Measuring Inflammation is Key to Overall Health
By Chris D. Meletis, ND
Creactive Protein (CRP) is an inflammation marker studied extensively for its possible role in heart disease. However, emerging evidence indicates that high levels of CRP are present in a number of other conditions. A search of the medical literature reveals that high levels of C-Reactive Protein are associated with obesity, chronic obstructive pulmonary disease, cognitive decline, kidney disease and a variety of other inflammatory disorders. In this article, I will present a brief overview of CRP and some of the conditions to which it is associated. Additionally, I will discuss how testing for CRP can offer a glimpse into the overall health of each individual's body.
CRP and Heart Disease
It's surprising but true: individuals who have perfect cholesterol can be at risk for a heart attack or stroke. How could that be? Unfortunately we have been oversold on what I term “the cholesterol myth.” Certainly, cholesterol is part of the heart disease equation. Yet to assume that controlling cholesterol alone absolves one from cardiovascular risk is like assuming that by merely obeying the speed limit one will not be involved in a car accident.
Cardiovascular disease kills more Americans annually than do the next seven causes of death combined. There are well known risk factors for heart disease, such as obesity, smoking, family history and elevated LDL (bad cholesterol). Yet, C-Reactive Protein (CRP), a measure of inflammation within the body that can be elevated without any overt signs, has been implicated as a “significant” cause of premature heart disease and the related deteriorated vitality.
In The New England Journal of Medicine 2002 it was reported that both elevated LDL and CRP were a combined risk factor working together to damage blood vessels. Even more powerful was the finding that the 27,939 women participants with low LDL and high CRP were at higher risk than those with high LDL and low CRP levels.1
The authors concluded, “These data suggest that the C-reactive protein level is a stronger predictor of cardiovascular events than the LDL cholesterol level and that it adds prognostic information to that conveyed by the Framingham risk score.”
CRP's involvement in heart disease may be partially due to its interaction with LDL cholesterol. CRP is present in atherosclerotic plaques and appears to promote atherogenesis. Intraplaque CRP interacts with oxidized low-density lipoprotein and macrophages in human atherosclerotic lesions. In vitro, CRP promotes the uptake of oxidized LDL and induces activity of matrix metalloproteinase-9 (MMP-9), which is implicated in plaque rupture.
To investigate this effect in vivo, researchers examined the effect of CRP on oxidized LDL uptake and MMP-9 production in rats. CRP significantly increased oxidized-LDL uptake in macrophages. CRP also significantly increased intracellular cholesterol ester accumulation. Furthermore, CRP treatment increased MMP-9 activity in macrophages.2
“Since oxidized LDL uptake by macrophages contribute to foam cell formation and plaque instability, this study provides novel in-vivo evidence for the role of CRP in atherosclerosis,” the study authors wrote. Other studies have found CRP levels to be higher in patients with silent myocardial ischemia (SMI) compared to coronary artery disease patients who did not have SMI.3
Noteworthy is that both the American Heart Association and the CDC (Centers for Disease Control) recommend CRP testing as a tool to identify risk for cardiovascular disease. This is not surprising since the presence of inflammation can be a warning sign years prior to an event.
Weight Gain Linked to Inflammation
Obesity is known to induce an inflammatory state in the body. In many studies, higher levels of CRP have been found in overweight subjects. Researchers who analyzed data from 10,492 white, African-American, and Hispanic-American participants of the 1999-2004 National Health and Nutrition Examination Survey, found that higher body mass index was significantly associated with higher CRP in all racial/ethnic groups for both men and women before and after adjustment for age, education, and health behaviors. Larger waist circumference was also associated with higher CRP levels in all racial/ethnic groups before and after adjustment. Results were similar after additional adjustment for medications that might affect CRP levels.4
High levels of CRP also are thought to affect memory. A number of trials have established that CRP levels are higher in subjects with cognitive impairment. Recently, researchers went one step farther in establishing a link between CRP and cognitive function when they tested the hypothesis that elevated serum concentration of high sensitivity C-reactive protein (hs-CRP) predicts cognitive impairment in elderly women. In the 12-year population-based follow-up study, scientists followed a total of 97 women who were between 60 and 70 years of age at baseline. After evaluating levels of hs-CRP in the subjects, the investigators measured cognitive function by using the Mini-Mental State Examination (MMSE) and a detailed cognitive test battery to measure memory and cognitive speed.
