There are particular sites in the body where immune cells interact with each other and are developed, including the bone marrow, the spleen in your abdomen and lymph nodes dotted around your body such as the neck and groin. Of particular anatomical significance, however, is our gut. Our digestive system is the closest contact to the outside world. Everything we eat and drink from our environment is covered in microbes and we have been in constant communication with them in our environment throughout our evolution via this 30-foot long tube. But rather than being fearful of them, it’s important to realise that most of the microbes that live in our digestive tract are integral to our health. Our microbiota, the population of microbes including viruses and fungi but predominantly bacteria, are mostly situated in the large intestine. As we have discussed, this huge population of foreign cells is responsible for digesting food, releasing vitamins from ingredients and maintaining our health128 (see here). The lining of the gut has to be super thin so the products of digestion and metabolites from gut microbe activity can pass through into the blood in order to be transported around the body.
The thin gut lining facilitating transfer of nutrients is necessary, but it’s also a route for harmful microbes and products to pass into our blood which could lead to damage, therefore our immune cells need to be constantly assessing and recognising friend from foe in these areas. It is relentless work to keep our human cells in harmony with foreign microbes, as well as detecting which of these organisms we need to get rid of. This is why so many immune cells are concentrated in our digestive tract and it explains why the gut has the largest amount of ‘lymphoid tissue’ that contains cells of the immune system.129
So, instead of simply using the analogy of an aggressive military force to describe our immune system, I like to see our immune cells as having just as much of a peacekeeper role in the complex world that is your human body. This is because the majority of cells contained within the body don’t actually belong to us. Microbial cells outnumber our own human cells and our health, particularly our immune health, depends on us keeping this population of microbes thriving. This objective is best served with a diet and lifestyle that nurtures them.
Having a robust and well-functioning gut population protects and bolsters our ability to deal with infections on several levels. Specific gut microbes maintain the integrity of the gut wall, preventing harmful pathogens or materials inappropriately entering the bloodstream. They secrete their own antibiotic and anti-fungal chemicals that attack harmful microbes, preventing them from colonising the gut. Beneficial microbes support an anti-inflammatory environment, which again is why good gut health improves cardiovascular disease and diabetes. The microbes themselves produce and release micronutrients that support our immune cells as well as protecting us from harmful environmental toxins.130 Keeping our microbiota in shape improves our immune health and involves eating colourful vegetables, fibre and a wide variety of whole foods. Dishes such as the Ethiopian Berbere Curry (see here) or the Pea Orecchiette (see here) are great ways to achieve this.
AUTOIMMUNITY
Because of a general recognition of the importance of the gut microbiota in immune-related diseases, researchers are increasingly looking at gut-focused treatments for problems related to imbalances in our immune system. Sometimes our immune cells can inappropriately send signals to fight infection or attack normal human cells that are perceived as foreign. This is a simplified explanation of autoimmunity which is different to something like hay fever or dust-mite allergy, which is an exaggerated immune response.131
It’s recognised that those who suffer from autoimmune conditions including psoriasis and rheumatoid arthritis tend to have imbalances in their gut populations.132 The research is still in its early stages but we also recognise that those who suffer from exaggerated immune responses, like in the case of asthma and eczema patients, may lack certain populations of gut bacteria that harmonise the body’s immune response.133, 134 This has led to the hypothesis that repopulating the gut microbiome with beneficial microbes may improve symptoms.
A theory gaining popularity to explain one of the causes of some autoimmune (AI) diseases is that the immune cells have been exposed to products that have entered directly into the bloodstream via ‘gaps’ in the lining of our digestive tract.135 These products have not been properly processed and identified by the immune system cells within the gut, and thus trigger an aggressive response that leads to harm of the normal tissue. It’s still under a lot of debate but it’s interesting to note that gut-focused treatments for AI disease, where potential triggers have been removed allowing the gut wall to repair itself, have led to some remarkable results.136, 137 I don’t have the space to dive into a full discussion of such a nuanced topic in this cookbook, but there is some interesting research on the horizon as well as a lot more we have to learn about process behind AI conditions and therapeutic dietary strategies. I suspect that it is more complicated than just nurturing the microbiome, but ensuring a healthy and thriving gut population using food could be a good starting point for helping with these illnesses and a lot of well-respected scientists in the field are in agreement on this.
ELIMINATION DIETS
It’s my responsibility to be honest about the validity of these interventions and assess whether you could benefit from them. There has been a lot of speculation regarding AIP (autoimmune protocol) diets and, although these appear to be restrictive and eliminate perfectly healthy items from your food, there have been some interesting and significant outcomes gained from their use. Depending on the condition, these short-term therapeutic dietary interventions may be beneficial, but I hasten to add that they should be actioned with the guidance of an experienced practitioner. I’m mindful of the scaremongering tactics surrounding components of food: gluten in flour, lectins in beans and other common ingredients. My advice is to maintain a high suspicion of anyone blatantly brandishing a single food as harmful for everybody and making outlandish and unhelpful claims. It makes no scientific sense to suggest gluten is bad for all citizens of the UK, for example, and I discussed the many reasons behind this in my first book. But I do believe there is a case for some patients to trial dietary strategies and many rheumatologist and immunologist colleagues are starting to use them carefully with interesting anecdotal successes.
MITOCHONDRIAL SUPPORT
In recent years, we’ve also begun to recognise the profound importance of a component of our cells called mitochondria. These are found in all of our cells and have been traditionally referred to as the ‘powerhouses’. These incredible batteries provide energy for all normal cell functions, but they’re also critical for recognising when an immune response is required.138, 139 Cutting a longwinded biology lesson short, we require healthy, functioning mitochondria for a robust immune system that can boost its metabolic activity to adapt to the increased demands of when your immune system needs to be more active. Whether it’s fighting an infection or balancing oxidative stress, your immune cells require more energy, and mitochondria are key to this. Supporting your mitochondria by preventing damage and providing them with fuel is therefore an essential immune-supporting strategy. Things that damage mitochondria include high-sugar diets and stress, and this gives us one explanation as to why poor diet and mental pressure appear to have detrimental impacts on our immunity.140
This is a very new area of research, so the evidence base behind what to eat for mitochondrial support is lacking, but that shouldn’t stop us from being able to make reasonable, educated adjustments to our lifestyles that we can СКАЧАТЬ