NUT 401 By : A.

S SYSTEM
Nutrition in Cancer Prevention
What is Cancer?
 Definition: Diseases of malignant Cells
 Tumor: a mass of tissue that serves no purpose.
 Malignant tumor: cancerous
 Benign tumor: noncancerous

How Cancer Spreads ?

 Cancer begins as a single abnormal cell that begins to multiply out of control. Groups of such cells form tumors and
invade healthy tissue,often spreading to other parts of the body.
 Metastasis: the spreading of cancer cells • Cells break away from primary tumor and invade surrounding tissues or
travel through the blood and lymphatic system.

The Incidence of Cancer

 1.3 million Americans are diagnosed yearly
 More than half will be cured.
 About 40% will die as a result of cancer.
 1 in 2 men and 1 in 3 women will be develop cancer during their lifetime.

Nutrition in Cancer Prevention

 It is estimated that one third of the cancer deaths each year in the US can be attributed to nutrition and other
lifestyle factors (not including smoking)
 Carcinogens (tumor promoters) are substances that promote the development of cancerous cells. They may come
from foods, from the air, or even from within the body. Most carcinogens are neutralized before damage can occur,
but sometimes they attack the cell's genetic material (DNA) and damage it. It takes years for a noticeable tumor to
develop. During this time, compounds known as inhibitors can keep the cells from growing. Some vitamins in plant
foods are known to be inhibitors.

Etiology

 Complex relationship
 Dietary carcinogens: naturally occurring and added in food preparation and preservation
 Inhibitors of carcinogenesis: antioxidants, phytochemicals
 Enhancers of carcinogenesis (Tumor promoter)
 Latency period between initiation and promotion Nutrition in Cancer Prevention
 Diets contain both inhibitors and enhancers of carcinogenesis
 Animal studies also test the effect of food and nutrition on cancer and provide guidance for epidemiological studies
 Dietary fat, is known to be a promoter that helps the abnormal cells growing quickly.

Fat
 High intake of total and saturated fat is associated with increased risk of breast, colon, lung and prostate cancers
 High fat diets are associated with obesity, which is linked with cancer of the colon, rectum, esophagus, gall bladder,
breast, endometrium, pancreas, and kidney.
 Animal fat (from meat and dairy) was associated with increased risk of prostate, ovarian and breast cancer in the
Nurses Health study.

Fat Raises Cancer Risks

 Higher omega-3 vs omega 6 may reduce risk of breast cancer.
 Low fat diet (<20% fat) may reduce risk of recurrence of breast cancer.
 Although the total amount of fat one eats is of concern, there is evidence that animal fat is much more harmful than
vegetable fat. One study noted a 200 percent increase in breast cancer among those who consume beef or pork five
to six times per week.
 Migration studies help to rule out the influence of genetics.
Energy Intake and Physical Activity
 Total energy intake is strongly associated with breast cancer in postmenopausal women
 Physical activity may have a protective effect
 Women who spent an average 3.8 hours per week in physical activities had lower risk of colon, reproductive cancers

Obesity is a Risk Factor for:

 Breast cancer (among postmenopausal women)
 Colon
 Endometrium
 Esophagus
 Gallbladder
 Pancreas
 Kidney
 Is also a risk factor for cancer recurrence

Protein
 Difficult to isolate effects of protein, since ↑ protein diets are ↑ in fat and ↓ in fiber
 Low protein diets seem to reduce the risk of cancer, while risk is increased by very high protein intakes
 Increased meat intake is associated with increased risk of colon cancer and advanced prostate cancer

Fiber
 Observational studies and case control studies indicate that fiber-rich diets are associated with a protective effect in
colon cancer
 Higher intakes of vegetables were inversely associated with colon cancer risk in one study
 But high fiber diets also tend to be lower in meat, fat, and refined carbohydrates.

Carbohydrate and Glycemic Index

 High glycemic-index diet associated with increased risk of cancers including ovarian, endometrial, breast,
colorectal, pancreas, and lung
 Limit processed foods and refined sugars and emphasize whole grains and low GI foods

Fiber Fights Cancer

 In 1970, British physician Dennis Burkitt observed that a highfiber diet reduces diseases of the digestive tract.
 He observed that in countries where diets are high in fiber (that is, plant-based diets), there were fewer cases of
colon cancer.
 The highest fiber intakes are found in non-industrialized nations where meat is scarce and plant foods fill the menu.
The United States and other Western nations whose diets are based upon animal products have the highest rates of
colon cancer.
 Bile acids are secreted into the intestine to help digest fat; there, bacteria can change the acids into chemicals that
promote colon cancer.
 Fiber may bind with these bile acids and evict them from the intestines. Also, bacteria in the colon ferment the fiber
creating a more acidic environment which may make bile acids less toxic.

