Ongoing (chronic) inflammation is associated with health conditions in just about every area of the body, including the brain. Although studies have yet to prove that chronic inflammation is the root cause of brain disorders and disease, it’s commonly found in people with Alzheimer’s, Parkinson’s, multiple sclerosis, and other neurological issues.1,2  

Researchers are seeking to understand how inflammation impacts the brain, enables disease, and how that knowledge can one day change the practice of medicine. Until then, there are lifestyle changes you can make to lower chronic inflammation throughout your body. 

Acute Versus Chronic Inflammation in the Brain

Short-term (acute) inflammation is a normal part of the immune response and healing. Redness that develops after cutting your finger or a knee that swells after a fall are outward signs your body is sending white blood cells to the injury site to begin the healing process. But inflammation becomes harmful when it persists unchecked for months or even years – that’s when it becomes chronic inflammation.

Inflammation in the nervous system, called neuroinflammation, is particularly harmful when it becomes chronic. Neuroinflammation is a normal immune response that protects the brain and central nervous system against infection and injury. But when the inflammatory process doesn't turn off, it begins causing damage to nearby healthy brain tissue and neurons.1

Determining why chronic inflammation develops is complex. Some experts theorize it’s the result of a malfunctioning immune system, an ongoing infection, exposure to pollution and other environmental triggers, conditions such as obesity, or lifestyle habits such as a poor diet. To complicate matters, sometimes chronic inflammation can occur even if there is no injury or other identifiable trigger.3,4

When Inflammation Breaks Down Protective Barriers

The human body has various checkpoints that allow the “good guys” through – such as nutrients – while blocking the “bad guys” – including viruses, bacteria, fungi, and toxic substances.

In the brain, this checkpoint is called the blood-brain barrier (BBB), which is a complex gatekeeper for the central nervous system. For the brain to function normally, the BBB must be functioning correctly. The BBB determines what substances can and cannot access the brain by utilizing multiple types of security-guard-like cells.5 

The endothelial cells, for example, form tight connections that make it difficult for harmful substances in the blood to sneak into the brain. Pericytes, which are specialized cells found in the lining of blood vessels, work in tandem with endothelial cells to determine what substances are allowed into the brain. Pericytes also help regulate blood flow and are thought to detect and destroy harmful invaders. Astrocytes are another significant component of the BBB. These cells not only help form the barrier but also actively work with neurons to regulate brain immune cells. Microglia provide another layer of protection, looking out for harmful substances and destroying them.6,7 

When all the key players are working together correctly, the BBB tightly controls the chemical makeup of the brain’s interstitial fluid (ISF), helping maintain homeostasis and keeping the brain hospitable for neurological activity. Stable ISF is critical for maintaining multiple brain activities, including properly functioning synapses, information processing, and neuron connectivity.8

Chronic inflammation can disrupt the function of the BBB’s components, weakening the entire structure. Because of its complexity, it’s difficult for the BBB to repair itself. In a weakened state, the BBB becomes more permeable and less selective about what it lets into the brain. It doesn't filter out neurotoxins, immune cells, or chemical agents that can worsen neuroinflammation, such as mast cells, T cells, lymphocytes, and cytokines. Experts believe this might make some individuals more susceptible to central nervous system problems.1,9,10 

In individuals with Alzheimer’s disease, inflammation appears to increase the level of amyloid-beta (β-amyloid) in the brain. It is thought that increased levels of β-amyloid contribute to Alzheimer’s disease by clumping together and blocking cell signals. β-amyloid might also contribute to making the BBB more permeable by turning on immune system cells that trigger neurological inflammation and disease progression.1,9,11

A breakdown in the BBB is associated with conditions such as schizophrenia, bipolar disorder, and major depressive disorder. It’s not clear, however, whether BBB changes are the cause or an effect of these neurological conditions or if they drive each other.5,10,12

Research continues to decode how inflammation and neurological disorders influence each other and whether targeting a compromised BBB for treatment might stop or even reverse the course of disease. In the meantime, there are lifestyle measures you can take that reduce inflammation.8 

What You Eat Influences Inflammation Levels

What you eat impacts inflammation in your body. Research shows that certain foods can affect the level of C-reactive protein (CRP) – a marker for inflammation – in the blood. Foods like processed sugars release inflammatory messengers that raise the risk of chronic inflammation. On the flip side, foods like fruits and vegetables lower inflammation by helping your body fight oxidative stress.13

To reduce chronic inflammation via your diet, consider:14

  1. Eating more plant-based foods. This includes fruits and vegetables such as berries, leafy greens, beets, pomegranate, and avocados. Other good choices are whole grains, legumes, ginger, turmeric, and green tea. These foods have ample antioxidants, which help prevent, delay, or repair cell and tissue damage.
  2. Focusing on healthy fats. Omega-3 fatty acids play a role in regulating the body's inflammatory process and might help decrease pain related to inflammation. You can find these healthy fats in fish like salmon, tuna, and mackerel, as well as smaller amounts in walnuts, pecans, ground flaxseed, and soy.
  3. Cutting back on red meat. Although red meat can be pro-inflammatory, you don’t have to eliminate it completely to see a benefit. Try substituting your lunchtime beef with fish, nuts, or soy-based protein several times a week. In addition, when you do choose red meat, eat a palm-sized portion instead of a 16-ounce porterhouse steak.
  4. Getting rid of processed foods. Sugary cereals and drinks, deep-fried food, cured meats (like bologna, hot dogs, pepperoni, and bacon), and pastries are all pro-inflammatory offenders. They contain plenty of unhealthy fats that are linked to inflammation. Instead, go for brown rice, uncured turkey bacon, or fruit instead of a nutrient-devoid, sugary dessert.  An air fryer can reduce the amount of oil typically used to cook fried foods. Good drink choices include sparkling water, infused water, unsweetened teas, and coffee. 

