I will look around for it. I am a little busy today. It was a genetic study on supplements a few years ago.
Supplements certainly are an industry. They even own collectively, lobbying organizations that fight to keep them unregulated. It is one of their biggest lies. Believing supplement companies blindly is as foolish as trusting big pharma or oil companies.
And yes, too much vitamin C mutates DNA, which can cause cancer. The key is 'too much'. Like psych drugs, even vitamins have paradoxical side-effects, although they are only with overdoses.
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PDD with Psychotic Features, GAD, Cluster C personality traits - No meds, except a weekly ketamine infusion