Food habits in athletes (PDF)

PDF hosted at the Radboud Repository of the Radboud University Nijmegen The following full text is a publisher's version. For additional information about this publication click this link. http://hdl.handle.net/2066/114091 Please be advised that this information was generated on 2022-06-27 and may be subject to change.  • Food habits in athletes A.MJ. van Erp - Baarl Ш ^   Food habits in athletes Een wetenschappelijke proeve op het gebied van de medische wetenschappen PROEFSCHRIFT ter verkrijging van de graad van doctor aan de Katholieke Universiteit Nijmegen, volgens het besluit van het College van Decanen in het openbaar te verdedigen op dinsdag 16 juni 1992 des middags te 12.45 uur precies door Agnes Maria Josepha van Erp-Baart geboren op 3 januari 1945 te Hulst  Promotores prof dr. ir W.H M. Sans, Rijksuniversiteit Limburg prof dr. R.A. Bmkhorst CIP-GEGEVENS KONINKI IJKE BIBLIOTHEEK. DEN HAAG Егр-Влагі, Agnes Mana Joscpha van Food habits in athletes / Agnes Maria Joscpha van Frp-Baarl — [si s n ] -III Proelschnfl Nijmegen — Met lit opg — Met samenvatting in het Nederlands ISBN 90-9004')26-0 Trefw sport en voeding Cover design: Martin van der Vaart The studies reported in this thesis were financially supported by the Netherlands Sporttolalisator Foundation Financial support from the Netherlands Heart Foundation and the Diabetes Fonds Nederland for the publication of this thesis is gratefully acknowledged.  Vcriv LcLM.b^Jr  Woord vooraf AI terugkijkend realiseer ik mij, dat de weg naar dit resultaat lang is geweest. Het is onmogelijk om alle mensen te bedanken, met wie ik heb samengewerkt, maar enkelen wil ik toch met name noemen. Als eerste Zr. Benedicto Nieuwhof. Als hoofd van de diëtetiekopleiding zei zij toen al:"Je moet maar in het onderzoek." Een raad, die ik toen nog niet kon plaatsen, maar die gaandeweg bewaarheid is. Het zou echter nog even op zich laten wachten, voordat ik die raad kon opvolgen. Een telefoontje van het pas gestarte GVO project kwam als een geschenk uit de hemel. De sfeer waarin daar werd samengewerkt en de erkenning van ieders bijdrage waren een verademing. In die periode heb ik o.a. Wim en Hans leren kennen. Wim, ik heb toentertijd nooit kunnen vermoeden dat jij mijn promotor zou worden. Zonder jouw steun en stimulans was het nooit zover gekomen. Hans, ik ben blij dat jij nu mijn paranimf wilt zijn. Vervolgens kwam er bij de werkgroep inspanningsfysiologie de mogelijkheid onderzoek te doen naar de voeding bij sporters. In eerste instantie gedurende 8 uur per weck, maar dank zij vereende krachten werd het na verloop van tijd uitgebreid tot 3 dagen per weck. Daar heb ik met vallen en opstaan het doen van onderzoek geleerd. Rob, ik geloof, dat ik het je niet altijd even gemakkelijk heb gemaakt. Jan, zonder jouw enthousiasme en Guus, Jos, Frans , Willem, zonder jullie morele steun was me dit ook nooit gelukt. Tijdens dit onderzoek hebben een aantal stagiaires meegeholpen met het onderzoek. Lily en Harrie, als LUW-studenten hebben jullie een wezelijke bijdrage aan mijn onderzoek geleverd. Van de studenten diëtetiek wil ik met name Jeanette en Miron noemen. Jullie kwamen met het idee om onderzoek naar diabetes en sport te doen. Van alle sportartsen is er een, die ik wil noemen. Peter, weetje nog in Bulgarije! Toen kwam het moment waarop sporlfysiologie ter discussie kwam te staan, en door de nood gedwongen heb ik mijn bakens verzet. Vanaf 1988 ben ik gaan werken binnen het Instituut voor Toxicologie en Voeding TNO. Daar ben ik nog steeds indirect betrokken bij het voedselconsumptieonderzoek. Allereerst als beheerder en later als coördinator van het Nederlands Voedingsstoffenbestand. Alwine, Corine en Ann, we hebben heel wat gefoeterd en afgelachen. Ik hoop dat we dat nog vaak zullen doen. In latere instantie kreeg ik de kans om de leiding van de groep diëtetiek op mij te nemen. Susanne, Hennie en Petra, ik hoop dat ik nog lang op dezelfde plezierige manier met jullie mag samenwerken. Theo, jou dank ik voor jouw stimulans en voor de gelegenheid die je mij bij TNO-Voeding geboden hebt dit onderzoek in de vorm van een proefschrift af te ronden. Tot slot dank ik alle atleten, die trouw hun voedingsdagboekjes hebben ingevuld. Zonder hun medewerking was dit onderzoek nooit mogelijk geweest.  Contents Abbreviations 2 1. Introduction 3 2. Nationwide survey on nutritional habits in elite athletes. Part 1: energy, carbohydrate, protein, and fat intake. 8 3. Nationwide survey on nutritional habits in elite athletes. Part 2: mineral and vitamin intake. 25 4. Magnesium and zinc intake of 25 groups of elite athletes. 39 5. Comparison of habitual dietary fat intake with plasma lipids in active sportsmen. 49 6. Energy intake and energy expenditure in top female gymnasts. 58 7. Reproducibility of urinary 3-methylhistidine excretion in human subjects consuming freely selected diets. 64 8. Food intake and dietary adaptations in intensively exercising insulin-dependent diabetes mellitus patients. 