Fruits and Vegetables

 Fruits and vegetables found to be associated with lower risk in 128 of 156 dietary studies
 Increased consumption of fruits and vegetables is associated with lower risk of cancers of the oral cavity,
esophagus, stomach, colon, rectum, and bladder
 Evidence less strong for hormone-related cancers such as breast and prostate cancer

People who develop cancer tend to have low intakes of :

 Raw and fresh vegetables

 Leafy green vegetables
 Lettuce, carrots, raw and fresh fruit
 Cruciferous (cabbage family) vegetables
 Flavenoids and lignans (soy, grains, vegetables) are associated with lower risk of sex hormone-related cancers
 Low in energy, good sources of fiber, vitamins, minerals
 Good sources of antioxidants (vitamins C, E, selenium, phytochemicals such as carotenoids, flavonoids, plant
sterols, allium compounds, indoles, phenols, terpenes
 Do not yet know what is the protective agent(s) so best to use food sources
Plant based foods may prevent cancer by
 Inhibiting hormone-dependent steps in tumor formation and protecting genetic material from carcinogenic agents.
 Fiber cannot be digested by humans early in the digestive process. It also draws water into the digestive tract.
 Suppressing free radical production
 Serving as bulking agents to dilute carcinogens and decrease gastrointestinal transit time
 Stimulators of physiologically active and anti-cancer enzymes
 Studies have shown that stomach cancer and breast cancer are less common on high-fiber diets.
 Fiber affects levels of estrogens in the body.
 Estrogens are normally secreted into the intestine, where the fiber binds with the hormone and moves it out of the
body.
 Without adequate fiber, the estrogen can be reabsorbed from the intestine into the bloodstream.
 High levels of estrogen are linked to a higher risk of breast cancer.
 In the U.S., the average daily fiber intake is 10 to 20 grams per day.
 Experts recommend 30 to 40 grams per day.
 The best sources of fiber are whole grains, beans, peas, lentils, vegetables, and fruits, Foods that are closest to their
natural state.

Supplementation in Persons at High Risk for Esophageal-Gastric Cancer in China

 Study in area of China with diet low in micronutrients and very high risk of esophageal and gastric cancer
 ß-carotene, vitamin E, and selenium at 5X the RDA was associated with significantly lower mortality from all cancers

Calcium and Cancer Risk

 Several studies suggest that foods high in calcium may reduce the risk for colorectal cancer and that calcium
supplements may reduce the formation of colorectal polyps.
 However, there is evidence that high calcium intake, especially supplements, is associated with increased risk of
prostate cancer.
 Bottom line: get calcium through food sources

Lycopene and Cancer Risk

 Lycopene is a red-orange carotenoid found in tomatoes and tomato-based foods
 Several studies show that consuming tomato products reduces the risk of some cancers, but unclear whether
lycopene is responsible
 Absorption of lycopene is enhanced when lycopene-containing vegetables are cooked and eaten with fat
 No evidence that supplements are safe and effective in cancer prevention.

Preserved Meats and Cancer Risk

 Some studies link eating large amounts of preserved meat to increased risk of colorectal and stomach cancers
 May or may not be due to nitrites
 Nitrites can be converted in the stomach to carcinogenic nitrosamines, which may increase the risk of stomach
cancer
 Vegetables and fruit retard the conversion of nitrites to nitrosamines

Cooked Meat and Cancer Risk

 Frying, broiling, and grilling meats at high temperatures creates chemicals that might increase cancer risk (cause
cancer in animals)
 Use techniques such as braising, steaming, poaching, stewing and microwaving

Soy and Cancer Risk

 Soy contains several phytochemicals (phytoestrogens) which have weak estrogen activity and appear to protect
against hormonedependent cancers in animal studies
 No evidence shows soy supplements reduce cancer risk
 High doses of soy may increase the risk of estrogen-responsive cancers, such as breast or endometrial cancers in
certain women
 Breast cancer survivors should consume only moderate amounts
Alcohol
 Alcohol associated with carcinogenesis in cancers of the mouth, pharynx, larynx, esophagus, lung, colon, rectum,
liver and breast.
 Act synergistically with tobacco, these risks skyrocket. Alcohol may potentiate the effect of smoking on laryngeal,
esophageal and stomach cancer.
 One of alcohol metabolite is a well-known carcinogen which is acetaldehyde.
 Alcohol may also act as a solvent to enhance the absorption of other carcinogens.
 Malnutrition associated with alcoholism may also be implicated
 Alcohol may induce the activity of certain enzymes that can convert some compounds to carcinogens.
 Alcohol could be also contaminated with a known carcinogen like nitrosamines, mycotoxins, tannins, and inorganic
arsenic which are potent carcinogens.

