Plant Food and Oral and Oropharyngeal Cancers

Plant Food and Oral and Oropharyngeal Cancers

Review of Eur J Cancer Prev 2003;12(1):49-56.

The two biggest risk factors for oral and oropharyngeal cancers are tobacco (smoking and chewing) and alcohol (drinking). However, even for individuals who have a history of smoking, chewing tobacco, and/or alcohol use, certain types of diet may increase or decrease risk of these cancers. A recent study published in the European Journal of Cancer Prevention looked at several dietary factors and risk of oral and oropharyngeal cancers. This article review discusses the findings of this study. The study indicates that eating more vegetables and fruit DECREASES risk of oral and oropharyngeal cancers.  We provide PRACTICAL information on what these findings mean.  We explain which specific foods appear to most decrease risk of oral and oropharyngeal cancers. Most importantly, we provide ideas for using this information in a dietary plan to reduce oral and oropharyngeal cancer risk. Factors such as past use of cigarettes and alcohol, age, and genetics cannot be changed, but diet and nutrition can! Along with quitting smoking and decreasing alcohol use, this type of information will allow people to take concrete and practical steps to decrease their risk of oral and oropharyngeal cancers.

Note: Numbers appearing at the end of sentences indicate research references. References are listed at the end of each article.

Background

As early as the 1970s & 80s, researchers have studied the connection between diet and oral and oropharyngeal cancers (1-10). Oral cancers include cancers of the lips and inside of the mouth including the front portion of the tongue and the roof and floor of the mouth. Oropharyngeal cancers include cancers of the back portion of the tongue and the part of the throat just behind the mouth. The two biggest risk factors for oral and oropharyngeal cancers are tobacco (smoking and chewing) and alcohol (drinking).  However, even for individuals who have a history of smoking, chewing tobacco, and/or drinking, certain types of diet may increase or decrease risk of these cancers. In the past 10-15 years, more research has suggested fruits and vegetables can decrease risk of oral and oropharyngeal cancers (11-25). This has led to interest in determining which specific vegetables, fruits, and nutrients might protect against these cancers. A study published in the European Journal of Cancer Prevention looked at several dietary factors and risk of oral and oropharyngeal cancers (26). It is hoped this type of research will help identify dietary factors that increase or decrease risk of oral and oropharyngeal cancer. Factors such as past use of tobacco and alcohol, age, and genetics cannot be changed, but diet and nutrition can! This type of information will allow people to take concrete and practical steps to decrease their risk of oral and oropharyngeal cancers.

What The Study Found

For this study (26), 375 people with oral and oropharyngeal cancers and 375 people without cancer were asked about their diet. Information on other diet and lifestyle factors, including use of tobacco and alcohol was collected and accounted for in the study.  Researchers classified people regarding the amounts and types of foods they had eaten in the past.  Researchers used this information to determine which foods and nutrients were related to having a history of oral or oropharyngeal cancer. Two important results came out of this study.

First, the researchers found that people who ate 8 or more servings of vegetables per week had approximately HALF the risk of oral and oropharyngeal cancer when compared to people who ate 3 or less servings of vegetables per week. In other words, eating MORE vegetables DECREASES oral and oropharyngeal cancer risk. This finding was MORE pronounced among smokers and drinkers. This means that eating more vegetables was especially protective against these cancers in people who smoke and drink alcohol.

Second, the researchers found that people who ate 11 or more servings of fruit per week had approximately HALF the risk of oral and oropharyngeal cancer when compared to people who ate 6 or less servings of fruit per week. In other words, eating MORE fruit DECREASES oral and oropharyngeal cancer risk. This finding was MORE pronounced among smokers and drinkers. This means that eating more fruit was especially protective against these cancers in people who smoke and drink alcohol.

What is a serving of vegetables?  

• 1 cup, loosely packed raw green leafy vegetables or 1/2 cup cooked greens
• 1/2 cup chopped of any other vegetable, cooked
• 6 oz vegetable juice

What is a serving of fruit?

• 1 medium apple, banana, or orange
• 1 melon wedge
• 1/4 to 1/2 cup berries or chopped fruit
• 1 to 2 oz dried fruit
• 3/4 cup fruit juice - this is 6 oz of 100% fruit juice, NOT fruit drink

What do these results mean?

If we assume that the people studied are similar to most people, then this study suggests that eating at least 8 servings of vegetables and 11 servings of fruit each WEEK, will decrease risk of oral and oropharyngeal cancers. This is only a little more than ONE serving of vegetables per day and about ONE AND A HALF servings of fruit per day.

Clearly, the most important things you can do to reduce your risk of oral and oropharyngeal cancers are to stop using tobacco (smoking & chewing) and to stop using alcohol (beer, wine, hard liquor), if you currently use these products. Tobacco, in particular, is a large risk factor for these types of cancer. Alcohol is a small to moderate risk factor for these cancers.  Using both tobacco and alcohol together is a very large risk factor for oral and oropharyngeal cancers. However, it is important to remember that even for people with these other risk factors, diet appeared to protect against oral and oropharyngeal cancers.

