According to medical experts from Harvard University, a 19-year study of 2,000 Chicago residents concluded that consuming vegetables rich in carotene can significantly reduce the risk of lung cancer. Among heavy smokers who ate these vegetables, the cancer rate was 1:8 compared to other smokers. Vegetables rich in carotene include potatoes, tomatoes, beets, asparagus, carrots, sweet potatoes, laver, kelp, and spinach. After passing through the human small intestine and lungs, carotene is converted into vitamin A, which activates and regenerates cell membranes, helping to maintain cells and prevent cancerous changes. Animal liver and eggs are also rich in vitamin A and can be consumed in moderation. Vitamin C can protect the tracheal mucosa of smokers. Therefore, vegetables rich in vitamin C should also be eaten regularly.
When carotene from vegetables is consumed with other non-vegetarian dishes, its absorption is increased. For example, the absorption rate for raw carrots is only 10%, but when cooked with meat or oil, the absorption rate of carotene can reach over 90%.