infant allergy
Studies considering peanut exposure during pregnancy and Although the new advice states that peanuts can
breastfeeding and the development of peanut sensitisation or now be given to infants after six months of age during
allergy were limited to two small case control studies, both with weaning, it still remains important to introduce foods that
around 25 cases of peanut allergy. While one of these studies could potentially trigger a food allergy to the infant’s
looked at peanut sensitisation and the other allergy, both mea- diet one at a time so that any allergic reaction can eas-
sured peanut consumption by the use of questionnaires. Both ily be spotted. It is also equally imperative that whole
studies (7,8) reported non-significant differences in develop- peanuts or whole nuts should never be given to children
ment of peanut sensitisation or allergy in the children of moth- under five because of the risk of choking.
ers who consumed peanuts more or less often in pregnancy Pregnant women who choose to avoid peanuts or
and/or during breastfeeding after adjustment for confounders. foods containing peanuts must remember the impor-
Nineteen human studies investigated dietary exposure tance of reading food labels, where peanut must be
(including avoidance and delay of introduction) of allergenic declared by law if it is an ingredient. Incomplete avoid-
foods in childhood and later development of food sensitisation ance of peanuts is common amongst pregnant women
or allergy. These comprised of eight trials, 10 cohort studies and who choose to avoid peanuts (3), and interestingly
one case control study. A range of exposures were investi- animal studies suggest that oral exposure to low doses of
gated, including cows’ milk formula vs. breast milk, the duration peanut protein may induce sensitisation, whereas high
of breastfeeding, the timing and introduction of solid food, as doses may result in tolerance (11). Thus, if applicable to
well as multifaceted interventions that looked at many differ- humans, incomplete avoidance of peanuts could prove
ent dietary and household exposures. The overall conclusion more harmful rather than protective against the devel-
from these studies was that there was no suggestion that either opment of peanut allergy or sensitisation in the child.
exposure to, or avoidance or delayed introduction of allergenic However, further studies are needed to confirm this in
foods in early childhood provides protection from subsequent humans.
development of sensitisation or allergy to foods. The topic of peanut consumption during pregnancy,
With regards to dietary exposure to peanut during childhood breastfeeding and early childhood continues to be an
and development of sensitisation or allergy, two of the multifac- area of great interest, as a number of studies are cur-
eted trials included peanut avoidance as one of the features rently underway investigating peanut and other food
of the intervention arm (9,10), as well as one case control study allergies with the intention of improving understanding
(7). Overall this evidence from human studies does not suggest of how and under what circumstances these conditions
that dietary exposure to, or avoidance or delaying introduction develop. It is hoped that these and other studies will
of, food proteins changes the likelihood of subsequently devel- provide more conclusive evidence within the next few
oping atopic sensitisation or clinical allergy. The small number of years. Until then, the available evidence does not sup-
studies found investigating peanut exposure during childhood port the avoidance of peanuts in maternal diets during
clearly highlights the lack of evidence available in this area. pregnancy or breastfeeding, or delayed introduction of
The number of human studies investigating the effects peanuts in the diets of children.
of non-dietary exposure to peanuts on the development of See www.food.gov.uk/safereating/allergyintol/pea-
sensitisation and allergy is also lacking. One study reported an nutspregnancy for further details on the peanut allergy
increased risk of peanut allergy in children who were exposed advice from the FSA.
to skin creams containing peanut oil (8). However, further The FSA has produced, in collaboration with six allergy
studies are necessary to clarify whether topical exposure to and nutrition organisations, a guide to buying food and
peanut protein presents a real risk with respect to sensitisation. eating in restaurants for people with a newly-diagnosed
food allergy or intolerance, including coeliac disease.
The new advice on peanut allergy www.food.gov.uk/news/newsarchive/2009/dec/aller-
The findings from the review were submitted to the COT, gyleaflet.
who concluded that its previous advice on peanut allergy Further reading: Thompson R, Miles L, Lunn J et al.
is no longer supported by the current scientific evidence. (2010) Peanut sensitisation and allergy: influence of early
UK Health Ministers were then advised to revise the Govern- life exposure to peanuts. British Journal of Nutrition 26: 1-9
ment’s precautionary advice to mothers to become in line
with the conclusions of the COT.
References
1 Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT)
A summary of the updated advice
(2000) Adverse Reactions to Food and Food Ingredients. A report from the Committee on Toxicity of
Chemicals in Food, Consumer Products and the Environment (COT) TSO, London
• Pregnant and breastfeeding • If a child already has a known al-
2 Venter C, Pereira B, Voigt K, et al. (2008) Prevalence and cumulative incidence of food hypersen-
women can choose to eat lergy (such as a diagnosed food
sitivity in the first 3 years of life. Allergy, 63, 354-9
3 Hourihane JOB, Aiken R, Briggs R, Gudgeon LA, Grimshaw KEC, DunnGlavin A and Roberts SR.
peanuts or foods containing allergy or diagnosed eczema), (2007) The impact of government advice to pregnant mothers regarding peanut avoidance on
peanuts (such as peanut but- or if there is a history of allergy in
the prevalence of peanut allergy in United Kingdom children at school entry. J Allergy Clin Immunol
119, 1197-202
ter) during pregnancy as part of the child’s immediate family (if
4 Hourihane JO, Kilburn SA, Dean P and Warner JO. (1997) Clinical characteristics of peanut allergy.
a healthy balanced diet, unless the child’s parents, brothers or
Clin Exp Allergy 27, 634–9
they themselves are allergic to sisters have an allergy such as
5 Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT)
(1998) Statement on peanut allergy
them or their health professional asthma, eczema, hayfever, or http://archive.food.gov.uk/dept_health/pdf/peanut.pdf
advises them not to. other types of allergy), then that
6 Dean T, Venter C, Pereira B, Grundy J, Clayton CB and Higgins B. (2007) Government advice on
• Peanuts and other nuts should child has a higher risk of devel-
peanut avoidance during pregnancy--is it followed correctly and what is the impact on sensitiza-
tion? J Hum Nutr Diet 20, 95-9
not be given to infants before oping peanut allergy. In these 7 Frank L, Marian A, Visser M, et al. (1999) Exposure to peanuts in utero and in infancy and the de-
six months of age, along with cases, foods containing peanuts
velopment of sensitization to peanut allergens in young children. Pediatr Allergy Immunol 10, 27–32
8 Lack G, Fox D, Northstone K, et al. (2003) Factors associated with the development of peanut
other foods that can trigger may still be introduced, but
allergy in childhood. N Engl J Med 348, 977–985
the development of a food parents should talk to their GP, 9 Arshad SH, Bateman B, Sadeghnejad A, et al. (2007) Prevention of allergic disease during child-
allergy, including seeds, milk, health visitor or a medical allergy
hood by allergen avoidance: The Isle of Wight Prevention Study. J Allergy Clin Immunol 119, 307–313
10 Chan-Yeung M, Ferguson A, Watson W, et al. (2005) The Canadian Childhood Asthma Primary
eggs, wheat, fish, shellfish, or specialist before giving peanuts
Prevention Study: outcomes at 7 years of age. J Allergy Clin Immunol 116, 49–55
any foods containing these or foods containing peanuts for
11 Strid J, Hourihane J, Kimber I, et al. (2004) Disruption of the stratum corneum allows potent
ingredients. the first time.
epicutaneous immunization with protein antigens resulting in a dominant systemic Th2 response. Eur

J Immunol 34, 2100–2109
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