Low-grade inflammation is a driving force behind many chronic diseases, including diabetes, cardiovascular disease, arthritis, depression, and Alzheimer’s disease. In fact, some experts believe that inflammation plays a role in almost every age-related health problem. This isn’t inflammation you can see or feel, like the burning and redness you get when you cut your finger, it’s smoldering, low-grade damage that takes place at the level of cells, tissues, and organs. In fact, you can be inflamed without knowing it. However, there are certain blood tests that check for inflammatory markers that can tell you whether you have low-grade inflammation. Unfortunately, most physicians don’t routinely order these tests.
As you might expect, diet plays a role in chronic inflammation. According to Harvard Health, dietary choices matter and we should limit fried foods, refined carbohydrates, foods high in sugar, and trans-fats, as these foods contribute to chronic inflammation. They also mention processed meat and red meat as a potential contributor to inflammation. This raises the question of whether a diet high in protein increase inflammation. Is there evidence of this?
Protein and Inflammation
Protein is an essential macronutrient that your body needs in a substantial amount, although it’s not a major energy source except during periods of starvation or excessive exercise. Protein is found in every cell in your body where it forms structural components with the cell and is used to make enzymes that run chemical reactions in the body. The amino acids in proteins are also used to build hormones, substances that act as chemical messengers to tell cells and tissues how to behave as well as antibodies that fight infection. Without protein, you wouldn’t have oxygen-carrying hemoglobin in your bloodstream, cartilage in your joints, or muscle tissue.
Protein also plays a key role in muscle repair. Since athletes and people who work out regularly damage their muscle tissue, they need more protein to rebuild it. In fact, dieticians say that athletes may need up to double the amount of protein daily that a sedentary person does. That might explain why so many athletes and bodybuilders are obsessed with protein and often reach for a high-protein shake after a workout.
Does consuming large amounts of protein have risks? Research doesn’t support the idea that a diet high in protein is harmful to normal, healthy kidneys. At one time, health care professionals had concerns about too much protein intake. When the liver breaks down protein, it must be processed by the kidneys. The concern was that a diet high in protein forced the kidneys to work too hard. This is potentially a concern for people who already have kidney disease but not for a healthy individual.
In fact, there are benefits to increasing the protein content of a diet. Research shows protein is the most satiating macronutrient, so you feel fuller longer after a meal that contains a source of protein. One study found that people who ate a high-protein diet consumed 10% fewer calories over the course of a day, likely due to the satiety factor.
Protein and Inflammation
So, what effect does a diet high in protein have on inflammation? Some short-term studies that looked at the impact of a diet high in protein on inflammatory markers showed an increase in markers of inflammation on a high-protein diet. However, the increase was seen with animal-based protein. They were also short term and may not apply longer term.
Fortunately, a more recent study published in the journal Nutrients took a long term approach. It looked at the impact of protein on inflammatory markers over a seven-year period. For the study, the researchers measured nine markers of inflammation in subjects and correlated these markers with various intakes of protein as part of the Framingham Heart Study Offspring Cohort.
Their findings? This study found lower scores for inflammation and oxidative stress in those who consumed a diet higher in protein. The benefits were greatest for those who consumed a higher ratio of plant-based protein as opposed to animal protein. Although correlational, this study suggests that consuming more protein, mainly plant-based protein, is linked with reduced inflammation.
Plant vs. Animal Protein
Why might plant-based protein have a more favorable impact on inflammatory markers than animal protein? Unlike animal protein, plant sources contain fiber. Some studies link a diet high in fiber with reduced inflammation. The way high-fiber foods reduce inflammation isn’t clear but it may be due to the effect fiber has on the gut microbiome. Studies show that diets high in plants lead to a more diverse population of gut bacteria. Having a more diverse microbiome is correlated, in general, with health. In addition, plant-based sources of protein, like nuts, beans, lentils, soy, avocado, and some vegetables contain phytonutrients with anti-inflammatory properties. Animal sources of protein are mostly devoid of fiber and phytonutrients.
But there’s another reason. Compounds that form when you cook meat may be responsible for some of the inflammatory effects of animal protein. When you cook meat to a high temperature, like barbecuing, grilling, deep-frying, or roasting, the proteins and fats in the meat form advanced glycation end products (AGEs) that are linked with inflammation and aging.
The Bottom Line
You need more protein if you work out, especially if you strength train or do high-intensity exercise. Research also suggests that adults over the age of 65 can benefit from more dietary protein. Fortunately, the latest studies suggest that consuming a diet higher in plant-based protein is not linked with inflammation. Adding lots of red meat and processed meat to your diet, based on some studies, could have a pro-inflammatory effect, although other foods are likely more harmful, such as ultra-processed junk food and soft drinks. Therefore, this data suggests that we shouldn’t fear protein but should shift to more plant-based sources of this essential macronutrient.
References:
· Current Developments in Nutrition. Volume 3 Issue 5. May 2019.
· Harvard Health Publishing. “Foods that Fight Inflammation”
· WebMD.com. “The Benefits of Protein”
· Nutrients 2017;9:336.
· Turner-McGrievy GM, Wirth MD, Shivappa N, et al. Randomization to plant-based dietary approaches leads to larger short-term improvements in Dietary Inflammatory Index scores and macronutrient intake compared to diets that contain meat. Nutr Res. Published online on December 2, 2014.
· Front Nutr. 2019; 6: 47.
· Nutr Rev. 2013 Aug;71(8):511-27. doi: 10.1111/nure.12035. Epub 2013 Jun 13.
· J Neurosci Res. 2008 Jul;86(9):2071-82. doi: 10.1002/jnr.21644.
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