In 109 people with early blood disorders, daily vitamin C did not slow abnormal cell growth; an exploratory look found fewer deaths

What the research found

Study (phase 2 randomized trial). The EVITA trial, published online in Cancer (2026; 132(19); doi 10.1002/cncr.70549; ScienceDaily 3 October 2026), enrolled 109 people in Denmark and the United States with a blood disorder that can become cancer or with a low-risk blood cancer. Fifty-five people took 1,000 mg of oral vitamin C a day and 54 took placebo for 12 months. The primary result, growth of the abnormal cells, was similar in the two groups. Vitamin C lined up with inflammatory-signal changes the authors read as favorable, and with fewer cases of anemia, pneumonia, acute aseptic arthritis, and internal bleeding. Gastrointestinal problems were more common on vitamin C. At a median 33.6 months, 35 people had died: 11 assigned to vitamin C and 24 assigned to placebo. That survival comparison was exploratory. Co-senior authors Peter A. Jones of Van Andel Institute and Kirsten Grønbæk of Rigshospitalet said it is too soon for a recommendation and that a larger phase 3 trial is needed. Educational notes. This is not a reason to take 1,000 mg of vitamin C to prevent cancer.

Evidence level: Clinical trial. This is among the stronger kinds of evidence, but one study rarely settles a question.

Read the original at Wiley / Cancer