In the last decade, the number of full-time registered dietitians (RDs) serving intercollegiate athletes in the United States has more than quadrupled. However, many student athletes may be at increased risk of nutrition-related problems that impact physical and academic performance, which include inadequate macronutrients, inadequate micronutrients, and excessive macronutrients. This narrative review reports the current literature to date on nutrition-related knowledge in collegiate athletes and the impact of sports RDs on student athletes’ nutrition knowledge and behaviors. To date, only observational and quasi-experimental studies have been published with regard to changes in nutrition knowledge and behaviors in NCAA athletes. While these studies report benefits of the RD as a member of the interdisciplinary student athlete support team, more well-designed randomized control trials are warranted to determine benefits related to health outcomes and sport-specific performance outcomes.

Green leafy vegetables (GLV) may reduce the risk of red meat (RM)-induced colonic DNA damage and colorectal cancer (CRC). We previously reported the primary outcomes (feasibility) of a 12-week randomized controlled crossover trial in adults with habitual high RM and low GLV intake with body mass index (BMI) > 30 kg/m² (NCT03582306). Herein, our objective was to report a priori secondary outcomes. Participants were recruited and enrolled in 2018, stratified by gender, and randomized to two arms: immediate intervention group (IG, n = 26) or delayed intervention group (DG, n = 24). During the 4 week intervention period, participants were provided with frozen GLV and counseled to consume 1 cooked cup equivalent daily. Participants consumed their normal diet for the remaining 8 weeks. At each of four study visits, anthropometrics, stool, and blood were taken. Overall, plasma Vitamin K1 (0.50 ± 1.18 ng/mL, p < 0.001) increased, while circulating 8OHdG (−8.52 ± 19.05 ng/mL, p < 0.001), fecal 8OHdG (−6.78 ± 34.86 ng/mL, p < 0.001), and TNFα (−16.95 ± 60.82 pg/mL, p < 0.001) decreased during the GLV intervention compared to control periods. Alpha diversity of fecal microbiota and relative abundance of major taxa did not differ systematically across study periods. Further investigation of the effects of increased GLV intake on CRC risk is warranted.

Preclinical and observational research suggests green leafy vegetables (GLVs) may reduce the risk of red meat (RM)-induced colonic DNA damage and colon cancer (CC). We sought to determine the feasibility of a high GLV dietary intervention in adults with an increased risk of CC (NCT03582306) via a 12-week randomized controlled crossover trial. Participants were randomized to immediate or delayed (post-4-week washout) intervention groups. During the 4-week intervention period, participants were given frozen GLVs and counseled to consume one cooked cup equivalent daily. The primary outcomes were: accrual—recruiting 50 adults in 9 months; retention—retaining 80% of participants at completion; and adherence—meeting GLV intake goals on 90% of days. Adherence data were collected twice weekly and 24-h dietary recalls at each time point provided nutrient and food group measures. The Food Acceptability Questionnaire (FAQ) was completed to determine acceptability. On each of the four study visits, anthropometrics, stool, saliva, and blood were obtained. Fifty adults were recruited in 44 days. Participants were 48 ± 13 years of age, 62% female, and 80% Caucasian, with an average BMI at screening of 35.9 ± 5.1. Forty-eight (96%) participants were retained and completed the study. During the intervention phase, participants consumed GLVs on 88.8% of days; the adherence goal of one cup was met on 73.2% of days. Dietary recall-derived Vitamin K and GLVs significantly increased for all participants during the intervention periods. Overall satisfaction did not differ between intervention and control periods (p = 0.214). This feasibility trial achieved accrual, retention and acceptability goals, but fell slightly short of the benchmark for adherence. The analysis of biological specimens will determine the effects of GLVs on gut microbiota, oxidative DNA damage, and inflammatory cytokines.

