It’s hard to open a magazine or health-related book without reading about inflammation and the importance of eating an anti-inflammatory diet. Knowledge about inflammation has gone mainstream. No wonder! We now know that inflammation is linked with most of the chronic health problems related to aging and to aging itself. For example, inflammation is a contributor to heart disease. Chronic inflammation damages the inner wall of blood vessels and sets the stage for cardiovascular disease. Inflammation also is a factor in insulin resistance, type 2 diabetes, obesity, some forms of cancer, degenerative diseases, and in autoimmune conditions as well.
What is Low-Grade Inflammation?
You’re probably most familiar with inflammation as the redness and swelling you get in when you burn yourself or stub your toe. This kind of inflammation is visible and you can feel the pain and see the redness and swelling. But low-grade inflammation is invisible to the eye because it’s happening within your tissues and blood vessels. It’s a smoldering type of inflammation that can go on for years undetected, silently causing its damage.
What causes this kind of chronic, low-grade inflammation? Some we bring on through lifestyle – eating a diet of foods that fuel inflammation or lifestyle habits like smoking or excessive use of alcohol. Another factor is obesity. Fat cells, particularly visceral fat cells deep in the abdominal cavity and pelvis, produce inflammatory chemicals called cytokines. These cytokines set inflammation into motion. Aging, itself, is associated with a rise in low-grade inflammation. This partially explains why chronic diseases become more common as the years past.
If you want to age successfully and avoid chronic diseases of aging, you have to reign in inflammation as much as possible. Yet, how do you know if you’re inflamed and how much inflammation is happening in your own body? There are some clues. For example, if you’re overweight or obese, you’re probably experiencing excess release of cytokines that is creating inflammation. Likewise, if you’re smoke, eat processed foods made with inflammatory oils, or consume more than your share of sugar, you’re also fueling inflammation. But is there an objective way to measure how inflamed you are?
Blood Markers of Inflammation
Is low-grade, chronic inflammation something you can measure? There are a few blood markers that can tell you how much inflammation is in your body. One of the most widely used is a blood test called C-reactive protein, or CRP. CRP is a protein produced by the liver and it rises in response to inflammation. In people who have certain inflammatory diseases, like rheumatoid arthritis or inflammatory bowel disease, or even periodontal disease, CRP is typically higher than normal. It can also go up in response to a burn, infection, injury, or cancer. Other conditions that can also mildly raise CRP include obesity and excessive alcohol use.
Since inflammation is also a driver of atherosclerotic heart disease, a high CRP may also indicate a greater risk of heart disease. One test that specifically measures inflammation inside blood vessels as a marker of heart disease risk is called high-sensitivity C-reactive protein, or Hs-CRP. People with an elevated Hs-CRP are four times more likely to have a heart attack than people with a normal value.
The problem with C-reactive protein as a measure of inflammation is that no one knows what the ideal value is. C-reactive protein levels vary based on gender, age, and ethnic background – but, in general, 1 mg/dl or higher is considered clinically significant and could indicate an undiagnosed health problem that’s causing a significant amount of inflammation. You can also experience a sharp rise in c-reactive protein if you have an infection, particularly a bacterial infection. The level usually comes back down once the infection has resolved
A CRP level of less than 1 mg/dl but greater than 0.3 is what you typically see in someone who has low-grade inflammation due to obesity, metabolic syndrome, diabetes, or an unhealthy lifestyle. This is the range that should make you take a closer look at your diet and lifestyle and take steps to reduce unhealthy habits that might be contributing to low-grade inflammation. This is the range you see in people who smoke, who are older, who don’t get enough quality sleep, who don’t exercise, or who have mental health issues, like depression. It’s also suggestive of underlying metabolic issues that could, over time, compromise your health.
CRP isn’t the only marker of low-grade, “hidden” inflammation, interleukin-6 or IL-6 is too, although it’s less commonly used in a clinical setting. The combination of the two markers – CRP and IL-6 provide useful information about health risks. One study showed that among seemingly healthy older people, those with the highest levels of these two blood markers were 260% more likely to die over the subsequent 4 years.
Other Sources of Low-Grade Inflammation
Allergies over-activate your immune system and can cause low-grade inflammation. Hidden, low-grade infections are another source of immune system activation that ramps up the body’s inflammatory response. There’s also growing evidence that diet impacts immune health and whether your immune system is turned up too high. For example, some studies suggest that processed foods, rich in omega-6 fats and trans-fats, and sugar fuel low-grade inflammation.
In addition, a study showed that consuming high-glycemic carbohydrates, carbs that raise your blood sugar rapidly, was linked with a rise in CRP. In contrast, Mediterranean diets are associated with a drop in inflammatory markers, like C-reactive protein. So, lifestyle plays a definite role in fueling or subduing low-grade inflammation.
The Bottom Line
Inflammation, even when it’s low grade is damaging to your health. In fact, it’s a factor in most chronic diseases of aging. One of the best tests for detecting inflammation is C-reactive protein, a blood test, or, in the case of cardiovascular disease, high-sensitivity C-reactive protein. These are tests you can talk to our doctor about.
MedicineNet.com. “C-Reactive Protein”
Eur J Public Health. 2007 Aug;17(4):340-7. Epub 2006 Oct 26.
Dr. Hyman. “Is Your Body Burning Up with Hidden Inflammation?”
Am J Clin Nutr March 2002. vol. 75 no. 3 492-498.
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