Comparing Acute, High Dietary Protein and Carbohydrate Intake on Transcriptional Biomarkers, Fuel Utilisation and Exercise Performance in Trained Male Runners

Manipulating dietary macronutrient intake may modulate adaptive responses to exercise, and improve endurance performance. However, there is controversy as to the impact of short-term dietary modification on athletic performance. In a parallel-groups, repeated measures study, 16 trained endurance runners (maximal oxygen uptake (V˙O2max): 64.2 ± 5.6 mL·kg−1·min−1) were randomly assigned to, and provided with, either a high-protein, reduced-carbohydrate (PRO) or a high-carbohydrate (CHO) isocaloric-matched diet. Participants maintained their training load over 21-consecutive days with dietary intake consisting of 7-days habitual intake (T1), 7-days intervention diet (T2) and 7-days return to habitual intake (T3). Following each 7-day dietary period (T1–T3), a micro-muscle biopsy was taken for assessment of gene expression, before participants underwent laboratory assessment of a 10 km treadmill run at 75% V˙O2max, n treadmill run at 70% vV˙O2max time to exhaustion (TTE) trial. The PRO diet resulted in a modest change (1.37-fold increase, p = 0.016) in AMPK expression, coupled with a significant increase in fat oxidation (0.29 ± 0.05 to 0.59 ± 0.05 g·min−1, p < 0.0001). However, a significant reduction of 23.3% (p = 0.0003) in TTE post intervention was observed; this reverted back to pre levels following a return to the habitual diet. In the CHO group, whilst no change in sub-maximal fuel utilisation occurred at T2, a significant 6.5% increase in TTE performance (p = 0.05), and a modest, but significant, increase in AMPK (p = 0.042) and PPAR (p = 0.029) mRNA expression compared to T1 were observed; with AMPK (p = 0.011) and PPAR (p = 0.044) remaining significantly elevated at T3. In conclusion, a 7-day isocaloric high protein diet significantly compromised high intensity exercise performance in trained runners with no real benefit on gene markers of training adaptation. A significant increase in fat oxidation during submaximal exercise was observed post PRO intervention, but this returned to pre levels once the habitual diet was re-introduced, suggesting that the response was driven via fuel availability rather than cellular adaptation. A short-term high protein, low carbohydrate diet in combination with endurance training is not preferential for endurance running performance.

Common proanthocyanidin-rich foods modulate gastrointestinal blooms of Akkermansia muciniphila in a diet-dependent manner

Developing methods to modulate growth of the mucin-degrading gut bacterium Akkermansia muciniphila could benefit patients with different health needs, as A. muciniphila has been associated with both positive metabolic health outcomes and detrimental neurodegenerative outcomes. Growth of A. muciniphila is sensitive to plant-derived polyphenols, and particularly proanthocyanidins (PACs), when administered in isolated form at supraphysiological doses. However, it remains unclear whether doses sufficient for these effects are achievable via diet. Here, we explore the extent to which nutritionally relevant doses of common polyphenol-rich foods - berries, wine, and coffee - influence A. muciniphila abundance in C57BL/6J mice under varying dietary conditions. By administering polyphenol-rich whole foods, comparing polyphenol-depleted and PAC-rich versus PAC-poor food supplements, and through gradient PAC-dosing experiments, we show that PAC-rich foods uniquely induce A. muciniphila growth at doses that are feasibly achieved through routine diet. Notably, the effects of PAC supplementation were detected against a high-fat diet but not a low-fat control diet background, highlighting the importance of habitual diet strategies in either amplifying or mitigating the prebiotic effects of PAC-rich food consumption. Ultimately, our work suggests that both PACs and diet influence A. muciniphila abundance with downstream impacts for human health.

Role of Diet in Modification of Gut Microbiota in Obesity: Review of Recent Literature

With the ever-increasing rate, obesity has become an epidemiological problem throughout the globe comprising about 39% of the world population as of now. Among several reasons, disruption of the gut microbial ecosystem might contribute to the pathogenesis of metabolic disorders, including obesity, metabolic syndrome, type 2 diabetes, and other associated comorbidities. Though the mechanisms related to dysbiosis are unclear, diet might play a modulating role where different dietary approaches manipulate microbial richness and abundance as well as stability. For instance, shifting of Firmicutes and Bacteroidetes ratio in the gut might have a role in association with the dietary approaches and ingestion duration. Along with altered gut microbial composition, microbial metabolites such as short-chain fatty acids (SCFA) after ingestion of non-digestible dietary starches may have an impact on host metabolism by regulating lipogenesis, gluconeogenesis, and inflammation with potential associations to health and obesity. The dietary approaches like carbohydrates, fibre, protein, and/or fat diet at various arrangements can make a shift in the composition of gut microbiota if introduced for a short period. However, the unique pattern of the gut microbes usually remains the same along with the longer period of habitual diet. Though the short-term dietary intervention or circadian rhythm influences a transient change in gut microbes, other than habitual diet, the understanding related to long-term dietary change-induced permanent alterations is minimum. Alternatively, the usage of prebiotics, probiotics as well as postbiotics could be beneficial to overcome dysbiosis. This review highlights the current knowledge and the interaction between the human intestinal microbiota and diet as a modifying factor, in obesity allowing the scientists to uncover novel targets and tools to use as customized therapy.

