Food allergies (FA) are a common problem we are all familiar with. But the actual extent in which they invade people’s lives worldwide is not as common knowledge. As more research on food allergies is coming out, it is becoming apparent that food allergies are on the rise globally both in developed and developing countries (WAO, 3), but exactly why is unclear. However, the statistics do not lie. This blog will focus on the overview of food allergies in different countries of the world including which types of food are most problem-some, the statistical prevalence, and the targeted population.
According to the WAO, globally around 220-250 million people suffer from food allergies. Of those, the life-threatening allergies tend to be more prevalent in children around 5-8%, than adults around 1-2% (6). In the US, the most common food allergies responsible for 90% of these allergies include: peanuts, tree nuts, milk, eggs, wheat, soy, fish, and shellfish (FARE). Surprisingly, these food allergies are not unique to the United States and happen to be common across the world.
Generally, in Asia the most common food allergens strong enough to cause anaphylaxis are milk, eggs, wheat, peanuts, and soybeans (Van Der Pole, Chen & Penagos, 2009). This is very similar to the US. However when different areas of Asia are assessed there is variance among food allergies due to unique eating habits. For example, In Singapore, the most common anaphylaxis causing food allergy is bird’s nest affecting 27%. Whereas milk and eggs are less than half at 11%. Looking at Japan, the most common anaphylaxis causing allergens are milk, eggs, wheat, peanuts, soybeans, sesame and buckwheat. In Korea, there is a bit of an age difference where the most common food allergies for children 6-12 years old are egg, milk, fish and seafood, whereas for children ages 12-15 they are seafood, peach, milk, egg and fish. An untypical food allergen in Korea is chestnut, yet it is the third most common diagnosed food allergen. A very unusual yet prominent food allergen across Asia is silkworm pupa. This is a traditional Chinese food. But for a price because, each year over 1,000 patients suffer anaphylaxis from this food. Buckwheat is not only common in Japan but China and Korea as well because it is used in large quantities to make common foods such as noodles, cakes, and biscuits (Van Der Pole, Chen & Penagos, 2009). Overall, the prevalence of food allergies in Asian countries varies according to region and breaks down as such: China (25.3%), Hong-Kong (4.6-8.1%), Singapore (4-5%), Japan (5.5%), Thailand (6.25%), and Korea (10.9%) (Van Der Pole, Chen & Penagos, 2009).
In Latin America, the overall occurrence of allergies is not documented. However, there are some stats on different areas, In Colombia for example, the overall prevalence of self-reported food allergies is 14.9% with fruits and vegetable, seafood, and meats being the most commonly reported. In Brazil the most commonly reported food allergens included fish, egg, milk, wheat, peanuts, soya, and corn. Similarly in Chile, Fr. Children between 3 and 5 years old the most common food allergens are milk, seafood, peanut ands soya. Not similarly and interestingly, the other most common allergen is orange at 3.1% for children over 5 years of age. In Mexico fish and cow’s milk are the culprits. Followed by seafood, soya, beans, orange, onion, tomato, chicken, nuts and strawberries (Van Der Pole, Chen & Penagos, 2009).
In Africa barely any information on food allergies has been done, but the small research that has, shows us the same trends we have been seeing where in patients under the age of 3 as well as over the age of 3, the most common food allergies are egg, peanut and milk.
Overall, you may be surprised to see that the food allergens most common to humans tend to be shared across the world. Below is a visual map of which allergens are most common, and where. Following that is a map showing which allergens are responsible for death, where, and how many in recent years.
Works Cited
Food Allergy Research & Education (FARE). (2014). Facts and Statistics. Retrieved from http://www.foodallergy.org/facts-and-stats
Food Allergy Research & Education (FARE). (2014). Allergens. http://www.foodallergy.org/allergens
Van Der Pole L., Chen J., Penagos M. (2009). Food allergy epidemic - Is it only a western phenomena? Current Allergy & Clinical Immunology, 22, 121-126.
World Allergy Organization (WAO). 2013. Food Allergy - A Rising Global Health Problem [Powerpoint]. Retrieved from http://www.worldallergy.org
Blog Entry #2: Global Food Allergies & Children.
Blog Entry #2: Global Food Allergies & Children.
Blog #1 introduced us to allergies across the world. One trend that was clear is that allergies are most common among children, regardless of location in the world. According to FARE, nearly 6 million, or 8% of children have food allergies in the US (FARE, 2014). That is 1 in every 13 children, approximately 2 per classroom (FARE, 2014). These rates are high and continue to increase. According to FARE, a 2013 study by the CDC showed that food allergies among children increased 50% between 1997 and 2011. That is significant. They also reported that food allergies result in more than 300,000 ambulatory care visits a year among children under the age of 18 (FARE, 2014). This is just in the US alone. This blog will focus on food allergies and children, how they are impacted globally and ways to accommodate the allergies.
