Dietary patterns with substantial proportions of energy from plant sources have been associated with favorable biomarkers of low-grade inflammation. Less is known of the relation between vegetarian-based dietary patterns and markers of inflammation and immune status. This systematic review and meta-analysis aimed to determine the relation between vegetarian-based dietary patterns and inflammatory and immune markers (C-reactive protein, tumour necrosis factor α, fibrinogen, natural killer cells, leukocytes, lymphocytes, thrombocytes, interleukins, and immunoglobulins). PubMed, Medline, and Cochrane scientific databases were searched to identify relevant studies. Random effects meta-analyses were conducted to assess the weighted mean differences (WMDs) for each outcome variable between vegetarian and non-vegetarian groups. Thirty observational and 10 intervention studies were included in the review. Pooled effects of vegetarian-based dietary patterns were associated with significantly lower concentrations of CRP (WMD: −0.61 mg/L; 95% CI: −0.91, −0.32 mg/L; P = 0.0001), fibrinogen (WMD: −0.22 g/L; 95% CI: −0.41, −0.04 mg/L; P = 0.02), and total leukocyte (WMD: −0.62 × 10³/μL; 95% CI −1.13 × 10³, −0.10 × 10³/μL; P = 0.02) compared with those following non-vegetarian dietary patterns in observational studies. Insufficient data were identified for a meta-analysis of intervention studies. This study provides evidence that vegetarian-based dietary patterns are associated with lowered serum C-reactive protein, fibrinogen, and total leukocyte concentrations. Future research should focus on large-scale intervention trials, contrasting differences in inflammation and immune status and function between vegetarian and non-vegetarian-based populations.

Background: Evaluation of the dietary fat consumption in athletes following vegan diets is scarce. The aim of this study was to explore the intakes, availability, and uptake of physiologically relevant fatty acids into whole blood, and consequently the Omega-3 Index (O3I) of endurance athletes following vegan and omnivorous dietary patterns. Materials: Males aged 18 to 55 years, engaging in ≥ four hours of training/week and following a vegan (>6 months) or omnivorous dietary pattern were eligible to participate. A 7-day food and training diary was collected and an incremental ramp running protocol used to determine peak aerobic capacity. A finger prick blood sample was collected to determine the whole blood fatty acid profile and O3I. Participants were grouped as following a vegan or omnivorous diet matched for age, training volume and peak aerobic capacity. Results: The vegan group (n = 12) consumed significantly less dietary total fat (122.2 g/day vs 84.1 g/day p = 0.007), saturated fat (43.74 g/day vs 18.42 g/day p < 0.0001), monounsaturated fat (49.6 g/day vs 35.64 g/day p = 0.039) and long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) compared to the omnivorous group (n = 8). Between group differences in whole blood fatty acid concentrations were observed including; linoleic, eicosapentaenoic, docosahexaenoic, n-6:n-3 and AA:EPA ratios. O3I in both groups were suboptimal (vegan: 4.13%, omnivorous: 5.40%) in terms of cardiac risk. Conclusion: Male endurance athletes should ensure their dietary LC n-3 PUFA intakes, particularly EPA and DHA fatty acids are sufficient to optimize their O3I.

Background/Objectives: The goals of sports nutrition are to support athletic performance. However, the diet quality of athletes remains poorly understood. This scoping review aims to synthesise the existing body of literature, evaluating the diet quality of adult athletes. Methods: The scoping review was conducted in accordance with guidance from the Joanna Briggs Institute. Database searches were conducted in Medline, Scopus, SPORTDiscus, Web of Science, and EMBASE. Eligible studies were observational, utilised a validated dietary quality assessment tool (diet quality index), and assessed athletes aged 18 to 65 years. Screening was performed independently by two researchers, with any conflicts resolved by a third researcher. Results: The search yielded 1142 articles, of which 18 met the inclusion criteria. Basketball athletes and gymnasts were the most frequently examined groups. Studies were dominated by one gender (n = 7 all males studies, n = 4 only female). Eleven diet quality tools were used, including variations of the Healthy Eating Index (n = 7). Overall diet quality was rated as poor (n = 3 studies), needs improvement (n = 12), or adequate (n = 3). Food groups where intake was suboptimal included wholegrains (n = 8), fruit (n = 5), and dairy intake (n = 3). The intake of protein-rich foods was adequate in n = 9 studies, whilst fat intake was excessive in 4 studies. Conclusions: These findings suggested that the diet quality of athletes is suboptimal and needs improvement in the areas of wholegrain, fruit, and dairy/alternatives intake. The inadequate intake of these food groups and the consumption of excessive fat intake may increase the long-term risk of developing non-communicable diseases and impair short-term performance and recovery. Further exploration is warranted to develop targeted nutrition education and interventions that address these inadequacies.