Diet and Chronic Inflammation

acute inflammation alcohol anti-inflammatory diet antioxidants c-reactive protein carbohydrates cardiovascular health chronic disease chronic inflammation cooking methods cytokines diabetes elimination diet fried foods inflammation inflammatory markers leaky gut mental disorders mental health mental illnesses obesity pro-inflammatory diet stroke trans fats vegetable oils Oct 21, 2023

An assortment of unhealthy inflammatory foods like French fries, burger, donuts, etc.

In the United States, six in 10 adults have a chronic disease, while four in 10 have two or more. Chronic health conditions include heart disease, cancer, stroke, diabetes, obesity, and arthritis. Mental disorders like depression and anxiety fall into the same category. Such persistent illnesses are the top causes of death and disability in the country. Even worse, their cases are expected to increase for the next 30 years at least.^1,2

The economy suffers from chronic diseases too. They drive over 200 billion U.S. dollars in annual health-care spending. What’s more, they cost around 150 billion dollars in lost work productivity every year.³

All chronic conditions have one thing in common: they result from chronic inflammation.⁴ In this article, we’ll explore:

What is Inflammation?
Acute vs. Chronic Inflammation
Inflammatory Markers
Foods That Promote Chronic Inflammation
Managing Chronic Inflammation Through Diet

Let’s begin by defining “inflammation.”

What is Inflammation?

Inflammation is the immune system’s response to infection or injury. It consists of phases involving inducers, sensors, mediators, and effectors.⁵

Inducers are harmful agents that trigger inflammation. Examples are bacteria, viruses, allergens, foreign bodies (such as a splinter), and dead tissue. Wounds, burns, radiation or chemical exposure, and other physical injuries can also act as inducers.⁵

The presence of inducers immediately activates sensors. These specialized proteins include pattern recognition receptors (PRRs) and toll-like receptors (TLRs). Sensors are found on immune cells like macrophages, mast cells, and dendritic cells.^5,6

Sensors then stimulate the production of mediators. These molecules induce pain and regulate other inflammatory reactions. Cytokines, hormones, nitric oxide, and oxygen-free radicals are examples of mediators.^5,7

In turn, mediators trigger effectors, which help contain and wipe out threats. Examples of effectors are neutrophils, lymphocytes, and plasma cells. These cells also repair damaged tissue so that the body can start healing.^5,8

Ultimately, inflammation is a crucial defense mechanism for health. But problems arise when this complex response gets out of hand.

Acute vs. Chronic Inflammation

During acute inflammation, blood vessels widen and get leakier. As a result, more blood and other fluids flow to the infected or injured area. Neutrophils play an important role in this process. The five signs of these events are redness, heat, swelling, pain, and stiffness (loss of function). The whole process lasts for a few days.^5,9

In contrast, chronic inflammation occurs slowly and continues for months to years. It can happen when acute inflammation fails to remove harmful agents, such as resistant microbes. Another culprit is a dysfunctional immune system — one that attacks healthy cells or is too weak to protect the body. Long-term exposure to chemicals in the environment can lead to chronic inflammation as well.²

In chronic inflammation, lymphocytes and plasma cells move to the affected body part. When this migration persists, tissue damage worsens. Even nearby healthy organs can get attacked.^2,10

Body pain, fatigue, weight gain or loss, and frequent infections are some symptoms of chronic inflammation.² These symptoms are typical of many other diseases though. For this reason, chronic inflammation is harder to spot than acute inflammation.

Inflammatory Markers

There are certain blood tests that can help measure inflammation levels. Markers of inflammation include C-reactive protein (CRP), fibrinogen, procalcitonin, and various cytokines.²

CRP is a simple and inexpensive test. High levels of this protein can indicate inflammation due to microbial infection or physical injury. CRP is also linked to chronic conditions like asthma, arthritis, lupus, inflammatory bowel disease (IBD), obesity, diabetes, heart disease, stroke, and cancer. Plus, elevated CRP levels have been found in patients with mental issues like anxiety, bipolar disorder, schizophrenia, and Alzheimer’s disease.^11,12,13,14

Usually, CRP is tested along with erythrocyte sedimentation rate (ESR). ESR measures how fast the red blood cells (RBCs) in a blood sample sink to the bottom of a test tube. Indirectly, ESR measures fibrinogen, a protein that aids in blood clotting. Increased fibrinogen (due to inflammation) makes RBCs clump together and sink faster, increasing ESR levels. Like a high CRP, a high ESR may result from infection, arthritis, and IBD. It is associated with kidney disease, heart disease, and certain cancers as well.^15,16

Blood levels of procalcitonin increase in response to bacterial infections and burns. Also, high procalcitonin is found in association with obesity, lung carcinoma, liver damage, and kidney disease.^16,17

Finally, cytokines are signaling proteins that help control inflammation. They include interleukins (IL), tumor necrosis factor (TNF), and colony-stimulating factors (CSF). Acute inflammation involves IL-8, IL-16, and granulocyte-CSF (G-CSF). Meanwhile, IL-1, IL-6, IL-11, TNF-ɑ, and granulocyte-macrophage CSF (GM-CSF) each play a role in both acute and chronic inflammation. The latter are thus used as biomarkers of chronic conditions. For instance, high IL-6 and TNF-α are tied to heart disease, diabetes, cancer, and arthritis. Elevated levels of these two cytokines are linked to depression, schizophrenia, and autism too.^18,19

Foods That Promote Chronic Inflammation

Certain foods are rich in pro-inflammatory substances. Thus, regular consumption of such offenders contributes to chronic inflammation. Common culprits are refined carbohydrates, vegetable oils, fried foods, grain-fed meats and farmed seafoods, and alcohol.

