Does the anti-inflammatory diet really exist?
Does that collagen smoothie really help prevent inflammation?
I was recently tagged in a Twitter thread in response to a post by Harvard Health about anti-inflammatory foods. Here’s the post, in case you’re wondering.
The thread was full of people telling Harvard that this infographic was super-misleading and not evidence-based.
Whaaa? Are these foods anti-inflammatory though?
It’s easy for us as healthcare professionals to say that certain foods are ‘anti-inflammatory,’ and to promote anti-inflammatory diets. But I think some of us (and me included at times) take it too far – just like Harvard did.
Sometimes, we need to pull back and examine the evidence, because, in the words of the great Jason Koop, ‘the people you need to be afraid of, are the ones who are set in their opinions and never change, even when the science does.’
I definitely never want to be that person, so in honor of Harvard’s supposed anti-inflammatory faux pas, I decided to take another look at the current evidence around anti-inflammatory foods and diets and explain to you all why it’s not all cut and dried.
What is an anti-inflammatory diet?
An anti-inflammatory diet is generally characterized as one that’s high in fruits, vegetables, healthy fats, legumes, and whole grains, while keeping refined carbohydrate and highly-processed foods to a minimum. Most of you know it as the Mediterranean diet.
To muddy the waters a bit, there are also a bunch of compounds that are promoted as being anti-inflammatory, such as turmeric, matcha, fish oil, resveratol, ginger, and many more.
Things really get messy when we also consider the differing opinions out there about inflammation and foods like dairy, seed oils, tomatoes and other nightshades, as well as lectin-containing grains and legumes.
It’s enough to confuse everyone. But one thing I can tell you for sure: never listen to anyone who tells you that foods like tomatoes and whole grains cause inflammation for everyone. If that was true, countries like Italy would be overrun with disease.
And although ‘inflammation’ has become a huge selling point for the wellness industry, it’s safe to say right now that a lot of the ‘anti-inflammatory’ claims that are made about certain foods don’t have solid evidence around them.
Like turmeric, which requires a large dose to get the apparent anti-inflammatory power of its active ingredient, curcumin. Yet we continue to see turmeric the spice in everything ‘anti-inflammatory.’
Like resveratrol from grapes, which we thought was an amazing reason to drink wine, but ended up being underwhelming in the research.
Like collagen, which is the darling of wellness culture, but only appears to work for inflammation in joint pain, and with only a specific type of collagen.
Similar to the Harvard post, there are so many articles online that list anti-inflammatory foods you should eat, but rarely are supported with causal evidence that comes from human studies. But people read this stuff and believe that it’s based on solid research.
It’s not. Because…..
Overall, nutrition research sucks.
We need to talk about nutrition science in general, because this is the crux of our Harvard problem. And that’s to say, that it’s inherently flawed AF. Yes, we all want to be as evidence-based as possible in whatever we do, but let’s face it: unless you can keep an entire population of people locked up in a lab for years on end, the best you’re going to get with a lot of nutrition hypotheses – like how a certain diet or food affects our health in the long run – is a link. Or, as I like to say, an ‘educated guess.’
In other words, if a population eats a diet rich in fruits and vegetables, and overall has fewer cases of cancer than another population that eats more ultra-processed foods, can we pin the fewer cancer cases on diet? Or is it a combination of diet, plus lifestyle? Maybe those people were also more active, or less of them smoked. Studies try to control for confounders like these, but that’s really, really tough to do.
We do know that when a certain result seems to pop up time and time again, this is a great sign. It doesn’t equal causation, but sometimes, a strong link is all we can get. We look for patterns.
We like to blame a lot of things on chronic inflammation: cancer and other diseases, mostly. The Harvard graphic gives us that ominous message: if you don’t eat leafy greens, you’re gonna get a horrible disease!!
There’s that ‘link’ again.
The questions we need to answer here are:
Can food ‘fight inflammation’?
Can food prevent chronic inflammation, and if so, by how much?
Can food cause chronic inflammation, and if so, by how much?
Here’s the short answer: we don’t know.
That’s because there has never been a study that proves any of it. At least, not on humans, and not without major confounders. Because so many other things in a person’s life – like genetics, activity levels, sleep patterns, for example – may also affect the amount of inflammation in their body. And nutrition studies aren’t equipped to tease these things out to the point where we can zero in on diet, food, or components in food – certainly not components of food – and be sure that they affect us one way or the other. I could list all the studies that have been done on inflammation and food recently, but this post would be way too long. Needless to say, the evidence isn’t great.
In my previous post about inflammation, my recommendations reflect the inconclusive science. Chronic inflammation definitely exists, but we aren’t 100% sure what role each individual food plays in it.
This 2018 study on the Mediterranean diet and its relationship with inflammation was unable to determine any specific foods as being ‘anti-inflammatory.’ It was also unable to draw conclusions about whether the diet itself, or the resulting weight loss, created the positive shift in inflammatory markers.
This interesting 2020 study in Gut looked at over 600 older adults who were put on a Mediterranean diet for one year. The diet was rich in fruit, vegetables, plant proteins, and fish (unsaturated fats), and low in fat, alcohol, sodium, and added sugars.
At the end of the year, the study found that participants who followed the diet the closest had the highest levels of ‘good’ bacteria in their guts, along with decreased inflammatory markers.
But studies like these leave me with more questions than answers.
How much of these changes were because of something other than diet?
What did the people actually eat over the course of one year? That’s a long time for that many people to be on a consistent diet.
What is an actual optimal mix of gut bacteria? We don’t know, especially because people from different countries have different bacteria in their microbiomes.
So what and how should we be eating?
Is it a stretch for Harvard, a trusted entity, to say that tomatoes and salmon are anti-inflammatory and that they can prevent diseases?
I get it: people like simple. Telling them to eat a diet full of fruits and vegetables is simple.
But neglecting to mention that 1. that the research isn’t super conclusive on any of these exact foods and 2. that it’s more about diet and lifestyle pattern than one component or another, isn’t doing anyone any favours. They could have also played with the verbiage a bit. I’ll never write, ‘X and Y are anti-inflammatory.’ I just don’t feel comfortable making that sort of definite proclamation about something so not definite. Instead, I usually use the words ‘may be’ or ‘thought to be’ to describe the evidence.
What most dietitians and scientists believe to be true is that overall diet – not individual foods – plus good genetics and lifestyle, may predict how much or how little inflammation you have in your body.
It’s not that you shouldn’t believe that certain foods may be beneficial. It’s that you should avoid drilling what you eat down into single foods or nutrients.
Does an anti-inflammatory diet exist?
Probably, but we don’t know exactly how much of which things has what effect, and in who.
But you’ll never catch me discouraging anyone from eating a varied diet full of plants and lean proteins, healthy fats, and some cake to top it off. Yup – enjoying life is important, too.
Drinking a turmeric smoothie or some green juice a couple times a week is unlikely to improve your health, especially if the rest of your diet isn’t great. You can’t change your genetics, of course, but there are things you can control. If you’re sedentary, stressed, or you’re constantly shorting yourself on sleep, all of these things seem to have negative impacts on our health.
It’s the interplay of everything, not just what you eat. In Harvard’s case, not just the tomatoes and fish, but everything. So while I caution you to believe everything you read about anti-inflammatory anything, I do think it’s worthwhile to adopt a global approach to health.
In other words?
Don’t hold your breath waiting for your turmeric latte to make you healthy.