Introduction

Recently, oat milk and other non-dairy alternatives have soared in the grocery industry. Similarly, other food allergies seem to be becoming more and more prevalent in American society. As this phenomenon gains traction, more research is being done to explain its origins.

What are food allergies?

Food allergies, due to IgE antibodies, result from a hypersensitive reaction from the human body’s immune system. Although a seemingly harmless food, some bodies can react in a dangerous way. One of the most dangerous reactions is anaphylaxis, where airways begin to close and blood pressure drops. According to the Centers for Disease Control and Prevention, milk, eggs, tree nuts, peanuts, fish, shellfish, soy, and wheat account for 90% of allergic reactions.

More common than food allergies is food intolerance. While food allergies have an immediate reaction, food intolerance is usually due to IgG antibodies and the symptoms are primarily concentrated in the digestive areas of the body. 

It is important to understand food allergies and food sensitivity in order to understand how different foods can affect the human body.

Factors

Nationally, representative surveys show an increase in food allergies of the US population over the past 10 years. In addition, other Western countries have been recognized/identified  for having the highest rates of food allergies across the globe, with food anaphylaxis rates on the rise in Australia, the US, and the UK. 

What factors cause this increase?

Certain genetic factors, as well as reduced microbial and vitamin D exposure, have been pointed to as the cause for many allergies. Aside from genetics, environmental factors also have an impact on the growing rates of food allergies. In the popular case of peanut allergies, environmental peanut exposure is associated with increased allergy risk. 

Researchers have interestingly proposed the dual exposure hypothesis for food allergy. This hypothesis states that early exposure to allergens (like peanuts) through the skin can lead to higher rates of food allergies than early exposure through the digestive tract. One study that focused on babies who were exposed to a form of peanuts on their skin showed the children to have an increased risk of peanut allergies after 5 years. Several other studies have analyzed and continued to analyze this theory, all coming to the similar but promising conclusion that introducing peanuts in the diet of infants showed higher rates of immune tolerance for the allergen.Another popular food intolerance is cow’s milk. One study found cow’s milk allergy (CMA) to be 15% inheritable. However, other factors like childhood development also play a role. One study found evidence that individuals who immigrate early in their lives have a higher risk of sensitization than those who immigrated later in life. Interestingly, CMA is more prevalent in males among children, but this trend reverses in adults with 80% of those with CMA being female.

CMA studies that compare sensitivity by race and ethnicity are less reliable. When population statistics from 2005-2006 were compared, no apparent differences were found. Another study that used physician diagnosis and self-reporting methods found that non-Hispanic, Black, and Asian participants had a 50% lower risk of food sensitivity than white participants, but was later discredited because the use of physician diagnosis as a parameter was said to negate the significance of the estimate. Ultimately, more studies need to be done regarding food sensitivity across different races and ethnicities.

Furthermore, epidemiological (having to do with disease or disorders) factors also affect immune tolerance. Pet ownership and the presence of older siblings have been shown to create high microbial diversity and even higher protection against asthma, or a wider range of microorganisms in the human body. This is good news as high microbial diversity has been proven to aid with higher immune tolerance across the board. 

Overall, the general theme is that the introduction of a healthy gut microbiome in early child development helps with food intolerances. Other environmental and demographic factors may also contribute, as well as genetic factors. It is important to note that developed countries do not have as much research done, and socioeconomic factors can strongly affect the outcomes of this data. Once further studies are done in different communities, a true comparison can be made.

Further research

Interestingly, this topic is heavily studied in children but not in adults. This means that most research does not take into account developed food insensitivity or food allergies that were discovered later in life. 

The bottom line is that this topic is severely under-researched. Several risk factors are apparent in conducting studies that make many researchers back away from the challenge. However, a continued push to study and understand our diets will benefit humans’ quality of life and reduce food-related hospitalization rates.