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 IBD 
Research : UCB Vitamin

Biomarkers in Children and Environmental Pollution
 Collaborators 
University of California, Berkeley
Gladys Block, Principle Investigator
Chris Jenson, Study Director
Nina Holland, Primary Investigator
Karen Huen, PhD



Purpose of the Study

The purpose of the UCB Vitamin research study is to examine the effect of supplemental antioxidants, vitamin C and E, on measures of inflammation and oxidative stress. Recent research has found that compounds found in the blood that are associated with inflammation and oxidative stress, may increase the rise of heart disease. Antioxidants nutrients such as vitamin C and E may reduce the levels of these compounds in the blood, which in turn may reduce the rise of heart disease.

Study Hypotheses

  • Antioxidant supplementation will decrease C-reactive protein (CRP), a marker of inflammation, and biomarkers of oxidative damage to lipids and membranes, in nonsmokers. The effect on CRP will be stronger for treatment with vitamin C than with vitamin E.
  • Women will have higher baseline CRP and lipid peroxidation biomarkers than men of similar age.
  • Body fat will be significantly positively associated with baseline CRP and lipid peroxidation
  • Some but not all of the gender difference will be explained by differences in body fat.

Specific Aims

  1. To determine whether antioxidant supplementation can lower the inflammation marker C-reactive protein (CRP) and lipid peroxidation biomarkers, in a randomized controlled intervention study of nonsmokers. Secondary aim.
          1a. To determine whether one treatment is significantly more effective than the other.
          1b. To determine whether treatment effects differ by gender or body fat

  2. To determine whether there are gender or body fat differences in baseline CRP or in baseline lipid peroxidation, in nonsmokers, independent of other covariates. Secondary aim.
          2a. In women, to determine whether menopause status is associated with higher baseline CRP or lipid
                peroxidation, independent of covariates

Study Design Overview

Nonsmokers (n=400 to achieve a final sample of 360) will be recruited from the San Francisco Bay Area. Prior to randomization, blood will be drawn and assayed for C-reactive protein (CRP), biomarkers of oxidative damage, serum antioxidants and other serum factors (see details: “Laboratory Processing Procedures”). Subjects will then be randomized to one of three intervention groups. After two months of supplementation with either placebo or one of two different antioxidants, blood will again be drawn and assayed for the same factors as at baseline. The primary outcome of the intervention study will be change in CRP and change in oxidation biomarkers. Baseline blood values of CRP and lipid peroxidation prior to intervention will be analyzed to confirm differences by gender and BMI.

Rationale

In a previous randomized trial we observed treatment effects of antioxidant supplementation on C-reactive protein, in addition to treatment effects on lipid peroxidation. Oxidative damage has been associated with numerous disease conditions and C-reactive protein has been shown to be “remarkably consistent” in its association with cardiovascular disease. Thus, this is potentially a very important observation. However, our previous randomized trial did not intervene on subjects who were not actively or passively exposed to cigarette smoke. We and others have shown that persons not actively or passively exposed to cigarette smoke do have elevated C-reactive protein and oxidative damage. Thus, it is important to now conduct a randomized trial on this group, who represent the majority of Americans. If such a randomized trial of antioxidants is shown to reduce C-reactive protein and oxidative damage, it would provide an inexpensive and nontoxic approach to reducing these well-established risk factors for disease.

In addition, our previous study observed higher C-reactive protein and lipid peroxidation in women compared to men. If this is true, it is of great importance for understanding women’s greater susceptibility than men to agents such as tobacco and alcohol, as well as for understanding those diseases more common in women, such as osteoarthritis. However, two-thirds of subjects in our previous baseline study were either actively or passively exposed to cigarette smoke. It is critical to confirm the higher CRP and oxidation in women compared to men in a sample not exposed to cigarette smoke at all. Such an observation, if confirmed in non-cigarette smoke-exposed subjects, would open new avenues of research on women’s health. It is also critical to determine whether that observation is independent of women’s higher percentage of body fat, and independent of menopausal status. This could not be done in our previous study because we did not have appropriate measures of either of those factors.

Our previous study also observed higher CRP and oxidation in obese persons compared to those of normal weight. A higher CRP among the obese is well established, but the link with oxidation is new. As noted, oxidative damage has been associated with numerous disease conditions. If confirmed it would be very important, as it could lead to new approaches to both understanding and managing the health problems associated with obesity. But again, two-thirds of subjects in our previous baseline study were either actively or passively exposed to cigarette smoke. It is critical to confirm the oxidative effects of overweight and obesity in a non-cigarette smoke exposed sample.

In summary, our previous intervention study included smokers as well as passive smokers. In addition, that study did not measure body fat (except as BMI), assess menopause status, or intervene on persons who neither smoked nor were passively exposed. We now propose a study in nonsmokers not passively exposed, to test the effects of antioxidant supplementation on C-reactive protein and oxidative damage. In the baseline data prior to intervention, we will attempt to confirm our previous finding of higher oxidation and C-reactive protein in women, in a much larger sample, and determine the independent effects of obesity and menopause on those factors.

Vitamin Project in the News

theheart.org, 'Could an orange a day keep BP down?', Jan. 6, 2009

KQED Radio Forum with Michael Krasny, Nov. 26, 2008

Healthhabits blog, 'Vitamin C Puts Out the Fire of Inflammation', Nov. 17, 2008

Pharmaceutical chemistry and Drug blog, 'Vitamin C Lowers Levels Of >Inflammation Biomarker Considered Predictor Of Heart Disease", Nov. 17, 2008

Laboratory Processing Images

A scheme of sample processing is shown below.



 Publications 

Block G, Jensen CD, Dalvi TB, Norkus EP, Hudes M, Crawford PB, Holland N, Fung EB, Schumacher L, Harmatz P. Vitamin C treatment reduces elevated C-reactive protein. Free Radic Biology Med. 2008.

Block G, Jensen CD, Morrow JD, Holland N, Norkus EP, Milne GL, Hudes M, Dalvi TB, Crawford PB, Fung EB, Schumacher L, Harmatz P. The effect of vitamins C and E on biomarkers of oxidative stress depends on baseline level. Free Radic Biol Med 2008, 45:377-384.

Holland NT, Pfleger LP, Berger E, Ho A, Bastaki M. Molecular Epidemiology Biomarkers - Sample Collection and Banking Considerations. Toxicology and Applied Pharmacology, 206:261-68, 2005.