Dr Tiffany Weir, professor of food science and human nutrition at Colorado State University, spoke to Vitafoods Insights about her research looking at how interventions with functional foods, specifically powdered blueberries, affect vascular dysfunction in postmenopausal women.
Weir, who will present her findings at the 16th World Congress on Polyphenols Applications 2023, running on 28 and 29 September at Corinthia Palace, Malta, studies how the gut microbiota and diet can influence the development of chronic disease.
Variability in individual responses to polyphenol benefits
Dietary polyphenols are known to be beneficial for human health; however, there is wide variability in individual responses, which may be due to differential processing of polyphenols by the gut microbiome.
Enzymes in the gut microbiota that metabolise polyphenols can influence their bioactivity and bioavailability. Weir wants to understand whether these polyphenol-metabolising enzymes are predictive of individual responses in vascular endothelial function to a dietary blueberry intervention in post-menopausal women.
“There are specific individuals who are responders to the blueberry intervention compared to individuals who are not responders – and so we're really interested in digging deeper and seeing if metabolism of polyphenols in the gut is part of what relates to the basis of response,” she told Vitafoods Insights.
“And then if we can identify that as a factor, is there something that we could do about it? Is there a way that the polyphenols could be protected if they're getting broken down to inactive compounds, or is there a way that we could add in a probiotic or do something to change the gut environment to make the polyphenols more bioavailable if we see that the opposite is happening – that the gut isn't metabolising the polyphenols to a point where they could be taken up?”
Dietary interventions offer opportunity to act before chronic disease develops
Findings in the area could ultimately help to inspire interventions before chronic disease develops, Weird explained.
“Vascular dysfunction is a preclinical manifestation – so if you have vascular dysfunction, you don't necessarily already have other cardiovascular disease, but you're headed down that road. So it's a really nice model to look at prevention and interception of diseases,” she said.
“I think with diet and even dietary supplements, probiotics, things like that, that's the space that we need to be working in – because once disease is manifested, it's going to be really hard to reverse that just using diet approaches and just using supplemental approaches.
“But before you get there, I think that's where the opportunity is to be able to use diet and polyphenols, supplements, probiotics and things like that, to prevent you from going down that road.”
The risk of cardiovascular disease for women increases “almost exponentially” after menopause, Weir said, making the potential of intervention at the menopause transition an exciting one.
Healthspan was a key word, she added.
“Yes, we can live a long time – but if we're taking a million drugs and we can't do any of the things we like to do, is it worth it?” she asked.
Polyphenol metabolism could inform precision nutrition approaches
Understanding how polyphenols are metabolised in the gut could potentially identify new approaches for nutrition interventions, Weir said.
“A lot of people view nutrition as sort of a pseudoscience and supplements even as a pseudoscience because there are papers that come out that say, ‘Yes, these work’ and then ones that come out that [say, ‘No, they] don't’ – and it's really hard to come to a consensus,” she said.
“I think that it's not that they work or they don't work – it's that they work for some people and they don't work for other people.”
Ultimately, understanding polyphenol metabolism in the gut will help to advance the field of precision nutrition, she added.
“We're definitely, I think, moving in that direction of saying, ‘Yes, we can't make these blanket dietary guidelines and say this is going to be good for everybody,’” she said.
“This is hopefully opening up the door to much more detailed examination of those gut microenvironments and the bioavailability question.”
Asked about next steps for research, she said: “The next step is [to] try to follow up and see how much do those specific microcosms influence on the bioavailability of the compounds? And those are tricky questions to get out, especially in humans.”
But she sounded a note of optimism, adding: “There's so many neat new tools that are coming out, from simulated gut models to these capsules that you can take … that will sample at different spots along the GI tract.
“I think it's really cool what we can do now – and what we're going to be able to do in the future.”
Weir will be speaking at the 16th World Congress on Polyphenols Applications 2023, taking place on 28 and 29 September at Corinthia Palace, Malta.