Health benefits of dietary polyphenols
Dr Paul Kroon
Health benefits of dietary polyphenols
The overall aim of our research is to understand how consuming foods or diets that are rich in polyphenols can deliver health benefits, in particular on the risks of developing cardiovascular disease, liver disease and diabetes. As well as refining healthy eating guidelines, we will support the development of future foods with verified abilities to reduce disease risk. Within this research we are also looking at how individuals vary in their ability to absorb, metabolise and extract health benefits from polyphenols, allowing for more personalised nutrition advice. Our research could potentially provide the evidence underpinning a health claim for one or more polyphenol-rich foods/beverages, providing substantial benefits for the bioeconomy and bringing an increased choice of healthy foods supported by scientific evidence.
A major aspect of our work involves undertaking high quality randomised, controlled dietary intervention studies to quantify the effects of consuming appropriate doses of polyphenols on lipid / carbohydrate metabolism, via the measurement of biomarkers of dyslipidemia, glycaemia and of disease risks such as lipids/lipoproteins and fasting glucose/insulin. We are currently focused on anthocyanins, which are the brightly coloured compounds in berries such as raspberries, blueberries, blackcurrant and in vegetables such as red/purple cabbage and red/purple potatoes. We also use non-targeted approaches including transcriptomics (RNAseq), metabolomics (LC-MS, NMR) and gut microbiota profiling.
We complement this research with studies to uncover plausible mechanisms for how ingested polyphenols affect the absorption and metabolism of lipids (cholesterol) and carbohydrates at the molecular level. We undertake detailed analyses of polyphenols and their human and microbial metabolites using QQQ LC-MS. With our synthetic chemistry capability, we can identify and accurately quantify large numbers of known and predicted metabolites. We maintain our own library of polyphenols, which is very valuable as a research tool because these are largely not available commercially. We also collaborate with Prof. Cathie Martin’s group in the John Innes Centre, using the various unique flavonoid-expressing tomatoes that this group has developed to compare polyphenol efficacy and mechanisms within the same complex food matrix (tomato).
We seek to apply our knowledge of how polyphenols are metabolised and interact with our cells and tissues in the development of future foods. For example, directly consuming the most active metabolites is likely to be more effective and be subject to less individual variation than consuming polyphenols that need to be transformed into the active forms. With this information we have the potential to change the plant foods that are recommended to consumers as healthy by policy makers and the products marketed by the food and pharmaceutical industries.
We are seeking to exploit the basic knowledge we gain from our research by engaging with consumers to provide evidence-based nutritional information and with the food industry to develop new foods with health benefits and health claims. Our human dietary interventions and our basic research to establish sound evidence of plausible mechanisms of action is in keeping with the requirements for making health claims.
We collaborate with research teams across Europe in our research to understand the factors that cause the large individual variation in response to consuming food bioactives such as polyphenols. We are members of the POSITIVe COST Action consortium and are undertaking systematic reviews of published data and meta-analyses of raw data from multiple human studies to determine how factors such as age, gender, genotype, BMI and diet affect how individuals respond to polyphenol-rich foods and diets.
This may in the future allow us to provide tailored dietary advice, based on our research into the factors that cause the large differences between individuals in the way they absorb polyphenols and the magnitude of the beneficial effects they exert. An understanding of the effects that particular genotypes and phenotypes exert on the response to polyphenols will be a further step towards personal nutrition.