About

Dr. John Erdman is a professor associated with the University of Illinois, as indicated by the context of the webpage. The webpage features a gathering of past lab members at the ASN conference, with Dr. Erdman present among other colleagues and former students. The content emphasizes his role within a research environment focused on nutrition, as evidenced by references to nutrition conferences and events such as the Nutrition 2023 Conference in Boston and the Personalized Nutrition Innovation Day. However, the page does not provide specific details about his research focus, background, or key contributions beyond his association with the university and participation in nutrition-related professional gatherings.

Research topics

• Medicine
• Internal medicine
• Biology
• Biochemistry
• Food science
• Artificial Intelligence
• Genetics
• Chemistry
• Mathematics
• Radiology
• Pharmacology
• Nuclear medicine
• Immunology
• Gastroenterology
• Chromatography
• Ophthalmology

Selected publications

• Examining widely held propositions on human dietary protein needs and benefits: a critical review of the science that shapes both the data and our understanding of an essential macronutrient

  Figshare · 2026-05-08

  articleOpen access

  The essentiality of protein in the human diet is unequivocal. Yet researchers, clinicians, and lay people often believe numerous propositions about dietary protein despite insufficient supporting or refuting data in some instances. To address this disconnect, and to “pressure-test” current beliefs about dietary protein, the Indiana University School of Public Health-Bloomington convened a workshop in February 2025 titled “<i>Human Dietary Protein Needs and Benefits: A Critical Assessment of Postulated Propositions.”</i> More than 20 international experts discussed (1) methodologic issues affecting data acquisition and interpretation; (2) “optimal” dietary protein intakes and effects on muscle protein synthesis rates, muscle protein accretion, muscle growth, and muscle repair; (3) protein needs during weight loss; (4) acute protein intake thresholds above and below which protein is no longer related to anabolism; and (5) dietary protein intakes above which protein may be detrimental to health. The experts rated each proposition on a scale from “<i>existing evidence strongly supports the proposition</i>” to “<i>existing evidence seems sufficient to rule out the viability of the proposition.</i>” In most instances, the experts believed additional research was warranted. For many propositions the research base was insufficient in terms of quality (rigor), quantity (sample size, study duration), or pertinence (e.g., use of surrogate markers).

  PublisherDOI

• The Urinary Tract commensal <i>Peptoniphilus</i> spp. Encodes a Novel 17β-Hydroxysteroid Dehydrogenase

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-04-01

  articleOpen access

  Abstract Microbial steroid metabolism represents an underappreciated extension of the vertebrate endocrine system, with growing evidence that host-associated microbes contribute to the diversity and bioavailability of sex steroids within human tissues. Emerging studies have linked microbial androgen metabolism to urinary microbiome composition and to resistance to androgen deprivation therapy (ADT) in prostate cancer. While microbial pathways capable of converting steroid precursors such as cortisol to androgens, via the steroid-17,20-desmolase pathway, such as DesG-mediated interconversion of androstenedione to testosterone have been reported, the diversity of enzymes mediating downstream androgen interconversion remains incompletely defined. Here, we investigate the androgen-forming capabilities of anaerobic bacteria from the male genitourinary microbiome, focusing on NADPH-dependent 17β-hydroxysteroid dehydrogenases (17β-HSDHs) that catalyze interconversion of androstenedione and testosterone. We isolated androgen-forming bacterial strains from human male urine and identified a previously uncharacterized 17β-HSDH encoded by Peptoniphilus obesi , demonstrated that this enzyme catalyzes the NADPH-dependent reduction of androstenedione to testosterone and the reverse oxidation reaction. Sequence similarity searches further identified a homologous 17β-HSDH in Anaerococcus , which was synthesized and functionally validated, revealing conserved activity despite low sequence identity to the previously characterized urinary tract enzyme DesG. The enzymes were found to have broad substrate specificity for C19 and C18 17keto− and 17β-hydroxysteroids. Together, these findings expand the known diversity of microbial 17β-HSDHs and identify previously unrecognized androgen-forming activities within the genitourinary microbiome. Importance Microbial steroid-transforming pathways may provide a mechanism by which commensal anaerobes contribute to androgen availability in the genitourinary tract. By identifying novel 17β-hydroxysteroid dehydrogenases from Peptoniphilus and Anaerococcus , genera repeatedly associated with prostate cancer, this study provides mechanistic insight into how microbial steroid metabolism may influence hormone-driven disease.

