Consumption of Pomegranate Juice Attenuates Exercise-Induced Oxidative Stress, Blood Pressure and Urinary Cortisol/Cortisone Ratio in Human Adults

Oxidative stress is exacerbated in overweight and obese individuals after acute exercise compared with their non-obese counterparts. Antioxidant supplementation of the diet may be one intervention to reduce exercise-induced oxidative stress in this vulnerable population. The aim of this study was to investigate whether polyphenol-rich pomegranate juice attenuates post-exercise oxidative stress and contributors to oxidative stress (glucocorticoids) and blood pressure in healthy overweight subjects. Healthy male and female subjects participated in a randomized placebo controlled parallel pilot-study (mean BMI: 26.7 ± 6.6 kg/m2). Two groups of participants (n=12) received either 500 ml/day of pomegranate juice (containing 1685 mg GAE) or placebo (matched for total energy). Participants completed two standardized 30 min treadmill tests (50% Wmax) at baseline and after one week of the intervention. Exercise-induced lipid peroxidation (MDA) was significantly lower following pomegranate juice consumption compared with placebo (31.2 ± 10.6 to 26.5 ± 9.8 MDA μmole/day) (p=0.035). Urinary free cortisol was reduced from 179.4 ± 53.2 to 125.6 ± 43.5 nmole/24h which was significant (p=0.042). In addition, there was an increase in urinary free cortisone from 112.2 ± 40.4 to 187.6 ± 90.2 nmole/24 h (p=0.045), and a significant decrease in the urinary free cortisol/cortisone ratio (p=0.009) from 1.6 ± 1.1 to 0.67 ± 0.55 following one week of pomegranate juice intake. Pomegranate juice consumption was also found to decrease systolic blood pressure pre-exercise (136.7 ± 11.7 to 131.8 ± 8.8 mmHg (p=0.007), and post-exercise from 158.8 ± 15.8 to 148.1 ± 12.3 mmHg (p<0.01) and diastolic blood pressure (86.3 ± 10.6 to 82.5 ± 6.8 mmHg (p=0.04) and 103.1 ± 12.5 to 93.9 ± 11.5 mmHg (p=0.001), pre and post exercise, respectively. Correlation between the change in cortisol/cortisone ratio with the effect on blood pressure showed a negative significant association post pomegranate juice intake (p=0.028 for systolic and p=0.008 for diastolic BP). There were no changes in lipid peroxidation or blood pressure following placebo treatment. In conclusion, these findings suggest that pomegranate juice consumption prior to an acute bout of moderate intensity exercise may help to alleviate exercise-induced oxidative stress, and lower blood pressure in the overweight and obese population

Antioxidant activity, protective effects and absorption of polyphenolic compounds

The objectives of the studies presented in this thesis were to identify and quantify the major phenolic components of red wine and to assess the contribution of individual compounds to the total antioxidant activity. Red wines were analysed for their phenolic content and antioxidant activity using a range of complementary techniques including HPLC-tandem mass spectrometry, preparative HPLC and HPLC with an on-line antioxidant detection system. HPLC-MS2 revealed the presence of a number of flavoids and phenolic compounds of which 19 were identified, with gallic acid, the flavin-3-ols and anthocyanins being the most abundant. Preparative HPLC was used in an effort to isolate the antioxidant components in red wine and 60 aliquots were collected. Each wine fraction was analysed for total phenolics, catechins and anthocyanins, while antioxidant activity was determined by electron spin resonance spectroscopy (ESR). The preparative HPLC step did into completely separate the compounds in red wine, nonetheless increasing antioxidant activity was highly and significantly associated with total phenolics (r = 0.816, P 50% of the total antioxidant capacity of each wine, while gallic acid contributed between 24-44%. The flavonols and anthocyanins were minor antioxidant components in red wines. By combining HPLC, MS2 and on-line assessment of antioxidant activity, the major phenolic compounds present in red wine were identified, together with their direct contribution to the total antioxidant activity

Olive Oil Nutraceuticals in the Prevention and Management of Diabetes: From Molecules to Lifestyle.

Lifestyle is the primary prevention of diabetes, especially type-2 diabetes (T2D). Nutritional intake of olive oil (OO), the key Mediterranean diet component has been associated with the prevention and management of many chronic diseases including T2D. Several OO bioactive compounds such as monounsaturated fatty acids, and key biophenols including hydroxytyrosol and oleuropein, have been associated with preventing inflammation and cytokine-induced oxidative damage, glucose lowering, reducing carbohydrate absorption, and increasing insulin sensitivity and related gene expression. However, research into the interaction of OO nutraceuticals with lifestyle components, especially physical activity, is lacking. Promising postprandial effects have been reported when OO or other similar monounsaturated fatty acids were the main dietary fat compared with other diets. Animal studies have shown a potential anabolic effect of oleuropein. Such effects could be further potentiated via exercise, especially strength training, which is an essential exercise prescription for individuals with T2D. There is also an evidence from in vitro, animal, and limited human studies for a dual preventative role of OO biophenols in diabetes and cancer, especially that they share similar risk factors. Putative antioxidative and anti-inflammatory mechanisms and associated gene expressions resulting from OO biophenols have produced paradoxical results, making suggested inferences from dual prevention T2D and cancer outcomes difficult. Well-designed human interventions and clinical trials are needed to decipher such a potential dual anticancer and antidiabetic effects of OO nutraceuticals. Exercise combined with OO consumption, individually or as part of a healthy diet is likely to induce reciprocal action for T2D prevention outcomes

