Eating salmon during pregnancy may help prevent asthma
If you are pregnant it may be wise to eat salmon. According to a new study it lowers your child's risk of developing asthma, which is a rather common ailment. But what is it in salmon that prevents asthma, and what about those who dislike the taste of fish?
Asthma is a chronic inflammatory condition of the lungs (that does not involve bacteria) with recurrent bouts of breathing difficulty, coughing, chest tightness or wheezing. 50 per cent of asthma cases are seen among children under the age of 10 years. Therefore, we have every reason in the world to prevent this chronic ailment with natural solutions and - as far as possible - avoid using medication that is known to cause side effects.
Groundbreaking discovery of long-term effects of salmon
Philip Calder, a professor at the University of Southampton, headed a randomized, controlled study called Salmon in Pregnancy, in which a group of pregnant women were asked to eat salmon twice a week from the 19th week of their pregnancy. Six months after birth, their children were submitted to various allergy tests. The tests were repeated when the children were around two or three years of age. The results of these tests were compared to similar tests carried out on a control group with children of mothers who had not consumed salmon during their pregnancy.
There were no differences in the allergy rate when the children were six months of age. However, at the age of two or three there were fewer cases of asthma among the children whose mothers had eaten salmon during their pregnancy.
These groundbreaking results are another good example of Professor Calder's thorough research of the long-term effect of diet on the immune defense.
The immune defense before and after childbirth
A newborn baby only possesses the non-specific immune defense (also known as the innate immune system), which can handle most infections. After birth, the child develops the specific immune defense, which includes the special immune troops and antibodies. It takes a few years for this part of the immune defense to develop entirely. In the case of asthma, the specific immune defense overreacts by producing too many IgE antibodies and histamine. According to Calder's study, certain nutrients in salmon are able to control the specific immune defense.
Special nutrients in salmon
Salmon, which is a very oily fish, contains several nutrients that appear to be involved in the prevention of asthma. Most important are the omega-3 fatty acids, EPA and DHA, which have anti-inflammatory properties and which are building blocks of the brain and nervous system in the fetus. The intake of omega-3 fatty acids has been reduced drastically over the past decades. On the other hand, the intake of omega-6 from margarine and junk-food has increased tremendously, and that disturbs the balance between these two types of fatty acids.
Even though the positive effects of the Salmon in Pregnancy study are primarily ascribed to the omega-3 fatty acids, it is only fair to say that salmon also contains selenium, iodine, iron, vitamin B12, vitamin B3 (niacin), vitamin B6, and vitamin D, all of which have several functions in the development of the fetus. Lack of dietary fish and organ meat, a problem that is only made worse by our nutrient-depleted soil, helps explain why so many of us get too little selenium. Also, many of us get too little vitamin D from the diet, and we are not able synthesize vitamin D in our skin during the winter period because the sun sits too low in the sky.
Professor Calder receives prestigious award for his research in fatty acids
Over the past 25 years or more, Professor Calder's research has revealed how a lack of different fatty acids in our diet can cause an array of common diseases such as asthma, atherosclerosis, and inflammatory bowel disease like Crohn's disease.
Professor Calder presented the results of his Salmon in Pregnancy study at a San Diego conference for experimental biology and was nominated to receive the Danone International Prize for Nutrition 2016 for his research in the diet's influence on the immune system, inflammation, and the cardiovascular system.
Omega-3 and other nutrients from fish or supplements
Fish, on one hand, contains many nutrients that are important for normal development of the fetus and the immune system later in life. On the other hand, fish is contaminated with mercury and other environmental toxins that can damage the fetus.
Fish at the top of the food chain contain the most pollution. For that reason, health authorities advise pregnant women to limit their intake of tuna and other types of predatory fish.
However, there are no warnings about smaller fish and salmon. It is, nonetheless, a good idea to avoid salmon that has been caught in the Baltic Sea, as these fish may contain larger concentrations of heavy metals and other types of pollution. Instead, choose organic salmon.
Pregnant women who dislike the taste of fish may opt for a high-quality fish oil supplements. Also, it is a good idea to make sure to get plenty of selenium, iodine, folic acid, and other nutrients that are found in special vitamin supplements for pregnant women.
The omega-3 content in salmon and capsules
100 grams of salmon contains around 3 grams of fish oil, which is the same as three large fish oil capsules.
University of Southampton: Oily fish eaten during pregnancy may reduce risk of asthma in offspring. ScienceDaily 2016
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