Trouble with a Capital "T" Folks, we've got trouble, with a capital "T," and that rhymes with "P" and that stands for "protein" - as in C-reactive protein (CRP). (Apologies to "The Music Man" author, Meredith Willson.) But according to recent research, a common vitamin may help reduce the inflammation that triggers a rise in CRP, which can play a role in creating blood clots that lead to strokes and heart attacks. A study that appears in the March 2006 issue of the American Journal of Clinical Nutrition (AJCN) concludes that vitamin C may have anti-inflammatory effects. Researchers at the Royal Free and University College Medical School in London recruited more than 3,250 men over the age of 60. None of the subjects had diabetes or had suffered a heart attack or stroke. Food frequency questionnaires were used to determine fruit and vegetable intake. Blood samples were also taken to measure vitamin C and CRP, as well as tissue plasminogen activator (t-PA), a marker of endothelial dysfunction (an abnormal function of cells that line the inner surface of blood vessels). Researchers found high fruit consumption to be linked with a 25 percent reduced risk of inflammation, while inflammation risk was nearly cut in half among those who had high blood levels of vitamin C. Intake of the vitamin was also significantly associated with lower concentrations of t-PA. An editorial that appears in the same issue of AJCN notes that the study focused on elderly white males, so the "findings cannot be translated to men aged less than 60 y, women, or people of other races." But HSI Panelist Allan Spreen, M.D., disagrees. When I asked Dr. Spreen to comment on the study, he wrote: "I can assure them (for what it's worth) that the results CAN be translated to women, other races and age groups - the participants just have to be human. Vitamin C in high doses has been known for decades to kill ANY virus or bacteria (pretty strong statement there) if given in adequate dose. Though C-reactive protein was not known back then, and interest specifically in inflammation may not have been the primary thrust of such work, inflammation would decrease as infectious insult was alleviated." The accompanying editorial also points out that the study was, "not a randomized placebo-based clinical trial, and thus the authors' conclusion is not firm and cannot be used for policy guidelines." Fair enough. But I'd like to call their attention to a placebo-based clinical trial that I told you about in the e-Alert "Putting the C in CRP" (4/28/04). In that study, 160 subjects (all were smokers or regularly exposed to second-hand smoke) were divided into three groups; one group received 515 mg of vitamin C each day, one group received an antioxidant mix combining vitamin C, alpha-lipoic acid, and vitamin E, and a third group received a placebo. Researchers took blood samples from each subject before the two-month supplementation period, and again when the test period was finished. Analysis showed that CRP levels rose slightly for those in the placebo group. Subjects who took the antioxidant mix experienced a small decrease in CRP (just under 5 percent). But in the vitamin C group, CRP dropped an average of nearly 25 percent. In that e-Alert I wrote: "If future studies confirm these findings (which the UC team describes as the first of its kind), vitamin C supplements might eventually be considered part of the standard protocol in addressing elevated CRP." More investigations are needed to confirm an association between vitamin C intake and CRP management, but it appears that research is heading in the right direction. Sources:
"Associations of Vitamin C Status, Fruit and Vegetable Intakes, and Markers of Inflammation and Hemostasis" American Journal of Clinical Nutrition, Vol. 83, No. 3, March 2006, ajcn.org
"Is Vitamin C an Antiinflammatory Agent?" Ishwarlal Jialal and Uma Singh, American Journal of Clinical Nutrition, Vol. 83, No. 3, March 2006, ajcn.org "Vitamin C Could Reduce Inflammation" Food Navigator, 3/8/06, foodnavigator.com
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