In a global research study on the food allergy burden on children, Prescott et al. collaborated with the World Allergy Organization (WAO) and collected data from 89 countries and examined the differences in food allergy prevalence based on different factors, among children. This blog will heavily focus on this work as it brings to light important global trends.
The prevalence of food allergies in children is prominent, but they vary quite a bit depending on location. In preschool children under the age of 5 years, food allergies ranged from 1% in Thailand to 10% in Australia. In Northern Sweden based on history of clinical reaction and food-specific IgE, the tallies reached 3.2%, with Asia not far behind with 3.4% in Taiwan. In older children under these conditions, the food-allergy prevalence ranged from 0.3% in Korea to 5.3% in Sweden and 7.6% in Taiwan. The studies in Africa are limited but it is thought for older children they hover around 5%. For food allergies in children based on self or parental reporting, the US and Canada have a prevalence rate of 7-8%. Similar rates were found in the Middle East, Spain, Poland, the Netherlands, and France. Even Higher rates around 15% were reported in the UK, Germany, Iceland and Colombia. In African countries such as Mozambique, the self-reported rate of food allergies is as high as 19% and 17% in Tanzania. In South America, rates were 10% for 1-8 year olds and 12% for 9-16 year olds which is similar to results in Spain and Italy. The results in these countries are pretty high but lower rates were also found in Asian countries such as Japan, Hong Kong and Korea where prevalence was reported around 5% or less. As well as European countries such as Slovenia, Estonia, Switzerland, Greece and Belgium also with rates 5% or less. What is interesting here is clearly, self or parental reporting of food allergies in children is very high. There have been a few studies done proving this is overestimation where they compared the self-reporting percentages to the official OFC percentages with the same population and the self-reported prevalence rates were much higher (Prescott et al., 2013). It makes you wonder what is going on in the cultures that makes parents believe their children have food allergies when according to medical standards, they don’t. Perhaps it could be related to access to resources to get testing to determine if the food allergies are medical, or perhaps it could be due to cultural beliefs surrounding foods, or even ignorance as to what it means to have a biological food allergy. I think more research should be done in this area to understand this clearly large global trend. However, very high prevalence rates of food allergies in children based on very accurate measures do exist. In analysis done in Australia, medical food allergy in infants was 10%. 8.9% prevalence with egg allergy and 3% prevalence with peanut allergy (Prescott et al., 2013).
This leads us to the discussion of which foods are triggering the allergies. Still looking at Prescott et al’s work, the most common food allergens in children under the age of 5 were similar across most regions typically including cows milk, egg, peanuts and seafood. However the rates and distribution of these vary. For example in Australia, New Zealand and Asia, egg allergy is more common than milk allergy whereas in the Americas and Middleast cow’s milk is consistently more common. In Europe these two foods are more equally common for this age group. Also in Asia, fish and seafood are in the top five most common food allergies for preschool children (Prescott et al., 2013). I thought this was interesting to ponder considering cultural factors. Consider how seafood is a staple to the Asian diet. Asian children are therefore exposed to seafood much earlier in life compared to places such as the US where seafood is typically a taste acquired with age. Because children are exposed to the food early in Asian countries, it makes sense they would have reported higher rates of food allergies. Whereas in other areas such as the US, young children aren’t being exposed to these foods so there’s no allergies to report. Just something to think about when exploring how these food allergy patterns come about.
Looking at older children over the age of five, Prescott et al. says there is slightly more variation in the most common food allergies reported. This time peanuts, tree nuts, seafood, egg and milk have the highest prevalence across countries. However looking at locations separately, peanuts and other nuts are the most common allergens in the US, Western Europe, and Australia. Whereas in Eastern Europe the most common allergen for this age remains egg. In the Middle East, sesame is in the top five most common allergens and in Turkey, beef is the most common. Beef was also found to be in the top five most common food allergies in Poland, Colombia, and Mozambique (Prescott et al., 2013).
