Characterization of Blueberry (Poly)phenolics in Foods, their Metabolites in Human Biological Samples and Anti-Inflammatory Effects of Phytochemicals In Vitro

Blueberries’ popularity is in part supported by the health benefits associated with their consumption. Research has strongly focused on their polyphenol and anthocyanin concentration, one of the highest amongst commonly consumed foods. Polyphenols have demonstrated antioxidant effects in vitro, and consuming polyphenol-rich foods is associated with protective effects towards non-communicable diseases, but their direct bioactivity in the human body remains to be fully understood. It is estimated that about 90 to 95% of the initial polyphenol intake reaches the colon without being absorbed. Instead, phenolic compounds go through extensive biotransformations, consisting of catabolism into smaller compounds mostly carried out by the gut microbiota and enabling their absorption, and/or conjugation through phase II metabolism. Hence, the compounds resulting from dietary consumption and circulating in the blood are mostly phenolic-derived metabolites while the parent compounds found in blueberries are present at very low concentrations. It is crucial to understand the metabolic fate of blueberry polyphenols to be able to characterize the bioactive compounds to which health benefits are attributed. The main objectives of this dissertation were to determine the metabolites resulting from blueberry consumption and evaluate the anti-inflammatory effects of blueberry phytochemicals in vitro. Several food products were prepared with wild blueberry powder, and the stability of the polyphenols in the products was assessed during storage at different temperatures, for up to 8 weeks. The most stable products were then used in a clinical trial to supplement children with wild blueberry powder (or a placebo) for 5 days. Plasma and urine samples were collected hourly on the 6th day for 5 hours. Phenolic-derived metabolites were characterized in the samples using an ultra-high performance liquid chromatography method coupled with mass-spectrometry/mass spectrometry multiple reactions monitoring, which suitability to identify and quantify the targeted metabolites was previously assessed. The literature surrounding blueberries and their health benefits is extensive, but the variety of models and the large range of polyphenols concentrations used, some of them not being representative of their low bioavailability, makes it challenging to interpret observed effects. To address some of these considerations, blueberry polyphenol and volatile extracts were developed and tested in two models of inflammation to determine the potential anti-inflammatory effects of blueberry native phytochemicals at low concentrations. The results obtained in this dissertation provide a phenolic-derived metabolite profile in the plasma and urine of children after blueberry or placebo consumption, and show a clear difference between the two groups. The blueberry polyphenol and volatile extracts significantly decreased the production of the pro-inflammatory interleukin-6 in whole blood, but only at high concentrations that are unlikely to be recovered in the blood, for phenolic compounds, after consumption of one serving of blueberries. No clear modulation of markers of inflammation were observed in the human macrophage cell culture model. These results strengthened the initial hypotheses that blueberry native compounds may not exert strong bioactive effects in vivo due to the molecules undergoing extensive biotransformations once consumed, and support the need to include metabolite compounds in further research assessing health benefits of blueberry consumption

The Effects of Blueberry Phytochemicals on Cell Models of Inflammation and Oxidative Stress

Blueberries have been extensively studied for the health benefits associated with their high phenolic content. The positive impact of blueberry consumption on human health is associated in part with modulation of proinflammatory molecular pathways and oxidative stress. Here, we review in vitro studies examining the anti-inflammatory and antioxidant effects of blueberry phytochemicals, discuss the results in terms of relevance to disease and health, and consider how different blueberry components modulate cellular mechanisms. The dampening effects of blueberry-derived molecules on inflammation and oxidative stress in cell models have been demonstrated through downregulation of the NF-κB pathway and reduction of reactive oxygen species (ROS) and lipid peroxidation. The modulatory effects of blueberry phytochemicals on the mitogen-activated protein kinase (MAPK) pathway and antioxidant system are not as well described, with inconsistent observations reported on immune cells and between models of endothelial, dermal, and ocular inflammation. Although anthocyanins are often reported as being the main bioactive compound in blueberries, no individual phytochemical has emerged as the primary compound when different fractions are compared; rather, an effect of whole blueberry extracts or synergy between different phenolic and nonphenolic extracts seems apparent. The major molecular mechanisms of blueberry phytochemicals are increasingly defined in cell models, but their relevance in more complex human systems needs further investigation using well-controlled clinical trials, in which systemic exposures to blueberry-associated molecules are measured concurrently with physiologic indices of inflammation and oxidative stress

Dynamique et profil du microbiote issu de produits végétaux fermentés et évaluation préliminaire de leur modulation du microbiote intestinal in vitro

International audienc

Changes in Polyphenolics during Storage of Products Prepared with Freeze-Dried Wild Blueberry Powder.

