Does vitamin A lower cancer risk?

　　Vitamin A (retinol) is obtained from foods in 2 ways: it can be pre-formed from animal food sources (retinol) and made from beta-carotene in plant-based foods. Vitamin A is needed to maintain healthy tissues. Vitamin A supplements, whether in the form of beta-carotene or retinol, have not been shown to lower cancer risk, and high-dose supplements may, in fact, increase the risk for lung cancer in current and former smokers. And retinol can cause serious p roblems if too much is taken.