“As we age, just naturally through a combination of genetics and the sum total of our environmental exposures, our immune systems develop a natural propensity for wanting to engage in chronic inflammation,” explains Dr Nathan Curran, a functional Medicine Practitioner at London’s Reborne Longevity Clinic.

“If we’re trying to prevent chronic disease, it needs to go beyond just screening for the disease,” he adds. “We need to be screening for the actual triggers of the disease before they emerge.”

What is inflammation?

Inflammation isn’t bad per se. It’s the immune system’s response to any traumatic event in the body tissues – for example, a scraped knee or finger cut. In case of “acute” inflammation, our immune system releases inflammatory cells and cytokines (small proteins that stimulate more inflammatory cells) to neutralise the invading virus or start healing injured tissue. You will experience redness, warmth and swelling, but it will be over in a matter of days. “Acute inflammation serves a very important role in keeping us alive,” says Curran.

In our evolutionary history, in order to protect our bodies from pathogens and poisons, we developed a hyperactive immune system, explains Ravella, author of A Silent Fire: The Story of Inflammation, Diet and Disease.

The problem is inflammation is not always harmless.

“Chronic” inflammation happens when this response is switched on all the time, leaving your body in a constant state of alert. The body continues to send white blood cells on the attack in the absence of any threat. This disrupts normal bodily functions and can result in healthy tissues and organs being attacked. Plus your body never gets a chance to recuperate.

Inflammation and cholesterol

The whole topic of inflammation became a bit more “personal” last October when I learnt I have “a propensity for excessive inflammation on a genetic level” when I did a DNA test at Curran’s clinic.

The clues were there already: I had high cholesterol and was a point from being pre-diabetic. I sneezed incessantly (and very loudly) after too much fizz or sugar, both of which raise inflammation.

“You have an ‘eager/active’ variant of the gene,” Curran tells me. “This means a relatively mild trigger has the potential to trigger a disproportionately large/sustained release of TNF-alpha (a pro-inflammatory protein), unless we moderate the impact of this genetic variation through an anti-inflammatory lifestyle, omega-3s, Vitamin D and so on.”

I immediately Google TNF-alpha and find that, worryingly, this cytokine is implicated in acute and chronic inflammatory conditions including, sepsis, rheumatoid arthritis and dementia.

“Just because you have the genetic propensity doesn’t mean it will be translated into excessive inflammation,” he adds, “but you need to be mindful of your lifestyle and dietary exposures.”

But there’s my family’s history of heart disease to consider, too. “When cholesterol accumulates in the arteries, it creates inflammation because it gets modified and oxidised,” explains British Heart Foundation Professor of Cardiovascular Medicine at the University of Cambridge, Ziad Mallat. “And then the body recognises it as a stranger. This inflammation initially serves to clear the oxidised cholesterol from the arteries. But when the body is exposed continuously to this aggression, the clearance capacities become overwhelmed and the inflammation becomes chronic. This causes more build-up of fatty material in the arteries and later may create clots in the arteries, and cause heart attack and stroke. The same thing happens when you have high glucose in diabetes, or if you smoke; it causes injury to the arteries and that creates chronic inflammation.”

The shock motivated me to change my diet (I gave up free sugar, brought my cholesterol down naturally for this paper). Then in March I asked my GP for a CRP (C-reactive protein) blood test (CRP is produced by the liver and if there’s a higher concentration of CRP than usual, it’s a sign of inflammation) and, phew, it’s normal at the moment. The sneezing has stopped.

“You were really lucky, because your sneezing was so obvious and not everybody has that,” says Thaddeus Stappenbeck, MD, PhD chair of Inflammation and Immunity at Cleveland Clinic. “Most people have more vague symptoms, like they don’t have the energy they used to, or they’re not sleeping well.”

