PT on the Net Research

Inflammation, Health and Performance


There are a host of health complications related to inflammation ranging from decreased aerobic performance to a primary contributor to many chronic diseases. Unfortunately, the inflammatory process can begin in individuals at a very young age, and if unnoticed, it can have detrimental health effects later in life. This can have a significant impact on quality of life, physical activity status and activities of daily living. It is obvious that the inflammatory process is an important one to understand, but more specific to this article are the nutrition interventions that can be made to improve the inflammatory response in the body.

Basics of Inflammation

On a daily basis, the body encounters a host of invaders such as bacteria and viruses, which are usually attacked and destroyed by internal inflammatory defenses because the body is made to handle a small amount of inflammation. In lower amounts, inflammation can be somewhat beneficial in the blood clotting process. However, when the body’s defenses cannot ward off a full defensive attack to these invaders, some body systems become compromised, and health and performance can start to decline.

There are two main types of inflammation: classic and silent. Classic is the type that is most common and easiest to treat because the visual signs are obvious. Redness, swelling and pain often accompany classic inflammation, and the normal culprits are soft tissue or musculoskeletal injuries. The typical course of action to alleviate the pain is ice, rest, compression and elevation, as is commonly prescribed by health professionals. This type of inflammation does have a performance effect since it usually prevents an individual from exercising due to an injury.

In contrast, silent inflammation can have significant negative health consequences along with non-acute injury performance effects. Individuals can still exercise, but as described later, the quality of exercise can be compromised when silent inflammation is present in high amounts. This type of inflammation is often involved in disease states such as heart disease, Alzheimer’s, rheumatoid arthritis and cancer. There are no visual signs of this type of inflammation as it does its damage on the cellular level. Blood tests are necessary for the screening of silent inflammation.

One of the more popular blood markers that is assessed by physicians is C-reactive protein (CRP). This is a globulin (protein) found in the blood that represents acute inflammation. It is a very good marker of silent inflammation, and while it is certainly worth having screened, it is important to note that it is a marker of acute not chronic inflammation. Thus, an acute infection or other short term stress to the body can produce high levels of CRP and create an inaccurate marker of chronic inflammation.

Another method to assess the inflammatory state at the cellular level is the essential fatty acid ratio in the blood. Essential fatty acids (EFAs) are components of cellular walls, and by looking at the ratio of pro- to anti-inflammatory EFAs, it is possible to assess a more accurate marker of chronic inflammation at the cellular level. The EFA ratio compares arachidonic acid (pro-inflammatory) to eicosapentaenoic acid (anti-inflammatory effects). I will talk more about this later in the article, but the take-home message is that by assessing the EFA ratio at different points throughout the year, an individual can ensure that his nutrition program is providing him what he needs to keep inflammation in a lower state during different exercise cycles (heavy versus light, competition versus off season). Because inflammation is increased with strenuous exercise, it is important to realize that nutritional changes must be made during these heavier times of exercise throughout the year. Thus, the EFA ratio becomes a key component in tracking progress and maintaining inflammation at a healthy level.

The Science of Inflammation

It has been known for some time the benefits that food has on health and performance. However, the consumption of fat, once touted as “bad,” is a key component in the inflammatory process. Certain types of fat can improve the body’s ability to fight inflammation. The metabolism of fatty acids is quite complex and while this will not be a biochemistry lesson, it is important to understand, from a basic biochemical perspective, how different types of fats can have pro- or anti-inflammatory tendencies by way of turning on and off certain hormones, all activated by the food that is put in the mouth.

These hormones, called eicosanoids, are made by essential fatty acids and are responsible for producing pro- or anti-inflammatory responses in the body. The different subgroups of eicosanoids include prostaglandins, thromboxanes, leuekotrienes, lipoxins, endocannibinoids and resolvins. Anti-inflammatory eicosanoids have positive physiological functions in the body including vasodilation, the prevention of blood clots, a reduction in pain and an improvement in immune system function. It is obvious that activating these eicosanoids has a more beneficial effect on the body rather than the eicosanoids that produce pro-inflammatory effects.

