Clinically diagnosed food allergies are thought to have doubled in roughly the last decade, with now as many as 15 million people—and 8 percent of children—affected in the United States alone. Simultaneously, hospitalizations for severe allergic reactions have increased seven-fold. Why? Here are the top four reasons allergies are on the rise:
1. Outdated erroneous guidelines
Guidelines used to urge parents to avoid major allergens like nuts, fish, and eggs until toddlerhood, but scientists now think this advice may have accelerated the current food allergy epidemic. The immune system likely has a critical period to learn that all foods—especially allergenic foods—are safe. If exposure is delayed or inconsistent, an allergy can develop.
Parents are now encouraged to introduce potential allergens, especially peanuts and eggs, to babies as young as 3 to 6 months old—assuming they are developmentally ready for food. And then it's recommended that they continue to feed them allergens regularly (perhaps up to twice a week) for the first five years of life. If your baby has severe eczema or a family history of allergies, you may want to have them evaluated before exposing them, but don't delay. Early and regular exposure may be particularly important for high-risk babies.
2. Lack of sunshine
While the outdated recommendations almost certainly contributed to the rise in food allergies, they are unlikely to be the only culprit. Many immune system disorders including allergies, multiple sclerosis, schizophrenia, and Parkinson's disease increase as you get farther from the equator and some scientists suspect the cause is inadequate amounts of sunshine.
These studies can sometimes smack of astrology: One undertaken in Boston found that people visiting a hospital due to food allergies are more likely to have an autumn or winter birthday. The reason, however, is not the alignment of the stars but perhaps exposure to one star—the sun. These patients may have received too little sunlight in infancy, inhibiting the production of vitamin D, an essential immune system ingredient, which may have made food allergies more likely.
Unfortunately, the answer does not simply lie in vitamin D supplementation. Vitamin D supplements have problems of their own and have even been linked to increased rates of allergies. Moderate exposure to sunshine is likely the best bet.
3. The hygiene hypothesis
The development of a healthy immune system may also suffer from an overly clean environment. I am, unfortunately, not saying that basic housework is the problem here. Our world is "too clean" due to many necessary sanitation measures that eradicate pathogens and provide us with luxuries like clean water and uncontaminated food. These measures have curbed infectious diseases and infant mortality rates and improved life spans. But with the good also comes some bad. The immune system evolved receiving stimulation from pathogens during its development. An immune system that largely develops without these challenges may act paranoid, reacting to a peanut as if it's poison.
Our sanitized environments—along with the average cosmopolitan lifestyle in which we spend little time mucking about in nature—are also suspected to make it hard for our trillions of helpful microbes to thrive. Our microbiome helps train our immune system to work correctly. An impoverished microbiome, some scientists speculate, may affect our immune system's ability to correctly "decide" if a certain food is friend or foe.
4. All of the above
It's also possible that all the above matter when it comes to the development of allergies in our modern world. That is, an infant immune system that is deprived of adequate sunlight, pathogens, good microbes, and allergen exposure may be particularly at risk for developing allergies.
There are only two things parents can do to fight back; first: send our kids outside to play in the sun and the dirt, and second: embrace major food allergens (eggs, peanuts, tree nuts, seeds, dairy, fish, shellfish, soy, kiwi, banana ,and whole wheat) for meals and snacks. If your toddler or child doesn't like one of these foods, try to offer it in different forms (kiwi-sesame-smoothie, anyone?) until you find something your little one loves.