Food allergies: how to build an athlete’s diet

A food allergy does not forbid playing sports, but it requires more careful nutrition planning: foods that usually provide protein, calcium, iodine or omega-3 fatty acids drop out of the diet. The editorial team looked at how to build a complete diet for an athlete with an allergy without losing either performance or safety.

Allergy, intolerance and ‘fashionable’ restrictions

A food allergy is a reaction of the immune system to a food protein. Most often it is mediated by IgE-class antibodies: within minutes or hours of contact with the allergen, hives, swelling, itching in the mouth, vomiting and difficulty breathing occur, and in the most severe cases — anaphylaxis. There are also non-IgE-mediated forms, which develop more slowly and more often affect the digestive tract.

Food intolerance is a fundamentally different phenomenon. The best-known example is lactase deficiency: a person lacks the enzyme to break down milk sugar, and an excess of lactose causes bloating and diarrhoea. This is unpleasant but not life-threatening, and small amounts of the product are often tolerated well. For an athlete the difference is critical: with an allergy even a trace amount matters, with intolerance — the dose.

The third category is self-imposed restrictions without a medical diagnosis. Among athletes, giving up gluten ‘for better well-being’ is widespread. A study by Lis and co-authors showed that a significant proportion of athletes without coeliac disease follow a gluten-free diet, although there is no convincing evidence of improved results in them. Such restrictions also narrow the diet and can conceal the real cause of complaints.

Therefore the first step is to confirm the diagnosis with an allergist. Skin tests and the specific-IgE assay show only sensitisation; the clinical significance is assessed by a doctor taking the history into account, and if necessary by a supervised challenge test. The EAACI recommendations stress: unjustified exclusion of foods on the basis of tests alone leads to unnecessary deficiencies.

It is worth mentioning separately oral allergy syndrome: itching in the mouth from raw apples, pears or nuts in people allergic to birch pollen. Heat treatment often destroys the proteins responsible, so a baked apple may be perfectly safe. Such nuances make it possible not to cross whole groups of foods off the menu.

The main allergens and the risks to the diet

EU legislation (Regulation No. 1169/2011) defines 14 allergens whose presence the manufacturer is obliged to indicate on the label: gluten-containing cereals, crustaceans, eggs, fish, peanuts, soy, milk, nuts, celery, mustard, sesame, sulphites, lupin and molluscs. Ukraine, in the process of adapting its food legislation, is moving towards the same requirements.

For an athlete it matters not only the fact of exclusion itself, but also what ‘work’ the product did in the diet. Milk is protein, calcium, iodine and vitamin B2. Eggs are a convenient complete protein and choline. Fish is the main source of EPA/DHA and vitamin D. Wheat is a significant share of carbohydrates and fibre. When several such products are excluded at once, the risk of deficiencies rises substantially.

Cross-reactions must be kept in mind. A person allergic to cow’s milk often reacts to goat’s milk too; with a peanut allergy a reaction to lupin sometimes occurs; crustaceans and molluscs can cross-react with each other. These details are determined by an allergist, not a table on the internet.

Finally, in children an allergy to milk and eggs often resolves with age, whereas an allergy to peanuts, nuts, fish and crustaceans more often persists for life. Therefore, for an adult athlete diagnosed back in childhood, it makes sense to be re-examined: perhaps some of the restrictions can already be lifted.

How to cover the need for protein and micronutrients

The general needs of an athlete with an allergy are the same as for other athletes. The position statement of the Academy of Nutrition and Dietetics, Dietitians of Canada and ACSM recommends for most trained people 1.2–2.0 g of protein per kilogram of body weight per day, distributed across several intakes. Carbohydrates are dosed depending on the volume of training load. The task is to assemble these figures from the permitted foods.

With a milk allergy the main problem is calcium. It can be obtained from fortified plant drinks (choose those marked with added calcium), canned fish with bones (if there is no fish allergy), broccoli, almonds (if there is no nut allergy), and mineral waters high in calcium. If the requirement cannot be covered by food, a doctor may prescribe a supplement.

With a fish allergy, omega-3 fatty acids should be taken care of separately. Plant alpha-linolenic acid from flax or walnuts is converted into EPA and DHA only to a small extent, so a more practical alternative is microalgae oil — the primary source of DHA in the food chain. It is also worth monitoring the vitamin D level, especially in winter.

On a gluten-free diet it is easy for an athlete to fall short on carbohydrates: bread and pasta disappear, and substitutes are not always at hand. Rice, potatoes, sweet potatoes, buckwheat, cornmeal and fruit fully cover the needs even during high-volume training blocks. It is only important to plan snacks in advance so as not to be left without fuel while away.

