Challenging conventional beliefs, Neha Natu unravels the compelling investigation into whether early exposure to peanuts holds the key to eradicating peanut allergies.
Amidst the cheerful melodies of Christmas carols and the aromatic symphony of cinnamon and pine, a cosy gathering takes place in a warmly lit living room. The air is filled with the fragrance of freshly baked cookies, from classic peanut butter cookies to nut-crusted desserts, spiced cider, and the unmistakable scent of a beautifully adorned Christmas tree. In the midst of this cheerful atmosphere, someone accidentally ingests peanuts, unaware of their presence in a dish or treat. Within moments, their body responds to the allergen, triggering a rapid and severe allergic reaction. First comes the itching, then the swelling, difficulty breathing, and the plummeting blood pressure. The prevalence of peanut allergies has tripled in the past two decades, affecting an estimated 1.2% of the overall US population and about 2.5% of the paediatric population. They are also a leading cause of food allergy-related deaths in children.
The introduction of biological compounds to treat peanut allergies has the potential to revolutionise how these patient cases are managed. Their anticipated high cost, however, raises several issues for payers as to how to integrate these new therapies into formularies and treatment continuums. However, what if there exists an opportunity to address the root of the issue?
Early exposure to peanuts has been identified as a potential way to reduce the risk of developing peanut allergies. This concept, known as early allergen introduction, suggests that introducing small amounts of peanuts to infants at an early age — typically between 4 to 11 months — might help reduce the likelihood of developing a peanut allergy later in life. This approach completely contradicts older advice that suggested avoiding allergenic foods like peanuts in infancy to prevent allergies. Research, particularly the LEAP (Learning Early About Peanut Allergy) study, indicated that early introduction of peanuts to infants at high risk for allergies, such as those with a family history of allergies, significantly lowered the risk of developing peanut allergies. In 2015, 530 babies with eczema, egg allergies, or both were evaluated in a groundbreaking clinical LEAP experiment. Some youngsters were given limited amounts of peanut-containing foods, while others were warned to avoid them. Only 1.9 percent of the youngsters in the peanut-tasting group had acquired peanut allergy by the age of five. 13.7 percent of the youngsters in the avoidance group were allergic to peanuts. An analysis showed a 75% reduction in peanut allergies among children randomised to consume peanuts from early infancy. This significant reduction in peanut allergies with early peanut introduction in a large group of pooled randomised participants speaks volumes for the future of allergies.
The pivotal player in this recent research is commensal biota. Commensal biota refers to the collection of microorganisms, including bacteria, fungi, viruses, and other microbes, that reside in or on the human body without causing harm to the host. Particularly those in the gut microbiota, play a significant role in modulating the immune system and have been associated with reducing the risk of developing allergies. Exposure to diverse commensal bacteria early in life appears to support the development of immune tolerance. This exposure helps the immune system learn to tolerate harmless substances, such as certain foods or environmental factors, reducing the likelihood of developing allergies against them.
To dive deeper and understand how commensal microbiota balances diverse inflammatory responses, it is important to understand the balance between effector T helper cells. Effector T cells are a subset of T lymphocytes (a type of white blood cell) that play a key role in the immune response by directly responding to pathogens or infected cells. Specifically, T helper 1 (Th1) and T helper 2 (Th2) cells play crucial roles in the immune system and maintaining a balance between them is essential in protecting against allergic diseases. Th1 cells promote cellular immunity and are associated with suppressing allergic responses. Meanwhile, Th2 cells are initiating and amplifying allergic responses by promoting the production of antibodies and activating other immune cells involved in allergic reactions. Maintaining a delicate balance between Th1 and Th2 cells is critical for a well-functioning immune system that effectively combats pathogens while preventing inappropriate allergic responses. Neonates at birth are skewed towards greater Th2 cells, the cells responsible for the initiation of allergic reactions. However, the exposure to microbial antigens in the commensal microbiota stimulates Th1 cell expansion. Commensal bacteria in the gut and other mucosal surfaces interact with the neonate's immune system, aiding in its development and education. While it's a complex area with many factors at play, the studies suggest that early exposure to certain allergens might influence the composition of commensal bacteria and, in turn, affect the risk of developing allergies. Exposure to allergens, such as peanuts, when introduced gradually and appropriately, might help the immune system develop tolerance rather than an allergic response. This tolerance could be influenced by the interactions between the immune system, allergens, and the gut microbiota. This early introduction will increase microbial diversity, a controlled allergen introduction and the slow building of immune tolerance.
Exposure to allergens, such as peanuts, when introduced gradually and appropriately, might help the immune system develop tolerance rather than an allergic response.
Although the NIAID-Sponsored Expert Panel's 2017 Addendum Guidelines for the Prevention of Peanut Allergy in the United States recommend peanut introduction during infancy based on risk level, the researchers found that less than one in five carers in this study introduced peanuts to their infants by age 7 months. When more than 3,000 parents and caregivers of infants and young children were asked about this early exposure, nearly 9 in 10 weren’t aware of the new guidelines. Joshua Boyce, chief of the division of allergy and clinical immunology at the Brigham and Women’s Hospital in Boston has said that the adoption of the advice has “been slower than we had imagined. But the bottom line is that 80 to 90 percent of all peanut allergies are preventable in high-risk kids.”
However, this should be done under the guidance of a healthcare professional. It's important to consult with a paediatrician or allergist before introducing peanuts or any potential allergenic food to an infant.
However, this should be done under the guidance of a healthcare professional. It's important to consult with a paediatrician or allergist before introducing peanuts or any potential allergenic food to an infant, especially if there's a family history of allergies or if the baby has pre-existing conditions like eczema. The introduction of peanuts should be done gradually and with age-appropriate forms (such as peanut butter diluted with warm water or smooth peanut butter mixed into pureed foods) to reduce the risk of choking. Monitoring for any signs of allergic reactions, such as rash, vomiting, or difficulty breathing, is crucial when introducing peanuts or any new food to infants. Ultimately, decisions regarding the introduction of peanuts to babies should be individualised based on the infant's health history, family history of allergies, and guidance from healthcare professionals. Early introduction might be considered for some infants, but it's important to proceed cautiously and seek guidance from healthcare providers.