Effects of Dietary Antioxidants on Cardiovascular Risk Factors

The aim of the Antioxidant Study was to compare the efficacy of foods naturally rich in antioxidants with that of antioxidants in a pill form on markers of inflammation and plasma cholesterol in healthy adults at risk of cardiovascular disease.

Increasing the amount of antioxidants in your diet is thought to be one way to improve your health. If antioxidants do have a beneficial effect, one way to measure that is to examine possible changes in the levels of inflammatory markers in your blood. Participants were asked to consume an antioxidant supplement including carotenoids, mixed tocopherols, vitamin C and selenium, or a placebo for 8 weeks. The doses of antioxidants will be similar to the amounts suggested by the United States Department of Agriculture (USDA) recommended daily allowances (RDA). In addition, a group of participants will be asked to change their usual eating habits and consume more of certain foods that are naturally good sources of the four antioxidants contained in the pills. Eligible participants were asked to come to the Stanford Campus for 3 fasting blood draws over the period of 8 weeks and to complete diet and physical activity questionnaires at the beginning, middle, and end of the study period.

Participants were asked to increase antioxidant-rich food intake to approximately double their daily habitual intake and take a placebo pill.

Participants were asked to consume their usual diet and take a supplement containing carotenoids, mixed tocopherols, vitamin C and selenium, designed to approximately double their daily habitual intake.

Change from baseline in inflammatory Markers [monocyte chemotactic protein-1 (MCP-1), interleukin-6 (IL-6), and soluble intercellular adhesion molecule-1 (sICAM-1)] at 8 weeks

Blood concentrations of carotenoids, tocopherols, selenium, and vitamin C (to validate dietary change)

Dietary intake of carotenoids, tocopherols, selenium, and vitamin C (as measured by 3-day dietary recalls)

Inclusion Criteria:Overweight/obesity; high LDL cholesterol, pre-hypertension. Exclusion Criteria:1. Daily intake of > 5 servings of vegetables and fruits 2. Fasting blood glucose >140 mg/dL 3. BMI >40 4. Liver or renal disease; Atherosclerosis (e.g., CAD, PAD); Malignant neoplasm; Ongoing infection; Inflammatory disease 5.Currently taking the following medications: Anti-inflammatory drugs Lipid lowering drugs Anti-hypertensive drugs Calcium containing drugs Drugs known to affect blood coagulation Drugs known to affect antioxidant status 6. Pregnant or lactating 7. Inability to communicate effectively with study staff

Dewell A, Tsao P, Rigdon J, Gardner CD. Antioxidants from diet or supplements do not alter inflammatory markers in adults with cardiovascular disease risk. A pilot randomized controlled trial. Nutr Res. 2018 Feb;50:63-72. doi: 10.1016/j.nutres.2017.10.017. Epub 2017 Nov 2.