What’s hidden in spinach?

Spinach is one of the symbols of health. And for good reason. People on a diet can include the vegetable in their meals , because it is low in fat and low in calories. Thanks to its high content of antioxidants, it also exhibits anticancer, anti-inflammatory and anticoagulant effects. In addition, it is a real treasure trove of vitamins such as B2, B6, B9, C, E, K and folic acid.

The vegetable is also a good alternative for vegetarians, who need to provide their bodies with iron in particular, but also magnesium, selenium and dietary fiber [1]. However, there is something to watch out for when eating spinach. The green leafy vegetable contains oxalates, and these in turn can cause kidney stones [2].

Allergy to spinach occurs rarely, but it is possible. It mainly occurs in people working in food service and housewives [3].

Several allergenic proteins are found in spinach, among them Spi o and Spi o 2 [4]. In contrast, symptoms after eating this vegetable are most often associated with Alternaria-spinach syndrome. In it, a cross-reaction occurs between the mold fungus and just spinach. Specialists have shown the similarity of the mold allergen Alt a 1 with the protein found in this vegetable. This means that with an inhalant allergy to Alternaria, the body can also react after eating spinach [5]. Reactions resulting from allergy to this type of mold include rhinitis or conjunctivitis [8].

Spinach also crosses with birch pollen. This type of reaction manifests as oral allergy syndrome. A patient with a birch allergy, after eating spinach, may experience such discomforts as burning and tingling of the mouth and itching and swelling of the lips [6]. Spinach cross-reactivity can also occur with latex [7].

The symptoms that occur after eating spinach do not necessarily indicate an allergy at all. The vegetable contains large amounts of histamine, so people with intolerance to this substance should limit it. Intolerance occurs when we supply too much of it to the body or lack the enzyme that is responsible for breaking down this substance. When we can’t break it down, it enters the bloodstream and can cause symptoms such as headache, hives, redness and itching of the skin, and even bronchospasm, fainting, hypotension or arrhythmia [9].

Spinach is also rich in salicylates. Intolerance to these substances manifests as rhinitis, hives and shortness of breath, among other symptoms. It is worth mentioning that salicylates are also in the composition of painkillers, anti-inflammatory drugs and anticoagulants [10].

Therefore, it is a good idea to check whether the symptoms are due to a primary allergy, a cross-reaction or perhaps a food intolerance. To do this, it’s a good idea to see an allergologist, who will refer you to the appropriate tests and make a diagnosis.

• The first study on spinach allergy was conducted on a group of 80 Indian children between the ages of 2 and 14 with diagnosed asthma or wheezing. Using spot skin tests, the researchers showed that spinach was the most common sensitizing food allergen among the 13 tested. In addition, 25% of the children had skin reactions after eating spinach.
• Other cases of spinach allergy are also known. A 48-year-old woman developed oral allergy symptoms after eating the vegetable. Skin tests for spinach were positive.
• Another case involved a 23-year-old woman whose test results from both blood and skin tests showed an allergy to spinach. After eating it, the woman experienced swelling of the lips and tongue, as well as hives and angioedema.
• It turns out that allergic reactions caused by inhaling spinach powder are also possible. Such a case was described in a 30-year-old worker at a pasta factory [11].

So how do we find out if we have an allergy to spinach?  For this purpose, it is possible to conduct spot skin tests and blood tests that detect antibodies to this vegetable [12].

Natalia Gajek 

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translation: Julia Majsiak

Publication: 10.08.2023
Updated: 26.03.2025