79 9. General discussion and conclusions 92 Summary 100 Samenvatting 103 Curriculum Vitae 107  Abbreviations вм BW сно CPK CR cv ORDA E ЕЕ EI En% F FFM FM Hb Hb Al HDL HR HRM HPLC Ht IDDM LDL MJ Ρ PI RDA RMR S Τ VOo-max 3-MH body mass body weight carbohydrate creatine phosphate kinase creatinine coefficient of variation dutch recommended daily allowance endurance energy expenditure energy intake relative contribution to total energy intake fat fat free mass fat mass haemoglobin glycosylated haemoglobin high density lipoprotein heart rate heart rate memory high performance liquid chromatography haematocrit reading insulin dependant diabetes mellitus low density lipoprotein megajoule protein protein intake recommended daily allowance resting metabolic rate strength team sport aerobic power 3-methylhistidine 2  CHAPTER 1 Introduction Nutrition has attracted considerable attention in man's attempt to enhance physical performance. Almost every article or book about nutrition and sport starts with the conclusion that numerous athletes believe that special foods are necessary for optimal performance and that usual food intake is not sufficient to meet the athletes' physiological needs (1, 2, 16, 17, 18, 20). For this reason it is not surprising to see that food supplements are taken and a lot of special foods are regarded as the best for athletic performance (15, 19). Nutrition is mostly studied from the physiological point of view. From an abundance of studies it is well known that food intake and dietary manipulations arc of great importance for the enhancement of athletic performance. Basic change in food intake is related to the increasing need of energy, but it depends on the intensity, frequency and duration of the training or contest (2) to what extent total daily energy expenditure will increase. Total energy expenditure depends also on whether the exercise serves as a substitute for daily activities or is additional to it. With regard to the nutrients another physiological fact is the preference in substrate utilization in relation to performance and subsequently the importance of macronutrient intake (8). Already in the 1930s it was found that carbohydrate intake is important for physical performance at a high level of intensity and long duration. After the introduction of the muscle biopsy technique it became clear from the measurements of energy substrate flux that at exercise intensities of more than 70% of the VOo-max the shift towards CHO oxidation becomes increasingly important. At an intensity level of over 95% glucose serves as the only fuel for the exercising muscle. Recommendations are therefore made to increase carbohydrate intake to at least 55% of total energy intake (8). The second main fuel for muscle metabolism is fat (5). From a practical standpoint the lipid stores in the body are unlimited: 1 kg of adipose tissue is sufficient to supply energy for 10-20 h of exercise. However it should be mentioned that the intensity in which the exercise can be performed is limited. Up to 50% of VO^-max the fuel is mainly provided by the oxidation of fatty acids. At higher intensities carbohydrates become increasingly important (2). 3  Although the value of increased dietary protein as a determinant of athletic performance has been debated for many years, it is now generally accepted that protein is important for the actual athletic performance. A sufficient protein intake is important for the building of muscle mass and the recovery of damaged tissue. It is generally known that an increased need is found in groups like children, adolescents and pregnant women. If an athlete starts with regular physical training muscle mass will be built up. Nitrogen balance studies, urinary urea excretion studies, urinary 3-methyl histidine studies and metabolic tracer studies have shown that a protein intake of about twice the RDA (0.8 g/kg BM) might be necessary for the maintenance of the nitrogen balance of intensively exercising athletes (11, 18, 19). Another reason for an increased need for protein arises when total energy intake is lower than the energy actually expended. Brouns (6) has found that if energy intake is too low and repeated heavy sustained exercise is performed an intake of 1.7 g/kg BM causes a negative nitrogen balance. Lemon (13) has demonstrated that protein serves as an energy substrate when the glycogen stores are depleted and exercise is continued at a high intensity level. He calculated from urea secretion in sweat that a protein intake of 2 g/kg BM is probably sufficient to keep body protein in balance under these circumstances. On the other hand, if we look at the recommendations for protein intake in relation to athletic performance intakes of 4 to 5 g/kg BM are often advised. It seems, however, that these recommendations are often based on the protein intake usually found in intensively exercising strength athletes. Further investigations are necessary to establish reliable recommendations regarding optimal protein intake for various groups of athletes. In these studies the energy balance must be considered as well. The subject of vitamin and mineral supplements is perhaps the most intriguing one for athletes. Numerous studies have dealt with this problem (3, 4, 9, 14). The available evidence for vitamin and