Research Interests
Major goals of my research program include: 1) investigating interactions between plant phytochemicals (e.g., polyphenols, cannabidiol), gut microbiota, and host to define cause-effect mechanisms responsible for widely reported health benefits, and 2) translating laboratory findings into human intervention studies. Projects are highly multi-disciplinary and provide trainees with opportunities to gain experience in animal science, molecular biology, biochemistry, phytochemistry, analytical chemistry, mammalian cell culture, gut microbiology, and human intervention studies. In addition to wet lab skills, trainees gain experience in applying bioinformatics tools to analyze metabolomics and metagenomics datasets.
Dietary polyphenols
Polyphenol compounds found in fruits, vegetables, grains, spices, red wine, and chocolate have been linked to several health benefits, including decreased risk of cardiometabolic diseases. Identifying the mechanisms behind these benefits has proven challenging because dietary polyphenols are not readily absorbed by the gut into the bloodstream. This raises the question - how do dietary polyphenols benefit human health? Our research with grape polyphenols suggests they mediate metabolic improvements by changing the gut microbiota and their microbial metabolites, which signal to intestinal epithelium cells. Gut-derived hormones and absorbed microbial metabolites further modulate gene/protein expression in other peripheral organs and the brain which can promote metabolic improvements.
Polyphenols and possibly their metabolites act as prebiotics that feed beneficial microbes while also having selective antibacterial effects on pathobionts. Beneficial gut bacteria have potential to be developed as novel probiotics. Finally, synbiotics involve pairing probiotics with the prebiotics they consume so beneficial microbes are sustained in the gut ecosystem. Greater understanding of how dietary compounds and gut bacteria interact will bring us closer to precision nutrition approaches for health maintenance and disease prevention.
Women’s health
With increasing lifespan, women can expect to spend more than one third of their lifetime in menopause and post-menopause. Estrogen declines during menopause resulting in increased risk of gastrointestinal disorders, cardiometabolic disease, cognitive decline, and osteoporosis. Hormone replacement therapy can alleviate menopausal symptoms but also increases the risk of cancer and heart disease therefore other options are needed.
The estrobolome refers to gut bacteria that regulates systemic estrogen levels. Conjugated estrogen metabolites formed in the liver are inactive and excreted in feces and urine. Gut bacterial β-glucuronidases deconjugate estrogens to bioactive forms that are reabsorbed via enterohepatic circulation. We hypothesize that dietary and therapeutic compounds can alter the abundance and/or enzymatic activity of gut microbes regulating estrogen metabolism.
Cannabidiol (CBD) is a non-psychoactive terpenophenolic compound extracted from industrial hemp (i.e. Cannabis sativa L. with no more than 0.3% THC on a dry-weight basis). CBD has been reported to have anti-inflammatory, anti-anxiety, anti-proliferation, and neuroprotective properties suggesting it may help manage the symptoms of estrogen deficiency in menopausal and post-menopausal women. Using established murine models of menopause/post-menopause we are investigating the effects of CBD on inflammation, gut health, osteoporosis, and the gut microbes that regulate estrogen metabolism.
Industrial hemp, Cannabis sativa L.
Photo by Purni Wickramasinghe
Dietary fat is a modifiable risk factor that is understudied in post-menopausal females. Data suggest fatty acids and estrogens interact to regulate metabolism in post-menopausal females. In collaboration with RU colleagues, we are investigating the effects of different types of dietary fatty acids on metabolic, gut, bone, and cognitive health in murine models of menopause/post-menopause.
