Diet and Health Guidelines to Lower Risk of Cancer

1. Diet and Health Guidelines to Lower Risk of Cancer Presented by Janice Hermann, PhD, RD/LD OCES Adult and Older Adult Nutrition Specialist Oklahoma Cooperative Extension Service

2. Cancer • Cancer second leading cause of death in the United States • Cancer not a single disorder • Many types • Different characteristics • Occur in different body locations • Take different courses • Require different treatments

3. Cancer Development • Genes work together to regulate cell division and ensure new cells are replicas of parent cells • Process allows: • Body to grow • Replace dead cells • Repair damaged cells

4. Cancer Development • Cancer develops from mutations in genes regulating cell division • Mutations inhibit genes that ordinarily monitor and correct errors • Affected cells lose ability to stop cell division • Result is an abnormal mass of cells

5. Cancer Development • An abnormal mass of cells is called a tumor • Benign • Tumors that stop growing without intervention or can be surgically removed • Most often pose no threat to health • Malignant • Tumors that multiply out of control • Threaten surrounding tissues and health

6. How Cancer Develops • As a malignant tumor grows, blood vessels form to supply the tumor with nutrients • Eventually, the tumor invades more and more healthy tissue and may metastasize • Malignant cancers are described by: • Location • Size • Extent of growth • If spread to surrounding lymph nodes • If spread to distant sites in the body

7. Cancer Development

8. Cancer Development • Genetic Factors • Immune Factors • Environmental Factors • Physical Activity • Dietary Factors • Cancer Initiators • Cancer Promoters • Protective Factors

9. Cancer Development • Genetic factors • All cancers have a genetic component in that a mutation causes abnormal cell growth • Some cancers have a genetically inherited component as well • Example: someone with a family history of color cancer has a greater risk of developing colon cancer than someone without a genetic predisposition; however, this does not mean that they will develop colon cancer

10. Cancer Development • Immune factors • A healthy immune system recognizes foreign cells and destroys them • Theorized an ineffective immune system may not recognize tumor cells as foreign, thus allowing unchecked cell growth • Aging affects immune function, and incidence of cancer increases with age • Diseases that weaken the immune system can increase cancer risk

11. Cancer Development • Environmental Factors • Environmental factors known to cause cancer: • Exposure to radiation and sunlight • Water and air pollution • Smoking

12. Cancer Development • Physical Activity • Lack of physical activity may play a role in the development of some types of cancer • People whose lifestyles include regular, vigorous physical activity have the lowest risk of colon cancer • Physical activity may also protect against breast cancer by reducing body weight and by other mechanisms unrelated to body weight

13. Cancer Development • Dietary Factors • Estimates are 1/3 of cancers attributed to nutrition • Cancer Initiators • Some dietary factors may initiate cancer development • Cancer Promoters • Other dietary factors may promote cancer development once it has started • Protective Factors • Still other dietary factors may protect against cancer development

14. Diet and Cancer Studies • Epidemiological studies try to identify relationships between the diet of population groups and incidence of specific cancers • Diet complexity makes identifying relationships difficult • Thousands of chemicals in a diet • Diets contain initiators, promoters and protective factors • Changing one factor in the diet may change others, making identifying individual factors difficult • Many cancers have a long latency period, thus diet at initiation or promotion may not be the same as at diagnosis

15. Dietary Factors: Cancer Initiators • Pesticides • Some pesticides may be carcinogenic at extremely high doses, however, they are safe at the levels permitted on fruits and vegetables • The benefits of eating fruits and vegetables are far greater than any potential risk • Food additives • Those approved for use in foods are not carcinogenic

16. Dietary Factors: Cancer Initiators • Alcohol • Alcohol associated with increased risk of mouth, esophageal and breast cancer • Mouth and esophageal cancer are especially increased if alcohol is combined with smoking

17. Dietary Factors: Cancer Initiators • Alcohol • If alcohol intake causes liver cirrhosis, there is an increased risk of liver cancer • Malnutrition associated with alcoholism is also likely to be important in the increased risk for certain cancers • Thus, potential benefits of moderate alcohol intake for cardiovascular disease must be weighed against potential risks

18. Dietary Factors: Cancer Initiators • Food preparation methods • Cooking meat, poultry, and fish at high temperatures and smoking meat causes carcinogens to form on food surfaces which have been related to colon, breast and stomach cancer • High heat cooking methods such as grilling, broiling, and barbecuing • Healthier cooking methods include roasting, broiling, poaching, steaming, stewing, braising and microwaving • Fruits and vegetables appear to provide a protective effect

19. Dietary Factors: Cancer Initiators • Food preparation methods • Large amounts of salt-cured and salt-pickled foods have been related to stomach, colon and bladder cancers • Sodium and potassium nitrates used in salting, pickling, and curing processes • Nitrates can be converted into nitrite, which can form potential carcinogens nitrosamines • Diets with high amounts of fruits and vegetables contain vitamin C and phytochemicals can retard conversion of nitrites to nitrosamines

