Testing For C-reactive Protein May Save Your Life
By Susan Simmonds
Have you had your CRP levels tested? You should—because this simple blood test might just save your life.
C-reactive protein, or CRP, has long been used as a marker of inflammation in the body.1 High CRP levels are found in practically every known inflammatory state. Even if you have no symptoms of disease, elevated CRP levels may signal an increased risk for practically all degenerative disorders, including cardiovascular disease, cancer, diabetes, and more.2-6
Now, it turns out that CRP is more than just a marker of inflammation—it is also a cause of inflammation.7
Knowing your CRP status puts you in an enviable position. If it is elevated, you can take proactive steps to lower it, thereby slashing your risk of a long list of disorders related to chronic inflammation.
What Is CRP?
C-reactive protein (CRP) is manufactured throughout the body, especially by immune cells, the liver, and by adipocytes (fat cells).8 During the early phase of an inflammatory stimulus (such as infection or tissue injury) CRP levels rise dramatically.
CRP is an incredibly sensitive and robust “marker” of general inflammation.10 It’s used to track the progress of chronic inflammatory conditions such as rheumatoid arthritis, vasculitis, or inflammatory bowel diseases like Crohn’s disease.11-13 In those cases, increased symptoms accompanied by a rise in CRP signals a “flare” of the disease, and indicates the need to provide anti-inflammatory therapy.
More recently, however, CRP has been recognized as an active cause of inflammation in addition to simply being a marker of inflammation. 7 This important discovery opened the door for additional ways to fight chronic inflammation.
When CRP binds to specific molecules in the body, it participates in rapidly raising the production of inflammatory signaling molecules called cytokines and other inflammatory mediators.14 This is a healthy function of acute inflammation because it helps speed up the race to the scene of any damage, and quickly destroys invading organisms.15
However, when CRP rises unchecked, it can contribute to destructive chronic inflammation.
It is easy to see why Big Pharma is now hotly pursuing CRP-inhibiting drugs.16 Fortunately, there are a number of methods that lower CRP by changing the underlying conditions that cause it to rise.
What CRP Can Reveal About Your Health
The use of CRP has been a standard diagnostic practice for many years in determining the status of known inflammatory disorders,17 such as rheumatoid arthritis and Crohn’s disease, and in discriminating between inflammatory and functional bowel disorders.12,13,18
But as we keep learning more about diseases that have been linked with inflammation, CRP is turning out to be a useful research tool for both diagnosis and risk assessment. This is especially the case with two major killers of Americans: cardiovascular disease and cancer.
CRP levels are closely correlated with the risk of cardiovascular disease; the higher the CRP, the greater the risk.19,20 Even otherwise healthy people with modestly raised CRP levels have a significantly higher risk of future cardiovascular events.20
In one important study, patients with the highest CRP levels were at a 45% increased risk for coronary heart disease compared with those having the lowest levels.21 Another study found that people with elevated CRP levels were 60% more likely to develop ischemic heart disease and 30% more likely to have a cerebrovascular event, compared to those with normal levels.22 In addition, CRP levels have now been shown to be capable of predicting serious complications in hospitalized patients with coronary artery disease.23
Preliminary evidence suggests that CRP levels may even help distinguish between your risk for a fatal vs. a non-fatal heart attack, but that is far from established.24
Such risk increases seem to hold true for other conditions, such as diabetes, that also contribute to cardiovascular disease.25,26 Indeed, in one study, women with the highest CRP levels had a 16-fold risk for developing diabetes compared with those at the lowest levels.25 In another study, the risk was about 2.8-fold for both sexes.25,26
CRP is also associated with other cardiovascular-related conditions such as high blood pressure.
In people with high blood pressure, CRP levels are correlated with stiffness of arteries and atherosclerosis, as well as damage to organs such as the heart and kidney.27
In people with normal baseline blood pressure, CRP levels have repeatedly been shown to predict the later development of hypertension.27
And people with heart rhythm disturbances, such as atrial fibrillation, have significantly higher CRP levels than do normal controls.28
CRP levels are such strong indicators of cardiovascular risk that circulating levels of CRP are now being used to predict the likelihood of cardiovascular events and to assist in choosing therapy.27
In addition to being a marker of risk, there is growing evidence that CRP contributes directly to cardiovascular and diabetes risk. 26,27 Studies have shown the presence of CRP directly inside of most arterial plaques—and all heart lesions—after a heart attack.20 Indeed, in a damaged brain or heart after a stroke or heart attack, there is a correlation between CRP and the size of the affected area; this is strong support for a contributing role of CRP in these diseases.16
With the discovery that cancer is strongly related to overall inflammation status, there’s been growing interest in CRP as a predictor of prognosis in a variety of cancer types.29,30 And, with strong evidence that CRP is an active (and destructive) participant in promoting inflammation, there’s equally strong interest in discovering ways to actively lower a person’s CRP levels to reduce their cancer risk—or to promote their recovery if they already have cancer.