Although food allergies tend to target children in high rates, there are organizations in place and resources available to help aid these children and their families work with their food allergies. Examples are the Kids with Food Allergies Foundation, a branch of the Asthma and Allergy Foundation of America, the British Allergy Foundation, and the World Allergy Organization (WAO). The Kids with Food Allergies Foundation (KFA) is a great resource for families with a child affected by food allergy. They offer a plethora of information on how to cook for children with food allergies and how to substitute certain foods. There is also a section for recipes with hundreds of allergy friendly recipes. You simply click the food allergies your child has and it will filter the recipes to find ones that meet your needs. Below is a top eight allergy free recipe for chocolate chip cookies.
Works Cited
Food Allergy Research & Education (FARE). (2014). Facts and Statistics. Retrieved from http://www.foodallergy.org/facts-and-stats
Food Allergy Research & Education (FARE). (2014). Food Allergy Facts and Statistics for the US [pdf]. Retrieved from http://www.foodallergy.org/facts-and-stats
Kids with Food Allergies Foundation (KFA). (2014). Food Allergy Resources: Food & Cooking. Retrieved from http://www.kidswithfoodallergies.org/resourcetopic.php?topic=food-cooking
Kids with Food Allergies Foundation (KFA). (2014). Recipes. Retrieved from http://www.kidswithfoodallergies.org/recipes/showrecipe.php?id=1513
Prescott, S.L., Pawankar, R., Allen, K. J., Campbell, D. E., Sinn, J. KH., Fiocchi, A...Lee, B. (2013). A global survey of changing patterns of food allergy burden in children. World Allergy Organization Journal, 6, 1-12. Retrieved from http://www.waojournal.org/content/6/1/21.
Blog Entry #3: Theories on Food Allergy Variance
When thinking about allergies across cultures, it’s not just the statistics that are important to think about. The trends related to the environment and lifestyle of the cultures play an important factor as well. Looking at three articles on the hygiene hypothesis, food allergies in developing and emerging economies, and the epidemiology of food allergy risk factors, this blog will attempt to shed on some light on why food allergies vary across the world.
According to Boye (2012), “Rising prevalence of food allergy and intolerance in the developed world has attracted much attention in the last two decades.” This is because, as my other blogs stated, there is a clear difference between prevalence rates of food allergies in developed and developing countries with developed countries having significantly higher rates. There are many theories as to why this may be happening, and taken together it is probably a combination of many factors, but I will offer a few explanations.
Looking from a more global and broad perspective, the first theory is the hygiene hypothesis. According to Okada, Kuhn, Feillet and Bach (2010), the hygiene hypothesis claims that the changes of lifestyle in the industrialized and developed countries where things are sterile and disease is minimal, have lead to the increase in autoimmune and allergic diseases. Okada and colleagues state that, in 1998 one in five children in industrialized countries suffered from allergic diseases and this has increased in the last 10 years to the point of becoming an “epidemic phenomena” (1). Evidence for the hygiene hypothesis comes from epidemiological data based on migration studies where individuals migrating from low-prevalence areas to high-prevalence areas have children who acquire the immune disorders at the same rate as the host peoples. The hygiene hypothesis is also supported by animal models, human intervention trials, and homeostatic factors concerning T cells. According to Okada, Kuhn, Feillet and Bach (2010), these evidences could stem from changes in microbiota caused by the industrial lifestyle changes.
Looking at this issue with a narrower scope, Lack (2008), shows us that there is much more going on in the environment affecting allergic disease prevalence than just hygiene. These include, generic vulnerability, eczema, level of exposure to food allergens, and diet. In terms of genetics, it is possible to have a predisposition for a food allergy. For example, “A child has a 7-fold increase in the risk of peanut allergy if he or she has a parent or sibling with peanut allergy” (Lack, 2008, 1331). This is also a factor when talking about eczema and food allergy, where the more older siblings an infant has, the more protection they have from developing eczema (Lack, 2008, 1333). Firstly though, I’ll explain the relation between eczema and food allergy. According to Lack (2008), “Eczema is the first manifestation of the allergic march...between 33% and 81% of children with infantile eczema have IgE-mediated food allergy” (1332). This is due to the eczema affected skin being more permeable so allergens are able to penetrate it at higher rates and affect the immune system. This is called “cutaneous exposure” and is believed to increase food-allergic sensitization. Whereas low-dose oral consumption as an infant leads to tolerance of the food. This hypothesis exemplifies how food allergy rates vary in different parts of the world because, as Lack explains, beliefs on when to start exposing infants and children to allergy-related foods vary and a child’s level of cutaneous exposure to different food allergens also vary, based on location. He gives the example that in societies where a food (like a peanut) has a high consumption and therefore is present in the environment but infants are avoiding the food (like American Academy of Pediatrics suggested they should), you will see emerging allergies, because they are only getting cutaneous exposure. But in countries where consumption and environmental exposure of a food are high and infants are eating the food regularly, you will not see the allergy emerging, because they are creating oral tolerance (1334). Going off from that, the various types of food consumed in different countries lead to different food allergies. For example, Boye (2012), says that the most common food allergen in Singapore is birds nest. Infants and children are exposed to this very early in life. This is food allergy unique to this location and is not seen anywhere else. This is just an example of how diet can mediate food allergies.