The types of fat that are related to inflammation include saturated, trans and the polyunsaturates omega-3 and omega-6. Research has proven that the consumption of both trans and saturated fats are not extremely beneficial to health, but more specific to this article, they have been shown to have a pro-inflammatory effect. It is obvious that these types of fats should be minimized, but the real story lies behind the omega-6 and omega-3 fats.

Omega-6 fats, also called linoleic acid, are found in safflower, soybean, corn and sunflower oils. As can be seen from the following figure, these fats are eventually converted into pro-inflammatory eicosanoids. However, there is a step in this conversion that produces an anti-inflammatory fat, dihomo-gamma linolenic acid (DGLA).

The conversion of omega-6 fats to DGLA can be very beneficial. However, most Westernized diets are so high in omega-6 fats and low in omega-3 fats that it drives the conversion of omega-6 fats past the anti-inflammatory fat DGLA to arachidonic acid (AA), which then leads to pro-inflammatory eicosanoids being formed.

Additionally, both the omega-6 and omega-3 fat pathways share the same enzyme, delta-5 desaturase. This is extremely important because as mentioned previously, Westernized diets include such a high amount of omega-6 fats, thus the delta-5 desaturase enzyme is used more in the omega-6 conversion to pro-inflammatory eicosanoids rather than the omega-3 conversion to anti-inflammatory eicosanoids. Thus, altering this key enzyme is of great importance when attempting to shift the body’s inflammatory response. 

Consuming too much of the polyunsaturated, omega-6 fats can lead to a greater amount of inflammation in the body due to high levels of AA. The two key methods of decreasing the production of AA are by controlling insulin and consuming more omega-3 rich fats.

Insulin has a significant effect on the delta-5 desaturase enzyme. When insulin levels are high, it activates the enzyme to convert DGLA to AA, thus producing a more pro-inflammatory response in the body. Thus, controlling insulin levels through proper food intake becomes paramount. Combining a good source of lean protein with healthy fat along with a carbohydrate source will help to stabilize both blood sugar and insulin levels and will reduce the activation of the delta-5 desaturase enzyme.

Consuming more omega-3 fats will inhibit (or force its use in the omega-3 versus the omega-6 pathway) the delta-5 desaturase enzyme, thus reducing the conversion of DGLA to AA. Consuming more EPA in the form of food (fish) or fish oil supplements is crucial in modulating the effects of the delta-5 desaturase enzyme.

Inflammation and Food

Part of understanding the interaction of food and inflammation begins from what is already known: too much LDL cholesterol can negatively affect health. Too much of this cholesterol can cause the cascade of inflammatory events, and the oxidation of LDL is of particular concern in the inflammatory process. Therefore, it would make sense to control this as much as possible by reducing LDL cholesterol through choosing the correct foods. Enter saturated fats once again. There is a direct correlation between saturated fat intake and LDL cholesterol levels. To reduce LDL, it is recommended to consume less saturated fat in the overall nutrition plan.

As mentioned previously, you can use certain fats to increase or decrease inflammation. There are a host of other foods that also contribute, either positively or negatively, to the inflammation process. In no specific order, a brief list of foods that can produce a pro-inflammatory response (and those to decrease) include:

On a more optimistic note, here are some top food choices that have good anti-inflammatory properties and should be included more in the daily nutrition plan:

Other beneficial anti-inflammatory foods also include:

When it comes to inflammation and foods, the information can be a bit confusing and contradictory. There is a rating system that has been developed that makes choosing anti-inflammatory foods easier. This system is called the Inflammation Factor Rating system and provides an inflammation rating number to foods (data can be found at www.nutritiondata.com). While there is not a scale that provides good and bad ranges, this system at minimum provides individuals the ability to choose pro- or anti-inflammatory foods. This rating system uses information such as sugar, vitamin and mineral, saturated and healthier fat content to determine the inflammation rating. Processed foods and those with high sugar, saturated and trans fat content top the pro-inflammatory list while foods rich in lean protein, vitamins, minerals and healthy fats and non-refined or processed carbohydrates top the anti-inflammatory list.

According to this rating scale, some of the higher inflammatory foods include the following:

In contrast, here are a few foods that have a low inflammation factor:

It is important to remember that just because a food has a high inflammation factor rating, it does not mean it should not be consumed. Combining foods and producing an overall anti-inflammatory score is the key in meal preparation.

