Two apples a day lower serum cholesterol and improve cardiometabolic biomarkers in mildly hypercholesterolemic adults: a randomized, controlled, crossover trial

Background: Apples are rich in bioactive polyphenols and fiber. Evidence suggests that consumption of apples, or their bioactive components is associated with beneficial effects on lipid metabolism and other markers of cardiovascular disease (CVD). However, adequately powered randomized controlled trials are necessary to confirm these data and explore the mechanisms. Objective: To determine the effects of apple consumption on circulating lipids, vascular function and other CVD risk markers. Design: The trial was a randomized, controlled, crossover, intervention study. Healthy mildly hypercholesterolemic volunteers (23 women, 17 men), with a mean BMI (± SD) 25.3 (± 3.7)kg/m2 and age (± SD) 51.4 (± 11) years, consumed 2 apples/day (Renetta Canada, rich in proanthocyanidins), or a sugar and energy matched apple control beverage (CB) for 8 weeks separated by a 4-week washout period. Fasted blood was collected before and after each treatment. Serum lipids, glucose, insulin, bile acids, endothelial and inflammation biomarkers were measured, in addition to microvascular reactivity, using laser Doppler imaging with Iontophoresis and arterial stiffness, using Pulse Wave Analysis. Results: Whole apple (WA) consumption decreased serum total (WA: 5.89 mmol/l, CB: 6.11mmol/l; P=0.006) and LDL cholesterol (WA: 3.72 mmol/l, CB: 3.86 mmol/l; P=0.031), triacylglycerol (WA: 1.17 mmol/l, CB: 1.30 mmol/l; P=0.021) and intercellular cell adhesion molecule-1 (WA: 153.9 ng/ml, CB: 159.4 ng/ml; P=0.028), and increased serum uric acid (WA:341.4 μmol/l, CB: 330 μmol/l; P=0.020) compared with the CB. The response to endothelium dependent microvascular vasodilation was greater after the apples (WA: 853 (PU, perfusion units), CB: 760 PU; P=0.037) compared with the CB. Apples had no effect on blood pressure or other CVD markers. Conclusions: These data support beneficial hypocholesterolemic and vascular effects of the daily consumption of proanthocyanidin-rich apples by mildly hypercholesterolemic individuals

Effects of commercial apple varieties on human gut microbiota composition and metabolic output using an in vitro colonic model

Apples are a rich source of polyphenols and fiber. A major proportion of apple polyphenols escape absorption in the small intestine and together with non-digestible polysaccharides reach the colon, where they can serve as substrates for bacterial fermentation. Animal studies suggest a synergistic interaction between apple polyphenols and the soluble fiber pectin; however, the effects of whole apples on human gut microbiota are less extensively studied. Three commercial apple varieties-Renetta Canada, Golden Delicious and Pink Lady-were digested and fermented in vitro using a batch culture colonic model (pH 5.5-6.0, 37 °C) inoculated with feces from three healthy donors. Inulin and cellulose were used as a readily and a poorly fermentable plant fiber, respectively. Fecal microbiota composition was measured by 16S rRNA gene Illumina MiSeq sequencing (V3-V4 region) and Fluorescence in Situ Hybridization. Short chain fatty acids (SCFAs) and polyphenol microbial metabolites were determined. The three apple varieties significantly changed bacterial diversity, increased Actinobacteria relative abundance, acetate, propionate and total SCFAs (p < 0.05). Renetta Canada and Golden Delicious significantly decreased Bacteroidetes abundance and increased Proteobacteria proportion and bifidobacteria population (p < 0.05). Renetta Canada also increased Faecalibacterium prausnitzii, butyrate levels and polyphenol microbial metabolites (p < 0.05). Together, these data suggest that apples, particularly Renetta Canada, can induce substantial changes in microbiota composition and metabolic activity in vitro, which could be associated with potential benefits to human health. Human intervention studies are necessary to confirm these data and potential beneficial effects

