What causes inflammation? (And how to reduce inflammation)

If you mention the dangers of inflammation in mixed company, you’ll probably see plenty of vigorous head bobbing. Most people are now confident that inflammation is “bad” and anti-inflammatory foods, supplements, and behaviors are “good”.

They’re directionally correct. Too much unnecessary, long-term, and recurring immune activity—what we call chronic inflammation—is linked to heart disease, cancer, Alzheimer’s, liver disease, type 2 diabetes, and most other modern diseases you can name.

Chronic inflammation even accelerates aging. Among the longest-lived people on Earth, low levels of inflammation best predict their continued vitality.

But the “inflammation is bad” meme is overly simplistic. People have lost the plot. Maybe they never had the plot to begin with, so let me be clear: Not all inflammation is bad. Without immune activity, we couldn’t fight off an infection or heal a wound.

The problem is when the immune response goes too far, for too long, even when we don’t need it. This immune system confusion is what we want to minimize.

But what causes systemic inflammation? And what are the most practical ways to reduce it? I’ll answer those questions in a bit. First, I want to unpack what inflammation means.

What Is Inflammation?

According to Merriam-Webster, inflammation is ​​”a local response to cellular injury that is marked by capillary dilatation, leukocytic infiltration, redness, heat, and pain and that serves as a mechanism initiating the elimination of noxious agents and of damaged tissue”.

The dictionary is defining acute inflammation here. Though similar, it’s not exactly the type of inflammation we worry about in the context of chronic disease.

In fact, we need acute inflammation. It’s how we fight off the bad guys. Think about what happens when you cut yourself. The area hurts, turns red, scabs over, and eventually heals.

Acute inflammation is your army of immune cells charging through to fix the problem. First come the inflammatory cytokines. Then, these scouts signal the heavy artillery: platelets, leukocytes, and other immune particles that prevent infection and stimulate wound healing.

This isn’t to say that acute inflammation is always beneficial. Sometimes it does more harm than good.

Consider sepsis, a life-threatening condition borne of bacterial infection. To ward off the infection (often from E. coli) the immune system fires up BIG TIME. Sepsis fatalities, believe it or not, are typically due to inflammatory complications rather than the infection itself.

But while it’s important to understand, acute inflammation isn’t the type of inflammation I worry about. What I worry about is chronic inflammation.

Chronic Inflammation 101

Both acute and chronic inflammation involve the same immune cells, infiltrating the same tissues, trying to do the same jobs. But while acute inflammation involves a specific threat to be neutralized, chronic inflammation does not.

I like to think of chronic inflammation as chronic immune confusion. The soldiers are mobilized, but they shouldn’t be.

The problem is, any type of inflammation (necessary or not) causes cellular damage. When we need temporary inflammation to heal a scrape or fight a virus, this damage is a price worth paying. But when the inflammation becomes chronic, it’s all downside. I’ll make an example of heart disease to help illustrate.

Heart disease is a multifactorial process, but it’s clear that higher levels of inflammation create higher risk. In a nutshell, immune particles engulf oxidized LDL particles in the arteries, kicking off further immune activity that leads to the formation of atherosclerotic plaques. When these plaques eventually break off, they often get lodged somewhere in the circulatory system. That’s how heart attacks and strokes happen.

And it’s not just heart health. Chronic inflammation underlies every chronic disease in the book. So what’s causing it?

What Causes Chronic Inflammation?

Not every cause of chronic inflammation is within our power to change. Age is the obvious example. All other factors equal, an 80-something will be much more inflamed than a 30-something.

Other proinflammatory factors—like cigarette smoking, alcohol abuse, and air pollution—are more within our control, but I won’t spend much time on them today. I assume most people know that binge drinking and puffing tobacco increase chronic disease risk.

Instead, I’ll cover five modifiable diet and lifestyle factors linked to systemic inflammation. Let’s start with sugar.

#1: Refined carbohydrates

High-sugar diets are probably the biggest driver of chronic inflammation in modern society. In study after study, higher intakes of refined carbohydrates are correlated with higher levels of inflammation.

