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Chronic Inflammation and Cancer

Inflammation is becoming a popular topic when it comes to the issue of chronic disease. Chronic inflammation is not the classic swelling, redness, or puffiness you often experience when you are injured. Chronic inflammation is internal, invisible, and does not result in any immediate symptoms or side effects. Scientists have been researching the causes and pathways of the inflammatory response for decades. Research is beginning to show that hidden, chronic inflammation is linked to a variety of diseases, such as heart disease, diabetes, and cancer.

The process of inflammation in the body is extremely complicated. Over the last twenty years, research has been conducted in an attempt to uncover the pathways which cause chronic inflammation. Researchers have found that inflammation is a cycle that is tightly linked with oxidative stress.


What Is Oxidative Stress?

Oxidative stress occurs when there is an excess of reactive oxygen molecules, known as free radicals, in the body. Free radicals are produced normally as a byproduct of energy production (think aerobic respiration) in our bodies. These small molecules play a beneficial role in cell signaling, which is essential for daily functioning [i]. However, too much of a good thing can be bad.

Under certain conditions, free radicals can accumulate and wreak havoc in the body. Imagine a pin ball which bounces around, causing damage to the molecules and cells it impacts. Certain internal or external sources of stress can cause an increased production of free radicals over an extended period of time. Long-term stress leads to significant damage in the body.


Free Radicals versus Antioxidants

Free radicals have an arch enemy which goes by the name of antioxidants. Yes! These are the same antioxidants you hear about in fruits and vegetables, such as blueberries and carrots. Your body produces some antioxidants naturally, while others you consume in the food you eat. Antioxidants consumed in food consist of vitamin C, vitamin E, phytochemicals, and flavonoids, among others.

Antioxidants neutralize free radicals to keep them in check and prevent organ and other tissue damage. However, too many antioxidants can be harmful as well. In fact, in the presence of too much of any one kind of antioxidant, the protective effect of antioxidants is lost. Research has shown that high doses of antioxidants can cause damage similar to the damage caused by the free radicals which the antioxidants are supposed to eliminate [ii]. The popular common cold remedy of megadoses of vitamin C is likely to cause more harm than good.

Our bodies function in a very intricate balance, the truly unique beauty of nature. Under normal conditions, our system maintains this balance. However, certain conditions may knock the system off balance and send it into chaos.


Sources of Oxidative Stress

Oxidative stress occurs when there is an imbalance between the production of free radicals and their elimination by antioxidants. An excess of free radicals damages the biomolecules and cells within our body. Some of the sources of stress which begin the oxidative process include chronic bacterial, viral, and parasitic infections, chemical irritants, and nondigestible particles [iii].

Sources of injury from chemical irritants and nondigestible particles include smoking, UV radiation, air pollution, and exposure to allergens. Additional factors which can trigger an increase in free radical production include select autoimmune diseases, obesity, and alcohol consumption [iv]. In fact, the majority of cancers have been attributed to these factors. Almost 30% of all cancers have been attributed to tobacco smoke, 35% to diet, 14% – 20% to obesity, 18% to infections, and 7% to radiation and environmental pollutants [v].


The Link Between Oxidative Stress & Chronic Inflammation

The initiation of oxidative stress has been shown to lead to chronic inflammation. This is due to the processes triggered in response to the cellular damage which occurs during oxidative stress. Most often, free radicals cause damage to fats and proteins, which are found in abundance in cell membranes. Extensive damage to cell membranes can even cause cells to rupture [vi]. Free radicals also activate a variety of molecules that tell your body to ramp up production of inflammatory and cell regulatory molecules.

The activation of inflammatory molecules initiates the production of additional free radicals, amplifying the damage [vii]. Oxidative stress is a very complex cycle involving a host of products and reactants, each one affecting the other. Once the cycle begins, it is hard to end. After a period of time, the cycle of oxidative stress and the accompanying inflammatory response becomes a long-term event, and is considered chronic inflammation.


The Role of Chronic Inflammation in Cancer

The presence of chronic inflammation increases the risk of cancer. Continued inflammation and oxidative stress can cause cell damage, unfortunately affecting the entire body. A chronic inflammatory response can cause free radicals to interact with genetic material during cell replication. Genetic exposure to free radicals can make the genetic material susceptible to a variety of mutations. Our cells have repair systems which are built to recognize mutations, make corrections and repair the abnormal mutations. However, free radical exposure interferes with the repair system, and leads to further production of mutated cells. The connection between chronic inflammation and cancer is important to consider when developing your diet and nutrition plan

Damage to genetic material may result in the cell’s inability to function properly, and has been associated with the development of cancer cells. The development of cancer occurs in three stages: initiation, promotion, and progression. It has been found that oxidative stress has an effect during all three stages [viii]. Additionally, free radicals cause damage beyond genetic mutations. Research indicates that free radicals have the ability to promote tumor development, because they can turn on signaling pathways in the body that regulate cell proliferation, development of blood vessels, and metastasis [iv].  As a cancer caregiver or cancer survivor, there are some precautions that you can take to limit or reduce the presence of chronic inflammation in the body.


