Last fall, I was feeling exhausted and I was not sure why. Fatigue is one of the symptoms of fructose malabsorption, which I struggled with before I was diagnosed with it three years ago. Going on the low FODMAP diet and going through the process of figuring out what I could and could not eat helped ease many of my symptoms, including the fatigue. But, although I was feeling like I had more energy than I used to, I still felt chronically tired. I consulted with my doctor and we decided that I should get tested for allergies. A couple of years after moving to Boston I started having allergies certain times of the year so I expected that I was allergic to pollen. Interestingly enough, I am not allergic to pollen but highly allergic to dust mites and very slightly allergic to cats, which has not and will not make me stop snuggling my two cats. After buying cases for our mattress and pillows and washing our sheets in hot water instead of warm, I have been feeling better. When I was younger I did not know of anyone who had allergies but now I know many people who do. So I wondered if there has been an increase in allergies over the years? And if there has been, is it because the rate of allergies is rising or we are getting better at diagnosing them?
An allergy is when a small amount of food or other allergen triggers an immune response. This entails antibodies being produced, which target proteins in foods such as peanuts or pollen so they can be removed. Additionally, the mast cells in the body are activated releasing histamines which signals for the area that is affected (e.g., skin, ears, eyes, nose) to close up to prevent the irritant from getting deeper into the body. Allergies can be life threatening so it is important to understand them and prevent exposure to allergens that can trigger a response.
Surveys have indicated that the rates of allergies have been increasing throughout the world and they are projected to affect 30-35% of the population at some point. The number of children in the U.S. with peanut allergies has tripled between 1997 and 2008. In 2013, the Centers for Disease Control and Prevention reported that between 1997 and 2011, there was a 50% increase of allergies in children. Additionally, the European Academy of Allergy and Clinical Immunology claimed that there was a seven-fold increase in the past 10 years of children going to the hospital with anaphylaxis, a life-threatening severe allergic reaction.
Some of the causes for this increase:
Hygiene Hypothesis: Infants require different bacteria and organisms present to help them develop their immune systems. However, this is being limited in some cases due to our use of antibacterial soaps, detergents, and other products that have made our environment increasingly hygienic and sterile.
Antibiotics: We have been increasing our use of antibiotics in our soaps and as medicine. One of the consequences is that healthy and normal bacteria in the gut are killed with antibiotics and openings can occur which may lead to a leaky gut. This can allow foods that have not been properly digested and absorbed to leak out of the gut which can affect the immune system and lead to allergies.
Environment: There has been a rise in pollen due to an increase in carbon dioxide production and higher temperatures. This has led to a doubling of people who suffer from hay fever and hay fever can increase the chances of other allergies from fruit, vegetables, and nuts.
Food: Our diets have changed a lot in the past 50 years from home cooked meals made from local ingredients and fresh milk delivered to the door to an increase of processed foods and less fruits and vegetables. Because of this we have become deficient in certain nutrients. Two examples of this are Vitamin D and Omega-3 fatty acids that have roles in promoting the immune system. Studies have shown that the decrease in Vitamin D and Omega-3 in our diets have led to an increase of asthma and allergies in children. There are some conflicting studies on this topic, but research is still being done. Additionally, some processed foods have been shown to trigger an immune response. Interestingly, some studies have shown that exposing your child to potential allergens, like peanut butter at a young age decreases the chances of an allergy developing. Think of it as an inoculation.
GMOs (genetically modified organisms): Inserting genes from one organism into the DNA of another makes a genetically modified organism. A gene that is allergenic can therefore be introduced into the DNA of a non-allergenic food. For example, a gene from a brazil nut can be spliced into a soybean. That soybean can be grown and used in processed foods resulting in that food taking on the allergenic properties of the brazil nut. In the US, around 1996, GMOs started to be produced and sold with 1% of the corn in 2000 being genetically modified. Today, 90% of corn and 93% of soy are a GMO. In 1999, GMO soybeans began to be imported from the U.S. to the UK and there was an increase to 50% of the population having allergic reactions from the soybeans compared to 10% years before. Due to protests, the sale of the GMO soybeans was reduced, resulting in a stabilization of the number of cases of anaphylaxis.
While there is no doubt that we are getting better at diagnosing allergies, it seems based on studies that environmental factors and our diet are causes for the increase in allergies.
Do you know of other causes for the increase in allergies?
Photo taken by miheco on Flickr