At Cleveland Clinic, Stappenbeck’s research programme focuses on determining the root causes of inflammatory diseases with the goal of developing new therapies. “With certain types of inflammatory conditions, they can programme parts of your immune system so they simply malfunction which further fuels inflammation later. A really good example is sepsis. Patients who have had bloodstream infections and spent time in intensive care, if they survive and are able to leave the hospital, what’s well recognised is that parts of their immune system are no longer functional. So they’re at risk for repeat infections with worse overall inflammation.”

The role of diet and the gut microbiome in inflammation

The function of the immune system is to protect us from invaders – and to be able to tell apart the cells of our own body from other cells that don’t belong to us. And scientists have estimated that about 70% of the immune system lives in the gut microbiome. Chronic inflammation in the gut may be due to inflammatory bowel disease, such as Crohn’s disease or ulcerative colitis. But a modern Western diet high in ultra-processed foods can literally cause our whole body to be on fire, too. The poorer the quality of a meal, the higher the inflammatory response. Our microbiome (and the trillions of bugs in our intestines crucial to human health) is worryingly damaged, in contrast to our ancestors who had better gut health.

This sort of inflammation contributes to most of our “21st-century” diseases, says Stappenbeck. “The link between what’s going on in your gut microbiome, and diseases such as Alzheimer’s, Parkinson’s or sleep disorders or depression is really amazing. We’re learning, for example, that Parkinson’s disease probably starts in many of these patients in the colon and becomes more evident once brain lesions have developed. A lot of patients with Parkinson’s have very severe constipation because the neurons in their colon are damaged and don’t function properly. They could have been experiencing that for years without realising. So could we diagnose Parkinson’s earlier before the cells of the brain are damaged?”

Signs of chronic inflammation

Many people don’t know they have chronic inflammation until they’re diagnosed with another condition, like rheumatoid arthritis or Type 2 diabetes.

Though patients may have experienced symptoms long before a formal diagnosis, says Stappenbeck. “We and others now recognise there are likely pre-existing conditions to Crohn’s disease, for example. We see patients who start off by just feeling terrible, they’re chronically tired, have brain fog, lethargy, some sort of GI disturbance. It’s all connected.”

We still lack functional tests of our immune system to recognise people at risk. Though you can ask your GP to check inflammation levels with a CRP blood test to check inflammatory biomarkers (as part of your midlife check). C-reactive protein (CRP) in the blood may indicate infection or inflammation in the body which will require further testing. Though as Curran reminds us, it could simply be caused by a common cold.

How to reduce inflammation in your body

The good news is we can prevent, treat or even reverse chronic inflammation with medication and diet changes, says Ravella. “You’re able to see changes in the microbiome within a few days to weeks after changing your diet and that is going to jump-start positive change. From a disease-risk perspective, it may take longer.”

Modifications in diet, behaviour and lifestyle are the best place to start. “People who are able to keep up those anti-inflammatory dietary and lifestyle factors throughout their lives, have a better chance of retaining the physical and mental functionality they had in their youth,” says Ravella. “So that puts the way in which they age in a very different context. Obviously you will have the inflammation that’s a natural part of ageing, but you’re able to resolve inflammatory challenges far more seamlessly.”

1. Eat an anti-inflammatory diet

Many inflammatory issues start in the gut, so we need a diverse diet, rich in foods that fight inflammation. “What you include is actually much more important than what you exclude,” says Ravella. Aim for at least six portions of fruit/veg a day. Prioritise gut-friendly natural foods (leafy greens, like kale and spinach, plus cruciferous veg like broccoli, kale, cauliflower), grains, beans, spices and herbs which contain healthy fibre and chemicals.

Opt for healthy anti-inflammatory fats from sources like olive oil, nuts and seeds (chia seeds, flaxseed, walnuts, almonds). Studies have associated nuts with reduced markers of inflammation and a lower risk of cardiovascular disease and diabetes. Eat 50g of fibre a day (30g is not enough, argues Ravella). As well as oats and fibre-rich wholemeal bread, add in quinoa, bulgur, legumes each day. “Fibre is one of our most anti-inflammatory foods that can actually manipulate the immune system, yet 90% of UK adults are deficient in fibre,” says Ravella. Eat fatty fish like salmon, sardines, and mackerel. “A diet rich in omega-3 from oily fish is very effective at quelling chronic inflammation,” says Dr Curran.