Optimal CRP levels for everyone to strive for are under 0.55 mg/L in men and under 1.0 mg/L in women.
Interestingly, CRP is now associated with a number of cancers as a powerful tool for determining prognosis and survival.29-36 When CRP is measured at the time of diagnosis, high levels consistently predict poor survival, whereas normal (especially the lower-end of normal) levels predict good outcomes.30-36
In men with penile cancer, a CRP level greater than 20 mg/L at diagnosis is significantly associated with the probability of developing lymph node metastases, a sign of poor outcome.31
In patients with advanced stomach cancer, those with a CRP level greater than 17 mg/L had an 11% greater chance of dying within 3 months after diagnosis, compared to those with lower levels.32 A later study found that CRP greater than 10 mg/L was associated with a 77% increase in poor overall survival, with a 196% greater chance of having a higher disease stage, and an 81% increase in the likelihood of tumor recurrence.33
CRP is strongly associated with survival in patients with colon and/or rectum cancers. Those with elevated levels of CRP were more likely to have lymph node (local) and distant metastases, invasion of blood vessels and nerves, and a higher stage diagnosis.34 For patients with CRP greater than 5 mg/L, only 13.3% survived after 5 years, while 57% of patients with lower CRP were still alive 5 years later.34 Indeed, one study indicated that CRP was the only marker that was an independent predictor of disease-free survival.30 CRP concentrations were higher in a group of colorectal cancer patients, at 2.4 mg/L, compared with 1.9 mg/L in healthy controls, and those with the highest CRP were 2.6 times as likely as those with the lowest levels to develop such cancers.35
In pancreatic cancer, high plasma CRP levels at diagnosis indicated a 121% increased risk of dying from the disease.29
In breast cancer, a CRP level of greater than 10 mg/L, compared with a level of less than 1 mg/L,predicted36:
- A 96% greater risk of dying from any cause,
- A 91% greater risk of dying from breast cancer specifically, and
- A 69% greater risk of having additional breast cancer-related events.
How To Lower Your CRP
With high levels of CRP being so closely tied to cardiovascular disease and cancer, the question you’re probably wondering right now is, “How do I lower my CRP levels?”
For starters, your lifestyle has a direct impact on CRP levels. Certain dietary habits, such as a high intake of trans-fatty acids, can increase CRP levels, leading to a reason why trans fats increase cardiovascular risk to a greater degree than one would expect based on its adverse effects on blood fat levels.37
A 2013 study found that ideal health behaviors (such as diet, exercise, etc.) could lower CRP.38 In that study, people having four to six “ideal behaviors” had up to a 32% reduction in their CRP levels. Exercise alone has been shown to be a means of lowering high CRP. In fact, the higher the baseline CRP, the greater the impact of a reasonable exercise regimen on CRP.39
Eating foods cooked at high temperature can increase inflammation.40-42
Avoiding high temperature-cooked food can reduce production of pro-inflammatory cytokines and CRP, thus helping to extinguish the inflammatory fire raging in the bodies of most aging people today.40-43
Wouldn’t it be incredible if Americans could throw away side effect-laden pain killing drugs just by changing the way their food is prepared?
Some drugs, such as statins, have been shown to lower CRP levels in patients with elevated blood lipids.19,44 In fact, one study using rosuvastatin (Crestor®) showed that healthy people without raised blood cholesterol but with CRP levels greater than 2.0 mg/L reduced hs-CRP levels by 37% and reduced the frequency of major cardiovascular events (though the study didn’t address the long-term consequences of statin therapy).45 There are, however, other ways to lower CRP without a prescription.
Over a dozen dietary supplements have been shown to bring down CRP levels in laboratory or human models. Red yeast rice, for example, lowered CRP by nearly 24% in people with moderately high cholesterol;46 ginger reduced CRP in diabetic adults;47 and vitamin C reduced plasma CRP 24% in smokers.48
The table above describes 17 nutrients that have been shown to favorably influence CRP levels.
In order to determine your CRP level, all it requires is a low-cost blood test.
By lowering your CRP, you’ll be protecting yourself against chronic inflammation before it progresses to a life-threatening disease.