Refined carbohydrates — also called simple carbs — comprise sugars and starches. These carbs have a high glycemic index, which means they are quickly broken down and absorbed into the blood. So, eating refined carbs rapidly increases levels of blood glucose and insulin (the hormone that helps glucose enter cells for energy use or storage). Rapid glucose fluctuations boost the production of inflammatory chemicals called reactive oxygen species (ROS).^20,21

At the same time, some bacteria living in the gut thrive on a diet high in refined carbs. Such microbes can impair the mucus layer protecting the gastrointestinal (GI) tract from toxins. This condition is called a “leaky gut.” It allows harmful elements to leave the GI tract and reach the bloodstream easily, triggering inflammation.^22,23

Cakes, cookies, cereals, candy, soft drinks, and fruit juices contain a lot of refined sugars. As for refined starches, sources include white bread, rice, pasta, and potatoes.^24,25

Meanwhile, vegetable oils come from the seeds of plants like soybean. These widely used oils contain polyunsaturated fatty acids (PUFAs) — mainly linoleic acid (LA) — that stimulate ROS production. What’s more, processing of PUFA-rich vegetable oils produces trans fats. Studies show that a diet high in trans fats raises cytokine levels in the blood. Plus, it causes cellular stress through ROS production. Margarine, commercial baked goods, frozen pizza, and fried foods have a lot of trans fats.^26,27

Fried foods contain lipid oxidation products (LOPs) as well. LOPs, which form when PUFA-rich oils are exposed to high temperatures, contribute to a leaky gut.^28,29

Processed, fried, or grilled meats pose an extra problem. When meats are cooked at high temperatures, the process creates advanced glycation end-products (AGEs). These toxins promote inflammation by increasing cytokines.^30,31

Speaking of meats, it’s best to avoid those from grain-fed livestock and farmed seafood. Feeds for these animals are high in linoleic acid. This is true even if the grains used in the feed are organic. If they’re not organic, they often contain pesticides, antibiotics, and pollutants of various kinds. These chemicals activate the body’s inflammatory response.^32,33

Lastly, too much alcohol intake can disrupt the balance of microbes in the intestine, promoting a leaky gut. Consuming alcohol also triggers immune cells in the blood and liver to release cytokines. In turn, these proteins bring about liver inflammation and damage. The cytokines can also reach other organs including the brain, leading to changes in mood, behavior, and mental function.³⁴

Managing Chronic Inflammation Through Diet

Anti-inflammatory foods can help manage or treat chronic conditions. Complex carbs, prebiotics and probiotics, and good fats fight inflammation. So do grass-fed meats, foods cooked on low heat, and certain herbs and supplements.

With their low glycemic index, complex carbs increase blood glucose and insulin levels gradually. By keeping blood sugar stable, they protect against inflammation. Examples of complex carbs are whole-grain bread, quinoa, sweet potatoes, yam, and winter squash.³⁵

Many low-glycemic foods are rich in fiber and fall under prebiotics. This means they promote a diverse and healthy makeup of gut microbes that helps to reduce inflammation. Common prebiotic foods are garlic, onion, asparagus, and barley. On the other hand, probiotics contain live strains of bacteria, yeast, or both. They allow good microbe species, such as Bacteroides, Bifidobacterium, and Lactobacillus, to dominate and flourish in the gut. By doing so, they help improve gastrointestinal function and immune balance. Yogurt, sauerkraut, and kimchi are good sources of probiotics. Probiotics are available as supplements too.^36,37

Regarding good fats, sources include avocado, olive, palm, safflower, sunflower, and canola oils. These oils contain a monounsaturated fatty acid (MUFA) called oleic acid. It modulates immune cell activity, decreasing the production of cytokines like IL-6 and TNF-α.^38,39

When it comes to protein, organic, grass-fed meats; wild-caught fish and seafood; and cage-free eggs are healthy options. These foods come from animals whose diets are low in LA and other inflammatory substances. So, they are healthier to consume than grain-fed meats and farmed seafoods.

Cooking methods are important too. Those that use moist heat, lower temperatures, and shorter cooking times minimize the formation of AGEs. Examples of such methods are steaming, poaching, and stewing. Marinating meats in acidic solutions, such as vinegar or lemon juice, before cooking can lower AGEs as well.³⁰

As for herbs and supplements, some of them can reduce inflammatory markers like CRP, TNF-ɑ, and IL-6. They tend to be rich in antioxidants too — that is, they fight off ROS and similar toxins. Ginger, turmeric, cardamom, ginseng, rosemary, black pepper, and green tea all have anti-inflammatory properties.^40,41

Conclusion

Chronic inflammation drives all chronic health problems, whether physical or mental. One of its causes is long-term exposure to chemicals that damage cells. Many of these toxins come from the environment, including the foods you eat. The good news is, you can fight chronic inflammation and reverse chronic conditions by adjusting your diet.

It’s important to note that you’re an individual with specific dietary needs. So, a diet that works for someone else may be unsuitable for you. Click here to discover how a personalized diet plan can optimize your health and performance.

References