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Food allergen myths debunked - Part 2

September 2014

Given the life-threatening nature of food allergies, one would think that the stakes are too high for myths and pseudoscience. Unfortunately, this is not the case and confusion surrounding these conditions abounds. Food producers, in particular, need to be cognisant of these misconceptions, especially since their consequences may manifest in the manner in which allergens are controlled and how their risks are conveyed to consumers.

This second part of our two-part newsletter aims to dispel more common myths surrounding food allergy.

Myth #1: Only certain foods cause allergies

The truth: More than 160 foods have been reported to cause allergies. Although it is true that eight food groups (cow’s milk, eggs, soya, peanuts, tree nuts, fish, crustaceans and molluscs, and wheat) are responsible for the large majority (ca. 90%) of food-allergic reactions, any food has the potential to cause an allergy.

 

Myth #2: Goat’s milk is a safe alternative for those allergic to cow’s milk

Cow’s milk allergy (CMA) is one of the most common food allergies, affecting up to 5% of infants and young children. Goat’s milk and numerous other mammalian milks have been advocated as safe replacements for cow’s milk, however, this has been with very little scientific backing.

The truth: Several clinical studies have demonstrated that individuals with CMA will also elicit allergic reactions to the milks from other mammalian species, primarily due to the similarities in the casein proteins of these milks. Up to 90% of CMA patients have been shown to react to goat’s milk, meaning that goat’s milk cannot be regarded as a safe alternative for these individuals. CMA sufferers are also unlikely to tolerate the milk from sheep, water buffalo, deer and ibex. While cross-reactivity to milk from pigs, mares, donkeys and camels appears to be lower, comprehensive studies on the clinical tolerability of these alternative milks are lacking, thus their use by CMA individuals should be supervised by medical professionals.

* On a side note, there is evidence to show that 10 - 20% of CMA patients do not tolerate soy milk and about 10% also react to beef.

How did this myth arise?
Likely due to misleading reporting in the lay press, erroneous advisory by some physicians, as well as due to marketers looking for a competitive advantage of goat’s milk over cow’s milk.

Myth #3: All allergen-derived oils are safe for allergy sufferers

Edible oils can be derived from a large number of common food allergens, including fish, soybeans, peanuts and tree nuts, and not all of these can be broadly regarded as safe for allergy sufferers.

The truth: The safety of allergen-derived oils will depend largely on the extent of the refining process used in their production and the levels of residual protein remaining in the product thereafter. Crude or unrefined oils can contain significant amounts of protein (>300 ppm) and therefore will undoubtedly have the potential to cause allergic reactions. Highly-refined oils, on the other hand, are produced using multiple steps, including degumming, neutralising, bleaching and deodorizing, the combination of which should remove most or all of the protein which would trigger an allergic reaction. If highly-refined oils are added as ingredient to other foods, the concentration of any residual protein would be further diluted, which would also additionally reduce the risk of an allergic reaction.

In particular, caution should be taken when selecting gourmet oils or items from health food stores, especially those marketed as natural, cold pressed, expeller pressed or extruded, as the latter do not generally go through rigorous refining processes and may still contain potentially allergenic proteins.

Note: According to the South African Foodstuffs, Cosmetics and Disinfectants Act, 1972 (Act 54 of 1972) - Regulations Relating to the Labelling and Advertising of Foodstuffs, (R. 146/2010): “common allergen means egg, cow's milk, crustaceans and molluscs, fish, peanuts, soybeans, tree nuts and any significant cereals, as well as an ingredient derived from these foodstuffs that has retained its allergenicity in the final product”. Thus, even if an oil labelled as highly refined is used as an ingredient in a product, the allergen should be declared on the product labelling unless it can be reliably demonstrated that this has not retained its allergenicity in the final product, which may well necessitate oral challenge studies.

Myth #4: I’m allergic to nuts, so I should avoid any food with ‘nut’ in its title

Allergies to tree nuts are common and potentially life-threatening and for this reason they are listed among the group of legislated ‘common allergens’ that require declaration on food product labels in South Africa.

Note: According to the South African Foodstuffs, Cosmetics and Disinfectants Act, 1972 (Act 54 of 1972) - Regulations Relating to the Labelling and Advertising of Foodstuffs, (R. 146/2010), “tree nuts” are classified as the following: almonds, brazil nuts, cashew nuts, hazelnuts, macadamia nuts, pecan nuts, pistachio nuts and walnuts.

Due to their names, however, many people with tree nut allergies may believe that they should avoid foods such as ‘butternut’ (squash), ‘nutmeg’ and ‘coconut’ at all costs…

The truth: Just because the name contains the word ‘nut’, it does not necessarily mean that the food belongs to the group of ‘tree nuts’, nor that it should be avoided by tree-nut-allergic individuals.
• Butternut squash is a fruit and water chestnuts are aquatic vegetables – neither of these are classified as tree nuts and both are usually safe for consumption by tree-nut-allergic patients.
• Nutmeg is a spice derived from seeds, not from tree nuts. Allergy to nutmeg is rare and there is currently no solid scientific evidence to suggest that tree-nut-allergy sufferers are at risk from consuming nutmeg.
• Coconuts are members of the palm family and are only distantly related to tree nuts. Although the FDA classifies coconut as a tree nut for food labelling purposes, coconut does not appear on such lists in the EU and South Africa. Coconut allergies are extremely rare, with less than 10 cases being reported to date. One study published in 2007 indicated potential cross-reactivity between coconut, hazelnuts and walnuts, but this was only in one patient. While there are bound to be exceptions, the current understanding is that coconut probably does not pose a greater risk to nut-allergic consumers than any other food.

As a side note: ‘Donut’ also contains the word ‘nut’ and there is no evidence that this needs to be avoided by tree- nut-allergic individuals, unless of course the donuts contain tree nuts as ingredients.

References:
Bellioni-Businco, B., Paganelli, R., Lucenti, P., et al. (1999). Allergenicity of goat’s milk in children with cow’s milk allergy. Journal of Allergy and Clinical Immunology, 103:1191-1194.
Businco, L., Giampietro, P.G., Lucenti, P., et al. (2000). Allergenicity of mare’s milk in children with cow’s milk allergy. Journal of Allergy and Clinical Immunology, 105:1031-1034.
Katz, Y., Goldberg, M. R., Zadik-Mnuhin, G., et al. (2008). Cross-sensitization between milk proteins: reactivity to a" kosher" epitope?. The Israel Medical Association journal, 10: 85.
Restani, P., Gaiaschi, A., Plebani. A., et al. (1999). Cross-reactivity between milk proteins from different animal species. Clinical and Experimental Allergy, 29:997-1004.
Spuergin, P., Walter, M., Schiltz, E., et al. (1997). Allergenicity of alpha-caseins from cow, sheep, and goat. Allergy, 52:293–298.
Teuber, S.M., Peterson, W.R. (1999). Systematic allergic reaction to coconut (Cocus Nucifera) in 2 Subjects with hypersensitivity to tree nut and demonstration of cross-reactivity to legumin-like seed storage proteins. Journal of Allergy and Clinical Immunology, 103:1180-1185.
Vita, D., Passalacqua, G., Di Pasquale, G., et al. (2007). Ass's milk in children with atopic dermatitis and cow's milk allergy: crossover comparison with goat's milk. Pediatric Allergy and Immunology, 18:594.