Tue, Jul-11-23, 02:47
|
 |
|
|
Plan: Muscle Centric
Stats: 238/153/160
BF:
Progress: 109%
Location: UK
|
|
Allergies and weight gain: it’s all about the gut
Quote:
Allergies and weight gain: it’s all about the gut
Your microbiome affects all aspects of your health — and modern living has a huge impact on it, the surgeon Dr James Kinross tells Anna Maxted
These days it’s not unusual for Dr James Kinross, a consultant surgeon and clinical senior lecturer in colorectal surgery at Imperial College London, to see thirtysomethings in his clinic with bowel cancer. “This is no longer a disease of older people,” he says. As he writes in his important and devastating new book, Dark Matter — The New Science of the Microbiome, a millennial’s risk of bowel cancer is four times that of a boomer.
Not only that, food allergies have risen by 50 per cent in the past decade, disproportionately affecting young people. Allergy is now the most common chronic disease in Europe (I’m keen to know why I got hay fever for the first time after my second child was born).
Immunological conditions such as inflammatory bowel disease and rheumatoid arthritis are shooting up. And we may have vanquished smallpox, but there’s a global pandemic of non-infectious diseases such as obesity and Alzheimer’s slowly and painfully killing us.
To understand why we’re in crisis — and what we can do to recover our health and resilience — we must first understand the functions of our microbiome, the inner ecosystem of viruses, bacteria and other microbes, largely populating our gut, but also present on our skin and in our organs.
Most clinicians don’t get why Kinross is always talking about the microbiome. Modern medicine still runs on 19th-century principles (all bugs are bad, kill everything.) Meanwhile, for many, gut bug health still feels like a niche middle-class wellness trend.
We must care. Our microbiome impacts everything — and I mean everything: it’s critical to every part of our health, affecting brain function, mood, fertility, susceptibility to weight gain, illness, allergies, how we respond to cancer treatment and how fast we age. We and our bugs have “a symbiotic relationship”, Kinross says. But over the past 200 years of industrialisation, and especially since the end of the Second World War, we’ve been an abusive partner.
In our determination to kill pathogens, he says, “what we’ve completely forgotten is that there are symbionts and mutualistic microbes that promote wound healing, that promote our health, that regulate our immune system, that feed us, nurture us, that develop our brain, our liver, our lungs”.
Our lifestyle has decimated this inner ecosystem — “an internal climate crisis”, Kinross calls it. First, “antibiotics became completely ubiquitous in everything we touched and ate”. One study finds that a single five-day course of antibiotics can reduce microbial diversity — changes can be “acute and persistent’’. We also developed a drug addiction. “Four and a half trillion doses of medicine are given out globally each year.” Plus, “we have a westernised, globalised, homogenous diet”.
Think also urban living, isolation, lack of exercise, pollutants, plastic exposure, fluorinated water, dental fillings, bleach and pesticides. All these are modifiers of the microbiome. I’ll never again eat unwashed fruit.
The consequence of this damage collectively wrought on our ancient, protective microbiome is “this disconcerting and very dramatic rise in the epidemiology of chronic disease”, Kinross says. This is, broadly, because a healthy microbiome helps to educate and regulate our immune system, which is largely located in our gut.
“To understand why we’ve got rising rates of asthma, allergy and autoimmune diseases, you have to understand what the microbiome is doing,” he says. It’s the middle man sitting in between our environment and our immune system. “It’s the unifying theory of chronic disease.”
For anyone whose GCSE biology is hazy, the immune system is composed of the ancient innate system we’re born with and the adaptive system that learns as we go. Our microbiome interacts with every environmental factor we’re exposed to and continuously influences our immune system’s development, Kinross says. But we’re killing off or mutating many of the gut bugs we co-evolved with.
This loss or mutation of bugs — which keep the adaptive immune system’s memory in good order and protect against inflammation — means it may forget how to distinguish between bacterial friend or foe or fail to control inflammation, leading to “massive unregulated explosive immune responses causing an allergy”, Kinross says. Problems with the innate immune system for the same reasons lead to chronic inflammation, increasing susceptibility to chronic disease.
Kinross notes that in the 1940s farmers realised that if you gave livestock antibiotics they got fatter faster. “The reason that works is because when you decimate the gut ecology you promote inflammation, and that changes insulin resistance and then you gain weight.”
He thinks we’re like those farm animals. “Twenty-five per cent of our ten and eleven-year-olds are now obese.” We think of obesity as a metabolic dysfunction, but “it’s a microbiome dysfunction. And actually it’s an immune dysfunction.”
Having read Dark Matter, I admit to feeling despondent about having done my kids few microbial favours. I had to have caesareans — so no trips down the birth canal, “an important way to seed the microbiome”, and a higher likelihood of obesity, allergy and asthma. Nor could I breastfeed much, and breastfeeding is “the gut microbiome equivalent of the big bang”.
Kinross, who I sense is the kindest of doctors, says firmly, “I don’t want you to feel guilty for the choices you made because you made them for good reason and there were lots of benefits. My children were born by caesarian section; they all got antibiotics when they were young.” He adds, “If your kid is sick, and they’ve got a bacterial infection, for God’s sake give them antibiotics.” His daughter — who had pneumonia as a baby — would have died without them.
