Food allergy, a serious and potentially life-threatening medical condition, affects a growing number of Americans. According to Food Allergy Research and Education (FARE), 1 in 13 children now has a food allergy and every three minutes a food reaction sends someone to the emergency room.1
Food allergies are also estimated to affect nearly 4 percent of adults, according to the U.S. Centers for Disease Control and Prevention (CDC).2 While they are most common in babies and children, food allergies can develop at any age. Adults may even develop an allergy to foods they've previously eaten for years with no problem.
More than 170 foods have been reported to cause allergic reactions, but the eight major food allergens include milk, eggs, peanuts and tree nuts, wheat, soy and fish.3 However, as evidenced by the British teenager who recently died after eating sesame,4 this seed is also an emerging concern. The number of hospitalizations for food allergies have tripled from the late 1990s to the mid-2000s.5
Nearly 40 percent of children with food allergies have experienced a severe reaction, such as anaphylaxis. Typical food allergy symptoms may begin with hives, rash, nausea, vomiting or diarrhea. This may be followed by coughing and wheezing. In severe cases, anaphylaxis can occur, which is when your throat swells and you may not be able to breathe.
The rising prevalence of food allergies has been particularly noticeable in the West, where there is also rising numbers suffering vitamin D deficiency.6 Nearly 7 percent of children in the U.K. and 9 percent of those in Australia suffer from food allergies.7
Is It a Food Allergy or Intolerance?
Sensitivities and food reactions are often mistaken for allergies. A true food allergy is mediated by the immune system and triggered by an antibody reaction to a protein in a specific food or drink. While most develop during childhood, the most common allergies known to develop in adults are allergies to shellfish, tree nuts and peanuts.8
Food sensitivity, also called food intolerance, is an unpleasant — usually gastrointestinal — reaction to something you've swallowed, but is not mediated by your immune system.9 For instance, a true allergy to milk is different from lactose intolerance, which triggers gastrointestinal symptoms from an inability to digest proteins in the milk.10
Type 1 food allergies involve immunoglobulin-e (IgE), an antibody in the blood and mast cells found in all body tissues. Food allergies mediated by IgE are triggered after you've eaten a food for the first time, after which cells produce IgE for the part of the food triggering the allergic reaction, called an allergen.
IgE is released and attaches to the surface of mast cells. This process sets the stage for the next time you’ve eaten a food with the specific allergen. The protein interacts with IgE and triggers mast cells to release histamine. Since some food allergens are not broken down by heat or stomach acid, they cross immediately into your bloodstream and may cause reactions throughout your body.11
IgE reactions may start with itchiness in your mouth, followed by symptoms of vomiting, diarrhea and stomach pain. If the allergen reaches your blood, it can trigger a drop in blood pressure; in your skin you may experience hives or eczema; and in the lungs it may trigger wheezing. Each of these reactions can take a few minutes or a couple of hours to develop and signal an immediate food allergy.
A second type of food allergy, Type 3, also called delayed food allergy, is mediated by immunoglobulin-g (IgG). These reactions occur hours and possibly even days following your exposure to the allergen. Individuals who suffer from Type 3 food allergies are often allergic to more than two types of food, and larger amounts of food over multiple meals are needed to provoke this reaction.12
You may experience some of the same types of symptoms, making it difficult to distinguish between an IgE and an IgG response. Foods triggering an IgG response are often favorite foods eaten in larger amounts. IgG responses do not typically show up on a skin test.
Rising Prevalence of Allergies Corresponds to Increasing Vitamin D Deficiency
Food allergies associated with IgE affects 3 percent of the population, with severe effects on daily life. Manifestations of the allergy are not only gastrointestinal, but also affect other organ systems and may lead to an anaphylactic response.13
While vitamin D also has known effects on lung and immune system development, as well as support of the immune system after birth,14 including asthma and allergic responses, it is also significant in the regulation of IgE.
The increase in allergies and sensitivities to foods is likely related to environmental factors and Western lifestyles. Developing nations have lower rates of allergic responses, and individuals with allergies are likely to live in urban rather than rural areas.
Although there is no single explanation for the rise in prevalence, one significant factor is the overwhelming vitamin D deficiency suffered by those who live in urban areas.15
The link between vitamin D deficiency, which has almost doubled in just over a decade in the U.S.,16 and poor regulation of IgE responses, may be a significant factor. Both of these play a role in the development, severity and course of allergic diseases, and help explain, at least in part, why so many adults are now developing food allergies.
Australia has the highest rate of confirmed food allergies, with one study finding 9 percent of 1-year-olds suffering from egg allergy.17 Australia initiated one of their most successful health campaigns to increase use of sun screen in 1981 with the slogan “Slip! Slop! Slap!”18
At the time, the campaign was aimed at lowering melanoma rates, which the government believed was the result of spending too much time in the sun.
Today, nearly 25 percent of Australia's population is deficient in vitamin D. Despite these numbers, Choosing Wisely Australia, an initiative of NPS MedicineWise,19 does not recommend having routine testing for vitamin D unless you're specifically at risk, including those who:20
Have a health condition affecting vitamin D absorption from their diet |
Cover their body completely when outside |
Are a baby of a vitamin D deficient mother |
Spend the majority of their day indoors |
Take medications affecting vitamin D |
Avoid the sun completely |
Have naturally dark skin |
Suffer obesity |
Considering the prevalence of vitamin D deficiency, I strongly recommend getting your vitamin D level tested regardless of whether you fit into a high-risk category or not, and to make sure you’re actually within the ideal range of 60 to 80 ng/mL, and if below 60 ng/mL, take proactive steps to optimize your level. The fact of the matter is, most people are at high risk for vitamin D deficiency these days.