Reduce Your Risk of Chronic Inflammation

Veg Out

Eating a diet rich in fruits and vegetables, like the Mediterranean diet, is one of the best and safest ways to prevent cancer, and has been strongly associated with a decreased incidence of cancer [iii]. When possible, decrease your risk of chemical exposure by opting for sustainable and organic produce. If your access to these options is limited, be sure to thoroughly wash your fruits and vegetables in a veggie wash, or mixture of vinegar and water. Doing so will help wash away any bacteria or pesticides which accumulate on the skin during the growing period or during transport and storage. Here’s a sample menu to try.


Manage Autoimmune Diseases

Interestingly, individuals with autoimmune diseases, such as ulcerative colitis or Crohn’s disease, are nearly 5 to 7 times more likely to develop cancer [iii]. If you have an autoimmune disease, do your best to reduce exposure to external stress in your life and maintain a proper cancer diet based on your diagnosis. Your risk of cancer may be increased, but that does not mean there is nothing you can do to try and prevent or delay the onset of cancer.


Treat Bacterial or Parasitic Infections

Research has revealed that untreated bacterial and parasitic infections may increase one’s risk of cancer. For example, long term infections such as H. pylori may result in an increased risk of gastric cancer [iv].  Viral infections such as HIV, HPV, and Hepatitis B and C may also increase the risk of cancer. If you have experienced any of these infections, be sure to manage them through your primary care provider. In addition, be sure to manage your daily stress level, and consume a healthy diet to help protect your body against chronic inflammation.


Sit Less & Move More

Maintaining an active lifestyle is a major factor in staying healthy and fighting inflammation. Not only does exercise help reduce weight and maintain muscle mass, but regular long-term physical activity has been shown to have an anti-inflammatory effect in the body and protect against disease [ix].  The American Cancer Society recommends that adults should get at least 150 minutes per week of moderate-intensity activity. You can try yoga, walking, swimming, resistance training, or simple stretching.

Research is beginning to show that the amount of time one spends sitting may increase your risk of chronic disease, regardless of whether you exercise regularly or not [x]. Therefore, in addition to 150 minutes of planned exercise, try to reduce the time you spend sitting, by standing or walking more. If you work at a computer for the majority of your work day, try taking a 5 minute break every 60 to 90 minutes. Spend 5 minutes walking in place or take a few laps around the office. Before you know it, you will have spent 40 minutes walking during your 8 hour work day.


[i] Durackova, Z. Some current insights into oxidative stress. Physiol Res. 2010;59:459–469.
[ii] Scientific American. Antioxidant Supplements: Too Much of a Kinda Good Thing. Published February 23, 2015. Accessed December 9, 2015
[iii] Shacter E, Weitzman S. Chronic Inflammation and Cancer. Oncology. 2002;16(2):217-26
[iv] Grivennikov SI, Greten FR, Karin M. Immunity, inflammation, and cancer. Cell. 2010;140(6):883-99.
[v] Aggarwal BB, Vijayalekshmi RV, Sung B. Targeting inflammatory pathways for prevention and therapy of cancer: short-term friend, long-term foe. Clin Cancer Res. 2009;15(2):425-30.
[vi] Khansari N, Shakiba Y, Mahmoudi M. Chronic inflammation and oxidative stress as a major cause of age-related diseases and cancer. Recent Pat Inflamm Allergy Drug Discov. 2009;3(1):73-80.
[vii] Conner E, Grisham MD. Inflammation, free radicals, and antioxidants. Nutrition. 1996;12(4): 264-277
[viii] Reuter S, Gupta SC, Chaturvedi MM, Aggarwal BB. Oxidative stress, inflammation, and cancer: how are they linked?. Free Radic Biol Med. 2010;49(11):1603-16.
[ix] Kasapis C, Thompson PD. The effects of physical activity on serum C-reactive protein and inflammatory markers: a systematic review. J Am Coll Cardiol. 2005;45(10):1563-9.
[x] American Cancer Society. ACS Guidelines for Nutrition and Physical Activity. Published April 9, 2015. Accessed December 14, 2015.
Katrina Trisko

Katrina Trisko graduated from Boston University in 2013 with a degree in Dietetics and is currently completing her dietetic internship program through Teachers College of Columbia University in NYC, where she has finished coursework for a Masters in Nutrition and Exercise Physiology.


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