mineral requirements shows that there is no justification for the opinion that the general recommendations should be higher. Still supplementation is common practice. The main reason for doing so is probably the uncertainty of the athlete as to whether the nutritional value of his/her food intake is adequate. Summerizing this general information about macro- and micronutrient intake in relation to athletic performance one can conclude that nutrition has become an important aspect of todays ability to compete at an international top-level. Besides talent, training and material one has to take care of his/her nutrition in order to have optimal results. However for adequate nutritional advice information about habitual food intake of athletes performing at top level is needed. Until now a systematic approach to obtain data about food intake of elite athletes was scarce. Analysing these data one can learn about the nutritional needs under these circumstances and the problems athletes are faced to. Therefore we decided to start this project on food 4  habits of different groups of elite athletes in order to analyse the nutrient intake and meal pattern. From the health point of view it is important to obtain insight into the health risks incurred by the athlete. It is generally known that endurance-trained athletes tend to have higher HDL-cholesterol levels than the general population, a factor associated with a decreased risk for atherosclerosis. The diet of strength athletes is known to containing an abundance of protein. This normally coincides with a high intake of saturated fatty acids and cholesterol, known risk factors for the development of cardiovascular disease. The question may arise whether strength athletes have higher risks for the development of cardiovascular disease because of these food practices. As part of an experimental study on dietary intervention during strength training, we were able to evaluate the food intake and plasma lipid levels of different groups of active sportsmen. During the years that the actual food intake was studied many athletes came for advice with respect to weight maintenance or weight loss. In such types of sports as bodybuilding, rowing, weight-lifting, gymnastics and judo one has to compete in certain weight categories, or a minimum body and/or fat mass is required for optimal appearance and performance. Weight reduction is not a problem if time is available, and if the excess of weight is caused by an excess of fat mass. However in most cases time is very limited and body fat mass is already very low (9). Nutritionists often have to navigate between Scylla and Charybdis. One option is weight reduction with a concomitant decrease in functional muscle mass and thus the hazard of decreased performance. The other choice is to advice the athlete to take his weight for granted and to compete in another weight class. We have started to tackle this weight dilemma by addressing some aspects of this complex feature. First, we have assessed actual energy expenditure in female top gymnasts. This special group is often faced with weight problems, and sometimes it seems virtually impossible to decrease food intake. Secondly, the use of 3- methylhistidine (3MH) as an indicator of muscle protein breakdown has been studied in a group of physically active men and women. The question is whether 3 MH can be used as an indicator for muscle protein breakdown. Until now little information on the reproducibility over days was available (21). However weight reduction is usually spread over weeks. Special attention has therefore been given to the reproducibility over a longer period of time. A group of athletes of special interest are insulin-dependent diabetes mellitus (IDDM) athletes. Because of the lack of insulin response the substrate flow to the muscle is impaired. On the other hand, it is well recognized that exercise improves insulin sensitivity. Therefore IDDM patients are encouraged to take regular exercise to decrease the daily dose of insulin. In some cases diabetics decide to compete at a high athletic level. They are than faced with the problem how to adapt their nutritional habits to a very intensive training regime. Information relevant to this 5  category is scanty and the athletes still have to learn by trial and error (10, 11, 12) Therefore a nationwide study of intensively exercising IDDM athletes has been carried out Observation of the food habits of adult trained athletes could produce some information on how they deal with this complex problem In conclusion, for adequate nutritional advice basic information on actual food intake of intensively exercising athletes is needed Therefore in Chapter 2 the results on energy and macronutnent intake of 25 groups of elite athletes are presented Chapter 3 answers the question whether supplements are needed to have adequate intakes of calcium, iron and vitamins In Chapter 4 the intake of magnesium and ¿ine is discussed A comparison between habitual fat intake and plasma serum levels in active sportsmen is made in Chapter 5 In Chapter 6 the results on energy expenditure in female top gymnasts are given