Impact of proanthocyanidin-rich apple intake on gut microbiota composition and polyphenol metabolomic activity in healthy mildly hypercholesterolemic subjects

AbstractApples are a rich source of polyphenols and fiber. Proanthocyanidins (PAs), the largest polyphenolic class in apples, can reach the colon almost intact where they interact with the gut microbiota producing simple phenolic acids. These metabolites have the potential to modulate gut microbiota composition and activity and impact on host physiology. A randomized, controlled, crossover, dietary intervention study was performed to determine the broad effects of whole apple intake on fecal gut microbiota composition and activity. Forty heathy mildly hypercholesterolemic volunteers (23 women, 17 men), with a mean BMI (± SD) 25.3 ± 3.7 kg/m2 and age 51 ± 11 years, consumed 2 apples/day (Renetta Canada, rich in PAs), or a sugar matched control apple beverage, for 8 weeks separated by a 4-week washout period in a random order. Fecal and 24-h urine samples were collected before and after each treatment. The broad effects of apple intake on fecal gut microbiota composition were explored by the high throughput sequencing (HTS) of 16S rRNA gene lllumina MiSeq sequencing (V3-V4 region). Sequencing data analysis was performed using the Quantitative Insight Into Microbial Ecology (QIIME) open-source pipeline version 1.9.1. Specific bacterial groups were also enumerated using the quantitative Fluorescence In Situ Hybridization (FISH). Furthermore, the potential formation of microbial polyphenol metabolites, after apple intake, was explored in urine using Liquid Chromatography (LC) High-Resolution Mass Spectrometry (HRMS) metabolomics. Preliminary analysis showed no changes in gut microbiota abundances measured by Illumina MiSeq, after correction for multiple testing. Apple intake significantly decreased Enterobacteriaceae population (P = 0.04) compared to the control beverage, as determined with FISH. Twenty-four polyphenol microbial metabolites were identified in higher concentrations in the apple group (P < 0.05) compared to the control, including valerolactones, valeric and phenolic acids. In conclusion, preliminary data suggest that the daily intake of 2 Renetta Canada apples significantly decreased Enterobacteriaceae population, a family known for its pathogenic members, in healthy mildly hypercholesterolemic subjects. Moreover, several polyphenol microbial metabolites were identified, suggesting that microbial activity is crucial and a prerequisite for the absorption of apple polyphenols, producing active metabolites with potential health benefits

Greater impact of dietary fat manipulation than apolipoprotein E genotype on ex-vivo cytokine production – insights from the SATgenε study

Apolipoprotein E (APOE) genotype is believed to play an important role in cardiovascular risk. APOE4 carriers have been associated with higher blood lipid levels and a more pro-inflammatory state compared with APOE3/E3 individuals. Although dietary fat composition has been considered to modulate the inflammatory state in humans, very little is known about how APOE genotype can impact on this response. In a follow-up to the main SATgene study, we aimed to explore the effects of APOE genotype, as well as, dietary fat manipulation on ex vivo cytokine production. Blood samples were collected from a subset of SATgene participants (n = 52/88), prospectively recruited according to APOE genotype (n = 26 E3/E3 and n = 26 E3/E4) after low-fat (LF), high saturated fat (HSF) and HSF with 3.45 g docosahexaenoic acid (DHA) dietary periods (each diet eight weeks in duration assigned in the same order) for the measurement of ex vivo cytokine production using whole blood culture (WBC). Concentrations of IL-1beta, IL-6, IL-8, IL-10 and TNF-alpha were measured in WBC supernatant samples after stimulation for 24 h with either 0.05 or 1 lg/ml of bacterial lipopolysaccharide (LPS). Cytokine levels were not influenced by genotype, whereas, dietary fat manipulation had a significant impact on TNF-a and IL-10 production; TNF-a concentration was higher after consumption of the HSF diet compared with baseline and the LF diet (P < 0.05), whereas, IL-10 concentration was higher after the LF diet compared with baseline (P < 0.05). In conclusion, our study has revealed the amount and type of dietary fat can significantly modulate the production of TNF-a and IL-10 by ex vivo LPS-stimulated WBC samples obtained from normolipidaemic subjects

Apples and cardiovascular health: is the gut microbiota a core consideration?

