About

Dennis Cladis is an Assistant Professor in the Department of Food Science and Technology at Virginia Tech, with a focus on polyphenols, flavonoids, bioavailability, and metabolism. His research aims to evaluate how factors at every step of the food system impact polyphenol bioavailability, which is crucial for understanding their potential health benefits. His projects include nutrient phenotyping in collaboration with plant breeders to characterize polyphenol content and bioavailability of agricultural crops, studying the safety and dose-dependent metabolism of botanical dietary supplements, and investigating the role of polyphenols in slowing the progression of chronic kidney disease (CKD) and preventing related cardiovascular complications using animal models.

Research topics

• Food science
• Microbiology
• Chemistry
• Biochemistry
• Pharmacology
• Biology

Selected publications

• CherryZZZ: A Protocol for a Randomized, Double-Blind, Placebo-Controlled, Cross-Over Pilot Study Testing Tart Cherry Juice in Older Adults with Self-Reported Insomnia

  Nutrients · 2026-03-14

  articleOpen access

  Introduction: Two small, preliminary pilot studies report that 2 weeks of daily tart cherry juice consumption (half of the dose in the morning, half of the dose at night) may increase sleep quantity (assessed via a sleep diary or 1 night of polysomnography) in older adults with insomnia. A study of longer duration, with doses closer to bedtime, and daily objective monitoring of sleep via a wearable device may potentiate the observed impact of tart cherry juice intake on sleep. With the proposed changes to the study protocol, it is paramount to evaluate the study’s feasibility. Methods: The current study is a single-site, randomized, double-blind, cross-over pilot study in 20 older adults with self-reported insomnia. Eligible individuals will be randomly assigned to consume 16 oz. of tart cherry juice/day or placebo juice for 4 weeks each, separated by a 3-week washout period. Information on study feasibility, including recruitment rate, retention rate, safety, compliance, and study practicality, will be collected, as well as pre- and post-arm evaluations of sleep quantity/quality and biomarkers related to melatonin, cortisol, serotonin, and inflammation. Discussion: Identification of a dietary intervention that improves sleep quantity and quality may serve as a novel and feasible approach for older adults who suffer from insomnia. If successful, such a strategy would help mitigate the plethora of health consequences associated with poor sleep.

  PublisherOA PDFDOI

• Development and validation of ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method to quantify monotropein in blueberries

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-07-27

  preprintOpen accessSenior authorCorresponding

  ABSTRACT Blueberries ( Vaccinium species) are an economically important fruit crop rich in bioactive compounds like polyphenols and flavonoids. Interestingly, some blueberry cultivars also produce monotropein, which has bioactive properties, including anti-inflammatory and neuroprotective effects. However, methods to quantify monotropein in blueberries have not been optimized. To address this gap, an optimized analytical method for monotropein extraction and quantification using liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. Different extraction strategies were compared, including variations in temperature, time, and ultrasonication treatments. Optimal extraction was achieved by heating samples to 60°C for 15 minutes in methanol. The method had high percent recovery (89-110% intraday; 91-108% interday) and good repeatability (1.17-2.15% relative standard deviation (RSD) intraday; 4.68-7.16% RSD interday). This protocol was then applied to 28 blueberry cultivars, 14 of which had not been previously analyzed for monotropein. Monotropein ranged from 0-1807 ng/mg dry weight. The developed method provides a robust tool that can be applied to future evaluations of monotropein in diverse blueberry cultivars.

  PublisherOA PDFDOI

• Elemental analysis of 346 varieties of quinoa: Development and validation of microwave plasma optical emission spectrometry (MP-OES) method

  Journal of Food Composition and Analysis · 2025-01-29 · 5 citations

  article1st authorCorresponding
  PublisherDOI

• Dietary (Poly)phenols in the Management of Chronic Kidney Disease: A Narrative Review

  Dietetics · 2025-11-07

  articleOpen accessSenior authorCorresponding

  Chronic kidney disease (CKD) affects over 850 million individuals globally and has no cure. The treatment of CKD centers on lifestyle interventions, including dietary changes, that slow disease progression. As emerging evidence suggests that fruit and vegetable-derived (poly)phenols may slow CKD, the goal of this narrative review is to synthesize current knowledge on the role of dietary (poly)phenols in CKD. To identify relevant articles, we searched databases including PubMed, Google Scholar, and Web of Science to identify relevant articles, using keywords including (poly)phenols, CKD, gut microbiome, and cardiovascular disease, among others. The relevant articles were synthesized into a summary of the evidence for (poly)phenols as a therapeutic strategy in CKD, though the paucity and heterogeneity of available research in this area precludes the identification of specific doses or types of (poly)phenols needed to slow CKD progression. The review is supplemented through our discussion of the gut microbiota and microbially derived metabolites as key targets in mediating the progression of CKD itself as well as subsequent cardiovascular outcomes. Finally, we discuss the integration of (poly)phenol-rich dietary patterns into CKD nutrition guidelines, highlighting future research directions to elucidate the potential therapeutic role of (poly)phenols in CKD.

