Further to my previous article mentioning results showing little effect of vitamins C & E on incidence of cardiovascular events, a new study appearing today from UC – Berkeley demonstrated that vitamin C reduces the levels of C-reactive protein (CRP), an important biomarker of heart disease and diabetes.

The study looked at the effects of 1,000 mg/day vitamin C and 800 IU/day vitamin E vs placebo in 396 healthy, non-smoking adults. Participants who started out with CRP levels greater than 2 milligrams per liter (elevated levels) had 34 percent lower levels of CRP when treated with vitamin C compared with placebo. The recommended upper limit for vitamin C supplementation is 2,000 mg/day (although many people exceed this without negative consequences).

They also found a link between obesity and elevated CRP levels, assumedly because obesity represents a state of low-grade, chronic inflammation. In fact, 75% of obese people have elevated CRP levels.

Interestingly, no significant effects due to vitamin E on CRP levels were found.

So, according to this study, we can say that vitamin C supplementation reduces levels of CRP in people with elevated levels. Unfortunately, it’s not really clear whether the levels are reduced as a result of inflammation levels being reduced, or for some other reason. Simply reducing CRP would presumably have no beneficial effect – say, if the mechanism was that excess vitamin C was interfering with CRP synthesis in the liver.

A quick review of the literature, however, only yielded studies suggesting that vitamin C supplementation reduced inflammation by its effect in reducing inflammation biomarkers.

C-reactive protein (CRP)

CRP is produced in the liver and by adipocytes (fat cells). It was discovered as a substance in the serum of patients who were experiencing acute inflammation. It was initially thought to be secreted by pathogens, such as Streptococcus pneumoniae, one of the organisms responsible for pneumonia, because it was elevated in people with this and other diseases, including cancers.

Later, its synthesis in the liver was discovered, and its function as a way for the body to tag damaged cells and microbes that require removal by the body’s defense cells – macrophages – was elucidated.

Chronically high levels of CRP have been associated with risk for diabetes, hypertension, and cardiovascular disease. However, CRP itself is merely an indicator of disease and not a cause of the pathologies it is associated with.