A Question and Answer with Dr Janice Joneja

Question:

I have a question about a cow’s milk allergy and I am hoping you are able to help me. The product (Great Shakes by Hormell) is made of soy milk, but has “natural butter flavor” in the ingredient list. I checked with the company and they report trace amounts of cow’s milk protein:

Would a patient allergic to cow’s milk be able to have this?
What would be the “cut-off” amount of protein?

Answer:

The lowest dose of an allergen in a food likely to elicit a reaction in a sensitized individual is difficult to determine. As you are aware, every individual has a different limit of tolerance. Consumption of a dose above their own tolerance threshold will result in the development of symptoms. Determining an individual’s tolerance threshold requires careful measurement of the eliciting dose, usually administered in a step-wise process.
 
There have been several attempts to obtain statistics on populations in order to define “eliciting doses” of several food allergens in order to answer questions regarding individual safety such as posed by your patient. The statistics available are generally based on the lowest observed adverse effect level (LOAEL): that is, the lowest dose required to elicit symptoms in the smallest number of subjects in a sample population. This dose is different for each allergenic food. For milk, the LOAEL has been reported to be less than 0.1 mL based on double-blind placebo–controlled food challenge (DBPCFC) studies. (1) Another study indicated that 10% of the subject population reacted to 2.9 (1.5-5.4) mL milk. (2) 

In manufactured foods the detection limit for milk was determined to be 30ppm milk to ensure the safety of 98% of people allergic to milk. (3) However, studies vary in the results reported due to such factors such as variations in the population studied (e.g. children or adults), the country in which the research was conducted, and the method employed in collecting the data.
 
Furthermore, there is another complication in applying these statistics in individual cases: the DBPCFC measures the amount of the whole food administered as the challenge dose. In laboratory research studies, the level of the protein fraction of the food, not the whole food, is used as the challenge dose. Clearly, the dose of the protein will be significantly lower than that of the whole food, so the reports of threshold doses likely to elicit symptoms must be read with caution. 

(1) Moneret-Vautrin DA, Kanny G.  Update on threshold doses of food allergens: implications for patients and the food industry.  Curr Opin Allergy Clin Immunol 2004;4(3):215-219

(2) Eller E1, Hansen TK, Bindslev-Jensen C. Clinical thresholds to egg, hazelnut, milk and peanut: results from a single-center study using standardized challenges.  Ann Allergy Asthma Immunol. 2012 May;108(5):332-336

(3) Morisset M, Moneret-Vautrin DA, Kanny G. et al.  Thresholds of clinical reactivity to milk, egg, peanut and sesame in immunological IgE-dependent allergies: evaluation by double-blind or single-blind placebo-controlled oral challenges.  Clin Exp Allergy 2003;33(8):1046-1051

First published January 2015

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