Effect of Artificial Sweetener Aspartame on Gut Microbiota - A Narrative Review

Artificial sweeteners are used widely as sugar substitutes worldwide. Aspartame is the rapidly metabolised non caloric artificial sweetener commonly used in food and beverages. Use of aspartame can leads to Type 2 Diabetes, cardiovascular diseases, colon cancer, neurological and behavioural disorders. The gut microbiota plays an important role in maintaining good health and its dysbiosis leads to metabolic disorders. The present review investigates through the existing literature the effect of aspartame on gut microbiota. There is variation in results in different studies as both positive and inconclusive results are reported. Experimental studies also indicate change in gut microbiota of the infants of pregnant and lactating mothers leading to metabolic disturbances. The literature indicates that the baseline composition of gut microbiota and habitual dietary intake affects the host response to the intervention. So, to establish the relation of aspartame intake with gut dysbiosis it is important to design studies taking into consideration the baseline composition and habitual diet of the respondents and intervention diets should be carefully controlled. Although aspartame is considered to be safe for use by regulatory authorities but taking into consideration its wide use in food industry it is important to assess its health risks regularly in interest of consumer health and more studies are warranted with appropriate study designs.

Amino Acid Composition of Amniotic Fluid during the Perinatal Period Reflects Mother’s Fat and Carbohydrate Intake

Dietary content during pregnancy is important because it is necessary for the growth of the fetus. With the assumption that the nutritional status of the fetus can be monitored by measuring amino acid concentrations in the amniotic fluid, we investigated whether the habitual dietary intake of pregnant women affected the composition of the amniotic fluid and the significance of performing amniotic fluid analysis. The subjects were 34 mothers who delivered full-term babies by cesarean section. Three biological samples were collected from the mothers: blood, cord blood, and amniotic fluid. At the same time, the mothers’ prenatal nutritional intake information was also recorded. When the amino acid contents of the samples were compared with the mothers’ nutrient intake, many amino acids in the amniotic fluid were positively correlated with lipid intake, but not with protein intake. There was a negative correlation between lipid intake and carbohydrate intake, and the amino acid contents of the amniotic fluid were also negatively correlated with carbohydrate intake. The results of this study were consistent with those found in animal models, suggesting that the analysis of amniotic fluid may be a useful method to investigate the effects of habitual diet during human pregnancy on the fetus.

Effect of Daily Avocado Consumption on Vascular Health in Adults With Abdominal Obesity: A Sub-Study of the Habitual Diet and Avocado Trial, a Randomized Controlled Study

Objectives To examine the effect of providing 1 avocado per day for consumption over a 6-month period on cardiovascular health compared to habitual dietary intake in individuals with abdominal obesity. Methods The Habitual diet and Avocado Trial (HAT), a multicenter parallel randomized controlled trial, included participants ≥25 years of age with an elevated waist circumference (≥88 cm women; ≥102 cm men). Participants were randomized to either an experimental group (AVO: consumed 1 avocado/day for 6 months) or a control group (HD: consumed &lt; 2 avocados/month for 6 months). At the Pennsylvania State University, University Park (n = 126), vascular health was measured using a SphygmoCor XCEL (AtCor Medical) at baseline and at the end of the study period. Outcomes include central systolic blood pressure (cSBP), central diastolic blood pressure (cDBP), and pulse wave velocity (PWV), a marker of arterial stiffness. Mixed models were used to examine between-group differences in change across 6 months. Results The sample was 77% female (BMI 34 ± 4 kg/m2, waist circumference 105 ± 12 cm). No significant between-group differences in 6-month change were observed for cSBP (AVO: 1.06 mmHg 95% CI − 1.57, 3.69; HD: 0.35 mmHg 95% CI −2.26, 2.96; P = 0.62), cDBP (AVO: 0.07 mmHg 95% CI −1.82, 1.96; HD: −0.91 mmHg 95% CI − 2.79, 0.97; P = 0.34), or PWV (AVO: −0.18 m/s 95% CI −0.53, 0.17; HD: 0.08 m/s 95% CI −0.27, 0.43; P = 0.17). Conclusions Results suggest that providing adults with abdominal obesity 1 avocado per day to consume for 6 months is not associated with a statistically significant improvement in central blood pressure or PWV, compared to adults following their habitual diet. Additional research using larger samples and longer intervention periods is needed to clarify whether habitual avocado consumption yields clinically significant benefits to cardiovascular health. Funding Sources Hass Avocado Board and the National Center for Advancing Translational Sciences, National Institutes of Health (1UL1TR002014-01).

