When it comes to the battle of the dinners, the meal Shilpa Ravella ate the evening before we spoke ticked more anti-inflammatory boxes than the meal I ate.
Both our meals were meat-free, which is good – meat, and in particular red meat, has been shown to increase inflammation. But mine included an animal product (feta cheese), which is not quite so good. And while my meal had lots of different vegetables, including avocado and peas, which are both high in fibre, as well as olive oil and a few nuts, it had no whole grains or legumes.
Ravella’s meal, on the other hand, included both whole grains and legumes – quinoa and beans – as well as fresh coriander and a number of different spices. All these foods are known to prevent, and possibly even reverse, the hidden inflammation that is being linked to many modern chronic diseases. These include heart disease, cancer, diabetes and autoimmune diseases such as rheumatoid arthritis.
“I think we forget about spices and herbs,” says the author of A Silent Fire, which looks at the link between diet, inflammation and disease. “Spices and herbs are some of the most powerful anti-inflammatory foods that we can be eating, and it’s very easy to just throw in some spices and try to get some fresh herbs. It’s a great gain for a minimal effort.”
Ravella is a gastroenterologist who divides her time between New York, where she works at Columbia University’s Irving Medical Centre, and Hawaii, where she works in rural health care.
She says hidden inflammation is also linked to neurodegenerative diseases such as Alzheimer’s disease and mental illness such as depression.
“Hidden inflammation, silent and sinister, lurks in heart disease and smoulders beneath developing tumours,” she writes in the book. “It is tied to many other chronic conditions as well, including obesity, diabetes and neurodegenerative and psychiatric disease.”
Inflammation in itself isn’t bad. In fact, it’s a vital part of our immune response as our bodies mobilise to fight challenges such as infection and physical trauma. When we stub our toe, for example, we often develop redness, pain, heat and swelling at the site of the injury – all signs that our immune system is doing what it’s meant to do.
Since ancient times
“Inflammation is actually an ancestral response. And it evolved to protect our bodies from things like pathogens, or poisons, and traumas. All of these things were threats that ancient human beings routinely succumbed to. So inflammation is a healthy response that evolved to defend us against these things.”
However, modern life – how we grow our food and what we eat, the stressful way we live, our lack of physical exercise and falling levels of social interaction – means our immune systems are turning against us. As well as mobilising against pathogens, poisons and traumas, our immune systems mobilise against things our bodies have not evolved to cope with, such as highly processed food or food high in saturated fat. Modern beef, for example, has as much as 35% saturated fat. In comparison, antelope meat has 7% and anthropologists think this meat is similar to the kind our Palaeolithic ancestors ate.
The body’s response can produce hidden inflammation that grumbles on for years, causing unseen damage that can eventually lead to an unexpected heart attack or a cancer diagnosis.
“The problem now is that our modern world is so drastically transformed from ancient times, and our immune system becomes just very exquisitely sensitive to the new triggers in this world,” says Ravella. “So, it’s not the poison or the frequent, [potentially] fatal infection, or the frequent trauma that we’re dealing with, but things like daily stress or a bad diet or lack of exercise.”
In the case of heart disease, she says inflammatory cells can leech onto fatty plaques in the arteries, making the plaques more likely to build up, rupture and cause a heart attack or stroke. In the case of cancer, she estimates that about a quarter of all cancers are the result of overt tissue inflammation, particularly in the gut as well as organs such as the liver and lungs. Severe inflammation in the joints and brain, on the other hand, carry little increased risk of cancer.
It’s not surprising the gastroenterologist focuses largely on the role of our diet. As she points out, the gut is one of three major channels through which inflammatory triggers enter our system – the others being the skin and the lungs. She says the gastrointestinal tract is a particularly susceptible entry point for these triggers because of its large surface area – equivalent to a small studio apartment. So there are many opportunities for the gut to come into contact with potentially inflammatory outside substances.
“Much of the immune system lives in the gut, which is heavily exposed to the external world,” Ravella says.
Central to the gut’s role is our microbiome ‒ the trillions of germs, such as bacteria, viruses and fungi, that live in our gut. These interact with the food we eat to create components that are either anti-inflammatory or inflammatory. Take fibre, for example, which is a powerful anti-inflammatory. “Your gut bacteria are metabolising that fibre, digesting parts of it that you can’t digest, and they are creating all of these wonderful components, these metabolites that are able to calm inflammation, not just in the gut, but throughout the body.”
However, our gut bacteria respond differently to other types of food. In some cases, they cause our immune cells to become maladjusted, excited and more likely to mount an inflammatory reaction.
Not surprisingly, the foods most likely to produce this kind of reaction are the ones that are not part of our traditional diet: highly processed fare and foods high in saturated fat as well as sugar. As much as we may enjoy them, our bodies are not designed to cope with lots of fast food, sugary drinks, white bread, modern meat and dairy food.
With no visible signs of its existence, it can be hard to know if we are suffering from hidden inflammation. Possible clues are excess belly fat, which suggests high levels of a very inflammatory type of fat that wraps around our inner organs, known as visceral fat. High blood-sugar levels can also be a proxy for inflammation, as can a high BMI. Ravella says some cardiology clinics now test for high levels of C-reactive protein (CRP), an inflammatory marker that can indicate heart disease.