A Short Study Exploring the Effect of the Glycaemic Index of the Diet on Energy intake and Salivary Steroid Hormones

From PubMed via Jisc Publications RouterThe glycaemic index or load (GI or GL) is a concept for ranking carbohydrate-rich foods based on the postprandial blood glucose response compared with a reference food (glucose). Due to the limited research investigating the effect of the GI or GL of the diet on salivary steroidal hormones, this explorative short study was conducted. 12 female participants consumed a low GI and a high GI diet for three days each, followed by a washout period between each intervention. Saliva was collected at baseline, and following the low or high GI diets. Cortisol and testosterone concentrations were measured by enzyme-linked immuno-sorbent assay (ELISA). GI and GL were significantly different between the low and high GI diets ( < 0.001). There was a small but significant increase in salivary cortisol after the high GI diet (7.38 to 10.93 ng/mL, = 0.036). No effect was observed after the low GI diet. Higher levels of testosterone were produced after the low GI diet (83.7 to 125.9 pg/mL, = 0.002), and no effect was found after the high GI diet. The total intake of calories consumed on the low GI diet was significantly lower compared to the high GI diet ( = 0.019). A low GI diet was associated with a small but significant increase in salivary testosterone, while a high GI diet increased cortisol levels. Altering the GI of the diet may influence overall energy intake and the health and wellbeing of female volunteers.11pubpub

Antioxidant Rich Potato Improves Arterial Stiffness in Healthy Adults.

Arterial stiffness is an emerging risk factor for cardiovascular disease and dietary anthocyanins may be important in mediating vascular tone. The present study investigated the effect of consumption of an anthocyanin-rich potato, Purple Majesty on arterial stiffness measured as pulse wave velocity in 14 healthy male and female adults. Participants consumed 200 g/day of cooked purple potato containing 288 mg anthocyanins, or a white potato containing negligible anthocyanins for 14 days, separated by a 7-day washout period. Non-invasive assessment of vascular tone by pulse wave velocity was determined in addition to systolic and diastolic blood pressure, high-density lipoproteins, low-density lipoproteins, triglycerides, glucose, insulin and C-reactive protein. Pulse wave velocity was significantly reduced (p = 0.001) following Purple Majesty consumption for 14-days. There were no significant changes with any other clinical parameter measured, and no changes following white potato consumption. The findings from this short-term study indicate a potential effect of Purple Majesty consumption on arterial stiffness

Effect of Polyphenol-Rich Dark Chocolate on Salivary Cortisol and Mood in Adults

The aim of the present study was to investigate whether ingestion of polyphenol-rich dark chocolate improved salivary cortisol levels and subjective mood states in adults recruited from a health and social care setting. Twenty-six participants ingested 25 g/day of a high polyphenol dark chocolate (containing 500 mg of total flavonoids), or a similar amount of a control dark chocolate, containing negligible flavonoids, for 4-weeks. Twenty-four hour salivary glucocorticoid levels (cortisol and cortisone) were measured by an enzyme-linked immunosorbent assay, and subjective mood was assessed using a validated positive affect and negative affect schedule. Total daily cortisol, morning cortisol, and the cortisol/cortisone ratio, were significantly reduced (p<0.001), after ingestion of the high polyphenol dark chocolate only. There were no significant differences between groups for overall scores for positive affect and negative affect, however, there was an indication of improved positive affect as one attribute for strength (p=0.02), and within groups, negative affect was reduced (p=0.02), after high polyphenol dark chocolate only. No changes were observed after the control dark chocolate, or any other parameter measured. In conclusion, the findings from this small-scale study indicate lowering of salivary cortisol levels following polyphenol-rich dark chocolate, in adults recruited from a health and social care setting, with some small changes in mood states. Such changes may be attributable to their ability to inhibit 11β-hydroxysteroid dehydrogenase type-1 activity, and warrant further investigation

Effect of Polyphenol Supplementation on Memory Functioning in Overweight and Obese Adults: A Systematic Review and Meta-Analysis

Negative health consequences of obesity include impaired neuronal functioning and celldeath, thus bringing the risk of impaired cognitive functioning. Antioxidant properties of polyphenolsoffer a possible intervention for overweight people, but evidence for their effectiveness in supportingcognitive functioning is mixed. This review examined evidence from randomized controlledtrials concerning the effect of polyphenols on tasks requiring either immediate or delayed retrievalof learned information, respectively, thus controlling for differences in cognitive processes and relatedneural substrates supporting respective task demands. Searches of the PubMed/Medline,PsycInfo, and Scopus databases identified 24 relevant primary studies with N = 2336 participantshaving a BMI ≥ 25.0 kg/m2. The participants’ mean age for the 24 studies exceeded 60 years. Respectivemeta-analyses produced a significant summary effect for immediate retrieval but not for delayedretrieval. The present findings support a potential positive effect of chronic supplementationwith polyphenols, most notably flavonoids, on immediate retrieval in participants aged over 60years with obesity being a risk factor for cognitive impairment. We recommend further investigationof this potential positive effect in participants with such risk factors. Future research on all populationsshould report the phenolic content of the supplementation administered and be specific regardingthe cognitive processes tested