Professor Martin Wiseman, medical and scientific advisor for the World Cancer Research Fund (WCRF), said it is difficult to accurately predict the effect of high-dose vitamin supplements on the chances of cutting cancer.

“Many people think they can reduce their cancer risk by taking supplements, but the evidence does not support this,” he stated, adding some evidence existed linking vitamin use and increased cancer rates.

He said not enough was known to, “confidently predict the balance of risks and benefits” of high-dose supplementation.