Peanut allergy

Posted by Andrew Wadge on January 23rd 2008 in Science, safety and health

It’s easy to work out what the advice should be when the science behind an issue is clear cut but much more difficult when the evidence is incomplete or contradictory – as is often the case. For example, one particularly difficult issue the Agency is seeking to address at present is what sort of dietary advice we should be giving to mothers who are concerned that their child might develop a peanut allergy.

The current Government advice is that mothers whose children have a family history of allergic diseases (asthma, eczema, food allergies etc), should avoid eating peanuts during pregnancy and breastfeeding and avoid introducing peanuts into the child’s diet before 3 years of age. This advice is precautionary and was based on the evidence available in 1998, which suggested the possibility that infants could be sensitised to peanut allergens as a result of exposure before birth or during breastfeeding. 

However, there is now some emerging evidence that early dietary exposure to food allergens might be important in the development of tolerance to a food allergen. This has to be considered against confounding results from recent research conducted by the Agency that suggests that, if a child is exposed to low levels of peanut proteins in the home environment as a result of consumption of peanuts by other family members, this may be leading to peanut sensitisation, particularly if the child is not eating peanuts.

The Agency has recently commissioned a new project, which builds on a major intervention study, to look at the mechanisms behind the development of peanut allergy or tolerance. This should help us understand this issue much more clearly but will take several years to complete.  We are systematically reviewing all the scientific evidence that is already published and aim to be able to reconsider what our advice should be by the end of this year.  In the meantime our current precautionary advice stands.
 
I think this neatly illustrates the problems of determining policy in the face of incomplete and conflicting evidence.  But it is also illustrates why I think working at the interface between science and public health policy is so fascinating and why I enjoy this job.

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peanuts

Posted by Anonymous (not verified) on 06/02/2008 - 10:33

A Science news feature recently analyzed this complex issue http://www.sciencemag.org/cgi/content/full/318/5851/740

Dietary prevention of peanut and other allergies

Posted by Dr Rob Peers (not verified) on 25/01/2008 - 09:20

There seems to be a consensus among allergy and immunity researchers, that allergies and autoimmune diseases have greatly increased in recent years. This probably includes peanut allergy. The cause of this significant rise may be increased consumption, especially in pregnancy, of our old friend saturated fat, which by disturbing placental function may allow maternal cortisol hormone to reach the fetal brain, where it is known to programme lifelong anxiety disorder. The stress hormones (cortisol and noradrenaline) in anxious subjects upset the immune system, by depressing virus-fighting T helper-1 white cells, but boosting the activity of T helper-2 cells, which promote allergic responses and antibody production. Therefore, if an anxious child happens to have genes for allergy, we can expect trouble.
We can do two things to prevent such trouble--1) promote low-fat diet in pregnancy, to prevent anxiety disorder (which currently affects 20-30% of all people in affluent nations), and 2) prescribe an anti-anxiety diet for the child, which is a Seedy Diet (corn, whole grain cereals and legumes contain Inositol sugar, a natural and highly effective treatment for anxiety, which lowers stress hormone levels). The diet should also be low in sat fats (which cause systemic oxidation and low-grade inflammation), and relatively rich in healthy fish and vegetable oils, providing Omega-3 and Omega-6 Essential Fatty Acids. Omega-6 are found in soft margarines, olive oil, cold-pressed oils, NUTS!, legumes and avocado. Refined (deodorized) seed oils like canola, sunflower, soya and peanut oil are vitamin E deficient, they "burn" the human brain, and must be avoided, because in pregnancy they lead to ADHD/Hyperactivity in the child, and adults consuming such oils will develop Alzheimer's disease in later life.
My prediction that a low-fat, slightly oily, rather "Seedy" diet will reduce allergic responses is supported by the findings of an international asthma study: the ISAAC study found that 8-13 year olds in Holland consuming whole grains seemed to get less asthma, compared with grain-free kids. Indeed, the Inositol in such grains should treat not just anxiety, plus the aggravated allergic state seen in anxiety: the Inositol Hexaphosphate (phytic acid) in seeds is a powerful iron-chelating antioxidant, that probably has an anti-inflammatory effect in the reddened bronchial mucosa typically seen in asthmatic subjects. Let us hope the same applies to peanut allergy, hay fever and eczema! Let's do it!