Dietary fads come and go as fast as you can drink a mushroom latte. Dr Alex Ruani’s job as a researcher in nutrition science at University College London and chief science educator at the Health Sciences Academy is to track and scrutinise them, to filter out any lacking evidence so that it is only trends worthy of a wider audience that remain on her radar. It is rare that she gets so enthused by food science that it prompts changes in her diet. Yet a slew of new studies on anti-inflammatory eating has convinced her to do just that.
Acute inflammation is a normal biological response triggered by the immune system to offer protection when we are injured, ill or stressed. “You accidentally cut your finger, it swells, an inflammatory response helps to heal the wound and then it goes away,” Ruani says. “But when even low-grade inflammation persists and lingers in the body, it disrupts normal functioning of cells, tissue and organs, leading to metabolic complications, tissue damage and even the shortening of our lifespan.”
This chronic inflammation presents an under-the-radar threat to the body, quietly undermining our health while contributing “to the development and progression of almost every chronic condition we can think of, from Alzheimer’s disease, sub-fertility and depression to cancer, type 2 diabetes and strokes”, she says.
That diet might play a role in accelerating and slowing its progression was first promoted in alternative anti-inflammatory diet books a decade ago, but only now is the evidence robust enough for scientists to take it seriously. “There’s been an avalanche of research on meal-induced inflammation and the term ‘dietary inflammation’ has taken over scientific literature,” Ruani says. “It’s a revelation even to those of us who spend our lives engrossed in nutrition and has surprised me, but new proof is emerging all the time that you can help reduce low-grade chronic inflammation in the body through changing what you eat.”
Every meal triggers some level of inflammation and, if you are a grazer, your body is constantly battling this response. Yet some foods, including those high in fat and sugar, produce a greater inflammatory reaction than others, overloading your system and raising the risk of the prolonged, sustained inflammation that is associated with disease. “All of us experience some degree of inflammation following a meal, and this is triggered by digesting, absorbing and metabolising our food,” Ruani says. “However, different foods can exacerbate our meal-induced inflammation while others help to reduce it.”
Among the convincing recent trials to hammer home this message is a paper from researchers at the Harvard TH Chan School of Public Health that followed more than 200,000 men and women for 32 years. The findings show that people eating diets high in the most pro-inflammatory foods, including the obvious good-for-nothing sugary and refined or highly processed foods, white bread, pasta, processed meat and sweet drinks, had a 46 per cent increased risk of heart disease. In people who ate foods with the greatest anti-inflammatory potential, including leafy greens, oily fish, coffee and tea, markers for systemic inflammation were significantly lower.
A paper published last month in TheAmerican Journal of Clinical Nutrition showed that there were also individual variations in inflammatory responses to food. A team from King’s College London in collaboration with Massachusetts General Hospital invited more than 1,000 healthy participants to attend their research clinic for a day and provided them with two standardised meals containing precise amounts of fat, carbohydrate, fibre and protein — breakfast of a muffin and a milkshake followed by a muffin for lunch four hours later.
Blood samples taken throughout the day revealed that key markers of dietary inflammation nearly doubled six hours after eating a meal. Levels of inflammation after eating were higher in males than females, in older participants rather than younger ones, and in people with more body fat and greater body mass index. This supports previous research that weight loss reduces chronic inflammatory burden.
“Colossal increases in inflammation, by up to a whopping 190 per cent, were observed,” Ruani says, “but they also saw individual variations in response, suggesting we don’t all react in precisely the same way to every meal we eat.”
It’s not just what we eat but how food is prepared that affects inflammation. For Ruani, barbecued and fried food is out. “Frying and barbecuing generate genotoxins, such as acrylamides, that can cause DNA damage and raise inflammation in the body,” Ruani says. “My advice is to avoid anything cooked this way, including products that have been pre-fried such as tofu puffs or vegetable pakora.”
Salt is also on her warning list. “I love salt and used to add it to pretty much anything, thinking my blood pressure was fine and it wouldn’t cause me problems,” Ruani says. “But now there is firm evidence it contributes to low-grade inflammation and I have clamped down on it in my diet.”
Choosing foods that will limit low-grade inflammation is something we should all take seriously, Ruani says. “Chronic inflammation accelerates ageing in every way. It makes our skin age faster, our brain age faster, our detoxification organs — the liver and kidneys — age faster and the whole body doesn’t function as it should,” she says. “I am in my early forties and have a two-year-old daughter and want to live until I am 80, to be happy and to retain a sharp brain, which is why an anti-inflammatory way of eating is something I have adopted so wholeheartedly.” Here are Ruani’s suggestions for you to eat to do the same:
Top anti-inflammatory foods
Walnuts
A study in the Journal of the American College of Cardiology involving more than 600 adults in their sixties and seventies found that those asked to consume 30-60g of walnuts a day in addition to their daily diet for two years had 11.5 per cent lower levels of inflammatory biomarkers than participants who did not eat the nuts.
