Interest in the anti-inflammatory diet is increasing, according to Google Trends. But can some foods really reduce disease-causing inflammation – a condition linked to the immune system – and if so, who could benefit from the diet?
What is inflammation?
Inflammation is your body’s natural response to harm, such as infection, injury or toxin. When something damages your cells, your immune system kicks in. This causes short-term effects, such as swelling if you get a splinter. You wouldn’t want to prevent this from happening, so what is the anti-inflammatory diet actually for?
Those interested in the diet may be seeking to reduce long-term chronic inflammation, such as that caused by different types of arthritis. “Some researchers suggest elements of modern living can drive chronic inflammation”, says dietitian Sophie Medlin. Factors believed to promote it include smoking, being overweight, a sedentary lifestyle and drinking alcohol excessively.
Chronic inflammation has also been identified as a risk factor for a number of diseases, including heart disease, diabetes, some cancers and neurodegenerative conditions.
The perceived benefits of the anti-inflammatory diet could be direct, as it’s suggested certain foods can affect your inflammation levels, or indirect, as what you eat affects your weight and health, which in turn can be linked to inflammation.
What is the anti-inflammatory diet?
The anti-inflammatory diet is about choosing foods believed to fight inflammation and limiting those thought to contribute to it. Luckily, “lots of foods contain anti-inflammatory properties”, says Medlin.
Harvard University identifies a list of anti-inflammatory foods, including tomatoes, olive oil, green leafy vegetables, nuts, oily fish and fruits. “Foods on the pro-inflammatory list include fried foods, sugary drinks, refined carbohydrates, animal fats and processed meats”, continues Medlin.
Not getting enough of particular nutrients and micronutrients has been linked to inflammation. Foods high in refined carbohydrates, sugar, saturated fat and trans fatty acids – for instance some ultra-processed foods – and a diet low in fibre, natural antioxidants and omega 3, have also been linked to inflammation. Use the BBC Food nutrition calculator to find out how likely you are to be lacking in nutrients, based on your age and sex.
Some bacteria living in our gut are “known to produce anti-inflammatory properties”, says Medlin, so it is worth looking after your gut health by eating a varied diet including plenty of prebiotics and probiotics. Swap white breads, pasta and rice for the wholegrain, fibre-filled alternatives your gut bacteria like to ‘feed’ on – beans, pulses, legumes and many other vegetables are also high in fibre.
Numerous spices, including black pepper, ginger and turmeric, as well as garlic, have been linked to fighting inflammation. But more research is needed, as “very few studies were performed with actual foods”, but used extracts or capsules.
Evidence for the effect of an anti-inflammatory diet is not conclusive, though. “Many would question the link between the [list of foods by Harvard] and chronic inflammation in the otherwise healthy population”, says Medlin. But she continues, “a balanced diet that includes plenty of the foods on the anti-inflammatory list and not too many of the pro-inflammatory foods is good healthy eating advice”.
Do we all have the same inflammatory response to foods?
Inflammation triggered by the food we eat varies up to ten-fold, according to results from the Predict study published in June. This indicates that the impact of different foods on inflammation varies from person to person.
The study identified “a wide range of metabolic responses after eating in apparently healthy adults”, and linked a poor metablic response to food with “increased risk of conditions such as low-grade inflammatory diseases including heart disease, type-2 diabetes and obesity”.
A poor metabolic response is defined as “where the body takes longer and works harder to clear the body of fat and sugar”. Professor Tim Spector, senior researcher on the study, says “The metabolic response to food was so different between people in identical conditions. So, if they were given an identical muffin, for example, how much their sugar, insulin and blood fats went up varied about eight-fold between people. There was no average response.”Click or tap here for wholegrain recipes
Is the Mediterranean diet anti-inflammatory?
The Mediterranean diet, emphasising vegetables, fruits, wholegrains and lean protein, has been linked to lower levels of inflammatory-causing proteins. It encourages eating oily fish, such as salmon and sardines, which contain omega 3 and are linked to reducing inflammation (and which many in the UK don’t eat enough of, according to the National Diet and Nutrition Survey).
It has also been found to be effective for weight loss, which is significant because obesity is reported to “predispose to a pro-inflammatory state”.
The diet limits refined starches, sugar and saturated fat, which are on the pro-inflammatory list.
There is evidence that any anti-inflammatory effect of the Mediterranean diet can be felt within three months, but the the greatest impact is achieved after a year.Click or tap here for Mediterranean recipes
Will an anti-inflammatory diet help with arthritis?
Arthritis Action is clear no diet or type of food is proven to make arthritis better or worse, and states “the aim should be to eat a well-balanced diet and to keep to a healthy weight”. Dietitian Martin Lau, spokesperson for Arthritis Action, says “a healthy diet which promotes anti-inflammation, such as the Mediterranean diet, not carrying too much body weight, combined with specialist anti-rheumatic medications, could promote remission” in those with rheumatoid arthritis. It’s also important for those with different types of arthritis to watch their weight. In the case of osteoarthritis, this is to reduce strain on joints.
Some people believe nightshade vegetables, including tomatoes (which are on the Harvard list of anti-inflammatory foods), aggravate arthritis pain due to a chemical they contain called solanine. “There are no scientific studies done to prove that they actually cause inflammation or make symptoms worse”, says Kim Larson, a Seattle-based dietitian and Academy of Nutrition and Dietetics spokesperson. If you think they may be worsening your pain, the Arthritis Foundation recommends you “eliminate nightshades from your diet for a couple weeks and slowly reintroduce them. If you find that adding nightshades triggers arthritis pain, don’t eat them”. Other nightshade vegetables include aubergine, red bell peppers and potatoes.
The anti-inflammatory diet is not for everyone
The anti-inflammatory diet may not reduce inflammation for everyone, and could make symptoms worse for some. “If my inflammatory bowel disease patients or those with gut disorders followed Harvard’s anti-inflammatory diet, their problems may get worse, not better”, warns Medlin. If you have a medical condition, always consult your doctor or dietitian before altering your diet.