Give any 2 reasons why people may NOT want to take supplements that contain beta-carotene or vitamin E

Answer 1

Both vitamin E and beta-carotene have antioxidant properties that may help promote cardiovascular health.
It has been suggested that people who take vitamin E supplements may reduce their risk of cardiovascular disease, but early studies supporting this view may not have accounted for variation in the subjects such as illnesses or smoking histories. A large study that closely examined other studies of vitamin E intake versus cardiovascular disease found that increased vitamin E intakes are not protective and may actually cause more harm.
It has been suggested that increased intake of beta-carotene may reduce the risk of developing certain cancers such as lung cancer in smokers. Studies have shown that people taking beta-carotene supplements may be at increased risk for damage to their DNA, which can lead to cancer development, and that beta-carotene supplement intake in smokers actually increased the rate of lung cancer.
Foods provide lower levels of vitamin E and beta-carotene in association with other nutrients; thus, with foods there is less risk of effects from excessive amounts of either of these two nutrients alone.