Some vegetables contain vitamin E which is also an antioxidant. Good sources of vitamin E are nuts, seeds, some cereals and vegetable oils. Fat provides a large amount of energy so a high fat diet may make weight gain more likely. If such people also smoke, this makes the risk of cancer even greater. Carcinogens are substances which can start the process of cancer.
Tobacco smoke contains carcinogens which cause lung cancer.
Foods may contain carcinogens. However, the risk from carcinogens in foods is low because if they are present, it is usually in very small amounts. Aflatoxins are examples of carcinogens in foods. An example of these substances is those produced in peanuts that are contaminated by the growth of moulds. A large proportion of cancers are influenced by environmental factors.