“All of these different things can tell you if you have some inflammation going on in the body, and there are blood markers other than CRP, too. But it’s a bit too early now to start routinely using those in clinics; we just don’t have the data yet.”
The hidden nature of chronic inflammation means it works behind the scenes, slowly causing damage over many years. Even slim young people with no belly fat but with a poor diet and poor exercise habits may already have visceral fat around their inner organs that is causing hidden inflammation. “A teenager’s food habits can have implications for cancer causation down the line or the types of diseases they develop as they get older.”
Simply getting older causes inflammation, too; it is an inevitable part of ageing, a process known as inflammaging.
Reversing the damage
The good news is it’s possible for older people to both stop and reverse this inflammation through a healthy diet, more exercise and reducing their stress.
Ravella points to the so-called “blue zones” – where people live much longer, healthier lives, with less dementia and fewer mental-health issues – as proof of what is possible. What sets apart the people in places such as Okinawa in Japan and Nicoya in Costa Rica is both their diet, which is largely plant-based, and the fact that they remain active and social as they age.
“There’s a constellation of factors that promote health,” says Ravella. “It’s everything from the types of foods they eat, to how they exercise, to stressors and their social connections.”
And although those of us entering older age, having eaten more hot chips, sticky buns and red meat than we should have, can’t necessarily turn ourselves into blue-zoners, we can at least become a little more blue. A study published in the New England Journal of Medicine found it’s never too late to start undoing the damage caused by a poor diet. It found that even small changes, such as eating a handful of nuts every day, could improve long-term health. The study by the Harvard TH Chan School of Public Health followed about 74,000 people aged 30-75 for more than 20 years. The researchers say a 60-year-old who adopted a Mediterranean-style diet (and stuck with it) could boost their life expectancy by up to nine years and an 80-year-old could gain about three and a half years.
Among the foods that helped were fruits, vegetables, nuts, seeds, beans, whole grains and those rich in unsaturated fats and heart-healthy omega-3 fatty acids such as fish, avocados and olive oil.
Ravella says making these kinds of lifestyle changes will also help us to live better. Even if the changes are made after having had a heart attack or a stroke, they may help prevent a second one. A study published by American physician Caldwell Esselstyn in the Journal of Family Practice in 2014 found that adopting a whole foods diet (eliminating dairy, fish, meat and added oil) significantly reduced the likelihood of a cardiac event.
Half of the 198 people in the study had already had a heart attack or stroke. Of the 89% (177 people) who stuck to the diet, only one experienced a cardiac event. Of those who didn’t stick to the diet, 62% (13 out of 21 people) had at least one cardiac event.
Ravella says a better diet and more exercise may also improve the outcome of medical interventions such as a joint replacement or an organ transplant. Early studies have found, for example, that transplanted kidneys are less likely to be rejected if the recipients follow a Mediterranean diet.
“Making all of these lifestyle changes – diet, exercise, stress, social conditions, all of these things that decrease inflammation – also have the power to help you adapt to modern medicine, to all the positive things modern medicine can do for you.”
The good stuff
To help prevent and potentially reverse inflammation, it’s important to follow what is often called a Mediterranean diet. That means lots of vegetables, fruit, olive oil, a variety of leafy greens, wholegrains, legumes, herbs, spices, seeds and berries, with only small amounts of meat and fish.
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- Eat red, purple, red-brown or green plants: Plant food these colours have more phytochemicals which are anti-inflammatory. Studies have found that berries and greens such as kale and broccoli smother inflammation better than bananas and lettuce.
- Love the wonky stuff: Produce grown with fewer pesticides might not look perfect, but having to struggle for survival helps it build up more polyphenols, the anti-inflammatory antioxidants the gut loves, as well as salicylic acid, which is also anti-inflammatory.
- Eat lots of different plants: A 2019 study by the American Gut Project found that the more types of plants you eat, the more diverse your gut microbiome is. People who ate 30 types of plants (fruits, vegetables, grains, legumes, nuts and seeds) each week had a significantly more diverse microbiome than those eating 10 or fewer different plants. “Diversity is a marker of health in the gut microbiome,” says Ravella. “And we know that the gut microbiome affects inflammation throughout the body.”
- Use gentle cooking methods: The higher the temperature you cook your foods at the more likely they are to develop inflammatory byproducts. This is particularly the case for animal food – meat, cheese, butter and eggs. If you must roast, grill or fry food at high temperatures, make it fruit, vegetables, grains or legumes. “Most of the time you just want to gently sauté or bake your food.”
- Eat fermented food: Studies have shown that fermented foods are very anti-inflammatory. Toss a few tablespoons of fermented vegetables into your meal, and eat fermented breads – sourdough made in the traditional way, for example.
- Eat a good balance of omega-3 and omega-6 fats: Omega-3 fats are a type of polyunsaturated fat with a strong anti-inflammatory effect. They are found in foods such as fish (particularly salmon, herring and mackerel), greens including brussels sprouts and broccoli, walnuts, chia seeds and flaxseed. Omega-6 fats, found mostly in vegetable oils such as sunflower and soybean oil, are more inflammatory. It’s fine to eat both, but at the ratio our ancestors consumed them – four times the amount of omega-6 fat as omega-3, rather than 15 to 20 times the amount of omega-6 fat, as is the case today.
A Silent Fire, by Shilpa Ravella (Bodley Head,$40 )