There's some truth to the saying 'an apple a day keeps the doctor away'... however, it may not be for the reasons you assume. Today, I'd like to share some information on how apples can play a role in reducing inflammation while also improving gut health - two key factors to consider when trying to get histamine intolerance under control. In fact, I'd like to show you a little recipe for stewed apples that can hack your health and fast-track you to achieving your goal of better balance and reduced histamine symptoms.  So, let’s get down to business and discuss how two stewed apples a day can keep the doctor away!   Aryl Hydrocarbon Receptors (AhR) and the Gut A lot of research is being done on the aryl hydrocarbon receptor (AhR), which has shown to be involved in the influence of genetic transcription and expression of factors involved in immune responses, inflammatory cycles, antioxidant responses, detoxification processes, estrogen responses and the cell cycle ¹²³. It’s pretty amazing that AhRs are able to influence so many responses in our body, and the determination of which responses are influenced is the result of which proteins are bound by AhR. This process is decided at its initial stages by a combination of physiology, microbial interactions, and metabolic breakdown of foods. Overall, this is a big way of explaining that science is gaining a greater molecular and biochemical understanding of how food is able to influence genetic expression, and reduce the inflammatory response in individuals expressing ongoing symptoms. Apples, Gut Health and Inflammation After all of this science talk, you might still be wondering, how do apples have such a big impact on gut health? Apples are an excellent source of polyphenols that have shown the ability to modify bacterial populations in our gut towards a more favourable (non-problematic) balance. This has been observed to occur both by increasing the populations of beneficial bacteria, and suppressing several Gram-negative, inflammatory-inducing bacterial populations⁴. The benefits of these polyphenolic compounds have shown repeatedly to improve inflammatory responses operating through AhR, and thus make this process a highly interesting target for therapeutic use. The expected outcome of this therapy is a healthier intestinal environment, resulting in the reduction of gastrointestinal symptoms and improved gut health. In fact, it has even been shown in colitis-induced mouse models that giving the equivalent dosage of two apples per day produced an anti-inflammatory effect identical to administering 15g prednisone, a synthetic drug used to relieve inflammatory conditions⁵. Although it may seem like we're taking the 'long way around' here in regards to histamine intolerance symptoms and how this all ties together - the point to remember is that improving gut health and reducing chronic inflammation are keys in targeting the root cause of your histamine symptoms.    Another fantastic benefit of trying this easy, at-home remedy is that apples are generally friendly to most elimination diets* such as a low histamine diet, and provide a quick, safe and cost-effective method for trying to improve your health from your own home. Additionally, although some people with gastrointestinal issues may find apples a tad rough on their digestion, have no fear, as I’m here to give you a universal recipe that applies to most people along the spectrum of digestive distress. Stewed Apples Recipe for Histamine Intolerance The super-simple recipe discussed below was inspired by a lecture from Dr. Michael Ash during my Master's degree, who came up with some great methods of food preparation and pairing to maximize the benefits obtained from this home-remedy. In dealing with my own histamine issues, I turned to this recipe and it became a daily staple in my healing journey. Keep in mind, I've modified the original recipe slightly to accommodate a low histamine diet.  Simple recipe for improving gut health and reducing inflammation: Start by washing 6 organic apples (Dr. Ash recommends Granny Smith apples as being most likely to provide beneficial effects due to having the highest concentration of phenolic compounds). Peel and core the apples and chop them into small, even-sized pieces. Note that if you have strong digestion, you may wish to leave the skin on for higher polyphenol activity.  Place the apples into a heavy-bottomed pot and add ½ cup water. Cook the apples on the stove while stirring regularly until the apples form a soft, pulpy mass.  That's it - when I say simple, I really mean it. This recipe can be consumed at a dosage of two apples per day for a minimum of two weeks to begin achieving gastrointestinal benefits. Easy, right? An amazing thing about this super simple recipe is the amount of scientific complexity and consideration that has gone into it. Ingredient selection was determined based on scientific research examining the amount of polyphenolic compounds contained in different apple strains was conducted by Dr. Ash himself to determine Granny Smith apples to be the most beneficial for improving gut health. Additionally, stewing the apples allows increased exposure of the apple fibres to the lumen of the gut to enhance the efficiency of use greater than that of chewing, while also easing digestibility for those who experience digestive distress. At the time of this lecture, the complexity behind this super-easy recipe kind of blew my mind. Luckily, Dr. Ash seems to have taken care of the tough stuff and all we have to do is stew some apples.   *Note: In case there is IBS present or an intolerance to FODMAPs, some individuals may have hesitation when considering consuming two apples daily, as apples are excluded on the FODMAPS diet due to their fermentable properties. It is significant to note that for individuals with fermentation issues, it is not abnormal to experience temporary flare-ups of symptoms associated with the consumption of fermentable foods. It is important to consider that although FODMAPS is designed to exclude fermentable foods for temporary, symptomatic relief, some of those excluded foods may be essential in the long-term for achieving a permanently recovered gastrointestinal state.    1. Stockinger, B., Meglio, P., Gialitakis, M. and Duarte, J. (2014). The Aryl Hydrocarbon Receptor: Multitasking in the Immune System. Annual Review of Immunology, 32(1), pp.403-432. 2. Qiu, J. and Zhou, L. (2013). Aryl hydrocarbon receptor promotes RORγt+ Group 3 ILCs and controls intestinal immunity and inflammation. Seminars in Immunopathology, 35(6), pp.657-670. 3. Hooper, L. (2011). You AhR What You Eat: Linking Diet and Immunity. Cell, 147(3), pp.489-491. 4. Shinohara, K., Ohashi, Y., Kawasumi, K., Terada, A. and Fujisawa, T. (2010). Effect of apple intake on fecal microbiota and metabolites in humans. Anaerobe, 16(5), pp.510-515. 5. Skyberg, J., Robison, A., Golden, S., Rollins, M., Callis, G., Huarte, E., Kochetkova, I., Jutila, M. and Pascual, D. (2011). Apple polyphenols require T cells to ameliorate dextran sulfate sodium-induced colitis and dampen proinflammatory cytokine expression. Journal of Leukocyte Biology, 90(6), pp.1043-1054. 6. Stanford Hospital and Clinics: Digestive Health Center Nutrition Services. (2014). The Low FODMAP Diet (FODMAP=Fermentable Oligo-Di-Monosaccharides and Polyols). Stanford University Medical Center. 