Little Changes Can Lower Inflammation

Foods aren't the only way to reduce inflammation in the body. Maintaining a healthy body weight can reduce chronic inflammation because weight loss, on its own, is anti-inflammatory. You can also:

  1. Engage in moderate exercise for 20 minutes daily. Regular exercise such as brisk walking can reduce chronic inflammation.15
  2. Get quality shut-eye. People who regularly get the proper amount of sleep are less likely to have chronic inflammation than their counterparts who don’t get sufficient sleep. Aim to get the recommended amount every night, which is 7-9 hours for adults.3,4 
  3. Curb stress. When you're stressed, the immune system sends out pro-inflammatory cytokines. Techniques such as meditation and tai chi might help induce positive changes in the nervous system and immune system.16
  4. Quit smoking. Nicotine and cigarettes trigger inflammation and suppress anti-inflammatory processes. 3,9

The signs and symptoms of chronic inflammation are often subtle. Signs to look for include body pain, fatigue, sleeping problems, depression, anxiety, mood disorders, gastrointestinal upset, abnormal weight gain or loss, and frequent infections. As always, if you are concerned about your health, then make an appointment with your health-care professional.

A Word from Thorne

Would you like to explore nutritional supplements to support healthy brain function? Brain Factors is designed to optimize brain health by promoting brain-derived neurotropic factor (BDNF), a substance produced by the body that promotes the growth of brain and nerve cells, and by increasing NAD+, which enhances cellular energy production.* Learn more about BDNF.

SynaQuell supports brain health by enhancing cellular energy production and encouraging a healthy balance of inflammatory cytokines – and is particularly supportive if you engage in high-impact sports or other activities.* Do you think about feeding your brain cells? You might think about vitamins, minerals, and other nutrients that support the cells of your muscles, bones, joints, and heart, but what about the cells that make up your brain? Do you know what nutrients they need? Read more about nutrients to protect your brain or help it heal after an injury.

References

  1. Kempuraj D, Thangavel R, Selvakumar GP, et al. Brain and peripheral atypical inflammatory mediators potentiate neuroinflammation and neurodegeneration. Front Cell Neurosci 2017;11:216. 
  2. Xu L, Nirwane A, Yao Y. Basement membrane and blood-brain barrier. Stroke Vasc Neurol 2019;4: e000198. 
  3. Pahwa R, Goyal A, Bansa P, Jialal I. Chronic Inflammation. [Updated 2021 Sep 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022. 
  4. Furman D, Campisi J, Verdin E, et al. Chronic inflammation in the etiology of disease across the life span. Nat Med 2019;25(12):1822-1832.
  5. Millett CE, Burdick KE, Kubicki MR. The effects of peripheral inflammation on the brain – a neuroimaging perspective. Harv Rev Psychiatry 2022;30(1):54-58. 
  6. American Society for Microbiology. How pathogens penetrate the blood-brain barrier. https://asm.org/Articles/2020/April/How-Pathogens-Penetrate-the-Blood-Brain-Barrier. [Accessed June 14, 2022] 
  7. Galea I. The blood-brain barrier in systemic infection and inflammation. Cell Mol Immunol 2021;18:2489-2501.
  8. Sweeney M, Sagare A, Zlokovic B. Blood-brain barrier breakdown in Alzheimer disease and other neurodegenerative disorders. Nat Rev Neurol 2018;14:133-150.
  9. Huang X, Hussain B, Chang J. Peripheral inflammation and blood-brain barrier disruption: effects and mechanisms. CNS Neurosci Ther 2021;27(1):36-47.
  10. Sankowski R, Mader S, Valdés-Ferrer SI. Systemic inflammation and the brain: novel roles of genetic, molecular, and environmental cues as drivers of neurodegeneration. Front Cell Neurosci 2015;9:28. 
  11. Alzheimer’s Association. Inside the brain: a tour of how the mind works (part 2: Alzheimer’s effect. https://www.alz.org/alzheimers-dementia/what-is-alzheimers/brain_tour_part_2. [Accessed June 23, 2022]
  12. Haruwaka K, Ikegami A, Tachibana Y, et al. Dual microglia effects on blood-brain barrier permeability induced by systemic inflammation. Nat Commun 2019;10:5816.
  13. Mayo Clinic. Want to ease inflammation? Start with your grocery list. https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/want-to-ease-chronic-inflammation#. [Accessed June 23, 2022]
  14. Mayo Clinic. How to use food to help your body fight inflammation. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/how-to-use-food-to-help-your-body-fight-inflammation/art-20457586. [Accessed June 23, 2022]
  15. Duggal NA, Niemiro G, Harridge SDR, et al. Can physical activity ameliorate immunosenescence and thereby reduce age-related multi-morbidity? Nat Rev Immunol 2019;19:563-572.
  16. Slavich GM, Irwin MR. From stress to inflammation and major depressive disorder: a social signal transduction theory of depression. Psychol Bull 2014;140(3):774-815.