However, we shouldn’t misuse antibiotics. As he explains, “there are times in our lives” — like the first three to five years, especially the first 100 days — “where the microbiome is very vulnerable to environmental drivers”. Think allergens from dust mites, laundry detergent, cleaning agents, cigarette smoke and particulate matter. Colonising our young with symbiotic bacteria as quickly as possible is central to their health.
Another critically important time is during gestation — when the maternal microbiome sets up and educates the baby’s developing immune system. “And if it doesn’t do that effectively, the immune system is then much more vulnerable to environmental drivers,” he says. “It simply cannot process them.”
Generational depletion of the maternal microbiome, and the cultural and economic “hyperglobalisation” that began in the 1990s (Americanising our diet, for example) has created such “profound disruption” to younger generations’ microbiome that they are more susceptible to bowel cancer and chronic disease than their grandparents.
“You’re seeing these superblooms of bugs that are bad for us — that love to metabolise fat and animal protein, and a perpetuating cycle of changes in the immune system that ultimately leads to insulin resistance, morbid obesity and all the consequences that come with it,” Kinross says.
He believes that safeguarding the maternal microbiome and our children’s microbiome must be our focus in the prevention of chronic disease. And, surprisingly, there’s good news. We can make our microbiome more resilient.
One way is to be pragmatic about personal hygiene (yes, wash your hands after the loo — it stops the transfer of pathogens), but don’t be obsessive about cleanliness — “the pursuit of sterility is not a good strategy — and it’s impossible”. (A human can only be sterile if boiled in a bag.) I tell Kinross that my house is reasonably dirty, five cats come and go, and the kids tramp inside in outdoor shoes. Too much? “You’ve got lots of lovely ingredients . . . lots of pets, lots of children, lots of stomping in and out, lots of sharing, and that’s great,” he says. Indoor plants are beneficial too.
Diet, of course, is critical. A diet high in animal fat and animal protein, salt, refined sugars and extremely low in fibre doesn’t sustain the microbiome. “You’re not allowing it to develop into that healthy biodiverse ecosystem that gives us all the things that we need.” Ultimately, it drives disease “because those microbes that bloom on a high-fat diet communicate with the immune system and promote inflammation”.
If we were to eat 7g more fibre a day, “our risk of diabetes, obesity, stroke, cancer — everything drops. If we can get to the magic 30g daily it really helps.” Fibre, a non-digestible complex sugar usually from plants, acts like a gel in the gut, absorbing some of the toxins in our diet. It also helps us to absorb vitamin D.
Ultimately, Kinross says, fibres called “prebiotic fibres” are broken down and digested by bacteria, and “the major by-product of that is short-chain fatty acids — these magical molecules that are primary fuel for a lot of the cells that line the gut, and they also have anti-inflammatory properties”.
The effects of fibre on the microbiome were powerfully demonstrated in an experiment where two groups swapped diets. The participants were African-American men, who have the highest rates of bowel cancer of any ethnic population, and rural South Africans, who have a traditional lifestyle and eat up to 50g of fibre a day.
“After two weeks of nutritional exchange the American gut became much less inflamed and the African gut became much more inflamed,” Kinross says. “What that means is you can change your cancer risk quite quickly by making significant nutritional changes such as increasing fibre.”
The men’s gut bugs didn’t really change. “But we saw very dramatic changes in what those bugs were doing. They began to switch on the cellular machinery that they need to metabolise fibre. And we saw the metabolic consequences of that.” (More tolerable than suddenly doubling your fibre consumption is taking a prebiotic fibre supplement such as inulin, as Kinross does.)
Intermittent fasting, he adds, is a great way of regulating our populations of microbes. “It has an important anti-inflammatory effect.” Meanwhile, probiotics are not a panacea, “though there’s quite good data around cholesterol reduction and hypertension reduction”. For a probiotic to work it’s got to engraft into the gut, he says. “It’s got to sustainably live there. That takes from four to eight weeks, and you’ve got to take it regularly and feed it. Think about the foods that are going to help it.”
However, Kinross puts his patients on kefir. It’s cheaper than a probiotic, “it’s usually got quite a high dose of bugs — it’s also got the sugars and metabolites that they produce”. Try it for eight weeks. “If you’re getting bloating, discomfort and it’s not making you feel better, stop; if it is, keep going.”
Exercise alters our microbiome and its ability to metabolise food, but we should do it religiously. If laboratory mice exercise on wheels at their leisure you see small gut bug changes, Kinross says. “If you’re a little bit mean to that mouse and you say, ‘Look, you’ve got to go on that wheel every day’ — the changes in the biodiversity of the gut microbiome are much more dramatic and sustained.”
A helpful rule is — what’s good for our physical and mental health is good for our microbiome, he says. “See your friends and family and socialise and play and interact, and if you’ve got someone to kiss, kiss them.” (Ten seconds of kissing gifts 80 million bacteria to your partner.)
https://www.amazon.co.uk/Good-Sh-Sc...dp/0241543975/p
https://www.amazon.com/Good-Sh-Scie...dp/0241543975/p
|
https://www.thetimes.co.uk/article/...ealth-l820j7jjg
Last edited by Demi : Tue, Jul-11-23 at 12:50.
|
|
Linear Mode