There is now considerable scientific evidence that a diet rich in fruits and vegetables can improve human health and protect against chronic diseases. However, it is not clear whether different fruits and vegetables have distinct beneficial effects. Apples are among the most frequently consumed fruits and a rich source of polyphenols and fiber. A major proportion of the bioactive components in apples, including the high molecular weight polyphenols, escape absorption in the upper gastrointestinal tract and reach the large intestine relatively intact. There, they can be converted by the colonic microbiota to bioavailable and biologically active compounds with systemic effects, in addition to modulating microbial composition. Epidemiological studies have identified associations between frequent apple consumption and reduced risk of chronic diseases such as cardiovascular disease. Human and animal intervention studies demonstrate beneficial effects on lipid metabolism, vascular function and inflammation but only a few studies have attempted to link these mechanistically with the gut microbiota. This review will focus on the reciprocal interaction between apple components and the gut microbiota, the potential link to cardiovascular health and the possible mechanisms of action

Effects of apples on cardiovascular disease risk factors and gut microbiota

Evidence suggests that apples or their bioactive components (polyphenols and/or fiber) may have beneficial effects on lipid metabolism and other markers of cardiovascular disease (CVD). However, further adequately powered randomized controlled trials are necessary to confirm this evidence. Moreover, it has been shown that proanthocyanidins, the highest polyphenolic class in apples, reach the colon almost intact where together with fiber they interact with the gut microbiota. Recently, gut microbiota profiles and their metabolic output have also been suggested to influence CVD risk. This thesis investigated the potential interaction between modulation of the gut microbiota and cardiometabolic benefit in response to daily apple consumption. An in vitro batch culture fermentation identified that Renetta Canada variety significantly increased bifidobacteria, Faecalibacterium prausnitzii, and influenced microbial production of short chain fatty acids and phenolic microbial metabolites. Renetta Canada was therefore chosen for a randomized, controlled, crossover, dietary intervention study to determine the effects of apple intake on circulating lipids, vascular function, other CVD risk indicators and gut microbiota composition and activity in healthy mildly hypercholesterolemic subjects. Volunteers (23 women, 17 men), with a mean BMI 25.2 kg/m2 and age 51 years, consumed 2 apples/day, or a sugar matched control apple beverage for 8 weeks separated by a 4-week washout period in a random order. Blood lipids, bile acids, endothelial and inflammatory biomarkers and microvascular reactivity using laser Doppler imaging with Iontophoresis were measured. Fecal microbial profiles were monitored by 16S rRNA gene ilium ina MiSeq sequencing (V3-V4 region) and targeted groups of important gut bacteria quantified using Fluorescence in Situ Hybridization (FISH). Putative polyphenol metabolites of apple intake were identified in urine using LC-HRMS based metabolomics approach. Apple intake decreased serum total cholesterol (P=O.OOB) and LDL cholesterol (P=O.016) and vascular cell adhesion molecule-1 (P=O.037) compared with the control beverage. Apples had no effect on vascular function or other markers of CVD. No changes were observed in gut microbiota measured by 16S rRNA sequencing but apple intake significantly decreased Enterobacteriaceae enumerated by FISH compared with the control beverage. Valerolactones, valeric and phenolic acids were identified as microbial polyphenol metabolites among the 33 urine biomarkers related to the apple intake. These data suggest that the daily consumption of 2 Renetta Canada apples may result in beneficial effects on cardiovascular health and modifies both microbiota community structure and metabolic output

