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Ask the expert: Nutrition and food allergies – Taking supplements to help avoid nutritional deficiencies

Linda Kirste, RD

Linda Kirste is a Registered Dietitian. She works at HealthLinkBC where she operates the Allergy Nutrition Service ― a tele-practice-based service that provides nutrition education, as well as counselling and follow-up care for residents of British Columbia with food allergies.

This month, Linda provides her insight about whether it’s advisable for children and youth living with food allergies to take supplements to help avoid nutritional deficiencies. We hope you find this article from Linda interesting and informative!


Whether a child whose diet is restricted due to food allergy should take a vitamin or mineral supplement depends on a few factors. These include the overall quality of their diet and whether their intake of individual nutrients reach recommended levels.

While necessary food restrictions can have a big impact on food choices, a child’s usual food choices and eating patterns can have an even larger impact on their nutrient intakes.

The child that eats a wide range of healthy family foods, including nutritionally equivalent alternatives to substitute for their food allergens, may not need a vitamin-mineral supplement. When a child’s diet is adequate and balanced, dietary supplements may be more of a burden to take than a useful top-up to nutrient intakes.

The child with peanut and tree nut allergies who eats seeds and seed butters is a good example. For example, instead of eating peanut and tree nuts, pumpkin, sunflower, sesame, and hemp seeds, are similarly rich in protein, fat, potassium and magnesium, and are sources of iron.

The child with fish allergy, whose diet is otherwise balanced and adequate, is also unlikely to benefit from a vitamin-mineral supplement. Most vitamin-mineral supplements aren’t significant sources of omega-3 fats. To achieve an adequate intake of omega-3 fats, Canada’s Food Guide recommends eating at least two servings of fatty fishes a week. Fatty fishes include char, herring, mackerel, salmon, sardines and trout. Children with fish allergy can be offered alternate food sources of omega-3 fats instead. Rich sources include canola oil, ground flax seed, chia seed, omega-3 enriched eggs and walnuts.

There are over 30 known nutrients in a wide range of foods that are vital for human health. Eating patterns and available foods impact the amounts of each nutrient ingested. Food allergies can sometimes restrict variety and pose potential limitations on specific nutrient intakes. When a dietary supplement is needed to fill a gap, it is important to select the right one.

As an example, children with milk allergy may benefit from a supplement, but not necessarily a calcium supplement.

Cow’s milk is an important source of energy (calories), protein, calcium, and vitamins A, D, B12 and riboflavin. Calcium supplements are unlikely to contain all these nutrients. A multivitamin-mineral supplement isn’t likely to cover these needs either, as they don’t typically contain enough calcium.

Children with milk allergy can instead be offered a nutritionally equivalent drink to milk, such as a fortified soy beverage. Fortified soy beverages contain all the key nutrients found in 2% milk fat (M.F.) cow’s milk. Other milk alternatives such as fortified rice, almond and coconut beverages are low in protein. Children who drink them may benefit from a nutritional assessment and an individualized care plan to help ensure they meet their nutrient needs. Other foods rich in protein include legumes, seeds and nuts, fish, meat, poultry, and eggs.

Some children with milk allergy benefit from a vitamin D supplement, as there are few additional foods that contain this vitamin. These foods include fortified margarine (but some contain milk), eggs and fatty fishes. The daily recommended intake of vitamin D for children over 1 year of age is 600 international units (IU). Two-250 millilitre (mL) cups of fortified soy beverage offer about 200 IU, the same amount as two cups of milk.

For milk allergic infants and younger children, breast milk is an excellent source of a whole range of nutrients, including fat. However, breast milk is unlikely to fully supply the recommended amounts of calcium and vitamin D for children over 1 year of age. A tolerated infant formula is therefore recommended to complement breast milk until 2 years of age. Breastfed children over a year of age should be offered between 400 and 600 IU of vitamin D daily and may benefit from a liquid calcium supplement. The amount of calcium supplement to offer can be determined from a nutritional assessment.

If you’re concerned about your child’s nutrient intakes and/or your child has multiple food allergies, ask their doctor or nurse practitioner to refer them to a registered dietitian for a nutritional assessment. A paediatric dietitian is most likely able to help you with your child’s dietary needs. Paediatric dietitians work in hospitals, community health centres and in private practice.

Thanks Linda for your expertise!

To read Linda’s other articles with us, visit our blog section, or click here to read about:

Do you have a question you’d like to ask Linda in the months to come? If so, please send it along to us at info@foodallergycanada.ca.