This is the first study of the effects of fresh apples on cancer prevention in animals.
We have proposed that the additive and synergistic effects of phytochemicals in fruits and vegetables are responsible for their potent antioxidant and anticancer activities, and that the benefit of a diet rich in fruits and vegetables is attributed to the complex mixture of phytochemicals present in whole foods. Our findings add to the growing evidence that increased consumption of fruits and vegetables, including apples, would provide consumers with more phenolics, which are proving to have important health benefits. Furthermore, health benefits of the consumption of fruits and vegetables extend beyond lowering the risk of developing cancers and cardiovascular diseases to include preventive effects on other chronic diseases such as cataracts, age-related macular degeneration, central neurodegenerative diseases, and diabetes. Consumers should be encouraged to eat more and a wide variety of fruits and vegetables daily.
From a scientific and human health standpoint, this research may have a significant impact on consumers' food selection and also help promote the "5-A-Day" program, increasing the consumption of fruits and vegetables to reduce the risk of chronic diseases such as cancer and heart disease. We believe that a recommendation that consumers eat five to 12 servings of a wide variety of fruits and vegetables daily is an appropriate strategy to reduce the risks of chronic diseases including cancer and to meet their nutrient requirements for optimum health. A healthy population would also reduce the cost of health care in the nation.
In addition, this research will have a critical economic impact on New York and U.S. fruit and vegetable growers and their respective value chains. According to the USDA, Americans spend about $76 billion on fruits and vegetables every year. The concept that fruits and vegetable have potent antioxidant and anticancer properties will help New York and U.S. growers and related industries by increasing consumption of fruits and vegetable and their products.
impact statement issue
Cancer is one of the leading causes of death in the United States, and approximately 35 percent of cancer deaths are related to diet. Breast cancer is the most frequently diagnosed invasive cancer and the second leading cause of cancer deaths in women in the United States. Epidemiological studies have consistently shown that regular consumption of fruits and vegetables is associated with reduced risk of chronic diseases such as cancer and heart disease. However, the individual antioxidants studied in clinical trials, including beta-carotene, vitamin C, and vitamin E, do not appear to have consistent preventive effects comparable to the observed health benefits of diets rich in fruits and vegetables.
Apples are a very significant part of the diet and are one of the best sources of antioxidant phenolic compounds in the Western world. Cornell food scientists previously reported that fresh apples have potent antioxidant activity, and whole apple extracts inhibit the growth of colon, liver, and breast cancer cells in vitro in a dose-dependent manner, and they had activity inhibiting NFkB activation in human breast cancer MCF-7 cells. Those results suggest that natural phytochemicals in fresh fruits could be effective in helping to inhibit these cancers.
impact statement response
In research on apples, Cornell food scientists found that 100 g of fresh apples has an antioxidant activity equivalent to 1,700 mg of vitamin C. The Cornell researchers treated a group of rats with a known mammary carcinogen, 7, 12-dimethylbenz(a)anthracene (DMBA), and then fed them either whole apple extracts or control extracts. Rats treated with the carcinogen developed mammary tumors with 71 percent tumor incidence during a 24-week study. Application of low, middle, and high doses of whole apple extracts, comparable to human consumption of one, three, and six apples per day, reduced the tumor incidence by 17, 39, and 44 percent, respectively. Cumulative tumor numbers in the groups receiving low, middle, or high doses of apple extracts were reduced by 25, 25, and 61 percent, respectively, after 24 weeks. In the groups receiving low, middle, or high doses of apple extracts, tumor burden was reduced in a dose-dependent manner when compared to the control group fed no apple extracts.
Adenocarcinoma—a highly malignant tumor and the main cause of death in animals with mammary cancer—was evident in 81 percent of tumors in the control animals but in only 57, 50, and 23 percent of the rats treated with low, middle, and high doses of apple extracts, respectively.
The expression of proliferating cell nuclear antigen (PCNA), cyclin D1 and Bcl-2 decreased, and Bax expression and apoptosis increased with increasing the apple extracts.
In another study, Cornell researchers have identified a dozen compounds, called triterpenoids, in apple peels that either inhibited cancer cells from growing in the laboratory or killed them. Several of the compounds were newly discovered and not previously reported.
Another piece of apple research focuses on how apples may bolster the effects of chemotherapeutic drugs. Cornell researchers found that apple extracts can block the actions of a protein group that can lead to cancer cells becoming resistant to chemotherapy drugs. The protein group, nuclear factor-kappa B (NF-kB), is involved with cell proliferation and can be spurred into action by cancer drugs. In a recent study, we measured the effects of apple extract on NF-kB in human breast cancer cells. Along with the extract, the researchers tested several phytochemicals, including quercetin, resveratrol, and curcumin. Only apple extract and curcumin significantly blocked NF-kB in breast cancer cells.
impact statement summary
Cornell food scientists found that whole apple extracts prevent mammary cancer in a rat model in a dose-dependent manner at the doses comparable to human consumption of one, three, and six apples a day. They have identified a dozen compounds, called triterpenoids, in apple peels that inhibited cancer cells from growing. These studies demonstrated that whole apples effectively inhibited mammary cancer growth in the rat model; thus consumption of apples may be an effective strategy for cancer protection.
Other private funding
American Institute for Cancer Research (AICR), Ngan Foundation, and the U.S. Apple Association and the Apple Products Research and Education Council
