Not so sweet: True chocolate and cocoa allergy
The following is a summary of the stated research mentioned above. The content summarized here, including the figures and tables, all belong to the researchers (unless otherwise indicated). The summary attempts to stay as close to the original paper as much as possible with some adjustments in regards to jargon, length, or to focus on bean to bar aspects.
Image by @towfiqu999999
It is very rare for me to hear about a chocolate allergy. I had a participant in a work-related chocolate tasting recently who couldn’t taste with us due to a chocolate allergy. He was happy to learn but I believe his wife enjoyed the samples!
If you think you are having an allergic reaction to chocolate or any food, please call 911 or your local emergency number.
I will summarize this report of case studies which point out that there may be more reason to believe some people are allergic to chocolate. As the authors mention in the report, many medical professionals believe that what some suggest as an allergic reaction to chocolate is actually a reaction to other (not cocoa) ingredients commonly found in chocolate products (nuts, milk, etc.). The authors here suggest that there may be reason to believe some individuals are allergic to the storage proteins found in cocoa beans. Let’s read on.
jargon to discuss first
Here are some terms to understand before reading the case studies.
What is IgE?
IgE, or immunoglobulin E, is a type of antibody found in our bodies.
What is an antibody?
An antibody is a protein which combines with a substance the body sees as foreign or alien , and potentially harmful to the body. The body responds by reacting in various ways.
What is an IgE-mediated allergy?
This is an allergic reaction to food, which is caused by the IgE antibodies. Reactions occur very quickly, and can include throat tightening, mouth itching and swelling, tongue swelling, hives, nose discharge, eyes red and tearing, stomach upset, vomiting, weak pulse, agitation, or loss of consciousness to name a few.
What is an IgE test?
An IgE test measures the level of this antibody protein in our body. You may have more IgE antibodies in your blood if you have allergies or an allergic reaction. This can be found in the blood serum.
Skin prick test (SPT)
Introducing a known substance and potential allergen to the skin to see if the body reacts. This is done to see what one may be allergic too, and to what degree.
Case studies
Here are some case studies of various patients who appear to have an allergy to chocolate.
Patient 1
Two year old female with a history of eczema, reactive airway disease, rhinoconjunctivitis (inflamed nasal passage/mucosa) from exposure to dog, and hives and vomiting to cow’s milk-based formula and yogurt. Symptoms also occurred on two occasions after consuming chocolate. Figure 1A shows her cocoa skin prick test and serum allergen-specific immunoglobulin E (sIgE) results.
By 5 years old patient outgrew milk allergy. At 7 years of age she took part in a physician-supervised OFC (oral food challenge) using chocolate chips from Enjoy Life and Made Good Chocolate Chip Granola Minis, both manufactured in allergy-conscious facility without tree nuts or peanuts (stating those with milk, peanut, and tree nut allergies can safely consume their products).
Her oral food challenge was positive (Figure 2A) which included vomiting, wheezing, respiratory distress, and generalized hives. She was treated with intramuscular epinephrine and oral antihistamines.
Patient 2
Eight year old female with a history of wheezing after eating a pecan cookie dipped in chocolate, as well as itchy ears after eating ice cream with chocolate. Figure 1B shows her skin prick test and sIgE levels. She was also found to be sensitized to tree nuts.
At 9 years old she took part in a physician-supervised OFC using unsweetened cocoa powder by Hershey’s mixed with raspberry yogurt (which was previously tested to be tolerated by her). The cocoa powder was also manufactured in an allergy-conscious facility.
Her oral food challenge was positive (Figure 2B) and resulted in abdominal pain, coughing, and wheezing, and was treated with intramuscular epinephrine and oral cetirizine.
Patient 3
Eighteen year old male had man food allergies, asthma, allergic rhinitis, and eczema. At age 7 he had a OFC to chocolate (Hershey’s) and developed hives, cough, and wheezing treated with intramuscular epinephrine. By age 18, his cocoa sIgE level had decreased to less than 0.35 kUa/L and was scheduled for another OFC to cocoa with a physician.
He presented to the OFC while avoiding peanut, tree nuts, chickpea, lentil, green pea, and chocolate. He ingested Hershey’s milk chocolate, which is manufactured in a peanut-free plant and on a line of equipment that does not manufacture tree nut items.
His oral food challenge was positive which included facial swelling, facial flushing, hives, and wheezing. He was treated with 2 doses of intramuscular epinephrine, albuterol, cetirizine, and prednisolone.
Cocoa
Cocoa beans are seeds which come from the fruit of the cacao tree (Theobroma cacao). They belong to the family Malvaceae which includes cotton, okra, and durian. As a source of vitamins, minerals, and polyphenols, cocoa has been considered by some to be a nutraceutical.
On a study in ovalbumin-sensitized rats (reference 7), the researchers found that a cocoa-enriched diet over 4 weeks resulted in lower antiovalbumin IgE synthesis and a decrease in total serum IgE (antibody) concentration. They attributed this to the impact of the flavonoids found in cocoa. This study (reference 7) highlighted possible benefits of cocoa ingestion.
However, the researchers in this summary here suggest that cocoa also has the potential to be allergenic on its own. To date, according to the authors of this report, state there has not been any challenge-proven IgE-mediated allergy to chocolate. They do point out, however, that there are reports of allergic symptoms in those who work with chocolate/cocoa. They state chocolate confectionery workers show a high level of cocoa sensitization (31% from a group of 71 confectionery workers), and there is an increased prevalence of asthma and shortness of breath in sensitized versus non-sensitized workers (reference 8).
To date, there is known chocolate or cocoa allergen. So what is known? It is known that a 2S cocoa seed albumin (a type of storage protein found in seeds ) has a high sequence similarity (>52%) and identity (>38%) to several other plant 2S albumins known to be allergenic (such as those in the Brazil nuts). Essentially, the 2S storage protein found in cocoa is similar to the ones in other seeds which many people are allergic too. On top of this, the theobromine and caffeine in chocolate (alkaloids which slightly speed up heart rate) may be responsible for “pseudoallergic symptoms” which can be reported as allergic symptoms.
Summary
Here the authors have presented some cases of challenge-proven IgE-mediated chocolate/cocoa allergy where patients reacted convincingly with anaphylaxis to chocolate/cocoa oral food challenges. The report here suggests that although most reported chocolate/cocoa allergies are attributed to other allergens (peanut, tree nuts, milk) that there is some information to suggest a true allergy to chocolate and cocoa is possible.
