We all know that fruit and vegetables are nutritious and contain many nutrients. They play an important role in cancer prevention.
The following information is taken from You Can Prevent Cancer by Michael Colgan, PhD
The 600 identified pigmented compounds responsible for hundreds or red, orange, and yellow leaves in the autumn, were until recently not considered very important to us. Six of these carotenoids have been identified as major players to our health and are considered along with vitamin E as our main fat-soluble antioxidants. These are beta-carotene, lutein, lycopene, alpha-carotene, cryptoxhantin, and zeaxanthin.
Animal and human research shows that carotenoids enhance the immune response as well as protect the skin from UV Radiation damage.
Lower cancer risk with a diet high in carotenoids
According to Dr.Colgan in his book, You Can Prevent Cancer, resent research shows that carotenoids have an important anti-cancer function. By increasing the flow of regulatory signals, carotenoids can enhance the communication between cells. Normal cells can use this enhanced communication to talk to cells damaged by carcinogens, this will prevent the damaged cells from turning malignant. This communication also inhibits proliferation of already malignant cells. Our bodies produce malignant cells daily that can proliferate into cancer. According to Colgan's book, carotenoids provide strong protective mechanism to keep these cell under control.
Cancer research confirms the power of carotenoids. According to 60 recent studies, cancer patients have very low level of carotenoids. It is interesting to note that the lowest risk for numerous types of cancer are the people with the highest blood levels of carotenoids due to high intake of carotenoid-rich vegetables and fruit. For example, the breast cancer risk in women with a family history of breast cancer was dramatically reduced by high levels of beta-carotene and/or lutein and zeaxanthin. High serum levels of total carotenoids in women shows that cervical cancer risk is reduced. Patients with stomach and digestive tract cancers have low beta-carotene levels.
Where to find the carotenoids
Colgan writes that a diet that includes carrots, tomato juice, water melon, pink grapefruit and broccoli provides about 11,000 IU per day of beta-carotene and over 20,000 mcg of other carotenoids. You would only consume 1,000 IU if beta-carotene and 50 mcg of alpha-carotene per day if you eat ice berg lettuce, cabbage, white potato, a pear, and an apple instead. This would not be enough for protection.
Orange juice is not a good choice, but raw fresh oranges are great. Red bell peppers are a lot better than yellow. Pears, plums, and raspberries are low in carotenoids but tomatoes are loaded. Carrots are a good choice while cabbage is not. Romaine lettuce is a good choice while ice berg lettuce is not.
Colgan says in order to inhibit cancer, research shows that you need higher intake of carotenoids than what can be consumed in a diet. He recommends to include plenty of carotenoids from fruit and vegetables in your diet, and supplement with 20,00-30,000 mcg of mixed carotenoids.
Source: You Can Prevent Cancer, Michael Colgan, PhD