  PublisherOA PDFDOI

• Development and validation of ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method to quantify monotropein in blueberries

  PLoS ONE · 2025-11-21

  articleOpen accessSenior authorCorresponding

  Blueberries (Vaccinium species) are an economically important fruit crop rich in bioactive compounds like polyphenols and flavonoids. Interestingly, some blueberry cultivars also produce monotropein, which has bioactive properties, including anti-inflammatory and neuroprotective effects. However, methods to quantify monotropein in blueberries have not been optimized. To address this gap, an optimized analytical method for monotropein extraction and quantification using ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed. Different extraction strategies were compared, including variations in temperature, time, and ultrasonication treatments. Optimal extraction was achieved by heating samples to 60 °C for 15 mins in methanol. The method had high percent recovery and good repeatability. This protocol was then applied to 28 blueberry cultivars, 14 of which had not been previously analyzed for monotropein. Monotropein ranged from 0-1807 ng/mg dry weight. The developed method provides a robust tool that can be applied to future evaluations of monotropein in diverse blueberry cultivars.

  PublisherDOI

• Phosphorus Bioaccessibility of Processed Soy and Pulse Protein Products Measured by <i>In Vitro</i> Simulation of Human Digestion

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-05-17 · 1 citations

  preprintOpen access

  Abstract Objective Plant protein is gaining interest for dietary phosphorus management in CKD due to its potential benefits, including possible lower phosphorus bioaccessibility. However, data on phosphorus remain limited, particularly for processed plant protein products. This pilot study aimed to compare phosphorus bioaccessibility of processed plant protein products with their animal protein counterparts, using in vitro simulation of adult human digestion. Methods Soy protein (n=16), pulse protein (n=17), and animal protein (n=13) products representing food categories of beef, dairy, sausage/bacon, chicken/turkey were evaluated for phosphorus bioaccessibility using in vitro digestion based the INFOGEST protocol, followed by dialysis of the final digesta. Pre-digestion samples, final digesta, and final dialysate were analyzed for phosphorus content to calculate total and bioaccessible phosphorus and percent phosphorus bioaccessibility. Results Average percent phosphorus bioaccessibility of all processed soy and pulse products studied ranged from 32-100%, while animal products ranged from 81-100%. Average bioaccessible phosphorus and bioaccessible phosphorus-to-protein ratio were lower for many soy and pulse protein beef and chicken/turkey alternatives, soy protein milk alternatives, and pulse protein sausage alternatives than their animal protein counter products. Conclusion Some soy and pulse protein products offered lower bioaccessible phosphorus per 100g serving and per gram of protein than their animal protein counterparts. Thus, this pilot study suggests that certain processed plant protein products may be acceptable to include in a diet for phosphorus management in CKD. However, more data on phosphorus bioaccessibility in a larger number and variety of processed plant-based protein products is needed to better inform individualized guidance.

  PublisherOA PDFDOI

• Ripening Kinetics and Grape Chemistry of Virginia Petit Manseng

  Beverages · 2025-07-30 · 2 citations

  articleOpen accessSenior authorCorresponding

  Petit Manseng is a variety of Vitis vinifera gaining popularity in Virginia, USA because it consistently produces high quality grapes under variable growing conditions. However, its high sugar and acid levels complicate dry wine production. The goal of this study was to characterize Petit Manseng ripening kinetics from veraison to harvest to identify optimal harvest timing for producing dry white wines, using Chardonnay as a comparator because of its popularity in Virginia, well-known ripening kinetics, and ability to produce high quality dry white wines. A total of 74 samples of Petit Manseng and Chardonnay grapes were collected from five commercial sites over 2 years and evaluated for berry weight, pH, titratable acidity (TA), malic acid, total soluble solids (TSS), glucose, and fructose, with ripening kinetics modeled using segmented regressions. Results indicated that harvest timing and grape variety were the primary factors influencing ripening kinetics. In contrast, growing location and vintage had limited impact. In Chardonnay grapes, TA declined from 21 to 7.1 g/L and TSS increased from 6.1 to 19.5 g/L. In Petit Manseng, TA declined from 25 to 10.8 g/L and TSS increased from 8.0 to 23.6 g/L. Acid depletion plateaued ~2 weeks after sugar accumulation plateaued in Petit Manseng grapes, though the plateaus were similar in Chardonnay grapes. Linear discriminant analysis (LDA) completely separated grapes based on pH or TA vs. sugars, but not malic acid vs. sugars, suggesting that tartaric acid is driving acidity differences between cultivars. These data indicate that regardless of when grapes are harvested, winemakers may need to employ targeted acid management strategies with Petit Manseng because of its ripening kinetics.

