One of the most widely studied biomarkers for inflammation is high-sensitivity C-reactive protein (hsCRP), also referred to as CRP.
What is the significance of the different levels? In heart disease, individuals who have levels lower than 1.0 mg/L are in the optimal range for low risk of inflammation. Levels of 1-3 mg/L represent the average risk range, and greater than 3.0 mg/L is a higher risk profile.
Above 10.0 mg/L is less specific to heart disease, although still related, but more likely associated with other causes, such as infection and autoimmune diseases. This biomarker is derived from the liver.
CRP is not specific to heart disease, nor is it definitive for risk of the disease. However, the upside is that it may be helpful with risk stratification, which helps us understand where we sit on a heart disease risk spectrum and with progression in other diseases, such as diabetic retinopathy, depression and autoimmune diseases, among others.
Diabetic retinopathy — a complication of diabetes
We know that diabetes affects approximately 10 percent of the U.S. population and is continuing to rise at a rapid rate. Diabetic retinopathy is a complication of diabetes that affects the retina (back of the eye) and is a leading cause of vision loss.
One of the reasons for the vision loss is macular edema, or swelling, usually due to rupture of tiny blood vessels below the macula, a portion of the back of the eye responsible for central vision.
The Diabetes Control and Complications Trial (DCCT), a prospective study involving over 1,400 type-1 diabetes patients, showed an 83 percent increased risk of developing clinically significant macular edema in the group with the highest hsCRP levels compared to those with the lowest.
Although these results were with type 1 diabetes, patients with type 2 diabetes are at equal risk of diabetic retinopathy if glucose levels, or sugars, are not well-controlled.
Depression is very difficult to control and is a tremendous cause of disability. Well, it turns out that inflammation is associated with depression.
Specifically, in a prospective observational trial involving over 70,000 patients, rising levels of CRP had a linear relationship with increased risk of hospitalization due to psychological distress and depression.
In other words, compared to levels of less than 1 mg/L, those who were 1 to 3 mg/L, 3 to 10 mg/L and greater than 10 mg/L had increased risk from 30 percent to 84 percent to 127 percent, respectively.
What can be done t reduce inflammation?
This is the key question. In the Nurses’ Health Study, a very large, prospective observational study, the Dietary Approaches to Stop Hypertension (DASH) diet decreased the risk of both heart disease and stroke, which is impressive.
The DASH diet also decreases the levels of hsCRP significantly, which was associated with a decrease in stroke and heart disease.
In two recently published studies of my own patients, a Low-Inflammatory Foods Everyday (LIFE) diet also showed significant results in reducing inflammation.
Both are nutrient-dense with emphases on fruits, vegetables, nuts, seeds and legumes and a de-emphasis on processed foods, red meats, sodium and sweet beverages.
To stem the effects of inflammation, reducing hsCRP through lifestyle modifications and drug therapy may be a productive way of reducing risk, slowing progression and even potentially reversing some disease processes.
The LIFE and DASH diets are very powerful at achieving optimal levels of hsCRP without incurring potential side effects.
This is a call to arms to have your levels measured, especially if you are at high risk or have chronic diseases such as heart disease, diabetes, depression and autoimmune diseases. HsCRP is a simple blood test with easy-to-obtain results.