How does sugar drive inflammation? I wrote a deep dive blog on this topic, but here are the six mechanisms in brief:

1. By causing high blood sugar (hyperglycemia), a proinflammatory state.
2. By feeding proinflammatory gut bacteria and causing leaky gut.
3. By feeding pathogenic oral bacteria like S. mutans that can enter the bloodstream, increase inflammation, and accelerate heart disease.
4. By increasing fat production in the liver (that’s what fructose does) and creating inflammatory metabolites.
5. By raising insulin levels and decreasing the production of anti-inflammatory ketones.
6. By driving weight gain and obesity.

The last mechanism is significant. Sugar calories are empty calories. We overeat (or overdrink) them, gain a bunch of fat, and get stuck in an obesity-fueled inflammatory loop.

#2: Vegetable oils

Another cause of the obesity epidemic? Overconsumption of high-omega-6 vegetable oils.

Soybean oil, for instance, is the number one consumed fat in America. And yes, it’s making America fat.

By consuming too much omega-6 (linoleic acid) from soybean oil, we squeeze out the anti-inflammatory omega-3s from cells. Then cells secrete proinflammatory factors, which in turn drive fat accumulation, which in turn drives more inflammation. Nasty cycle.

If you really want to turn up the inflammation, just cook vegetable oils at high heat. This will generate compounds called oxidized lipids that, when ingested, can damage just about every major organ system. All of that said, I’ve seen people go crazy over the seed oil, N-6 topic. If you eat out every once in a while, you do not need to scrutinize what is in every ingredient on your plate. And if you want a handful of almonds, have it.

#3: Food intolerances

Most of our immune cells reside in the gut, so it’s no surprise that inflammation is often rooted there. When I’m working with someone who already eats healthy, I look at gut health and food sensitivities first.

Take whole grains, for instance. I know this is Paleo heresy, but they’re not necessarily the worst food in the world—whole grains do contain fiber, folks. Still, those with gut issues like my own tend to tolerate them poorly.

Grains are poorly tolerated because they contain compounds that trigger immune system confusion. The most famous is gluten, but there are dozens of others.

Beyond grains, other common trigger foods include:

• Dairy
• Eggs
• Nuts and seeds
• Legumes
• Soy
• Shellfish

Everyone is different, so it will take some trial and error (and monitoring of GI symptoms) to determine which foods are causing inflammation in your gut.

#4: Poor sleep

At six hours of sleep per night or less, the risk for most diseases rises significantly. I believe inflammation may drive a good bit of this effect.

In a 2009 study, researchers restricted young healthy men to 5 nights of short sleep (4 hours), then gave them 2 nights of recovery sleep (8 hours). During the sleep deprivation phase, the men showed elevations in inflammatory markers (CRP, IL-6, and IL-17) and heart rate.

The bad news is, these markers remained elevated even after the recovery sleep. In other words, “catching up” on your sleep during the weekend won’t help you all that meaningfully.

#5: Stress

Some level of stress is healthy. The stress from moderate exercise, polyphenols, or a challenging cognitive task triggers an adaptive response that leaves us stronger.

But as I’m sure many of us including myself know all too, stress can become overwhelming. And when stress becomes overwhelming, it can prevent us from functioning optimally. That includes our immune function.

A huge body of literature suggests that stress can activate inflammation in the brain, cardiovascular system, and other organ systems. This is probably the key link between stress and stress-related diseases.

How To Reduce Chronic Inflammation

When it comes to reducing chronic inflammation, I’m a big believer in the basics. That means focusing on diet, exercise, sleep, and stress management first.

Sure, there are anti-inflammatory drugs and supplements. (I do like the anti-inflammatory benefits of omega-3 fatty acids, for instance). But many of these compounds have side effects or long-term effects you might not want.

Start with nutrition. If you eliminate refined carbohydrates and vegetable oils, you’ll be ahead of 95% of the population for eating an anti-inflammatory diet.

The next step is to identify any food intolerances. Begin by cutting out grains, dairy, and other common triggers, then play with an elimination diet if gut symptoms persist. Getting your gut health handled is essential for minimizing chronic inflammation.

After you optimize your diet, turn to lifestyle factors. Get 7-9 hours of quality sleep per night. Manage your stress with meditation, yoga, or a few laughs. And exercise regularly. Exercise increases inflammation in the short term but decreases it in the long term.

Get the basics handled and you’ll be in good shape. Now there’s an idea worthy of some energetic head bobbing.