Why does histamine intolerance cause headaches and migraines?  By now you’re likely quite familiar with what histamine intolerance is and the symptoms it may cause.  After reading about the symptoms of histamine intolerance, you can probably understand why you get hives and skin rashes as a result of histamines being released into the skin. But... why would histamine intolerance be associated with such severe brain splitting headaches? Especially since the brain itself does not contain pain receptors, and is unable to feel pain? The answer might surprise you… Migraines and histamine intolerance While the brain doesn’t have pain receptors itself, the protective layers of tissue that surround the brain sure do. When we look at the mechanisms of headaches, they typically occur as a result of an increase in blood flow to the blood vessels located around and within these tissues, which cause pressure that activates the pain receptors they contain. These headaches, because of the effect on the vasculature, or blood vessels, are called vascular headaches.  So, what does this have to do with histamine intolerance? Think about what you already know about what happens to the skin when you have a histamine reaction: it becomes red and swollen, in addition to the itching. The reason for the swelling is an increase in fluid being deposited as a result of the heightened histamine load. And, now you know that an increase in fluid causes vascular headaches, so put the two together and you’ll quickly realise that an increase in histamine within the brain and its surrounding tissues can increase the pressure, which causes the pain (1).  Histamine compounds commonly deposit in these brain tissues as they are rich in the histamine H3 and H4 receptors. The rich histamine receptor distribution in the brain means that histamines form an essential part of neurological health, but it’s the excess that causes all of the problems (2).  The headaches are usually associated with pain in one location or multiple sites across the head, and it all depends on the receptors that are being activated. When you have a headache along with tearing of the eyes, nasal congestion and/or runny nose, facial sweating and/or a sense of agitation, it’s usually a histamine-related headache.  Now that you know why histamine excess causes headaches and how you can distinguish between another type of headache, the next question is: what do you do to stop these terrible headaches (and other symptoms associated with them)? Improve headaches and migraines with a low histamine diet Reducing the amount of histamine that the body contains is the very first step to improving histamine-related headaches. As you already know, one of the easiest ways to do so with relatively easy implementation is to follow a low histamine diet. Reducing the amount of histamine in your food, reducing the amount of histamine your body releases as a result of food, and reducing the impact on diamine oxidase (DAO) production all comes with eating a low histamine diet. This brings me to the second step: increasing histamine breakdown with DAO.  DAO, as you know, is diamine oxidase, which is the primary enzyme your body uses to break histamine down. Research shows that many people who experience migraines are actually deficient in this enzyme (3). In fact, around 90% of people who experience severe and debilitating migraines were found to have a deficiency in the ability to produce and maintain adequate levels of DAO (4). Along with an increase in histamines in food, and/or an increase in the production/release of histamines by the body, there is an overload of histamines in the body, they flood to the brain and cause those terrible headaches we’ve been talking about. Taking supplemental DAO, which has been used in some European countries as an innovative approach to migraine treatment, is in its early stages of regulation, but the results are promising (4).  If you, like so many others with histamine intolerance, simply can’t get rid of those bothersome headaches, put your focus on your diet as a start, as each meal provides an opportunity to improve your health and symptoms. Here is a handy low histamine food list that can help to get you started.  Remember that histamine intolerance is not a primary condition, meaning that it does not simply occur on its own. While you’re trying to manage your symptoms, keep looking for the underlying cause of your histamine intolerance. You can read more in this article about all things histamine intolerance.  References: Worm, J., Falkenberg, K. & Olesen, J. Histamine and migraine revisited: mechanisms and possible drug targets. J Headache Pain 20, 30 (2019). Alstadhaug, K.B. (2014), Histamine in Migraine and Brain. Headache: The Journal of Head and Face Pain, 54: 246-259. Izquierdo-Casas J, Comas-Basté O, Latorre-Moratalla ML, Lorente-Gascón M, Duelo A, Vidal-Carou MC, Soler-Singla L. Low serum diamine oxidase (DAO) activity levels in patients with migraine. J Physiol Biochem. 2018 Feb;74(1):93-99. Izquierdo-Casas J, Comas-Basté O, Latorre-Moratalla ML, Lorente-Gascón M, Duelo A, Soler-Singla L, Vidal-Carou MC. Diamine oxidase (DAO) supplement reduces headache in episodic migraine patients with DAO deficiency: A randomized double-blind trial. Clin Nutr. 2019 Feb;38(1):152-158.