20. Dietary Factors: Cancer Promoters • High fat diets • High dietary total fat and saturated fat may be related to increased risk of breast, colon, endometrial and prostate cancer • Omega-3 fatty acids however, may be protective • Thus same dietary fat advice applies to cancer protection as to heart disease • Reduce total fat and saturated fat • Increase omega-3 fatty acids

21. Dietary Factors: Cancer Promoters • High fat diets • May increase cancer risk by increasing: • Obesity • Bile acid production • Estrogen levels • Because fat is calorie dense it is difficult to distinguish between the effects of high dietary fat, and total calories

22. Dietary Factors: Cancer Promoters • High calorie intake • In most epidemiologic studies, a positive association has been seen with high calorie intake and promotion of breast, colon and endometrial cancer • Increased risk may be due to: • Excess calories themselves • Weight gain due to excess calories • High fat intake that often supplies excess calories

23. Dietary Factors: Cancer Promoters • Obesity may increase risk of colon, endometrial and breast cancer • Increased risk may be due to: • Extra weight • Adipose tissue production of estrogen • Extra calories • High fat intake that often supplies excess calories and contributes to weight gain • Protective effect of physical activity related to breast and colon cancer may be due in part to helping to control obesity

24. Dietary Factors: Cancer Promoters • Protein • Excessive muscle meat sources of protein have been related to increased risk of colon and prostate cancer • Not know if increased risk due to: • Protein level • Fat content • Fat type • Increased calories from fat • Other factor such as being low in fiber, antioxidants and phytochemicals • Further research needed

25. Dietary Factors: Cancer Promoters • Protein • In general tumor development is: • Suppressed by diets that contain protein below that required for optimal growth • Enhanced by protein levels two to three times the amount required

26. Dietary Factors: Protective Factors • Fruits, vegetables, whole grains and legumes • Epidemiological studies show a link between diets with plenty of fruits, vegetables, whole grains and legumes and reduced incidence oral cavity, esophagus, stomach, colon and lung cancer • Compounds in these foods that may help lower cancer risk: • Dietary fiber • Vitamin C • Vitamin E • Phytochemicals • Low fat

27. Dietary Factors: Protective Factors • Fruits, vegetables whole grains and legumes: Fiber • Fiber-rich diets may protect against colon cancer • In the intestine bile can be converted into potential cancer causing substances. Soluble fibers can bind bile acids and increase their excretion • Insoluble fibers absorb water making a larger, softer stool which can dilute potential cancer causing substances • A larger, softer stool moves through intestine faster so colon exposed to cancer causing substance for less time • Foods high in fiber are typically lower in fat, which may also help protect against colon cancer by reducing bile acid production

28. Dietary Factors: Protective Factors • Fruits, vegetables, whole grains and legumes: Antioxidants • Fruits, vegetables, whole grains and legumes also contain antioxidant nutrients that may protect against cancer • Antioxidants stop free radical oxidation which may help to prevent cell and tissue damage that can promote cancer • Possible these nutrients have many other effects in the body which lower cancer risk

29. Dietary Factors: Protective Factors • Fruits, vegetables, whole grains and legumes: Phytochemicals • Fruits, vegetables, whole grains and legumes also contain phytochemicals that may protect against cancer • Some function antioxidants, protecting against harmful cell damage from oxidation • Others lower cancer risk in different ways such as activating enzymes that destroy carcinogens

30. Dietary Factors: Protective Factors • Fruits, vegetables, whole grains, and legumes • Because it is not known which specific substances in fruits, vegetables, whole grains and legumes help to lower cancer and whether it is the substances themselves or their presence in food, the best recommendation is to eat a variety of these foods. • Best to get these nutrients from foods not supplements.

31. Dietary Factors: Protective Factors • Calcium • Calcium may have a role in lowering colon cancer; however, more research is needed • In the meantime, adequate calcium is known to be important for growth and bone development

32. Cancer Development • Evidence suggests millions of cases of cancer could be prevented by changes in: • Diet • Weight control • Physical activity • Smoking

33. Consequences of Cancer • Nonspecific effects of cancer include: • Anorexia and reduced food intake • Metabolic alterations • Tissue wasting and weight loss • Anorexia, tissue wasting, weight loss and fatigue typify cancer cachexia • Occurs in as many as 80% of people with cancer

34. Consequences of Cancer • Anorexia and Reduced Food Intake • Major contributors to wasting • With cancer body may not be able to respond to reduced nutrient intake and nutrient stores are rapidly depleted • Without adequate energy and nutrients, the body is poorly equipped to: • Maintain immune defenses • Support organ function • Absorb nutrients • Repair damaged tissues

35. Consequences of Cancer • Anorexia and Reduced Food Intake • Factors contributing to anorexia and reduced food intake: • Chronic nausea and early satiety • People with cancer frequently experience nausea and a premature feeling of fullness after eating small amounts of food • Fatigue • People with cancer often tire easily and lack the energy to prepare and eat meals • If cachexia develops, these tasks become even more difficult to handle