“Walnuts are one food that might lessen chronic inflammation, which could help to reduce the risk for heart disease,” said Dr Emilio Ros, the director of the lipid clinic at the Hospital Clinic in Barcelona and lead author of the paper, which was conducted in partnership with Loma Linda University. “They have an optimal mix of essential nutrients like alpha-linoleic acid and other highly bioactive components like polyphenols that likely play a role in their anti-inflammatory properties.”
Herbs and spices
Turmeric, touted for its anti-inflammatory effects, is an obvious choice, but the more herbs and spices in your diet the better, according to researchers at Penn State University. For a study in The Journal of Nutrition last year they showed that participants who added 6g of a herb-and-spice blend including basil, bay leaf, black pepper, cinnamon, coriander, cumin, ginger, oregano, parsley, red pepper, rosemary, thyme and turmeric to a high-fat meal had lower markers of inflammation than when they ate the same meal without spices. “We can’t say from the study if it was one spice in particular, but this specific blend seemed to be beneficial,” said Connie Rogers, associate professor of nutritional sciences and lead author of the paper.
Green and herbal teas
“Phenolic compounds such as epigallocatchin-3-gallate in green tea, have anti-inflammatory properties,” Ruani says. “Ginger, fennel, nettle and rosehip teas are also associated with the lowering of inflammatory markers.” A 2019 study in the British Journal of Clinical Pharmacology found that overweight women who consumed a 500mg extract of green tea while following an eight-week exercise programme consisting of three workouts a week — aerobics, circuit training and walking at 40-59 per cent of their maximum heart rate — experienced greater improvements in inflammatory markers than when they only exercised.
Yoghurt and cottage cheese
Many brands of cottage cheese contain fermented or live cultures, which are known probiotics. “These living bacteria can replicate in the gut and colonise it with more diversity, key to reducing inflammation,” Ruani says. If cottage cheese is not your thing, try kefir and yoghurt or fermented vegetables such as sauerkraut and miso for similar benefits. “Yoghurt is a great food to eat because the Lactobacillus bulgaricus and Streptococcus thermophilus bacteria it contains have anti-inflammatory roles in the body.”
Cherries
Cherries contain antioxidant compounds called anthocyanins that have been linked to reduced inflammation. In a review of the health benefits of cherries by scientists at the US Department of Agriculture a regular consumption of cherries lowered markers for inflammation in 11 of 16 published studies. Meanwhile, researchers at Oregon Health and Science University claim that tart Montmorency cherries may have the ”highest anti-inflammatory content of any food” and show that twice daily shots of cherry juice for three weeks led to significant reductions in inflammation markers in a group of women aged 40 to 70. Benefits were greatest among women who had the highest inflammation levels at the start of the study.
Light or medium-roast coffee
Rich in bioactive compounds with anti-inflammatory properties, including chlorogenic acid, coffee has been shown in several studies to have a positive effect on reducing inflammation. For a study in the Journal of Medicinal Food researchers measured the levels of caffeine and chlorogenic acid in arabica beans roasted at light, medium and dark levels. They found that while caffeine levels didn’t differ greatly between the various roasting levels, the lighter the roast, the higher its chlorogenic acid content — and the better the coffee protected against inflammation in laboratory tests.
Apples
Eating three apples a day for six weeks helped to lower markers for inflammation in a group of 46 overweight women, reports one study in The American Journal of Clinical Nutrition . The fruit is rich in the fermentable fibre pectin, which bacteria in the gut need to thrive and grow.
Blackberries, strawberries and blueberries
Berries are packed with polyphenol plant compounds that have anti-inflammatory effects, including anthocyanins, which are responsible for their red, blue and purple hue. “These polyphenols in berries slow down meal-induced inflammatory response,” Ruani says. One six-week study found that consuming strawberries before a high-fat and high-calorie meal reduced increases in inflammatory markers after the meal in men and women. Others have shown that a range of berries, including blackberries and blueberries, have a potent anti-inflammatory effect.
Oily fish
It is the rich content of long-chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) that give fatty fish such as mackerel and herring their anti-inflammatory properties. “Both EPA and DHA have been shown in studies to reduce the inflammatory marker C-reactive protein associated with heart disease,” Ruani says. “Egg yolks and flaxseeds are other good sources.” It’s better to eat the real foods than to pop a pill. Cardiologists at the Intermountain Medical Center Heart Institute in Salt Lake City reported last month that high levels of DHA “blunt the benefit of EPA” when combined in a fish-oil supplement.
Spinach, cabbage and kale
Researchers from the University of Pennsylvania found that participants asked to eat leafy green vegetables daily had higher blood levels of beta-carotene, which led to lower levels of widely accepted measures of systemic inflammation. Dr Joshua Dunaief, a researcher in the school of medicine and author of the paper, said, “Patients who adhered to the diet were able to lower their CRP levels from an average of 7 to 1.75 within six months, significantly lowering their risk of heart disease.” Dark leafy greens are rich in fibre, which Ruani says “feeds good bacteria in the gut, aiding a reduction in inflammation”.
Source: Sunday Times