Another interesting point Lack (2008), touches upon regarding the prevalence of food allergies is that researchers have suggested, “That differences in macronutrient and micronutrient dietary content could explain geographic differences seen in the prevalence of allergies...in different parts of the world and the increase in allergies” (1332). Lack says there are 2 hypotheses in relation to this topic including: the dietary fat hypothesis which argues that, “reduction in consumption of animal fats and corresponding increase in the use of margarine and vegetable oils has led to the increase in allergies,” and the vitamin D hypothesis which states that both inadequate amounts of vitamin D and excessive amounts of vitamin D can be responsible for the increase in asthma and allergies. Part of this has to do with exposure to sunlight which clearly affects different parts of the world differently, and partly with diet as it can have effects on the immune function (1333).
Overall, there are many bits and pieces of research lending theories on why the global trends of food allergies are the way they are, but there is still not enough to truly break down the patterns with reliable evidence. Lack, Boye, and Okada and colleagues give us just a glimpse of what is known about food allergies worldwide and all they agree there is much more to be understood.
Works Cited
Lack G. (2008). Epidemiological risks for food allergy. Journal of Allergy and Clinical Immunology, 121(6), 1331-1336. Retrieved from http://www.sciencedirect.com/science/article/pii/S0091674908007781#
Obye J.I. (2012). Food allergies in developing and emerging economies: need for comprehensive data on prevalence rates. Clinical and Translational Allergy, 2, 25. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3551706/
Okada H., Kuhn C., Feillet H. and Bach J.-F. (2010). The ‘hygiene hypothesis’ for autoimmune and allergic diseases: An update. The Journal of Translational Immunology, 160, 1-9. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2841828/
As you suggested, food allergies affect many individuals throughout the world, and contribute to many preventable deaths. I find it really interesting that those within the United States are most commonly allergic to foods such as peanuts, tree nuts, and milk, while other cultures are most commonly allergic to other foods such as soybeans. Thus, people from other countries that migrate to the United States may exhibit food allergies that are not common in America. Since American’s food-labeling regulations are geared to the American population, it is highly unlikely for foods such as soybeans to be labeled as a common allergen on the food label. In this regard, grocery shopping may become very difficult for these individuals. Therefore, I find it interesting that each country has different common food allergens, but that they may share a few with America.
ReplyDeleteIn my own research, I also found research performed to determine the link between crossing the border and food allergies. According to these researchers, the crossing of food and people across the border has contributed to food allergies in other countries. Crossing the border has contributed to the increased incidences of kiwi allergies in America and peanut allergies in other countries. Therefore, different countries may have different food allergens that have been impacted by the crossing of borders.
In your third blog, you focus on how different cultural beliefs across countries on when to expose children to food can impact whether or not a child has an allergy and the rate of an allergy. This ties in to my blog posts on the biology and chemistry of food allergies, and shows how biology and culture can be linked together and affect one another. I especially like your focus on macronutrient and micronutrients, and that differences among the consumption of these could perhaps be a cause of food allergies. Additionally, I never knew that eczema could have an impact on food allergies. This relation makes sense, as eczema exposes the body to the environment more. It seems as though one of the best things to do to prevent food allergies is to expose children to a food from a young age through both the environment and consumption. It will be interesting to see how different countries handle food allergies as more research is done on the causes.
ReplyDeleteResponse to Blog #2
ReplyDeleteI thought the different prevalence rates across different countries was very interesting. I was expecting that some of the "core" countries, like the United States and Canada would have higher self-report of food allergies because popular culture has made food allergies kind of "trendy". I also expected these countries to have a higher percentage because of their access to and quality of healthcare. I found it interesting that countries like Mozambique and Tanzania had some of the highest self-report ratings. I think of these countries as being more of "peripheral" countries. This led me to believe that food allergies may be less reported in these countries because they may not have access to or the best healthcare. In my own research, I found that there is a greater prevalence of food allergies among American families with a higher socioeconomic status. This is because they are more likely to have access to healthcare and are more likely to report food allergies. I thought it was interesting that this trend did not translate cross-culturally.