Browsing by Author "Wardenaar, F.C."

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The association between gastrointestinal injury, complaints, and food intake in 60-km ultramarathon runners.
Venrooij, N.F.J. van ; Wardenaar, F.C. ; Hoogervorst, D. ; Senden, J.M.G. ; Dijk, J.W. van ; Jonvik, K.L.
2022, Article / Letter to editor (Applied Physiology, Nutrition, and Metabolism, vol. 47, iss. 5, (2022), pp. 547-554)We aimed to assess the association between gastrointestinal (GI) injury, complaints, and food intake in 60-km ultramarathon runners. Thirty-three ultramarathon runners provided pre- and post-race blood samples for assessment of GI injury by intestinal fatty-acid binding protein (I-FABP), and inflammatory response by interleukin (IL)-6, IL-8, tumour necrosis factor alpha (TNF-α), and C-reactive protein (CRP). GI complaints and nutritional intake were reported by a post-race questionnaire. GI complaints were reported by 73% of the runners, of which 20% reported 1 or 2 severe complaints. IL-6, IL8, TNF-α, and CRP increased significantly from pre- to post-race (P < 0.001 for all biomarkers), while I-FABP did not (1375 [IQR: 1264-2073] to 1726 [IQR: 985-3287] pg/mL; P = 0.330). The 'GI complaints score', as the integral of the number and severity of GI complaints, did not correlate with ΔI-FABP (rs: -0.050, P = 0.790) or energy intake (rs: 0.211, P = 0.260). However, there was a significant negative correlation between energy intake and ΔI-FABP (rs: -0.388, P = 0.031). In conclusion, GI complaints were neither associated with food intake nor GI injury as assessed by plasma I-FABP response. Energy intake, however, was inversely related to the I-FABP response to exercise. This finding suggests that substantial energy intakes during exercise may prevent exercise-induced GI injury as assessed by the I-FABP response. Novelty: No association between gastrointestinal complaints and gastrointestinal injury (I-FABP response) or food intake was present. There was an inverse correlation between energy intake and plasma I-FABP response, suggesting that higher energy intakes may prevent gastrointestinal injury as assessed by the I-FABP response.
Protein Supplementation Does Not Further Augment Physiological Adaptations to Prolonged Endurance Exercise Training
Jonvik, K.L. ; Paulussen, K.J.M. ; Danen, S.L. ; Horstman, A.M. ; Wardenaar, F.C. ; Loon, L.J.C. van ; Dijk, J.W. van
2019, Article / Letter to editor (Medicine and Science in Sports and Exercise, vol. 51, iss. 6, (2019), pp. 791)
Protein Supplementation Does Not Augment Adaptations to Endurance Exercise Training
Jonvik, K.L. ; Paulussen, K.J.M. ; Danen, S.L. ; Ceelen, I.J.M. ; Horstman, A.M. ; Wardenaar, F.C. ; Loon, L.J.C. van ; Dijk, J.W. van
2019, Article / Letter to editor (Medicine and Science in Sports and Exercise, vol. 51, iss. 10, (2019), pp. 2041-2049)
Habitual Dietary Nitrate Intake in Highly Trained Athletes.
Jonvik, K.L. ; Nyakayiru, J. ; Dijk, J.W. van ; Wardenaar, F.C. ; Loon, L.J.C. van ; Verdijk, L.B.
2017, Article / Letter to editor (International Journal of Sport Nutrition and Exercise Metabolism, vol. 27, iss. 2, (2017), pp. 148-157)Although beetroot juice, as a nitrate carrier, is a popular ergogenic supplement among athletes, nitrate is consumed through the regular diet as well. We aimed to assess the habitual dietary nitrate intake and identify the main contributing food sources in a large group of highly trained athletes. Dutch highly trained athletes (226 women and 327 men) completed 2-4 web-based 24-hr dietary recalls and questionnaires within a 2- to 4-week period. The nitrate content of food products and food groups was determined systematically based on values found in regulatory reports and scientific literature. These were then used to calculate each athlete's dietary nitrate intake from the web-based recalls. The median[IQR] habitual nitrate intake was 106[75-170] mg/d (range 19-525 mg/d). Nitrate intake correlated with energy intake (ρ = 0.28, p < .001), and strongly correlated with vegetable intake (ρ = 0.78, p < .001). In accordance, most of the dietary nitrate was consumed through vegetables, potatoes and fruit, accounting for 74% of total nitrate intake, with lettuce and spinach contributing most. When corrected for energy intake, nitrate intake was substantially higher in female vs male athletes (12.8[9.2-20.0] vs 9.4[6.2-13.8] mg/MJ; p < .001). This difference was attributed to the higher vegetable intake in female vs male athletes (150[88-236] vs 114[61-183] g/d; p < .001). In conclusion, median daily intake of dietary nitrate in highly trained athletes was 106 mg, with large interindividual variation. Dietary nitrate intake was strongly associated with the intake of vegetables. Increasing the intake of nitrate-rich vegetables in the diet might serve as an alternative strategy for nitrate supplementation.
Nutritional Supplement Use by Dutch Elite and Sub-Elite Athletes: Does Receiving Dietary Counseling Make a Difference?
Wardenaar, F.C. ; Ceelen, I.J.M. ; Dijk, J.W. van ; Hangelbroek, R.W. ; Roy, L. Van ; Pouw, B. Van der ; Vries, JHM de ; Mensink, M. ; Witkamp, R.F.
2017, Article / Letter to editor (International Journal of Sport Nutrition and Exercise Metabolism, vol. 27, iss. 1, (2017), pp. 32-42)The use of nutritional supplements is highly prevalent among athletes. In this cross-sectional study, we assessed the prevalence of nutritional supplement use by a large group of Dutch competitive athletes in relation to dietary counseling. A total of 778 athletes (407 males and 371 females) completed a web-based questionnaire about the use of nutritional supplements. Log-binomial regression models were applied to estimate crude and adjusted prevalence ratios (PR) for the use of individual nutritional supplements in athletes receiving dietary counseling as compared with athletes not receiving dietary counseling. Of the athletes, 97.2% had used nutritional supplements at some time during their sports career, whereas 84.7% indicated having used supplements during the last 4 weeks. The top ranked supplements used over the last 4 weeks from dietary supplements, sport nutrition products and ergogenic supplements were multivitamin and mineral preparations (42.9%), isotonic sports drinks (44.1%) and caffeine (13.0%). After adjustment for elite status, age, and weekly exercise duration, dietary counseling was associated with a higher prevalence of the use of vitamin D, recovery drinks, energy bars, isotonic drinks with protein, dextrose, beta-alanine, and sodium bicarbonate. In contrast, dietary counseling was inversely associated with the use of combivitamins, calcium, vitamin E, vitamin B2, retinol, energy drinks and BCAA and other amino acids. In conclusion, almost all athletes had used nutritional supplements at some time during their athletic career. Receiving dietary counseling seemed to result in better-informed choices with respect to the use of nutritional supplements related to performance, recovery, and health.

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