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"Eating fish fights allergies”

It is not one of the easiest foods to introduce into a child's diet, but eating fish from an early age builds tolerance to the allergens responsible for hay fever and eczema. A Swedish study led by Emma Goksör presented this finding on the occasion of the annual meeting of the European Academy of Allergology and Clinical Immunology (EAACI)

JORDI MONTANER | NOVEMBER 16th, 2010

Apparently, allergies that we suffer in adolescence or adulthood may depend on what we ate when we were babies.
Also on what we did not eat. Many parents delay the introduction of fish into the diet of their children to avoid the child’s rejection of a food that nutritionists are discovering has more and more advantages. Science has now found that parents, in not feeding their babies fish, are doing wrong.

How did you come to this conclusion?
In 2003, our department at Gothenburg University studied the eating habits of more than 8,000 families in western Sweden and found that children who started eating fish before nine months old were less likely to develop allergic rhinitis at an average age of 4.5 years than children who started eating fish later in life. We conducted the study on the basis of two questionnaires, one on the children’s diet between six and twelve months of age and another on allergies they had at four to five years old.

Any more information?
It is noteworthy that one of every 20 children in the study developed allergic rhinitis symptoms at an age of four years, but among the fish eaters this incidence is reduced by half.

And we're talking about a country, Sweden, where it is very common to eat fish from an early age.
Indeed. In fact, the percentage of families that waited till after nine months to introduce fish into their children’s diet did not exceed 10%. It would be interesting to reproduce the study in countries with little tendency to eat fish and analyze the effects.

Limiting ourselves to the Swedish case, if we extrapolate the data...
We will see that eating fish before nine months avoids at least one in 10 forms of allergic rhinitis from the preschool age.

The big question: why does fish protect against allergies?
We do not know, nor do we know if its protective effect in childhood also extends into adult life. All the evidence, however, suggests that the quality of fat that we incorporate into our bodies when we start to eat determines our immune response to allergens. In this sense, the fatty acids from fish, blessed with so many beneficial properties, would help the development of the intestines and the immune system to better gauge the incorporation of proteins during the first years of life.

Some pediatricians prefer to delay the introduction of solid foods into the child’s diet.
Today there is no evidence to justify continuing baby foods and delaying the introduction of solid food. Moreover, doing so after nine months could jeopardize the allergic health of the child.

If we all start to consume fish, we will empty the sea (something we may, in fact, already be doing), and yet allergies do not stop growing.
Eating fish will not prevent the development of allergies. We do not encourage that people eat more fish, just that they do so a lot earlier than is normally done and that they do so with a preventive end. We know today that many rhinitis and asthmatic diseases that we consider incurable can, however, be prevented through the proper development of the immune system in childhood. It's cheap, sustainable and completely healthy. Still, allergies do not stop increasing in numbers...

Why?
Our team has studied the incidence of atopic eczema in children. In Sweden, 21% of children under one year old develop atopic eczema, but more significantly, the mean onset age of the first symptoms is located at 4 months old. Besides eating fish, we found that having pets at home (particularly birds) has a protective benefit.

In Sweden, infants are weaned later than in the rest of Europe. Does that have a benefit?
More than 80% of Swedish mothers breastfeed their babies and do it for a an average of 16 months. However, only one third of babies are exclusively breastfed. At around 30 weeks, half of Swedish children have already started to eat foods other than milk. What is clear is that breastfeeding in the first year of life will not protect against eczema by itself.

Genes also play an important role in allergies.
Of course. We know that if one in five Swedish babies develop eczema before one year old it is not just due to the food they do or do not eat. Family history of eczema will determine the risk very accurately. There are also risk factors unrelated to food or the genetic code: it is known that 10% of pregnant Swedish women don’t quit smoking, and this affects the infant's immune development.

What can you tell us about the protein filaggrin?
That it is of exceptional importance in the development of eczema. It is a protein involved in the formation of the epidermal epithelial’s immune defense. We know that a lack of filaggrin predisposes one to both eczema and atopy.

Returning to food, it has also been suggested that the early introduction of dairy (milk, butter, cheese) also prevents allergies.
There is a Dutch study that shows this protective role of lactose; however, in our study we observed that fish had the most significant impact.

INFANT ECZEMA
Infant eczema is a common allergic disease. If until now the hereditary thesis regarding the risks for this disease has prevailed, recent studies are beginning to show that the baby’s diet can play an important role in the severity or the early onset of eczema.
Even though the prevalence of childhood eczema has risen in recent decades, researchers have not yet found the reason for such an increase. Since in the countries of eastern Europe the incidence is much lower, some people point to differences in the composition of the intestinal flora that colonizes the digestive tract of infants. Some bacteria, in this sense, provide better protection than others. Also, research affirms the protective role of omega acids in fish and the lactobacilli in milk consumed in the first year of life and in full development of the immune system.

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