What is food sensitivity?
Before diving into key drivers of food sensitivities and intolerances, let’s clarify what exactly food sensitivity is and how it differs from food intolerance and food allergy.
Food allergy is a reaction of our immune system to food particles. This reaction is:
- mediated by immunoglobulins-E (“IgE”) antibodies
- possible even with traces of food present
- usually, immediate
- affects multiple organs
- could be severe and life-threatening
The symptoms of food allergy include swelling, hives, itching. In some cases, this reaction could cause anaphylaxis. There is currently no proven treatment for allergy.
Food sensitivity is also an immunological reaction to food particles, usually proteins. However, it is mediated by different types of antibodies, immunoglobulins G (“IgG”). The symptoms are less severe than with an allergic reaction and may appear anywhere between 3-72h. The symptoms of food sensitivity could manifest anywhere in the body and include skin conditions, fatigue, headaches, respiratory issues, joint pain. Eight food groups account for 90% of sensitivities: milk, soy, eggs, wheat, peanuts, tree nuts, fish, shellfish.
- Food intolerance is a non-immunological reaction to food that occurs when an individual struggles to break down certain food particles, often carbohydrates. The examples of food intolerance include:
- lactose intolerance when an enzyme “lactase” required to break down lactose is lacking.
- wheat sensitivity.
- irritable bowel syndrome, a condition where digestive reactions may occur as a result of eating particular types of carbohydrates found in some fruits, vegetables and beans.
- sensitivity to food additives, such as sulphites or artificial colours.
Food intolerance symptoms are less severe than food allergy and often limited to digestive complains, such as abdominal pain, bloating, gas, diarrhoea. It is still possible for individuals with food intolerance to tolerate a small amount of offending food.
Both food sensitivities and intolerances could be improved once the gut health is addressed.
We live in increasingly sterile environment, it is becoming even more apparent now, during the current global pandemic, as we constantly sanitise our hands, surfaces and homes.
Key drivers of food sensitivities and intolerances
Food sensitivities affect at least 100 million people worldwide, with the prevalence increased over 50% in adults and children in past few years. Food sensitivities and intolerances sit on intersection of inflammation, immunity and gut permeability. The common denominator of all three is out gut microbiome, or microorganisms along with their genetic material inhabiting our intestine.
Unlike humans who only have a limited number of enzymes capable of breaking down complex carbohydrates, gut microbes boast around 60,000 of enzymes capable of digesting different types of fibre of for us. Gut microbiome is crucial in training our immune system “to recognise” food particles and our own cells and not to attack them. In addition, the microbes produce energy required for regeneration and healthy growth of gut lining.
So, it should not come as a surprise that the loss of microbial diversity impairs all of the above. Impoverished microbiome drives inflammation in the gut, causing gut lining destruction, over activating the immune system and causing inability to digest the foods.
The symptoms of food sensitivity could manifest anywhere in the body and include skin conditions, fatigue, headaches, respiratory issues, joint pain.
The rise of food sensitivities is driven by the loss of gut microbial abundance, loss of intestinal integrity and dysregulated immune response, with the following factors contributing to it:
Use of antibiotics
The widespread use of antibiotics in the last 80 years undeniably saved millions of lives, however, there is also a darker side of antibiotics use. In 2017 in the U.K. 773 tonnes of antibiotics were dispensed, 36% or 282 tonnes of which are for the use of food-producing animals and 64% or 491 tonnes for humans.1 Everyday GPs issue 100,000 antibiotic prescriptions, with researchers estimating that 20% of these prescriptions being inappropriate.2
The research is very clear that the use of antibiotics causes short, long-term and sometimes permanent changes to the diversity of the intestinal microbiome. For example, a course of amoxicillin can disrupt microbiome composition for 30 days in average and up to 2 months in some people. Microbiome changes caused by a course of ciprofloxacin could persist for several weeks.3 As the nation we are overmedicated causing irreversible damage to the diversity of our microbiomes. Moreover, we are also exposed to antibiotics through animal produce and water supply. Antibiotics interfere with the interaction between the microbiome and immune system, resulting in a number of disorders, with food sensitivities being one of them.
Excessive cleanliness and “Hygiene Hypothesis”
We live in increasingly sterile environment, it is becoming even more apparent now, during the current global pandemic, as we constantly sanitise our hands, surfaces and homes. The “Hygiene hypothesis” states that excessive sanitation cause disturbances to the components of the immune system, causing dysregulation of the inflammatory response. On the other hand, exposure to soil, nature and animals have positive effect on microbiome diversity.
Diets low in fibre and high in sugars, additives and chemicals
Modern diets are deprived of fibre, which is the crucial nutrient for our gut. The average fibre intake in the UK is just 18g vs. recommended 30g per day. One of the last remaining hunter-gatherers tribes, the Hadza from Tanzania, consume a whooping 100g of fibre daily from c.600 different plants compared to less than 50 plant types we regularly consume in the West.
In addition, the list of food additives, such bulking agents, colourants, emulsifiers, also known as “E-numbers” has been growing exponentially in the last few decades. There is an accumulating evidence suggesting that food additives can disrupt gut microbiome, thereby promoting inflammation and tissue damage.
As we collectively deprive our microbiome of fibre and destroy it with medication, we are irreversibly losing microbial species and passing the impoverished microbiomes to the next generations spurring more food sensitivities and intolerances.
The best strategy to combat food intolerances would be supporting our microbiome through a balanced lifestyle and a diet rich in diverse plants.
Elena holds a Nutritional Therapy Diploma (DipION) from the Institute for Optimum Nutrition and is working towards BSc (Hons) Nutritional Therapy degree from the ION.