My fascination with the gut microbiome continues. The scientific studies are coming out thick and fast and there is more of a buzz than ever about the need for a healthy gut microbiome due to the deeply integrated relationship that the microbes in our gut have with our immune system. The more complex, numerous and diverse our gut microbes, the more sophisticated, adaptable and self-regulating our immune system. People of late have been talking so much about boosting or revving up the immune system, but this highly complex system does not simply need ‘turning up’, as an overly stimulated immune system is as dangerous as an under-functioning one. We need our immune system to be dynamic, responsive and alert without being so hyper-vigilant that it triggers chronic inflammation and harm to our own cells (this is the cytokine storm going on in the lungs of people with severe CV19).
With Covid 19 still very much part of our lives, we are hearing daily about the need to be metabolically fit and well to ensure we do not fall victim to this virus. The reality is that we are exposed to hundreds of thousands of viruses, fungi and bacteria on a daily basis and many of these will be at best commensal (beneficial) and at worst benign. Of course there are some really nasty bugs out there that can totally overwhelm both our gut bugs and immune system, but there are lots of things we can do to best arm ourselves against destructive invaders on a day to day basis and it’s all the good ol’ favourites: sleep well, manage stress, exercise regularly but not too much, don’t over do the alcohol and ‘treat foods’ and ensure you feed your healthy gut microbes at every meals. These practices allow us to develop and maintain a sophisticated immune system, 70% of which lines our digestive system and interacts with our gut microbiome to fight off any nasties and work alongside the myriad bugs we are exposed to second by second to keep us safe.
What is very clear in the most current data is the need for a diverse diet to keep our microbiome and our immune system tip top. This means we need to be making a conscientious effort to consume as many different plant-based foods as possible i.e. not mountains of 1 or 2 plant foods, but lots of different. Many people get into the habit of eating the same, limited range of foods day after day because it’s easy, safe and familiar. The problem with this is that the many different microbes that should inhabit our intestine depend upon the many different types of fibre in foods to provide daily fuel. It is thought there are around a thousand beneficial gut microbes and they will all be selective about which fibre they like to eat to fuel them and allow them to proliferate. We all have a different compliment of these microbes and the more diverse a diet we have, the more of a diverse range, which then confers many, many benefits to the entire body, not just our immune system.
Every time you eat, you are effecting the delicate ecology of the gut. Sugars, refined oils, processed foods, artificial sweeteners, emuslifiers, preservatives and alcohol will have a negative impact to some degree. Equally, eating the foods listed below instead of, or at least alongside those not-so-helpful foods and drinks, can improve the gut microbiome in a matter of hours.
If we eat a limited range of plant based foods, over time, we can lose gut microbe diversity and we therefore lose the benefit of whatever those good bugs were doing for us: from brain health, to genetic management, cellular healing, inflammation regulation, stress management, metabolic processing, detoxing of nasty chemicals and excessive hormones and, of course, immune regulation, we must take this seriously and think about feeding our gut bugs a wide range of fibrous foods.
Best foods for our microbiome, well, pretty much any plant foods i.e. fruit and veg, nuts and seeds, beans and lentils. However there are a few foods that are especially gut fuel superchargers and these are the foods that contain resistant starch. As the name implies, resistant starch resists digestion, reaching the lower intestine intact. There, the gut bugs feed on and ferment the fibre, benefiting them and us. Eat as often as possible a wide range of lentils, beans, pale green bananas, plantain and cooked then cooled (for at least 6 hours) potatoes as these foods are all high in resistant starch. High fermentable fibres in onions, leeks and garlic; brassica veg like kale, cauliflower and broccoli; bitter foods like chicory and radicchio plus asparagus, artichoke hearts, Jerusalem artichokes (aka fartichokes for their supercharging action for the gut bugs); black beans and lentils.
Further gut friendly guidelines:
- Every time you eat, at least half of your plate (ideally more) should contain a range of plant-based foods
- Aim for a wide range of these foods rather than just mountains of kale, broccoli, cabbage etc. You will get far more benefit from having a range of 5 or 6 veg than lots of even the most healthy veg like kale.
- Be brave and aim to buy and try a new veg / salad ingredient every time you go shopping.
- Use onions, garlic, herbs and spices to easily increase your food diversity
- Soak nuts and seeds (and wholegrains if you eat them) to improve digestibility and levels of soluble fibre.
- Prebiotic (not probiotic) supplements contain concentrated levels of these highly beneficial fibres and can easily be added to food and drink, but if you are prone to IBS / IBD, use with caution when you start out.