Inflammation is the body's natural response to protect itself against harm and can be characterized as either acute/localized or chronic/systemic.
You're probably more familiar with the acute type, which occurs when you bang your knee or cut your finger.
Your immune system dispatches an army of white blood cells to surround and protect the area, creating visible redness and swelling.
The process works similarly if you have an infection like the flu or pneumonia. In these settings, inflammation is essential—without it, injuries could worsen and simple infections could be deadly.
Resistance training is another example of acute inflammation. It causes micro tears to your muscle fibers with an ensuing normal inflammatory response that is a part of the repair and regeneration process.
All of the above are examples of healthy inflammation and are a necessary response our bodies perform to disease or injury.
On the other hand, there is systemic inflammation. Localized inflammatory response has nothing to do with systematic inflammation.
Systemic inflammation is where there are markers in your blood indicative of disease. This is a serious condition in which there is inflammation throughout the whole body. Systemic inflammation is usually chronic and can be caused by a severe bacterial infection (sepsis), trauma, heart disease, cancer or pancreatitis. It is indicative of inflammatory biomarkers that are at higher levels in your blood.
Does nutrition play a role in managing inflammation?
Cardiovascular disease is the leading cause of death in the United States, and dietary interventions play a huge role in preventing cardiovascular disease in adults, however there has been minimal improvement in diet quality among U.S. adults over the past several decades.
One of the major challenges facing promotion of a healthy diet in the U.S. has been conflicting recommendations for what macronutrients (carbs, proteins, fats) should be emphasized as part of a healthy diet.
However, it’s possible that the macronutrients matter less than simply eating healthy foods.
There is limited evidence for whether a healthy diet might directly improve mediators of coronary vascular disease 1 not to mention the effects of specific macros on direct measures of subclinical coronary vascular disease.
Let’s take a look below at some of the evidence-bases research in the area of nutrition and different types of diets on inflammation.
Healthy diets with different macronutrient profiles on inflammation
The Optimal Macronutrient Intake Trial to Prevent Heart Disease (OmniHeart) was conducted from 2003-2005 and was designed to examine 3 healthy diets with different macronutrient profiles and their effects on cardiovascular disease risk factors.2
The 3 healthy diets included a diet rich in carbohydrates; a diet rich in protein, about half from plant sources; and a diet rich in unsaturated fat, predominantly monounsaturated fat.
All 3 OmniHeart diets showed large reductions in blood pressure and low-density lipoprotein cholesterol after six-weeks, which were predicted to reduce 10-year coronary heart disease risk by 16-21% 2, but whether these diets had a direct impact on cardiac muscle cell injury or inflammation was not reported in the original study.
A recent investigation utilized stored specimens from the OmniHeart trial to determine the effects of 3 healthy diets on inflammation.
All 3 healthy diets lowered markers of inflammation over 6-weeks in participants with elevated blood pressure or hypertension. Outcome measurements were very similar despite the different macronutrient profiles of the 3 diets.
Together, these findings suggest that a healthy diet, regardless of the macronutrient profile, can directly mitigate subclinical cardiac damage and inflammation beyond traditional risk factors.3
In summary, consuming of a healthy diet directly lowered subclinical markers of cardiac damage and inflammation in addition to reducing blood pressure and low-density lipoprotein cholesterol. This occurred regardless of whether they were high in carbohydrates, protein, or fat.
This research provides strong support for a simplified dietary approach that emphasizes healthy foods rather than any one macronutrient as a means to reverse subclinical cardiac injury and inflammation in populations at risk for coronary vascular disease.
Low carbs vs low fat on inflammation
Another study examined the effects of an isocaloric (i.e., same number of calories) very low carbohydrate diet vs low fat diet on fasting lipids, postprandial lipemia (i.e., elevation of triglycerides after eating) and markers of inflammation in women average bodyweight and lipid levels.
These women conducted a crossover study (i.e., participated in both arms of the study) and consumed both a low fat (<30% fat) and a very low carbohydrate (<10% carbohydrate) diet for 4 weeks each 4.
C-reactive protein was measured as a biomarker of systemic inflammation and the proinflammatory cytokines IL-6 and TNF-α because they activate C-reactive protein production in the liver. Results indicated that, short-term manipulation of the macronutrient ratio does not affect any of these markers in women with normal lipid levels and bodyweight.
Weight loss has been shown to reduce C-reactive protein levels in overweight women.5 Therefore; a sub-caloric very low carbohydrate or low-fat diet, if used for weight loss, may lower C-reactive protein as was previously demonstrated.
Animal vs plant protein on inflammation
A recent study investigated the effects of diets high in animal protein vs plant protein on markers of inflammation.6 The diets were isocaloric with the same macronutrient composition (30% protein, 40% carbohydrates, and 30% fat).
They found diets high in protein (either animal or plant) significantly reduced liver fat, independent of body weight, and reduced markers of insulin resistance and hepatic necroinflammation. Essentially, both groups improved their levels of inflammation assessed by C-reactive protein with no difference between groups.6
This research indicates there is not difference between animal or plant protein on markers of inflammation.
Type of fat impact on inflammation?
Subclinical chronic inflammation is known to play an important role in the development of atherosclerotic cardiovascular disease. 7 This study investigated the association between dietary fatty acid intake and serum C-reactive protein concentrations in a representative sample of U.S. adults.
Results showed a correlation with higher levels of C-reactive protein, increased cholesterol intake and decreased polyunsaturated fatty acid intake. Essentially, this indicates a relationship between fatty acid intake and subclinical inflammation in this population.