Background: Zonulin is observed in animal models to regulate intestinal permeability and influenced by dietary intake, gut microbiota, and inflammation. We conducted a secondary analysis of a randomized controlled crossover trial (NCT03582306) in individuals with a BMI greater than 30 kg/m² and high habitual red meat intake and low habitual green leafy vegetable (GLV) intake. Methods: Participants were provided with frozen GLV during the first or last four weeks (immediate or delayed intervention) of the twelve-week trial. Biological and anthropometric measures were taken at the beginning and at each four-week interval. A subset of 20 participants was selected for this secondary analysis of the intestinal permeability and inflammation-related biomarkers: serum and fecal zonulin; serum lipopolysaccharide binding protein (LBP), Alpha-1-acid glycoprotein 1 (ORM-1), tumor necrosis factor α (TNFα), interleukin-6 (IL-6), and C-reactive protein; 8-hydroxy-2'-deoxyguanosine (8OHdG) and plasma Vitamin K1 as a marker of protocol adherence. Nutrient and food group intake from two-24-h dietary recalls collected at each time point were assessed. Fecal microbiota was measured by 16 s rRNA PCR sequencing. Changes in biological markers, dietary factors, and microbial taxa were assessed with Wilcoxon Sign Ranks Tests. Exploratory analyses of the relationship between changes in outcome variables were conducted with Spearman correlations. Results: No changes in serum and fecal zonulin and serum LBP were observed. Plasma Vitamin K (p = 0.005) increased, while plasma 8OHdG (p = 0.023) decreased during the intervention compared to the control. The only dietary factors that changed significantly were increases during intervention in Vitamin K and Dark GLV (p < 0.001 for both) compared to control. Fecal microbiota did not change significantly across all times points; however, change in serum zonulin was associated with change in Proteobacteria (ρ = − 0.867, p = 0.001) in females and Bifidobacterium (ρ = − 0.838, p = 0.009) and Bacteroidaceae (ρ = 0.871, p = 0.005) in men. Conclusions: A high GLV dietary intervention increased serum zonulin levels and had no effect on fecal zonulin. Lack of concordance between several inflammation-associated biomarkers and zonulin corroborate recent reports of limited utility of zonulin in obese adults free of lower gastrointestinal disease. Trial Registration information: https://clinicaltrials.gov/ct2/show/NCT03582306 (NCT03582306) registered on 07/11/2018.

Background/Objectives: Obesity is linked to a higher risk of cognitive impairment. The objective of this single blind randomized trial was to evaluate the impact of dark sweet cherry (DSC) intake on cognitive function in obese adults. Methods: Participants (body mass index (BMI): 30–40 kg/m², >18 years, without chronic diseases and/or antibiotic use) consumed 200 mL of DSC drink with 3 g of cherry powder (n = 19) or an isocaloric placebo drink (n = 21) twice daily for 30 days. Cognitive function was assessed at Day 1 (D1) and Day 30 (D30) using standardized cognitive tests and the NeuroTracker (NT) 3D training program. Blood biomarkers related to cognitive health (neurotensin, substance p, and oxytocin) and circadian rhythm (melatonin and cortisol) were assessed at D1 and D30 using a Luminex multiplex bead-based immunoassay. Results: DSC supplementation significantly improved working memory and concentration, as indicated by higher scores in the digit span forward (DSF, p = 0.006) and backward (DSB, p = 0.01) tests. However, processing speed, sustained attention, and visual spatial skills, assessed through the trail making (TMT) and digit symbol substitution (DSST) tests, as well as visual cognitive performance (VCP) evaluated by the NT program, showed no significant differences between groups. Neurotensin, associated with cognitive deficits, increased in both cherry and placebo groups but was significant only in the placebo group (p = 0.007). Similarly, melatonin increased in both groups, reaching significance only in the placebo group (p = 0.02), and it correlated positively with IFNγ, suggesting a compensatory response to inflammation. Conclusions: These findings suggest DSC supplementation may enhance specific cognitive functions in obese adults. Further clinical trials are needed to confirm these results.

Iron deficiency disproportionately affects young adult females and may impair cognitive performance. While supplementation has been studied, dietary interventions using iron-rich whole foods, particularly beef, remain underexplored. Beef provides highly bioavailable heme iron along with vitamin B12, zinc, choline, and creatine, nutrients implicated in neurotransmission, myelination, and cortical function. This review synthesizes evidence on beef consumption, iron status, and cognition that demonstrate improvements in attention, memory, and visuospatial processing in young adult females. We examine intervention doses, methodological differences, and limitations in current iron deficiency diagnostic thresholds. Despite mixed findings across studies, beef emerges as a feasible dietary strategy to support cognitive function in young adult females. Standardized cognitive assessments, longer interventions, and comparative analyses of alternative protein sources are needed to clarify the long-term cognitive benefits of beef. Considerations regarding red meat intake, sustainability, and evolving dietary patterns remain important. This review provides an evaluation of dietary iron from beef as a modifiable factor in cognitive performance. It also offers guidance for future research and raises concerns for balancing nutritional adequacy, health, and environmental considerations.