  PublisherOA PDFDOI

• Effects of Randomized Multivitamin Supplementation on Carotenoids and α-Tocopherol in the COcoa Supplement and Multivitamin Outcomes Study

  Journal of the Academy of Nutrition and Dietetics · 2026-01-24 · 2 citations

  articleOpen access
  PublisherOA PDFDOI

• Examining widely held propositions on human dietary protein needs and benefits: a critical review of the science that shapes both the data and our understanding of an essential macronutrient

  Critical Reviews in Food Science and Nutrition · 2026-05-08

  articleOpen access

  " In most instances, the experts believed additional research was warranted. For many propositions the research base was insufficient in terms of quality (rigor), quantity (sample size, study duration), or pertinence (e.g., use of surrogate markers).

  PublisherDOI

• Adhering to dietary guidelines does not yield flavanol intake levels associated with beneficial cardiovascular effects

  medRxiv · 2026-02-26

  articleOpen access

  Abstract Outcomes from the COSMOS trial have reinforced the notion of flavanols as important plant-derived bioactives contributing to cardiovascular health. As discussions continue on whether specific dietary reference values for flavanols are warranted, it is possible that existing dietary guidelines emphasizing fruits and vegetables already yield sufficient flavanol intake levels. If this were the case, developing flavanol specific dietary reference values might be unnecessary. This study therefore aimed at assessing whether adherence to dietary recommendations for fruit and vegetable intake and overall diet quality achieves flavanol intake levels of 500 mg/day, the amount proven to mediate cardiovascular benefits in the COSMOS trial. Flavanol intake was objectively evaluated using two validated and complementary biomarkers, 5-(3□,4□-dihydroxyphenyl)-γ-valerolactone metabolites (gVLM B ) and structurally related (–)-epicatechin metabolites (SREM B ), in two geographically distinct studies: COSMOS (US; n=6,509) and EPIC-Norfolk (UK; n=24,154). The results showed that higher fruit and vegetable intakes and diet quality (assessed via the alternative healthy eating index–aHEI) were associated with increased flavanol intake in COSMOS. Nevertheless, fewer than 25% of participants meeting dietary guidelines achieved an estimated flavanol intake of ≥500 mg/day. Similar findings were observed in EPIC-Norfolk as well as through flavanol intake simulations considering fruits and vegetables commonly consumed in the US diet. In conclusion, adherence to existing dietary guidelines does not yield flavanol intake levels comparable to those shown to provide cardiovascular benefits in COSMOS. Thus, specific dietary reference values for flavanols may still be necessary if aiming to increase the intake of these dietary compounds. Graphical abstract

  PublisherOA PDFDOI

• Examining widely held propositions on human dietary protein needs and benefits: a critical review of the science that shapes both the data and our understanding of an essential macronutrient

  Figshare · 2026-05-08

  articleOpen access

  The essentiality of protein in the human diet is unequivocal. Yet researchers, clinicians, and lay people often believe numerous propositions about dietary protein despite insufficient supporting or refuting data in some instances. To address this disconnect, and to “pressure-test” current beliefs about dietary protein, the Indiana University School of Public Health-Bloomington convened a workshop in February 2025 titled “<i>Human Dietary Protein Needs and Benefits: A Critical Assessment of Postulated Propositions.”</i> More than 20 international experts discussed (1) methodologic issues affecting data acquisition and interpretation; (2) “optimal” dietary protein intakes and effects on muscle protein synthesis rates, muscle protein accretion, muscle growth, and muscle repair; (3) protein needs during weight loss; (4) acute protein intake thresholds above and below which protein is no longer related to anabolism; and (5) dietary protein intakes above which protein may be detrimental to health. The experts rated each proposition on a scale from “<i>existing evidence strongly supports the proposition</i>” to “<i>existing evidence seems sufficient to rule out the viability of the proposition.</i>” In most instances, the experts believed additional research was warranted. For many propositions the research base was insufficient in terms of quality (rigor), quantity (sample size, study duration), or pertinence (e.g., use of surrogate markers).

