Infant eczema is a common skin condition, affecting around 1 in 5 young children. Eczema is linked to childhood asthma and food allergies and many theories have been proposed to explain the development of atopic eczema.
One of these theories suggests that the microflora in the gastrointestinal system of infants influences immune system activity, thereby triggering or contributing to skin reactions and allergy symptoms. A significant amount of research backs up this theory, including a recent review that adds weight to the idea that prebiotic supplementation of infant formula or breast milk can help in preventing eczema in infants up to 2 years old.
Preventing Eczema – Prebiotics Cut Eczema Risk by Almost a Third
The new research looked at four studies involving 1428 infants aged 4 months to 2 years old who received prebiotics or acted as a control. What they found was that there was a 32% cut in relative risk of eczema in children receiving prebiotics.
They didn’t find any significant difference between the risk of allergy and the type of infant milk however. The researchers worked out that the number needed to treat to benefit was 25, meaning that for every 25 infants given prebiotic supplementation one would be helped to prevent eczema.
The studies included in this review were, unfortunately, not of the highest quality and only one study looked at the effects of prebiotics in high-risk children. Some of the studies did find a highly significant reduction in risk of eczema in low-risk children. This study found an associated reduction in the risk of asthma and eczema but not allergies overall.
Infant Immunity and Gut Health
Infant gut immune systems are not fully developed by the time of birth and the relative lack of exposure to microbes in early life (due to more rigorous hygiene practices) is thought to be one reason for the increase in allergic diseases. The hygiene hypothesis is now called the microflora hypothesis of allergic diseases and essentially describes the interaction between the immune system residing in the gut and the gut microbiome, i.e. its bacterial make-up.
The gut is more permeable in early childhood, thereby allowing undigested proteins, bacteria and other pathogens to enter the bloodstream and trigger undesirable reactions. Where an unfavourable bacterial environment exists in the gut this can reduce a child’s capacity to properly digest food and contribute to a leaky gut meaning that undigested proteins, such as gluten, escape from the gut and are then viewed as foreign invaders by the immune system, triggering the development of a food allergy or sensitivity.
Microflora and Allergies
Children who are regularly exposed to a variety of microbes have an improved oral tolerance, as has been demonstrated in animal studies where mice raised in germ-free environments develop no tolerance for microbes. Supplementing the mice with bifidobacteria helps reconstitute this tolerance.
Poor gut microflora diversity has been associated with the development of atopic eczema, and lower populations of Lactobacilli and Bifidobacteria have been found in infants who later go on the develop allergies. Providing both the beneficial bacteria and prebiotics to feed them is key to reestablishing a healthy microbiome in infants and adults alike.
What Are Prebiotics?
Prebiotics are found in breast milk, fruit, vegetables and other foods of plant origin and are known to selectively feed beneficial bacteria in the gut. Commonly used prebiotics include inulin from chicory root, as well as fructo-oligosaccharides found in fruits.
These food components are indigestible and can be added to breast milk, infant formula or foods meant for adult consumption to help encourage the growth and activity of the good bacteria (probiotics) in the gastrointestinal and genitourinary tracts.
More Evidence Prebiotics Cut Eczema Risk
In two studies, supplementation with prebiotics has been seen to help prevent eczema. One study looked at supplementing infant formula with a galacto-oligosaccharide (GOS)/fructo-oligosaccharide (FOS), compared to maltodextrin in high-risk infants from birth to 6 months.
This study found that the risk of eczema at 6 months was significantly reduced (9.8%) in the GOS/FOS group compared to the control group (23.1%); the effect was sustained until 2 years. In another study looking at children in 5 European countries, infants under 2 months who received formula supplemented with prebiotics had a 44% lower incidence of atopic dermatities at 1 year, compared to regular formula users.
Adding both probiotics and prebiotics to infant formula can help combat pathogens and may help prevent infant diarrhoea and antibiotic-associated diarrhoea. The make-up of gut flora has also been implicated in the development of behavioural issues in childhood and susceptibility to autoimmune conditions like juvenile arthritis.
Atopic eczema is the most prevalent allergic disease of childhood and probiotic administration has been found time and again to help cut the risk of this skin issue in the first two years of life. More recently, evidence has emerged showing that probiotic and prebiotics administration could help in preventing eczema up until the age of 4, in addition to helping prevent respiratory allergies. Up to 8% of young children develop food allergies, and around 34% develop asthma.
