Researchers from Sweden’s Uppsala University have arrived at some surprising findings about food sensitivities after following 2,307 adult Europeans for nine years.
The researchers compared immunoglobulin E (IgE) sensitization to a variety of possible foods and allergens along with food hypersensitivity questionnaires over a period of nine years. The subjects were from four regions of Iceland and Sweden.
The researchers found that about 21% of the subjects variously reported food sensitivities with certain fruits, nuts, vegetables, dairy, seafood, spices and wheat products. Among the 2,307 people, 496 had a food sensitivity.
They found that skin reactions were the most common symptom, but other symptoms included diarrhea, vomiting, congestion, headache and breathlessness after eating the foods. A full 131 of the 496 food sensitive subjects reported other various symptoms.
Surprisingly, the researchers found that while most IgE antibodies to those foods sensitive to went down during the nine-year period among the subjects, their perceived hypersensitivity to those foods did not go down.
At the beginning of the study around 6% had food sensitivities, and at the end of the nine years, only 2% had IgE-sensitization to those foods. This was a 63% drop in IgE sensitivity for those foods.
Meanwhile nearly 21% of the population said they regularly experienced symptoms of food sensitivity at the beginning and at the end of the nine years.
Among those IgE sensitivities that dropped the most during the nine years was IgE antibodies to peanuts and IgE antibodies to soy.
In other words, even though their IgE antibodies fell off significantly, there was no decrease in reported sensitivity symptoms.
This of course was curious to the researchers. They could not explain it.
This is one of the first studies that has followed IgE together with perceived symptoms over an extended period among adults. The researchers stated:
“This is the first study to our knowledge assessing food hypersensitivity and IgE levels against food allergens in a longitudinal setting.”
Among the various IgE sensitivities found among the population, food sensitivities actually had one of the lowest rates of IgE sensitivity.
Other sensitivities among the 2,307 included cats, mites and timothy grass (highest). The IgE sensitivity levels for these did not drop off as the food sensitivity IgE levels did over the nine-year period.
The researchers concluded:
“the prevalence of food hypersensitivity remained unchanged while IgE sensitisation to food allergens decreased in this 9 year follow up study performed in adults. The prevalence of IgE sensitisation towards food allergens decreased to a larger extent than the prevalence and persistence of IgE sensitisation to aeroallergens. The biological explanation for the high prevalence of food hypersensitivity should be further investigated.”
Patelis A, Gunnbjörnsdottir M, Borres MP, Burney P, Gislason T, Torén K, Forsberg B, Alving K, Malinovschi A, Janson C. Natural History of Perceived Food Hypersensitivity and IgE Sensitisation to Food Allergens in a Cohort of Adults. PLoS One. 2014 Jan 10;9(1):e85333. doi: 10.1371/journal.pone.0085333.