The study above was also supported by a systematic review and meta-analysis which demonstrated that short-term marine-derived omega-3 fatty acid supplementation decreases systemic inflammatory biomarkers in different populations.9
The research indicates that the strongest evidence for any one particular nutrient improving inflammation is Omega-3 fatty acids. The research done in this area is either neutral or demonstrates a benefit on inflammation by replacing saturated fat with omega-3 fatty acids.
Sugar and inflammation
Sugar also gets touted as being pro-inflammatory. People that consume a lot of sugar also tend to have high levels of inflammation because they eat more overall calories; therefore, adding more bodyfat. Adipose tissue itself is inflammatory because it secretes adipokines which are a family of hormones and cytokines that can have inflammatory effects.
Observational studies have found that dietary glycemic load is positively associated with C-reactive protein concentrations in healthy humans suggesting that the type of carbohydrate ingested influences inflammatory activity.
A recent study investigated the effects of a diet with a high content of sucrose or artificial sweeteners on the inflammatory markers C-reactive protein, haptoglobin, and transferrin in an overweight population.10
Overweight men and women consumed daily food and drink supplements containing either sucrose or artificial sweeteners for a period of 10 weeks.
The sucrose diet caused an increase in total caloric intake and a weight gain of 1.6 kg in contrast to a weight loss of 1.2 kg in the group receiving the artificially sweetened drinks and foods. The minor changes in body weight did not have any significant effect on the differences in inflammatory markers between the two groups.
Research indicates that as long as calories are controlled while manipulating sugar content; there are no difference in markers of inflammation. Differences in inflammation seem to be due to an energy effect.
Keep in mind that it’s quite difficult to eat a reduced calorie diet while also eating high sugar. High sugar tends to be in foods that are hyper-palatable, nutrient deficient, easy to over-consume; and eat too many calories.
Mechanistically, the research indicates that sugar alone is not inflammatory. Practically, it may be inflammatory when you are attempting to decrease sugar intake in order to control overall adipose tissue so you don’t secrete more adipokines.
Bottom line and my thoughts
Current research indicates that controlling fat mass is more important than the means of control.
Essentially, whatever method/nutrition plan that provides the best adherence consistently and is most sustainable for you as an individual will probably be the best nutrition plan for controlling inflammation.
There is absolutely no evidence demonstrating that there is a special anti-inflammatory diet. It’s all about finding something sustainable for you personally and controlling fat mass. It’s clear from the research that varying the macronutrient profile in your diet will make little difference on inflammation when total calories and total weight is controlled.
Controlling fat mass and thus inflammation is good but it’s important to keep in mind the overall picture of what you are trying to achieve. If you are striving to build some lean muscle (which you should) and lose bodyfat, I don’t think extremely low-carb diets are the way to go. I covered this topic previously on how a low-carb/keto diet is NOT effective for gaining lean muscle tissue.
I think if you eat a sensible diet with all macronutrients and focus a little on getting marine-derived omega-3 fatty acids, you will be on the right track in both controlling inflammation and achieving the body, energy levels and health you desire.
References:
1 Juraschek, S. P. et al. Effect of type and amount of dietary carbohydrate on biomarkers of glucose homeostasis and C reactive protein in overweight or obese adults: results from the OmniCarb trial. BMJ Open Diabetes Res Care 4, e000276, doi:10.1136/bmjdrc-2016-000276 (2016).
2 Appel, L. J. et al. Effects of protein, monounsaturated fat, and carbohydrate intake on blood pressure and serum lipids: results of the OmniHeart randomized trial. JAMA 294, 2455-2464, doi:10.1001/jama.294.19.2455 (2005).
3 Kovell, L. C. et al. Healthy diet reduces markers of cardiac injury and inflammation regardless of macronutrients: Results from the OmniHeart trial. Int J Cardiol 299, 282-288, doi:10.1016/j.ijcard.2019.07.102 (2020).
4 Volek, J. S., Sharman, M. J., Gomez, A. L., Scheett, T. P. & Kraemer, W. J. An isoenergetic very low carbohydrate diet improves serum HDL cholesterol and triacylglycerol concentrations, the total cholesterol to HDL cholesterol ratio and postprandial pipemic responses compared with a low fat diet in normal weight, normolipidemic women. J Nutr 133, 2756-2761, doi:10.1093/jn/133.9.2756 (2003).
5 Tchernof, A., Nolan, A., Sites, C. K., Ades, P. A. & Poehlman, E. T. Weight loss reduces C-reactive protein levels in obese postmenopausal women. Circulation 105, 564-569, doi:10.1161/hc0502.103331 (2002).
6 Markova, M. et al. Isocaloric Diets High in Animal or Plant Protein Reduce Liver Fat and Inflammation in Individuals With Type 2 Diabetes. Gastroenterology 152, 571-585 e578, doi:10.1053/j.gastro.2016.10.007 (2017).
7 Smidowicz, A. & Regula, J. Effect of nutritional status and dietary patterns on human serum C-reactive protein and interleukin-6 concentrations. Adv Nutr 6, 738-747, doi:10.3945/an.115.009415 (2015).
8 Mazidi, M., Gao, H. K., Vatanparast, H. & Kengne, A. P. Impact of the dietary fatty acid intake on C-reactive protein levels in US adults. Medicine (Baltimore) 96, e5736, doi:10.1097/MD.0000000000005736 (2017).
9 Li, K., Huang, T., Zheng, J., Wu, K. & Li, D. Effect of marine-derived n-3 polyunsaturated fatty acids on C-reactive protein, interleukin 6 and tumor necrosis factor alpha: a meta-analysis. PLoS One 9, e88103, doi:10.1371/journal.pone.0088103 (2014).
10 Sorensen, L. B., Raben, A., Stender, S. & Astrup, A. Effect of sucrose on inflammatory markers in overweight humans. Am J Clin Nutr 82, 421-427, doi:10.1093/ajcn.82.2.421 (2005).
