Abstract Objective: To investigate the impact of Vitamin C supplementation on enhancing immune function and reducing oxidative stress in adults.

Context: Vitamin C, a powerful antioxidant, plays a vital role in immune defense by supporting various cellular functions of the immune system. It helps protect against oxidative stress and contributes to the body's ability to fight infections. Vitamin C deficiency has been associated with impaired immunity and a higher susceptibility to infections like pneumonia and the common cold.

Methods Used: A double-blind, placebo-controlled trial was conducted on 150 participants aged 25-55. The participants were randomly assigned to either receive 500 mg of Vitamin C daily or a placebo for 12 weeks. Blood samples were collected at baseline and after the study period to evaluate immune cell activity, oxidative stress markers, and Vitamin C levels.

Researchers' Summary of Findings: The group supplemented with Vitamin C showed a significant increase in white blood cell activity, including higher levels of lymphocytes and enhanced phagocytic activity of neutrophils. There was also a marked reduction in oxidative stress markers such as malondialdehyde (MDA), compared to the placebo group.

Health Implications: Regular Vitamin C supplementation may improve immune system performance by supporting white blood cell function and reducing oxidative damage. These findings suggest that Vitamin C plays a crucial role in maintaining optimal immune health, particularly in individuals prone to infections or high oxidative stress environments.