Allergies: A Case for Playing in the Dirt

When my mom and dad were growing up the had virtually no classmates with peanut allergies, having asthma was uncommon, and eczema was rare. What has changed?

There are a number of theories as to why we have seen a dramatic rise in allergies and allergy induced immune conditions, together known as atopic diseases, and why the over $20 billion allergy treatment market is expected to reach roughly $40 billion in the next 10 years. Atopic diseases now impact more than 20% of people worldwide. Nearly 1 in 5 children (18.9%) have a seasonal allergy, 10.8% have eczema, and 5.8% have a food allergy. Companies like Curex, a telemedicine provider treating allergies, asthma, and eczema through immunotherapy options and personalized treatments, aim to profit off the dramatic increase in these types of conditions. Building off of last week’s newsletter, one of the main suspects of this rise in allergies is processed foods and the lack of diversification in children’s diets, specifically in America. Modern diets are now high in processed foods, low in fiber, and lack the variety and biodiversity necessary for a health gut microbiome leading to underdeveloped immune systems, in turn contributing to rising allergy rates.

Until 2008, the American Academy of Pediatrics (AAP) advised against the introduction of allergenic foods, such as peanuts, until 3 years old. This was discovered to have been a huge misstep in food guidance as delayed the introduction of these foods has likely contributed to the drastic increase in food allergies. Without early exposure to these common foods, there’s a higher chance that allergens are introduced via skin or respiratory track. By introducing foods such as milk, eggs, peanuts, sesame, fish, and wheat early, babies can be sensitized and lower their risk of developing food allergies. This recommendation was based only on expert opinions and there was no convincing data to support the position at the time. Since delayed introduction of allergenic foods in infants' diets has been now linked to increased food allergies, early exposure is now considered beneficial in promoting tolerance. Companies Fig and Amulet aim to reduce the friction for consumers dealing with these food allergies by providing both software and hardware to detect allergens potentially consumed in everyday life.  

The hygiene hypothesis is another theory that suggests reduced exposure to microbes from excessive cleanliness may lead to an underdeveloped immune system, making children more susceptible to allergies. Children exposed to more germs, such as those in daycare or with older siblings, tend to have lower allergy rates, supporting the idea that early exposure to microbes is beneficial. Post-COVID specifically, the excessive use of hand sanitizer and compulsive hand washing that took place, could seemingly contribute to the weakening of kids’ immune systems and increase in food allergies.

Another theory that has surfaced is that increased exposure to environmental pollutants and chemicals can trigger allergic reactions. The skin, acting as a barrier, can be compromised by these exposures, leading to increased sensitization. Environmental pollutants can damage airway linings and make the body more susceptible to allergens like pollen. Certain particles found in the air can also increase the likelihood of developing asthma. Genetic predisposition plays a role, with family history being a risk factor for developing allergies. However, environmental factors often interact with genetic susceptibility. Changes in DNA epigenetics, or DNA methylation which is influenced by environmental factors, can affect immune responses and contribute to allergy development. Reduced sunlight exposure and subsequent vitamin D deficiency have also been associated with higher allergy rates, as vitamin D is crucial for immune function.

The microbiome and composition of gut bacteria has proven to be a crucial element is crucial in developing immune tolerance. Having a diverse microbiome early in life is essential to improving the immune system and decreasing risk of allergies. Factors like mode of delivery (ie. C-section vs. vaginal) and breastfeeding can influence the diversity of your microbiome. The company Tiny Health (which I angel invested in) provides tests for babies and mothers to find out what microbes are present and help treat and prevent chronic diseases caused by the lack of diversity or disruptions in the microbiome. Given the overprescription of antibiotics, specifically in infancy, there has been an increased disruption of the microbiome leading to higher rates of allergies. Children who take antibiotics early in life are at a greater risk of development a whole host of conditions like asthma, celiac disease, and eczema.

It is clear that the rise in allergy rates is correlated with the industrialization of our society and food sources. Pollutants, processed foods, improved hygiene, increased access to antibiotics, all unfortunately contribute to this spike in allergies we are seeing. While there are certain steps we can take, such as exposing our kids to food allergens early and letting them play in the dirt, it is difficult to ensure kids are never going to grow up and develop one allergies, eczema, or asthma. The good news is there are many advocates and companies working to ensure we have access to the tools, resources, and knowledge needed to combat the rise in atopic diseases. The more we try to understand why these changes are happening the better equipped we will be to develop effective prevention and treatment strategies.