• Draw up a list of ‘basic’ safe foods in each group: protein, carbohydrates, fats, vegetables.
• Plan the menu for the week and prepare portions in advance — this reduces the risk of accidental contact with the allergen.
• Once a year assess your nutritional status together with a doctor: ferritin, vitamin D, and if necessary calcium and B12.
• Work with a sports dietitian if two or more staple foods are excluded.

Sports nutrition and labelling

Protein powders are one of the riskiest categories for people with an allergy. Whey and casein protein are milk proteins, so with a milk allergy they are contraindicated, even if the product is low in lactose. Whey isolate solves the lactose problem but not the allergy: the allergenic proteins do not go anywhere.

The alternatives are beef, egg (if there is no egg allergy), pea, rice or combined plant protein. It should be borne in mind that plant sources have less leucine, so it is useful to combine different proteins or to increase the portion slightly. Soy isolate is a complete source of protein, but soy itself is on the list of major allergens.

Read the label carefully: under EU requirements allergens are highlighted in the ingredient list. The phrase ‘may contain traces of…’ means that the corresponding raw material is used at the production site and cross-contamination cannot be ruled out. For a person with a severe allergy it is better not to buy such a product, even if the allergen itself is not listed in the ingredients.

Bars, gainers and ‘sports baked goods’ often contain peanuts, nuts, milk proteins, soy and gluten all at once. Energy gels and isotonic drinks are usually simpler in composition, but they too are worth checking, especially the flavoured variants. A useful habit is to bring your own verified food supply to competitions and not to rely on feed stations.

For athletes competing at official events there is one more relevant requirement — to choose supplements that have passed independent testing for prohibited substances. This has nothing to do with allergy, but the combination of the two criteria narrows the choice even further, so the assortment is worth compiling in advance.

Exercise-related anaphylaxis

There is a special form of allergy that concerns athletes in particular — food-dependent exercise-induced anaphylaxis. A person may calmly eat a food at rest and calmly train on an empty stomach, but the combination of these two factors within a span of several hours triggers a severe reaction. The trigger most often described is wheat, in particular the protein omega-5-gliadin.

It is thought that exercise increases absorption of the allergen from the intestine, changes blood flow and lowers the activation threshold of immune cells. Additional cofactors are non-steroidal anti-inflammatory drugs, alcohol, lack of sleep, heat and menstruation. This is precisely why the reaction may not occur every time, which complicates diagnosis.

The practical recommendations described in the literature come down to avoiding the trigger food for a few hours before training, refraining from NSAIDs before exercise, and training in company. For people with diagnosed anaphylaxis, a doctor prescribes an adrenaline auto-injector, which should always be carried — in the sports bag, not in the changing room.

Coaches and teammates must know about the diagnosis and be able to recognise the first signs: itching, redness, swelling of the lips, hoarseness of the voice, dizziness. Anaphylaxis is an emergency: adrenaline is administered immediately, and then an ambulance is called even if the condition improves.

For teams that travel to training camps it is useful to have a written action plan for an allergic reaction and to agree the menu with the venue’s kitchen in advance. This is a simple organisational matter that genuinely saves lives.

Editorial conclusions

A food allergy is not a death sentence for a sporting career. The main things are a clear diagnosis, an understanding of which nutrients the excluded food ‘takes away’, and a well-thought-out system of substitutions.

The most vulnerable points of the diet are protein and calcium with a milk allergy, omega-3 and vitamin D with a fish allergy, and carbohydrates on a gluten-free diet. All of them are covered by ordinary foods if nutrition is planned in advance.

Sports nutrition requires meticulous reading of labels, and exercise-related anaphylaxis requires a separate safety plan and constant access to adrenaline as prescribed by a doctor.

The editorial team also recommends reading our materials on choosing plant protein, on vitamin D in athletes and on nutrition before competitions.

References

1. Muraro A, Werfel T, Hoffmann-Sommergruber K, et al. EAACI food allergy and anaphylaxis guidelines: diagnosis and management of food allergy. Allergy. 2014;69(8):1008–1025.
2. Sicherer SH, Sampson HA. Food allergy: a review and update on epidemiology, pathogenesis, diagnosis, prevention, and management. J Allergy Clin Immunol. 2018;141(1):41–58.
3. Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: nutrition and athletic performance. J Acad Nutr Diet. 2016;116(3):501–528.
4. Lis DM, Stellingwerff T, Shing CM, et al. Exploring the popularity, experiences, and beliefs surrounding gluten-free diets in nonceliac athletes. Int J Sport Nutr Exerc Metab. 2015;25(1):37–45.
5. Feldweg AM. Food-dependent, exercise-induced anaphylaxis: diagnosis and management in the outpatient setting. J Allergy Clin Immunol Pract. 2017;5(2):283–288.
6. Regulation (EU) No 1169/2011 of the European Parliament and of the Council on the provision of food information to consumers. Official Journal of the European Union. 2011;L304:18–63.