Impact of a food-based dietary fat exchange model for replacing dietary saturated with unsaturated fatty acids in healthy men on plasma phospholipids fatty acid profiles and dietary patterns

Purpose: UK guidelines recommend dietary saturated fatty acids (SFAs) should not exceed 10% total energy (%TE) for cardiovascular disease prevention, with benefits observed when SFAs are replaced with unsaturated fatty acids (UFAs). This study aimed to assess the efficacy of a dietary exchange model using commercially available foods to replace SFAs with UFAs. Methods: Healthy men (n=109, age 48, SD 11y) recruited to the Reading, Imperial, Surrey, Saturated fat Cholesterol Intervention-1 (RISSCI-1) study (ClinicalTrials.Gov n°NCT03270527) followed two sequential 4-week isoenergetic moderate-fat (34%TE) diets: high-SFA (18%TE SFAs, 16%TE UFAs) and low-SFA (10%TE SFAs, 24%TE UFAs). Dietary intakes were assessed using 4-day weighed diet diaries. Nutrient intakes were analysed using paired t-tests, fasting plasma phospholipid fatty acid (PL-FA) profiles and dietary patterns were analysed using orthogonal partial least square discriminant analyses. Results: Participants exchanged 10.2%TE (SD 4.1) SFAs for 9.7%TE (SD 3.9) UFAs between the high and low-SFA diets, reaching target intakes with minimal effect on other nutrients or energy intakes. Analyses of dietary patterns confirmed successful incorporation of recommended foods from commercially available sources (e.g. dairy products, snacks, oils, and fats), without affecting participants’ overall dietary intakes. Analyses of plasma PL-FAs indicated good compliance to the dietary intervention and foods of varying SFA content. Conclusions: RISSCI-1 dietary exchange model successfully replaced dietary SFAs with UFAs in free-living healthy men using commercially available foods, and without altering their dietary patterns. Further intervention studies are required to confirm utility and feasibility of such food-based dietary fat replacement models at a population level

Impact of a food-based dietary fat exchange model for replacing dietary saturated with unsaturated fatty acids in healthy men on plasma phospholipids fatty acid profiles and dietary patterns

Purpose: UK guidelines recommend dietary saturated fatty acids (SFAs) should not exceed 10% total energy (%TE) for cardiovascular disease prevention, with benefits observed when SFAs are replaced with unsaturated fatty acids (UFAs). This study aimed to assess the efficacy of a dietary exchange model using commercially available foods to replace SFAs with UFAs.Methods: Healthy men (n=109, age 48, SD 11y) recruited to the Reading, Imperial, Surrey, Saturated fat Cholesterol Intervention-1 (RISSCI-1) study (ClinicalTrials.Gov n°NCT03270527) followed two sequential 4-week isoenergetic moderate-fat (34%TE) diets: high-SFA (18%TE SFAs, 16%TE UFAs) and low-SFA (10%TE SFAs, 24%TE UFAs). Dietary intakes were assessed using 4-day weighed diet diaries. Nutrient intakes were analysed using paired t-tests, fasting plasma phospholipid fatty acid (PL-FA) profiles and dietary patterns were analysed using orthogonal partial least square discriminant analyses.Results: Participants exchanged 10.2%TE (SD 4.1) SFAs for 9.7%TE (SD 3.9) UFAs between the high and low-SFA diets, reaching target intakes with minimal effect on other nutrients or energy intakes. Analyses of dietary patterns confirmed successful incorporation of recommended foods from commercially available sources (e.g. dairy products, snacks, oils, and fats), without affecting participants’ overall dietary intakes. Analyses of plasma PL-FAs indicated good compliance to the dietary intervention and foods of varying SFA content.Conclusions: RISSCI-1 dietary exchange model successfully replaced dietary SFAs with UFAs in free-living healthy men using commercially available foods, and without altering their dietary patterns. Further intervention studies are required to confirm utility and feasibility of such food-based dietary fat replacement models at a population level