How can I change my diet to reduce my oral or oropharyngeal cancer risk?

What should you do to help reduce your risk of getting oral or oropharyngeal cancer? Remember, most importantly, stop smoking and drinking, if you currently have these habits. However, according to this study (26), increasing your intake of PLANT foods, mainly vegetables and fruit, may be helpful for protecting against oral and oropharyngeal cancers.  And amazingly, even for those who have a long history of smoking and drinking, eating vegetables and fruit still appears to help reduce risk of oral and oropharyngeal cancers! Use the tips below to accomplish the goal of eating more vegetables and fruits.

Quick Tips On How to Eat More Cancer Fighting Foods

• Rely on frozen produce during the off season.
• Add a handful of frozen blueberries, strawberries, or blackberries to your cereal.
• Stuff your favorite omelet with low-fat shredded cheese, tomatoes, and frozen spinach (cook and drain spinach first); Garnish with strawberries or peaches for a fruit serving.
• Keep little 6 oz cans of low sodium vegetable juice handy for a quick serving of vegetables.
• Have a glass (6 oz maximum) of 100% fruit juice; try a new juice each week for variety.
• Snack on baby carrots and humus; you get both vegetables and legumes (beans) with this snack.
• For a tasty salad, steam several cups of frozen or fresh vegetables (cauliflower, carrots, broccoli, Brussels sprouts), until tender and crisp; Add 1/4 to 1/2 cup of salad dressing; Mix well and refrigerate until chilled; Instead of store-bought salad dressings, try your own mix of balsamic or apple cider vinegar and olive oil; If you find it too difficult to mix your own salad dressing, chose a brand that does not contain the words 'hydrogenated' or 'partially hydrogenated' in the ingredient list; Examples of this type of dressing include Annie's Naturals, Chelton House, and Seeds of Change. These are just a couple of examples. There are many companies that offer similar products. READ the label. If you see the words 'hydrogenated' or 'partially hydrogenated', chose a different product.
• Improve the nutrition value of your family's favorite main dish casserole by adding one cup of frozen mixed vegetables. Be sure to look for the veggie blends that include cauliflower, broccoli, and carrots.
• Stuff your favorite potato with antioxidant-rich toppings such as stewed tomatoes, green and red peppers, onions, broccoli, and low-fat cheese. Try a sweet potato instead of a white potato and you get even more nutrition value. 
• Get acquainted with green leafies. Try adding a few leaves of kale, chard, mustard greens, collard greens, dandelion greens, or any other green leafy food to your regular salad. Try our recipe for Sweet Spicy Kale to get more green food in your diet.
• Replace snack foods (pretzels, chips, crackers, etc.) with vegetables & fruits. Purchase pre-chopped and pre-washed vegetables and fruit, if you are busy. These may cost more, but if you eat them, it is worth the investment in your health!
• Focus on variety; The more color you eat in your plant foods, the better.
• Try to eat all colors of plant foods including orange, red, green, yellow, blue, purple, and dark green; Think of carrots, sweet potatoes, peppers, mangoes, papaya, blueberries, eggplant, kale, collard greens, spinach, etc.; Most people do not get enough variety for maximum cancer-fighting effect!
• Start basing your diet around UNPROCESSED whole plant foods including vegetables, fruit, whole grains, and legumes. Do this instead of basing your food choices around fast food, microwave meals, or instant dinner trays. These items contain unhealthy fats and too many calories. Plus, they DO NOT contain the healthy cancer fighting nutrients of whole plant foods.
• Try to have three-quarters of your plate covered by fruit, vegetables, whole grains, and legumes. It is ok to have one-fourth of your plate covered by chicken, meat, or fish. Chose fish more often - it is a healthier choice than other meats.

Recent studies confirm that a HIGH FIBER diet will reduce risk of oral and oropharyngeal cancers (27,28) too! Vegetables and fruit are a natural source of high fiber. If you eat more of these foods, you will also be eating more fiber. Try these additional tips to increase fiber with other foods.

Quick Tips On How to Eat More Fiber

• Eat a high-fiber, whole grain cereal, such as All-Bran, Bran-Buds, or Raisin Bran; Chose a cereal with at least 6 grams of fiber per serving.
• Chose whole grain, high fiber breads. Chose bread with at least 3 grams of fiber per serving.
• To be sure your bread products are whole grain, read the ingredient list. If you see the word 'enriched', then the product is NOT whole grain. Instead look for words such as 'whole grain', 'stone ground', 'whole ground', 'whole wheat flour', 'whole oat flour', and 'whole barley flour'. These words tell you that this food is a whole grain.
• Learn to love legumes (beans). Legumes are a terrific source of fiber and other healthy nutrients.
• Eat low-sodium bean or lentil soup for lunch; it's quick and convenient and counts as a serving of legumes. Legumes are loaded with fiber.
• Use canned beans; rinse well and sprinkle on salad to add protein and fiber to your meal.
• Use whole grain pasta instead of plain, white pasta. One brand to try is Hodgson Mills; this is found in most local grocery stores.

NOTE: If you are in cancer treatment, these diet changes may not be right for you.

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Publish Date; 10/2003