobic exercise independently alter cytokine production and leucocyte function. There is limited evidence for the combined effect of these treatments on immune function, particularly in patients with risk factors for CVD. We hypothesised that exercise would enhance the anti-inflammatory effects of n-3 PUFA. In a randomised, placebo-controlled study, fifty volunteers were allocated double-blind to consume either sunflower oil (6 g/d, placebo) or DHA-rich fish oil (6 g/d; about 2 g n-3 PUFA; 1·6 g DHA /d) for 12 weeks. Volunteers were further randomised to undertake regular exercise (walking 3 d/week for 45 min at 75 % of maximum heart rate) or maintain their usual physical activity for 12 weeks. Immune functions were assessed in blood taken initially and after 12 weeks. There was no effect on cytokine production by T cells and monocytes. Superoxide anion production from stimulated blood neutrophils was decreased by fish oil (19·5 (sem 8·5) %, P = 0·016) but not by exercise, and this change was negatively correlated with the incorporation of DHA into erythrocytes (r–0·385, P = 0·047). Participation in regular exercise maintained neutrophil bactericidal activity, which decreased in non-exercising subjects (2·9 (sem 0·7) %, P = 0·013). Neutrophil chemotaxis and adherence were not significantly affected by exercise, oil, or the combination of the two. Thus the combination of moderate exercise and fish-oil supplementation, which reduces cardiovascular risk, may also help to counteract inflammation.