Early Exposure to Allergens May Reduce Allergy Risk
In addition to vitamin D deficiency, a theory of dual allergen exposure may also explain the rise in pediatric food allergies. This was the basis for the LEAP study from King's College London, in which they evaluated how early exposure to peanuts may affect the development of a peanut allergy.21
The prevalence of peanut allergy in children has doubled in the past 10 years in countries where parents are advised to avoid exposure to peanuts during pregnancy, lactation and infancy.
The researchers randomly assigned 640 infants, 4 to 11 months old, with a history of severe eczema, egg allergy or both, to either eat or avoid peanuts until they were 60 months old. The children were assigned to groups based on preexisting sensitivity to peanut extract, determined by a skin-prick test.
Of the 98 participants treated who initially had a positive peanut allergy test, 35 percent of those who avoided peanuts had a peanut allergy at 60 months, compared to just 10 percent of those who consumed peanuts. Dr. Gideon Lack, lead investigator for the study, commented:22
“For decades allergists have been recommending that young infants avoid consuming allergenic foods such as peanut to prevent food allergies. Our findings suggest that this advice was incorrect and may have contributed to the rise in the peanut and other food allergies.”
These results have been validated in subsequent studies, finding late introduction of fish and eggs is associated with an increased risk of allergy development.23 A metadata analysis from the Imperial College London, which evaluated 146 studies with over 200,000 children, also concluded that feeding egg between the ages of 4 and 6 months may reduce the child’s risk of developing an egg allergy.24
Other Health Benefits of Vitamin D Optimization
Vitamin D deficiency has become so widespread it's been called a pandemic by a Harvard Medical School researcher.25 The short list of health benefits attributed to vitamin D optimization include improving your immune system, strengthening muscles, bones and teeth and improving your cardiovascular health.
Over the past decades, thousands of studies have evaluated the benefits of vitamin D and have linked low levels to a host of chronic health conditions. In fact, this site was one of the leaders to help catalyze interest in vitamin D over 15 years ago.
Unfortunately, some studies claim supplementation at amounts over 4,000 IUs/day may lead to health problems. Research by GrassrootsHealth negates such concerns, showing toxicity is not an issue until you hit 30,000 IUs a day.26
What’s more, the recommended vitamin D level and dosage established by the National Academy of Medicine is actually the result of a mathematical error that has never been corrected. You can read more about this in my previous article, “Are Americans Really Getting Too Much Vitamin D? A Critical Look at Recent Media Warnings.”
There is a long list of studies confirming the correlation between vitamin D status and cancer risk. Maintaining sufficient levels of vitamin D also helps to lower all-cause mortality and risk of Type 2 diabetes.
During pregnancy, optimal levels of vitamin D help to reduce the percentage of preterm birth, and subsequently higher risks of ADHD, asthma, autism and vision problems associated with early birth. Low levels of vitamin D are also associated with depression, metabolic syndrome,27 cardiovascular disease28 and lung disease.29
Maintain Healthy Levels to Help Prevent Disease
My recommendation is to get your vitamin D level tested twice a year, when your level is likely to be at its lowest (midwinter) and highest (midsummer). This is particularly important if you're pregnant, planning a pregnancy or if you have cancer.
Research30 suggests it may require 9,600 IUs of vitamin D per day to get a majority (97.5 percent) of the population to reach 40 ng/mL, but individual requirements can vary widely. If you've been taking a certain amount of vitamin D3 for a number of months and retesting reveals you're still not within the recommended range, then you know you need to increase your dosage.
Over time, with continued testing, you'll find your individual sweet spot based on your usual safe sun exposure and have a good idea of how much supplementation you need to maintain a year-round level of 60 to 80 ng/mL, which research suggests is the ideal range for optimal health and disease prevention.
GrassrootsHealth offers vitamin D testing through its D*Action study, and has an online vitamin D calculator you can use to estimate your vitamin D3 dosage once you know your current serum level.
The Synergism Between Vitamin D3, Magnesium, Calcium and Vitamin K2
Pamela Lutsey, public health researcher at the University of Minnesota, points out excessive vitamin D may cause over absorption of calcium, which in turn may result in calcium deposits in your heart and kidneys. Indeed, it is important to maintain not only the proper balance of vitamin D and calcium, but also magnesium and vitamin K2.
Lack of balance between these four nutrients is why calcium supplements have become associated with increased risk of heart attack and stroke, and why some experience symptoms of "vitamin D toxicity." I use quotation marks here, because the problem is not so much excess vitamin D as it is a lack of vitamin K2.
Part of the explanation for these adverse side effects is that vitamin K2 is what keeps calcium in its appropriate place. If you're K2 deficient, added calcium can cause more problems than it solves, by accumulating in the wrong places. Similarly, taking megadoses of vitamin D supplements without sufficient amounts of K2 can lead to inappropriate calcification, which is what Lutsey is suggesting.
While the optimal ratios between vitamin D and vitamin K2 have yet to be established, Dr. Kate Rheaume-Bleue (whom I've interviewed on this topic) suggests for every 1,000 IUs of vitamin D you take, you may benefit from about 100 micrograms (mcg) of K2, and perhaps as much as 150 to 200 mcg.
Maintaining an appropriate calcium-to-magnesium ratio is also important, as magnesium helps keep calcium in your cells so they can function better. Historically, mankind ate a diet with a calcium-magnesium ratio of 1-to-1,31 but Americans tend to have a higher calcium-to-magnesium ratio in their diet, averaging about 3.5-to-1.
Magnesium and vitamin K2 also complement each other, as magnesium helps lower blood pressure, which is an important component of heart disease. So, anytime you're taking magnesium, calcium or vitamin D3, remember to take all the others into consideration as well, as they all work synergistically with each other.