  PublisherDOI

• Reflection Spectroscopy Skin Carotenoids Correlate with Serum Carotenoids in School-Aged Children

  Journal of Nutrition · 2026-02-11

  articleOpen access

  BACKGROUND: Serum carotenoids are thought to reflect higher consumption of fruits and vegetables. However, venous blood draws are invasive and not suitable for pediatric populations. Reflection spectroscopy (RS) offers a noninvasive alternative for measuring carotenoids in the skin; however, the relationship between RS-assessed skin carotenoids and serum carotenoids in children remains understudied. OBJECTIVES: This study aimed to test the hypothesis that RS-assessed skin carotenoids would significantly correlate with serum and dietary carotenoids in children. METHODS: This was a cross-sectional study among children (n = 51, 11.0 ± 1.9 y). Serum carotenoids were quantified using high-performance liquid chromatography. Skin carotenoids were assessed using the Veggie Meter, a pressure-mediated RS device. Dietary carotenoids were measured via 7-d food diaries and analyzed using the Nutrition Data Systems for Research software. Height and weight were measured to calculate the BMI percentile. Log transformation was applied to all carotenoid variables to address right-skewness. Pearson's partial correlations were conducted, adjusting for age, sex, and BMI percentile. Benjamini-Hochberg false discovery rate (FDR) correction was applied for multiple comparisons. RESULTS: Most participants (76%) had a normal BMI percentile for age and sex. Skin carotenoids significantly correlated with serum lycopene (r = 0.31, P = 0.034), β-cryptoxanthin (r = 0.49, P < 0.001), β-carotene (r = 0.75, P < 0.001), lutein (r = 0.45, P = 0.002), zeaxanthin (r = 0.36, P = 0.013), and total carotenoids (r = 0.65, P < 0.001). Skin carotenoids were significantly correlated with several dietary carotenoids, including β-carotene (r = 0.48, P = 0.0095), α-carotene (r = 0.38, P = 0.041), lutein/zeaxanthin (r = 0.37, P = 0.041), and dark green vegetable intake (r = 0.43, P = 0.033). Dietary and serum carotenoids were not significantly correlated with each other after FDR correction. CONCLUSIONS: RS-assessed skin carotenoids demonstrated robust correlations with serum carotenoids, supporting their utility as a noninvasive biomarker of carotenoid status in school-aged children.

  PublisherDOI

• The overlooked impact of background diet and adherence in nutrition trials

  Food & Function · 2025-01-01 · 2 citations

  articleOpen access

  biomarker-based analyses: total cardiovascular disease (CVD) events 0.83 (0.65; 1.07); 0.79 (0.59; 1.05); 0.65 (0.47; 0.89) - CVD mortality 0.53 (0.29; 0.96); 0.51 (0.23; 1.14); 0.44 (0.20; 0.97) - all-cause mortality 0.81 (0.61; 1.08); 0.69 (0.45; 1.05); 0.54 (0.37; 0.80) -- major CVD events 0.75 (0.55; 1.02); 0.62 (0.43; 0.91); 0.48 (0.31; 0.74). These results highlight the importance of taking background diet and adherence into consideration in RCTN to obtain more reliable estimates of outcomes through nutritional biomarker-based analyses.

  PublisherOA PDFDOI

• Polyunsaturated Fatty Acid Concentrations Are Reduced in the Cerebral Cortex of Mice When Fed an Alpha-Tocopherol Deficient Diet

  Current Developments in Nutrition · 2025-05-01

  articleOpen accessSenior author
  PublisherDOI

• Vascular Roads to a Healthier Brain: Lutein Moderates the Influence of Arterial Stiffness on Cognitive Function

  Journal of Nutrition · 2025-09-03 · 3 citations

  articleOpen access
  PublisherOA PDFDOI

Recent grants

• NIH Grant R03CA112649

  NIH · $144k · 2008

• NIH Grant R01CA125384

  NIH · $1.4M · 2013

Frequent coauthors

• Steven K. Clinton

  The Ohio State University

  118 shared

• William D. O’Brien

  University of Illinois Urbana-Champaign

  75 shared

• Johanna T. Dwyer

  Office of Dietary Supplements

  73 shared

• Douglas A. Balentine

  Center for Food Safety and Applied Nutrition

  68 shared

• Mário G. Ferruzzi

  Arkansas Children's Nutrition Center

  68 shared

• Matthew J. Kuchan

  Abbott (United Kingdom)

  68 shared

• Catherine Kwik‐Uribe

  Mars (United States)

  68 shared

• P. Courtney Gaine

  66 shared

Labs

• John Erdman LabPI