Mediterranean diet in pregnancy may protect against asthma
Publication Date:15/01/2008
Pregnant women who eat a Mediterranean-style diet, rich in fruit, vegetables and fish, may reduce the chances of their child developing asthma symptoms in later life.
What do we know already?
Lots of studies have looked at the effect of what we eat on allergic diseases such as asthma and eczema. But these studies have tended to look at specific foods. There hasn’t been much research comparing one type of diet with another during pregnancy.
The Mediterranean diet describes a type of diet once common in Mediterranean countries. It means you eat a lot of vegetables, fruit, bread and cereals, legumes (beans and lentils) and nuts. It includes fish and olive oil. Red meat and dairy products, sweets and fast food are eaten much less.
It’s likely that lots of things affect a child’s chances of getting a disease like asthma. The genes you inherit from your parents are likely to be important, as well as the area where you grow up (for example, whether you live near a busy road). Studies so far suggest that the mother’s diet in pregnancy may also play a part.
What does the new study say?
This study found that children of women who'd eaten a Mediterranean-style diet while pregnant were less likely to have symptoms of asthma (a long-lasting wheezy chest) or to have allergies measured by a skin-prick test. The children were tested at ages 6 to 7.
The researchers also looked at the children's diet. They found their diet didn't make as much difference to their chances of having allergies as their mother's diet in pregnancy. However, they said the children's diet probably had some effect, but the figures were not clear.
Tell me more about the study's findings
The researchers followed about 500 pregnant women and their children in Menorca, a Spanish island. The mothers filled in questionnaires about their diet during their pregnancies. Once a year, after their children's birth, they answered more questions and reported all their children's episodes of illness during the year. Finally, when the children were aged 6 to 7, the mothers were questioned about their children's current health, and their diet. The children all had skin-prick tests to see if they had allergies to common airborne particles, such as pollen.
Almost 6 in 100 children had both wheezy chests and allergies at the age of 6 to 7, and 17 in 100 children had allergies diagnosed by the skin-prick test. During the study, 13 in 100 children had had a persistently wheezy chest at some age.
The children whose mothers ate a Mediterranean-style diet during their pregnancy were less likely to have had any of these health problems, once the researcher took into account other factors like a family history of asthma.
Where does the study come from?
The study was carried out by a group of researchers from universities in Greece, Spain and Mexico. It was published in Thorax, a medical journal owned by the British Medical Association.
How reliable are the findings?
The difficulty with trying to find causes for illnesses such as asthma is that there are many possible causes. Studies can only look at a few possible causes at any one time. So we can't say that eating a non-Mediterranean diet causes asthma. What the study can show is that, when you take account of as many other things as you can think of, eating a Mediterranean diet in pregnancy seems to help protect children from having a wheezy chest or allergies.
The study doesn't say if the children were actually diagnosed with asthma. They use the parents' reports that the children had wheezy chests instead. So we don't know whether the diet actually prevented asthma, although a wheezy chest is the most common symptom of asthma.
The study was a reasonable size and the researchers took care to take account of as many factors as possible. So the results are likely to be quite reliable.
What does this mean for me?
If you are pregnant, you'll want to eat a healthy diet, both for your sake and for your unborn baby. We know that the Mediterranean diet is healthy in lots of ways. Eating plenty of fruit and vegetables, and only moderate amounts of red meat and sugary foods, is a good idea for healthy eating generally.
However, it's important to note that pregnant women do need plenty of calcium in their diets, to help the baby build strong bones. You get a lot of calcium from dairy products like milk and cheese. In the study, the women ate plenty of dairy products while they were pregnant, even though the Mediterranean diet is usually low in these. It's probably not a good idea to cut down on dairy products when you are pregnant, although you should avoid mould-ripened or blue-veined cheese like stilton and brie. (That's because this type of cheese may contain germs called listeria, which can harm the unborn baby.)
What should I do now?
If you are uncertain about the best diet to eat while you are pregnant, ask your midwife for help. They should be able to give you plenty of information. Eating plenty of fruit and vegetables is healthy for you and your baby, and may help protect against allergies.
From:
Chatzi L, Torrent M, Romieu I, et al. Mediterranean diet in pregnancy is protective for wheeze and atopy in childhood. Thorax. Published online January 2008.
To find out more, see our information on asthma.
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This information does not replace medical advice. If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.
