You may never have noticed a C-reactive protein (CRP) level on your blood test results. But it's an important marker of inflammation — and one that can help predict your risk for a heart attack.
About CRP Levels
When illness or injury strikes, CRP levels in the bloodstream rise as your immune system goes into action. CRP is secreted by the liver, and levels can rise 1,000 times when your immune system is activated in the face of injury, according to an April 2018 report in Frontiers in Immunology. Without this response, injuries would fester and infections would turn deadly.
There are actually two types of inflammation that drive up CRP levels: acute and chronic, according to Harvard Health Publishing. Acute is the swelling around a twisted ankle or a cut. Tennis elbows, volleyball shoulders and basketball knees all heal thanks to a rapid response. The same process springs into action to fight infections like flu or pneumonia.
After an acute injury or illness, once health improves, the CRP should drop back down to a low level. Chronically high CRP levels can be the result of the toxic damage done by smoking cigarettes or from an inflammatory disease, like rheumatoid arthritis. They can put your heart health at risk.
"Increased inflammation can be caused by all kinds of things," says Eleanor Levin, MD, a cardiologist and clinical professor of cardiovascular medicine at Stanford Health in Portola Valley, California. "They can include infections and rheumatism in the joints. But if you don't have any of those, and you just have increased inflammation along with an increased CRP level, that has been associated with a three times greater risk of heart attack."
How to Reduce CRP
The right foods help lower CRP and can help reduce the threat to your heart from high CRP levels. Dark, leafy greens like spinach, kale and collards fight inflammation, as do all types of berries, cherries, plums, onions, turmeric, red grapes and green tea. Salmon, sardines, mackerel, bananas, olive oil and flaxseed oil work, too, according to Harvard Health Publishing.
A study in the journal Current Atherosclerosis Reports in March 2019 points out that a plant-based diet that focuses on foods like whole grains, fruits and vegetables, nuts, legumes and oils can be especially beneficial. To tackle high CRP, you'll also want to avoid sugars, soda, high-fructose juices, pasta, white bread and other refined grains.
Read more: 10 Anti-Inflammatory Foods to Add to Your Diet
A Nutrition, Metabolism and Cardiovascular Diseases study in June 2019 details how losing weight is also key to lowering CRP levels because excess weight breeds inflammation throughout the body.
"We now know that obesity is associated with increased inflammation," Dr. Levin says. If you don't have another cause of inflammation, and you have overweight or obesity even though you exercise, you should lose weight, she says. "Even if your cholesterol is not super high, obesity is a pro-inflammatory state."
In fact, we know that half of all heart attack victims have normal cholesterol levels, according to the American College of Cardiology.
Other important lifestyle steps include taking care of gum disease. If flossing or brushing makes your gums bleed, see your dentist. And, of course, quitting smoking is essential.
Know Your CRP Level
Guarding against the damage of a high CRP starts with knowing this number. A simple CRP test measures your level, but a high-sensitivity C-reactive protein test, called an hs-CRP test, will also help evaluate your risk for heart disease, according to the Mayo Clinic.
CRP is measured in milligrams per liter (mg/L). For the standard test, under 10 mg/L is considered normal. Anything above that indicates that you have an infection or a chronic condition. With the hs-CRP test, under 2mg/L is considered lower risk and above 2mg/L is considered higher risk for heart problems.
If your level is high, work with your doctor to find and treat any underlying cause and bring down your CRP.
Is This an Emergency?
- American College of Cardiology: "Half of Patients With Ideal Cholesterol Have Underlying Heart Risks; Many Patients With Optimal Health Have Dangerous Plaque Buildup in Their Arteries"
- Eleanor Levin, MD, cardiologist, clinical professor, cardiovascular medicine, Stanford Health, Portola Valley, Calif.
- Harvard Health Publishing: "Playing With the Fire of Inflammation"
- Mayo Clinic: "C-Reactive Protein Test"
- Current Atherosclerosis Reports: "Plant-Based Diets for Cardiovascular Disease Prevention: All Plant Foods Are Not Created Equal"
- Frontiers in Immunology: "Role of C-Reactive Protein at Sites of Inflammation"
- Nutrition, Metabolism and Cardiovascular Diseases: "Longitudinal Association of Adiposity and High-Sensitivity C-Reactive Protein From Adolescence Into Early Adulthood"