Wild blueberry (WBB) powder can be added to the formulation of foods to encourage consumption of health-promoting polyphenolics, but the stability of polyphenolics throughout storage is important. We determined the stability of polyphenolics in five products (ice pop, oatmeal bar, graham cracker cookie, juice, and gummy product) prepared with WBB powder. Samples stored at 21 °C, 4.4 °C, or -20 °C (ice pops only) were analyzed at 0, 2, 4, 6, and 8 weeks for polyphenolic content and percent polymeric color. Total anthocyanins decreased over storage and storage temperatures in all products. However, the ice pop and the refrigerated juice both retained over 90% of their initial total anthocyanin content. The refrigerated oatmeal bar also showed good retention of anthocyanins (86%), but the gummy product retained only 43% and 51% when stored at 4.4 °C or 21 °C, respectively. The lower amount of polyphenolic compounds recovered in the gummies stored at 4.4 °C compared to 21 °C may be attributed to reduced extraction efficiency as a result of gel hardening at refrigerated temperature. Chlorogenic acid and flavonols were generally more stable than anthocyanins throughout storage

Changes in Polyphenolics during Storage of Products Prepared with Freeze-Dried Wild Blueberry Powder.

Wild blueberry (WBB) powder can be added to the formulation of foods to encourage consumption of health-promoting polyphenolics, but the stability of polyphenolics throughout storage is important. We determined the stability of polyphenolics in five products (ice pop, oatmeal bar, graham cracker cookie, juice, and gummy product) prepared with WBB powder. Samples stored at 21 °C, 4.4 °C, or -20 °C (ice pops only) were analyzed at 0, 2, 4, 6, and 8 weeks for polyphenolic content and percent polymeric color. Total anthocyanins decreased over storage and storage temperatures in all products. However, the ice pop and the refrigerated juice both retained over 90% of their initial total anthocyanin content. The refrigerated oatmeal bar also showed good retention of anthocyanins (86%), but the gummy product retained only 43% and 51% when stored at 4.4 °C or 21 °C, respectively. The lower amount of polyphenolic compounds recovered in the gummies stored at 4.4 °C compared to 21 °C may be attributed to reduced extraction efficiency as a result of gel hardening at refrigerated temperature. Chlorogenic acid and flavonols were generally more stable than anthocyanins throughout storage

Auton'Al 60: Prevention program for the loss of autonomy of elderly in France

Abstract Introduction The loss of autonomy in elderly varies according to the individual health status, but also to the social and psychological environment. Multiple risk factors play a role, including limited access to a balanced diet, physical inactivity or a poor social network. Prevention programs must therefore be based on a multidimensional approach, but are rarely studied with regard to their effectiveness. Materials and methods The objective of the Auton'Al 60 program is to prevent the loss of autonomy related to diet, physical activity and mental health in elderly, aged 60 to 89, in the county of Oise, North of France. Between February and July 2018, 7 different prevention workshops were conducted in 5 geographical areas (urban and rural). A blog and a monthly newsletter have been created to limit the loss to follow- up. Evaluation was based on an in-depth interview at T0 inquiring about the level of autonomy, the dietary habits and the health status, as well as on 2 self-administered questionnaires during and at the end of the program. In addition, each workshop has been evaluated separately according to key indicators. Statistical analysis was performed using SPSS 17. Results 69 workshops have been completed during 5 months. In total, 91 subjects (27.8% men - 71.9% women) participated in at least one workshop, with a mean age of 69.1 years (± 6.3). 72.6% of the subjects were present at 6 or 7 workshops, and 49.5% participated in all activities. A state of loss of autonomy was reported by 6.7% of the participants. 32.6% of the population were chronic-disease-free and 43.8% had a normal BMI (kg / m 2 ). The prevalence of obesity was 15.7%. The program showed effectiveness to decrease the consumption of high-fat products in 52.9% as well as the consumption of sugary products in 60.9% of the participants. Furthermore, 23.2% of the subjects started a new social activity during the program. However, compared to other age groups observed fragility seemed to be particularly high in elderly aged from 66 to 69 years. Conclusion The Auton'Al 60 program confirms the heterogeneity in the level of autonomy, health status and health behavior in elderly. The multidimensional approach has shown satisfactory effectiveness. Prevention strategies have been developed for isolated or low-income subjects and are under current evaluation