  PublisherOA PDFDOI

• List of contributors

  Tea in Health and Disease Prevention · 2024-10-01

  book-chapterOpen access
  PublisherDOI

• Dietary Phosphorus Levels Influence Protein-Derived Uremic Toxin Production in Nephrectomized Male Rats

  Nutrients · 2024-06-08

  articleOpen access1st author

  Gut microbiota-derived uremic toxins (UT) accumulate in patients with chronic kidney disease (CKD). Dietary phosphorus and protein restriction are common in CKD treatment, but the relationship between dietary phosphorus, a key nutrient for the gut microbiota, and protein-derived UT is poorly studied. Thus, we explored the relationship between dietary phosphorus and serum UT in CKD rats. For this exploratory study, we used serum samples from a larger study on the effects of dietary phosphorus on intestinal phosphorus absorption in nephrectomized (Nx, n = 22) or sham-operated (sham, n = 18) male Sprague Dawley rats. Rats were randomized to diet treatment groups of low or high phosphorus (0.1% or 1.2% w/w, respectively) for 1 week, with serum trimethylamine oxide (TMAO), indoxyl sulfate (IS), and p-cresol sulfate (pCS) analyzed by LC-MS. Nx rats had significantly higher levels of serum TMAO, IS, and pCS compared to sham rats (all p &lt; 0.0001). IS showed a significant interaction between diet and CKD status, where serum IS was higher with the high-phosphorus diet in both Nx and sham rats, but to a greater extent in the Nx rats. Serum TMAO (p = 0.24) and pCS (p = 0.34) were not affected by dietary phosphorus levels. High dietary phosphorus intake for 1 week results in higher serum IS in both Nx and sham rats. The results of this exploratory study indicate that reducing dietary phosphorus intake in CKD may have beneficial effects on UT accumulation.

  PublisherOA PDFDOI

• Quantifying the Quinoa Ionome: Mineral Content of 346 Quinoa Varieties

  Current Developments in Nutrition · 2024-06-29

  articleOpen access1st authorCorresponding

  Objectives: Cereal and pseudocereal crops are nutrient-dense, dietary staples for many populations around the world. Quinoa is an emerging pseudocereal crop that is rich in essential minerals while also being more resilient to environmental stressors than other cereal crops like wheat, maize, and rice. Because of this, quinoa production has tripled since 2006, with researchers seeking to develop agronomically beneficial varieties. However, there has been little attention given to how these breeding efforts affect the nutritional quality of the quinoa. Thus, our objective is to characterize the ionome of an established quinoa germplasm. Methods: A total of 346 quinoa varieties from the Washington State University collection were analyzed for mineral content. Quinoa samples were ground into a powder before being dry ashed in a muffle furnace, resolubilized in nitric acid, and analyzed via microwave plasma atomic emission spectroscopy (MP-AES) for 18 minerals, including Ag, Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Ni, P, Pb, Sr, and Zn. Results: Mineral concentration ranged widely across the varieties analyzed: Al (6.5-152 ppm), B (6.0-15.5 ppm), Ba (1.4-20.2 ppm), Ca (368-1259 ppm), Cu (2.5-5.9 ppm), Fe (39.7-163 ppm), K (6189-13002 ppm), Mg (1708-3062 ppm), Mn (11.7-23.9 ppm), P (2367-6787 ppm), Sr (3.3-17.5 ppm), and Zn (22.7-82.1 ppm). On average, a 200 g serving of quinoa would meet the recommended dietary allowance (RDA) for B, Mg, Mn, and P, while a 400 g serving would meet the RDA for Cu, Fe, K, and Zn. Heavy metals, including Ag, Cd, Co, Cr, Ni, and Pb, were below the limit of detection. Conclusions: Quinoa is rich in essential minerals and low in heavy metals, though there is significant diversity in the mineral content of the varieties analyzed. Our results will be used in concert with agronomic data to identify varieties that have beneficial mineral and agronomic traits as future breeding targets to maximally benefit consumers and growers. Funding Sources: None.

  PublisherDOI

Frequent coauthors

• Connie M. Weaver

  San Diego State University

  39 shared

• Kathleen M. Hill Gallant

  Indiana University – Purdue University Indianapolis

  37 shared

• Mário G. Ferruzzi

  Arkansas Children's Nutrition Center

  33 shared

• Annabel Biruete

  Purdue University West Lafayette

  26 shared

• Kendal Burstad

  University of Minnesota

  15 shared

• Suzanne C. Bart

  Purdue University West Lafayette

  12 shared

• Sharon M. Moe

  Indiana University School of Medicine

  12 shared

• Phillip E. Fanwick

  Purdue University West Lafayette

  11 shared