2. Cut out refined carbohydrates

Diets high in processed meats, butter, sweets, sugary drinks and refined grains are linked to higher inflammation and an increased risk of coronary heart disease. Ultra-processed foods are highly inflammatory due to their high content of saturated fats, sugars, salt, and additives like emulsifiers and sweeteners, which can negatively impact the gut microbiome and trigger inflammation. “They’re like Frankenfoods,” says Ravella.

Sugar also feeds inflammatory microbes in the gut, damaging our gut microbiome and leading to more inflammation.

3. Limit alcohol

Among other things, booze profoundly disrupts your gut bacteria and gut and liver function. “All the data suggests it’s really a toxin, essentially equivalent to cigarettes in provoking chronic inflammation. Limiting exposure to alcohol as best you can is a good strategy,” says Stappenbeck.

4. Exercise

Aim for at least 150 minutes of moderate-intensity physical activity (like walking) per week. Partly because it can help to prevent obesity, which causes inflammation and partly because it comes with its own benefits. A 2017 study conducted by the University of California San Diego School of Medicine found that even one 20-minute session of moderate exercise can stimulate the immune system.

5. Get more sleep

“Sleep is very important in draining toxic material from the brain through a specialised lymphatic system that cleans the brain, and it is very active at night,” says Prof Mallat, “and all of this is very important in terms of shutting down inflammation.”

6. Spend time in nature

“Taking a walk in the woods can help us de-stress, but also exposes us to bacteria, viruses and fungi that can boost our own,” says Ravella. “Too many people are on screens in concrete buildings and don’t go out.”

7. De-stress

Burnout exacerbates inflammation. “If you are operating constantly in a state of constant threat perception, that will drive your immune system to a state of hyper-vigilance,” explains Curran. “Your thoughts are communicated to your immune system through stress hormones, so high levels of cortisol or adrenaline (all of the fight-or-flight signalling agents) shifts your immune system into a state of high alert, where the smallest trigger sets off a massive inflammatory cascade.”

8. Take vitamin D

Vitamin D is hugely important for regulating inflammation, says Curran. It helps to support the body’s immune response, improving your ability to fight off illness and disease.

9. Try intermittent fasting

Research based on workers during Ramadan in Indonesia suggests intermittent fasting can help limit inflammation. It can facilitate weight loss, prevent the progression of Type 2 diabetes and consequently improve cardiovascular risk, increase longevity, and reduce disease.

10. Cut back on exposure to polluting chemicals

Certain cleaning supplies and body care products contain chemicals that may inflame us, so read labels carefully. “We call it sterile inflammation,” says Stappenbeck. “Usually with inflammation, you have an infectious agent. But it’s this sterile inflammation in the absence of any kind of infectious agent, that’s worrying. We also need to further study the emerging role of microplastics and their interaction with the microbiome, especially in the gut, since this is something that’s usually ingested.”

You can get a water filter and avoid bottled water, he adds, though the majority of microplastics come from our clothes when they are washed. So avoid polyester, nylon and acrylic. Choose natural fibres like cotton, wool, linen. Wash less frequently, use cold water, run full loads, and consider investing in a washing machine filter or a laundry bag designed to capture microplastics.

Air quality is also key. “All the epidemiological studies suggest that in terms of lung disease, your postcode, and how much pollution you breathe in really matters.” A 2019 study by King’s College London found London had the highest levels of airborne microplastics yet recorded, with a rate of microplastic deposition over 25 times higher than China, and seven times higher than Paris.

“If you live in an area with high amounts of air pollution, that’s obviously going to affect your lung function, or if your water supply is contaminated with high amounts of microplastics.”

Air purifiers, especially those with HEPA filters, can effectively remove microplastics and other airborne pollutants. And if you live in a polluted area like London avoid exercising outside at dawn or dusk when pollution peaks.