Supplementation

It is obvious that consuming more omega-3 fats, controlling blood insulin and reducing consumption of some vegetable oils and processed foods is beneficial in controlling inflammation. Additionally, the use of fish oil supplements also has strong merit in promoting an anti-inflammatory state due to the biochemical nature of inhibiting the delta-5 desaturase enzyme.

Fish oil supplements are growing in popularity for many reasons. One reason is because it is often difficult to consume enough omega-3 fats from fish and other foods. In fact, one 3-ounce serving of salmon will have only 900-1200 milligrams of omega-3, far too low to have a significant, clinical dose for some individuals. There is also the contamination factor when eating fish, specifically levels of mercury (refer to the table below). Because of this, individuals simply do not consume enough omega-3 fat to exhibit positive health outcomes.

  Mercury Level in ppm Omega-3 Fats (mg per 3 ounces)
Salmon (fresh/frozen) 0.014 900-1200
Flounder (sole)   0.050  480 
Pollock  0.041  450 
Crab 0.060  400
Scallops   0.050  290 
Shrimp  below detectable limit 290
Catfish 0.050 270
Clams below detectable limit 250
Cod 0.095 210
Canned tuna 0.120 200

Much of the research done on fish oil supplements has been in the cardiovascular disease (CVD) area, but because silent inflammation happens at the cellular level throughout the entire body, use of fish oil supplements can greatly benefit active individuals who do not have CVD. When the endothelial lining (the lining of the artery) becomes inflamed, there is a higher amount of vasoconstriction, and thus less oxygen and nutrients are able to be delivered to working muscles during exercise. Omega-3 fats are associated with biomarkers reflecting healthy endothelial function, thus having a positive response on flow mediated dilation.

The American Heart Association guidelines state that individuals without CVD consume omega-3 rich fish and other vegetable sources of alpha-linolenic acid two times per week. For those with documented CVD, one gram of EPA and DHA is recommended and for those with high triglycerides, two to four grams of EPA and DHA is recommended. Consuming more than three grams of EPA and DHA per day should be done under a physician’s care. 

Additionally, it is important to note that many active individuals will periodize the amount of EPA and DHA they consume based on their training load. Doses up to 15 grams per day is sometimes the norm in elite level athletes who are undergoing a high amount of strenuous activity on a daily basis. It is obvious that there are different suggestions when it comes to consuming fish oil supplements, and it is recommended you consult with a sports physician or sport dietitian prior to implementing a higher dosing protocol.

Conclusion

The body requires small amounts of inflammation to regulate certain body processes such as normal blood clotting. However, too much inflammation has a negative effect on health and performance. If left alone, chronic inflammation can have a significant impact on health and performance. By implementing a few dietary strategies such as controlling blood insulin, reducing intake of certain vegetable oils and increasing the intake of fish oil (EPA and DHA) through food and possibly supplements, it is possible to better control systemic inflammation.

References:

  1. Baer. D. et al. Dietary fatty acids affect plasma markers of inflammation in healthy men fed controlled diets: a randomized crossover study. American Journal of Clinical Nutrition, 79, 969-973. 2004.
  2. Bray, G. et al. The influence of different fats and fatty acids on obesity, insulin resistance and inflammation. Journal of Nutrition, 132, 2488-2491. 2002.
  3. Esmaillzadeh, A. et al. Home use of vegetable oils, markers of systemic inflammation, and endothelial dysfunction among women. American Journal of Clinical Nutrition, 88, 913-921. 2008.
  4. Mozaffarian, D. et al. Dietary intake of trans fatty acids and systemic inflammation in women. American Journal of Clinical Nutrition, 79, 606-612. 2004.
  5. Nim Han, S. et al. Effect of hydrogenated and saturated, relative to polyunsaturated, fat on immune and inflammatory responses of adults with moderate hypercholesterolemia. Journal of Lipid Research, 43, 445-452. 2002.
  6. Ostrowski, K. et al. Pro- and anti-inflammatory cytokine balance in strenuous exercise in humans. Journal of Physiology, 515(1), 287-291. 1999.