An Increase in Mediterranean Dietary Score, Through SunGold® Kiwifruit, Potentially Improves Mental Wellbeing

Objectives Research suggests that high adherence to Mediterranean dietary pattern significantly improve depression and anxiety symptoms. Thus, the objective was to utilize the novel and validated Mediterranean Diet Serving Score (MDSS) method to assess habitual intake of a study cohort, which evaluated SunGold® kiwifruit and psyllium powder interventions, against the Mediterranean diet recommendations. The link between the MDSS and mental wellbeing were then explored. Methods The project's data was collected during the randomized cross-over controlled trial Christchurch Irritable Bowel Syndrome cohort to investigate mechanisms for gut relief and improved transit - Psyllium and Kiwifruit translation study (COMFORT-PSYKI). Participants were randomized into two interventions: psyllium powder or SunGold® kiwifruit. MDSS was evaluated from dietary records with the recommended serving sizes obtained from the New Zealand Food Composition Database. Depression and anxiety score were collected through the Patient-Reported Outcomes Measurement Information System (PROMIS) survey. Results The habitual diet of the participants (n = 45, mean age 39 ± 15 years) had a low MDSS (mean 5.04 ± 2.38, out of 24 points) when compared against the Mediterranean pyramid recommendations. Their MDSS improved with daily consumption of two SunGold® kiwifruit significantly (mean 6.27 ± 2.81, P-value &lt; 0.05) compared to Psyllium powder (mean 5.58 ± 3.05, P-value = 0.906). Moreover, mean depression (42.33 ± 6.08, P-value) and anxiety (43.24 ± 7.71) scores were reported lower with the higher MDSS of SunGold® intervention at 42.33 ± 6.08 (P-value = 0.315) and 43.24 ± 7.71 (P-value = 0.906), respectively. Conclusions This project suggests that consuming two SunGold® kiwifruit daily could significantly enhance participants’ habitual diet to meet the Mediterranean diet recommendations and healthy eating guideline. This improvement could potentially lead to a reduction in depression and anxiety symptoms. The feasibility of the novel MDSS method was also demonstrated to be suitable for dietary pattern assessment among adult New Zealanders. Future investigations are warranted to confirm the association between dietary pattern and mental wellbeing. Funding Sources This project was funded by Zespri International Limited (Zespri) and Callaghan Innovation R&D Experience Grant.

Protocol for Pilot Study Testing the Effect of Avocado Consumption on Skin Aging

Objectives Avocados are an excellent source of bioactive compounds such as monounsaturated fatty acids, sterols, polyhydroxylated fatty alcohols and carotenoids. A common cause of photoaging is exposure to UV light, as the radiation generates oxidative stress, which leads to inflammation and erythema of the skin. Studies have demonstrated that topical application of bioactive compounds from avocado reduce UVB-induced photoaging. Ultraviolet-B (UVB) protection by oral avocado consumption has not been clinically investigated in humans. Therefore, it is the objective of this pilot study to determine if the consumption of one avocado daily for 16 weeks can increase resistance to UVB radiation and reduce skin aging in healthy women. Methods This study is a randomized, two arm, parallel group comparison of daily avocado consumption vs. habitual diet. Eligible participants are females, at least 25 years of age, Fitzpatrick Skin type II-IV, in good health with an increased waist circumference of 35 cm. Participants will be excluded if they are habitually eating 2 avocados per month, allergic to avocado and any unstable medical conditions. At screening, informed consent and HIPAA authorization will be reviewed and signed. In addition, Fitzpatrick Skin type and response to UVB will be assessed. Subjects will consume 1 avocado a day (Hass Avocado) or maintain habitual diet (up to 2 avocados/month) daily for 16 weeks. Skin will be assessed at weeks 0, 8 and 16. Minimal erythema dose (MED) will be determined by exposing the inner arm covered by a sleeve with 6 cut out windows with an increasing dose of UVB using the Dermalight 90. Facial melanin index, hydration and sebum will be determined using the mexameter MA18, corneometer CM825 and sebumeter SM815 probes attached to the Cutometer dual MPA 580 (Courage&Khazaka electronic GmbH, Koeln, Germany). 22 participants will be enrolled in each group considering a 10%dropout rate. Results Primary outcome will be the effect of daily avocado consumption on MED assessed by UVB exposure compared to habitual diet. Secondary outcomes will be the effect of daily avocado consumption on facial skin elasticity, sebum, melanin and hydration status as assessed by cutometer compared to habitual diet. Conclusions This study is currently recruiting participants. Funding Sources Hass Avocado Board.