36. Consequences of Cancer • Anorexia and Reduced Food Intake • Factors contributing to anorexia and reduced food intake: • Pain • People in pain may have little interest in eating, particularly if eating makes pain worse • Mental stress • A cancer diagnosis can cause distress, anxiety, and depression, all of which may reduce appetite • Facing and undergoing cancer treatments causes additional psychological stress

37. Consequences of Cancer • Anorexia and Reduced Food Intake • Factors contributing to anorexia and reduced food intake (cont.): • Effects of cancer therapies • Therapies for cancer (including medications, chemotherapy radiation therapy, surgery, and bone marrow transplants) can affect food intake by causing nausea, vomiting, altered taste perceptions, food aversions, inflammation of the mouth and esophagus, dry mouth, mouth sores, difficulty swallowing, intestinal cramping, diarrhea, and constipation

38. Consequences of Cancer • Anorexia and Reduced Food Intake • Factors contributing to anorexia and reduced food intake (cont.): • Obstructions • A tumor may partially or completely obstruct a portion of the GI tract, causing complications such as nausea and vomiting, early satiety, delayed gastric emptying, and bacterial overgrowth • Some patients with obstructions are unable to tolerate oral diets

39. Consequences of Cancer • Metabolic Alterations • Metabolic changes can also exacerbate wasting • Increased protein turnover, but reduced muscle protein synthesis • Increased gluconeogenesis, further straining supply of body proteins • Increased triglyceride breakdown, but decreased fat synthesis • Many develop insulin resistance • Metabolic alterations help explain why people with cancer fail to regain lean body mass or maintain healthy body weights even when receiving adequate energy and nutrients

40. Consequences of Cancer • Tissue Wasting • Weight loss often evident at time cancer diagnosed • Factors contributing to wasting • Anorexia and reduced food intake • Metabolic alterations • Cytokines released by both tumor and immune cells induces a hypermetabolic, catabolic state • Diversion of nutrients to support tumor growth result in lower energy and nutrients available to healthy tissues • Severe tissue wasting, often seen in the later stages of cancer, may be ultimate cause of death

41. Cancer Treatments • Primary medical treatments for cancer are: • Surgery • Chemotherapy • Radiation Therapy • Aim is to remove cancer cells, prevent further tumor growth, and alleviate symptoms • Medical treatments can effect nutritional status

42. Cancer Treatments • Surgery • Performed to remove tumors • Can affect nutritional status • Acute metabolic stress caused by surgery raises protein and energy needs and can exacerbate wasting • Surgery may also contribute to pain, fatigue, anorexia and reduced food intake • Blood loss further contribute to nutrient losses

43. Cancer Treatments • Chemotherapy • Used to inhibit tumor growth • Interfere or prevent cell division • Affect rapidly growing cancer cells • Unfortunately, most of these drugs can effect normal cells (especially rapidly dividing cells, such as those in the GI tract, skin and bone marrow) and can effect nutritional status due to: • Anorexia • Nausea • Malabsorption • Diarrhea

44. Cancer Treatments • Radiation Therapy • Bombarding cancer cells with radiation induces formation of reactive oxygen species, such as superoxide and hydroxyl radicals, which can damage cellular DNA and cause cell death • Radiation can effect normal cells and can effect nutritional status • Radiation to head and neck may damage salivary glands and taste buds, causing dry mouth and altered taste • Radiation to lower abdomen can cause radiation enteritis, inflammation of the small intestine, causing nausea, vomiting, diarrhea, and malabsorption

45. Cancer Treatments • Bone Marrow Transplants • Replace bone marrow destroyed by chemotherapy or radiation • Primary treatment for leukemia • Can substantially effect nutritional status • After bone marrow is destroyed, immune function is suppressed, increasing the risk of foodborne illness • Effects of transplant include anorexia, dry mouth, inflamed mucous membranes, altered taste, and diarrhea • Patients often unable to consume adequate food and may require nutritional support

46. Cancer Treatments • Medications to combat anorexia and wasting • Medications sometimes prescribed to stimulate the appetite and promote weight gain

47. Cancer Treatments • Alternative therapies • 60 to 80% of cancer patients combine complementary and alternative medicine (CAM) approaches with standard treatment • Many people do not discuss their use of complementary and alternative medicine approaches with their physicians

48. Cancer Treatments • Alternative therapies • Dietary supplements and herbal remedies among most frequently used CAM • Many supplements can be used without risk; however, others may have adverse effects or interfere with conventional treatments • St. John’s wort can reduce effectiveness of some anticancer drugs • Antioxidant supplementation may interfere with chemotherapy and radiation treatment

49. Nutritional Therapy • Objectives of medical nutrition therapy are to: • Minimize tissue wasting and weight loss • Protein and energy needs are considerable to prevent tissue wasting and weight loss. • Correct nutritional deficiencies • Help people maintain their strength and immune function • Provide a diet that can be tolerated and enjoyed despite the complications of illness

50. Nutrition Therapy • Nutrition therapy depends on the type and severity of cancer, side effects of treatment and patient’s nutritional status • In addition, factors may interfere with eating