The reproducibility study of urinary 3-methylhistidine excretion is discussed in Chapter 7 Food intake and dietary adaptations in IDDM athletes are presented in Chapter 8. Finally in Chapter 9 the several aspects elaborated in the previous chapters are integrated Emphasis is laid on the practical consequences of proper nutritional advice Although the athletes need energy and nutrients (protein, vitamins, minerals) they still eat natural food items and not single nutrients in pills, powders, etc It is the basics of nutrition that are essential to the well being of athletes However, this aspect is often underestimated by exercise physiologists and manufacturers of special sport food products References 1 Anonymous Advice conterning sport food supplements (dutch) NelhJNutrAS 73-97,1987 2 Aslrand PO К Rodahl Textbook of work physiology Nutrition and physical performance McGraw Hill Book Company, pp 483-521, 1977 3 Beek EJ van der Vitamins and endurance training Food for running or faddism claims Sports Med 2, 175-197, 1985 4 Belko AZ Vitamins and exercise-an update Med Sci Sports Exerc 19 5, S191 S196, 1987 5 Bjorntorp Ρ Importance of fat as a support nutrient for energy metabolism of athletes J Sports Sc 9,71 76. 1991 6 Brouns F Food and fluid related aspects in highly trained athletes Sportwelenschappelijke onderzoekingen 15 Uitgeverij De Vrieseborch, Haarlem, 1988 7 Brownell KD Steen SN, Wilmore JH Weight regulation practices in athletes analysis of metabolic effects Med Sa Sports Exerc 19, 546-556, 1987 8 Costili DL Carbohydrate for exercise, dietary demands for oplimal performance Int J Sports Med 9. 1-18. 1988 9 DokkumWvan The need for minerals and trace elements in athletes (dutch) In WHM Sans, M Stasse Wolthuis (eds) Sport en Voeding Samson Stafleu, Alphen aan de Rijn 1988 10 Franz MJ Exercise and the management of diabetes mellitus J Am Diet Assoc 87. 872-881, 1987 11 Horton ES Metabolic aspects of exercise and weight reduction Med Sci Sports Exerc 18, 10 18, 1985 6  12 Kemmer FW, M Berger Exercise and diabetes mellitus. Physical activity as a part of daily life and its role in the treatment of diabetic patients Med Sa Sports Exerc 4, 77-88. 1983 13 LemonPR Protein and exercise update 1987 Med Sci Sports Exerc 9. 5, S179-S190, 1987 14 McDonald R, Keen CL Iron, magnesium and/mc nutrition and athletic performance Sports Med 5, 171-184, 1988 15 Nieman DC, JR Gates, JV Butler et al Supplementation patterns in marathon runners J Am Diet Assoc 89. 1615-19. 1989 16 Panel summary statements First international conference on nutrition and fitness Am J Clin Nutr 49. 5,5931-937, 1989 17. Position of the American Dietetic Association Nutrition for physical fitness and athletic performance for adults J Am Diet Assoc 87. 933-939 1987 18 Simopoulos PS Opening address Nutrition and fitness from the first Olympiad in 776 ВС to 393 AD and the concept of positive health Am J Clin Nutr 49, 921-926, 1989 19 Weight LM, Noakes TD, Labadanos D et al Vitamin and mineral status of trained athletes including the effects of supplementation Am J Clin Nutr 47, 186-191, 1988 20 Williams MH Ergogemc aids in Sport, Champaign 111 Human Kinetic Publishers 1983 21 Young VR. Munro Η N N-methylhistidine (3-melhylhistidine) and muscle protein turnover An overview FedProc 37, 2291-2300, 1978  CHAPTER 2 Nationwide survey on nutritional habits in elite athletes. Part I. Energy, carbohydrate, protein, and fat intake A.M.J. van Erp-Baart, W.H.M. Saris, RA. Binkhorst, JA. Vos and J.W.H. Elvers (published in Int J Sports Med 10, S3-S10, 1989) Abstract Information about habitual food intake was systematically obtained from elite endurance, strength, and team sport athletes. The athletes (n = 419) trained at least 1-2 h daily and competed on an international level. A 4- or 7-day food diary was kept. For analysis of the data, a computerized food table was used. Mean energy intake varied from 12.1-24.7 MJ per day for male and 6.8-12.9 MJ per day for female athletes. Protein intake was in agreement with or higher than the Dutch recommendations. Contribution of carbohydrate intake to total energy intake varied from 40-63%. Fat intake tended to meet the criteria for a prudent diet (< 35%). Snacks contributed about 35% to the total energy intake and the bread/cereals and dairy food groups were the most important energy sources. It is concluded that in general there are two major concerns. In those sports in which body composition plays an important role, energy and thus nutrient intake is often marginal. In all groups of athletes intake of carbohydrate is insufficient. Introduction In nutrition many beliefs and misconceptions exist with respect to athletic performance (35, 9, 21, 15). For example in the old days meat was associated with muscle and strength, and until now many athletes believe they need an abundance of protein-rich food to have an optimal performance. In the nutritional sciences recommendations for adequate nutrient intake are available. Also specific information about the best composition of the athletes' diet has become available in the last 2 decades (32, 33, 16). However, beside information about the needs, 8