Combined Prenatal and Direct Infant Probiotic Supplementation Best
The most significant benefits have been seen with combined prenatal and postnatal probiotic supplementation with Lactobacillus rhamnosus appearing to be the most effective strain. This means that infants are more likely to be born with a healthy and robust gastrointestinal flora and to receive ‘top-ups’ by way of supplemented breast milk or infant formula throughout the first few years of life.
Over 23 randomized, placebo-controlled intervention studies have investigated the use of probiotic supplementation on development of allergy and eczema in childhood and around 60% of the studies show a reduced risk of eczema in early childhood. The other studies are often in high-risk individuals. Childhood eczema is a fairly reliable indicator of the likelihood of developing respiratory allergies in later life and by preventing eczema this may also help prevent asthma and other immune issues.
Probiotics in Pregnancy – Preventing eczema
One large study involved giving four probiotic supplements to women from the 36th week of pregnancy, and to infants from birth to 6 months, alongside a prebiotic oligosaccharide. The probiotics were Lactobacillus rhamnosus GG (LGG), L. rhamnosus LC705, bifidobacterium lactis Bb12 and propionibacterium. The infants were monitored up to 2 years old and those who, along with their mothers, received the supplements had a 20% reduced incidence of eczema, and a 30% reduction of atopic eczema compared to placebo.
The same children were assessed at the age of 5 and those delivered by caesarian section who received probiotics and prebiotics were found to have a significantly reduced incidence (just 17%) of IgE-associated eczema and food-specific IgE-sensitization. Children delivered by caesarian miss out on ingesting bifidobacteria from the vaginal canal and have delayed colonisation of beneficial bacteria. This can be corrected with probiotic supplementation.
In another study 474 pregnant women given Lactobacillus rhamnosus HN001 or placebo for a month prior to giving birth and for six months after birth if breastfeeding, and with infants given direct probiotic supplementation from birth until 2 years had a a 50% reduction of eczema (26.8 vs. 14.8%). Those receiving bifidobacterium animalis subsp lactis HN019 had no significant change in risk, highlighting the importance of specific strains in preventing eczema.
The same study found that at 4-year follow-up L. rhamnosus continued to be associated with a reduction in eczema, as well as with respiratory allergies. The children in the lactobacillus group had less rhinoconjunctivitis, suggesting that preventing eczema early could prevent other atopic conditions.
The same protection against allergy doesn’t seem to occur as consistently with just prenatal supplementation or just postnatal supplementation; it is the combination that appears most effective in preventing atopic eczema in childhood, as well as allergic diseases later.
Some Probiotics Cut Eczema Risk by Half
In some studies supplementation with Lactobacillus F19 between 4 and 13 months (while weaning) halved the frequency of eczema at 13 months. Another study found that LGG, L. acidophilus La-5 and Bifidobacterium animalis taken for a month before birth and then three months after birth (while breastfeeding) led to a relative risk of just 51% of atopic eczema by 2 years of age.
Probiotics Beneficial to both Mothers and Infants
In another study maternal supplementation with L. rhamnosus LPR and B. longum BL999 for 2 months prenatally and up to 2 months after birth, while breastfeeding, led to an odds ratio of 0.17 for atopic eczema up to 2 years of age, compared to placebo. Another group who received Lactobacillus paracasei ST11 and BL999 had an odds ratio of 0.16. Other studies have noted a reduction in mother’s symptoms of allergic disease when taking probiotics which could have a range of benefits for both mother and child.
In conclusion, combined prenatal supplementation and direct infant supplementation after birth, such as with a probiotic powder in breast milk or formula, appears to offer the best protection against childhood eczema. Additionally, only specific strains of probiotics have shown benefit, namely L. rhamnosus, the most effective strain studied so far. The effect of prenatal and direct infant probiotic supplementation for preventing eczema has been shown to be sustained up until 5 years old.
Osborn DA, Sinn JKH. Prebiotics in infants for prevention of allergy. Cochrane Database of Systematic Reviews 2013, Issue 3. Art. No.: CD006474. https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006474.pub3/pdf/CDSR/CD006474/CD006474_abstract.pdf
Mikael Kuitunen, Probiotics and Prebiotics in Preventing Food Allergy and Eczema. Curr Opin Allergy Clin Immunol. 2013;13(3):280-286. https://www.ncbi.nlm.nih.gov/pubmed/23594506