The results indicated that higher baseline hs-CRP was associated with poorer memory at the 12-year follow-up after adjustment for age, education and depression, and further adjustment for the use of hormone replacement therapy, smoking, serum LDL cholesterol and body mass index. Memory at 12-year follow-up worsened in proportion to increasing hs-CRP at baseline.5
The researchers concluded, “High serum hs-CRP concentration predicts poorer memory 12 years later in elderly women. Hs-CRP may be a useful biomarker to identify individuals at an increased risk for cognitive decline.”
A new study investigating CRP in patients with chronic obstructive pulmonary disease (COPD) indicates this inflammatory marker is often elevated in patients with this lung disease. When researchers measured levels of CRP and the proinflammatory cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in COPD patients they found that CRP was the only inflammatory marker studied that was elevated in subjects with stable COPD. In subjects with severe or very severe COPD, TNF-alpha also was elevated. CRP and TNF-alpha also were significantly elevated in COPD patients with a low body mass index (BMI) compared to those with a normal-to-high BMI.6
According to the study authors, “The present study confirms that circulating CRP levels are higher in stable COPD patients and may thus be regarded as a valid biomarker of low-grade systemic inflammation. In addition, CRP is significantly higher in COPD patients with a low BMI and thus, together with TNF-alpha, may be considered an indicator of malnutrition in COPD patients.”
New CRP Test
Identifying your CRP risk, and then taking the proactive steps to control both overt and silent inflammation within your body and the bodies of those that you care about is critical for anyone serious about healthy aging.
To take the mystery out of whether you possess high levels of this risk factor for “silent inflammation,” which can erode even the healthiest foundation, testing for CRP is highly encouraged. A new, simple CRP test available here allows patients to collect samples at home and send them to a nationally certified lab. Collecting a sample for the test is easy and results will be mailed directly to you.
The bottom line is that inflammation in the 60,000 miles of blood vessels that nourish the 75 trillion cells in your body is believed to play a critical role in atherosclerosis as well as obesity, cognitive decline and a host of other inflammatory conditions. As I share with all my patients, testing is an ideal way to be proactive with your health as opposed to waiting until you are forced to be reactive. For more information about inflammation's destructive role in the body, please view the latest webinar “Inflammation: Eroding Away Even the Healthiest Foundations” available on the website.
1. Ridker, P.M. et al. Comparison of C-reactive protein and low-density lipoprotein cholesterol levels in the prediction of first cardiovascular events. New England Journal of Medicine. November 14, 2002. 347(20): 1557-1565.
2. Singh U, Dasu MR, Yancey PG, Afify A, Devaraj S, Jialal I. Human C-reactive protein promotes oxidized low-density lipoprotein uptake and matrix metalloproteinase-9 release in wistar rats. J Lipid Res. 2008 Feb 2. Published online ahead of print.
3. Jia FP, Lei H, Qin S, Ma KH, Liao H. Elevated serum high sensitivity C-reactive protein and endothelial dysfunction in silent myocardial ischemia. Zhonghua Nei Ke Za Zhi. 2007 Nov;46(11):919-22.
4. Wee CC, Mukamal KJ, Huang A, Davis RB, McCarthy EP, Mittleman MA. Obesity and C-reactive Protein Levels Among White, Black, and Hispanic US Adults. Obesity (Silver Spring). 2008 Feb 7.
5. Komulainen P, Lakka TA, Kivipelto M, Hassinen M, Penttilä IM, Helkala EL, Gylling H, Nissinen A, Rauramaa R. Serum high sensitivity C-reactive protein and cognitive function in elderly women. Age Ageing. 2007 Jul;36(4):443-8.
6. Karadag F, Kirdar S, Karul AB, Ceylan E. The value of C-reactive protein as a marker of systemic inflammation in stable chronic obstructive pulmonary disease. Eur J Intern Med. 2008 Mar;19(2):104-8.|