Coffee and Tea

 Coffee has been investigated as a possible risk factor for a variety of cancers, but does not appear to be associated
with increased cancer
 Regular drinking of green tea and other sources of polyphenols may reduce the risk of stomach cancer
 Consumption of very hot drinks may increase the risk of esophageal cancer

Hyperinsulinemia and Cancer

 Increased body mass index may promote hyperinsulinemia and metabolic syndrome
 Insulin resistance/hyperinsulinemia, higher estrogen levels, and insulin-like growth factor I may act synergistically
to promote tumor growth, particularly mammary tumors.

Food Safety and Cancer

 Naturally occurring carcinogens (aflatoxins in peanuts, safrol in plant oils, tannins in grains and grapes,
benzopyrene formed by smoking meat and fish)
 Naturally found in plant foods like celery, parsley, figs, mustard, pepper, citrus oils
 Pesticides
 Choose in-season, locally grown produce
 Rinse fruits and vegetables and remove outer leaves before eating
 Use proper food storage to prevent growth of fungal carcinogens
 Marinate protein foods to decrease cooking time
 Use cooking methods to avoid contact of foods and food drippings with flames
 Use lower cooking temperatures with protein foods

AICR Diet and Health Guidelines for Cancer Prevention

 Choose a diet rich in a variety of plant-based foods
 Eat plenty of vegetables and fruits.
 Maintain a healthy weight and be physically active.
 Drink alcohol only in moderation, if at all.
 Select foods low in fat and salt.
 Prepare and store food safely.

American Cancer Society Guide to Nutrition and Activity

 Eat a variety of healthful foods, with an emphasis on plant sources.
 Eat five or more servings of a variety of vegetables and fruits each day.
 Include vegetables and fruits at every meal and for snacks.
 Eat a variety of vegetables and fruits.
 Limit French fries, snack chips, and other fried vegetable products.
 Choose 100% juice if you drink fruit or vegetable juices.
 Choose whole grains in preference to processed (refined) grains and sugars.
 Choose whole grain rice, bread, pasta, and cereals.
 Limit consumption of refined carbohydrates, including pastries, sweetened cereals, soft drinks, and sugars.
Lifestyle Changes to Prevent Oral and Esophageal Cancers
 The best advice to reduce the risk of oral and esophageal cancers is to:
 Avoid all forms of tobacco
 Restrict alcohol consumption
 Avoid obesity
 Limit intake of animal products, especially red meat and high-fat dairy products
 Eat five or more servings of vegetables and fruits each day Lifestyle

Changes to Prevent Pancreatic Cancer

 Avoid tobacco use
 Maintain a healthful weight
 Remain physically active
 Eat five or more servings of vegetables and fruits each day

Lifestyle Changes to Prevent Stomach Cancer

 Eat at least five servings of vegetables and fruits daily.
 Stomach cancer rates are falling due to reduced infection with h. pylori

Diet Recommendations for Cancer Survivors

 Cancer survivor may harbor undetected primary or disseminated cancer cells
 A “cured” cancer pt is at increased risk for other primary cancers in the same organ or other organs
 General dietary guidelines are also appropriate for recovering cancer pts
 Dietary regimens should :
a) avoid stimulating growth and spread of remaining tumor cells and
b) provide maximum prevention against new primary tumors

Recommendations for Cancer Survivors

 Limit total fat intake to 15-20% of total calories. Monounsaturated fats are preferred.
 Aim for 10-12 daily servings of a variety of whole vegetables and fruits.
 Consume 4-6 servings of whole grains daily. Breast cancer pts should eliminate or severely restrict alcohol intake
 Consider a Vitamin E supplement of 200 IU/day to replace deficit from reduced fat intake
 Standard dose multivit daily (not to exceed 100% RDA). This does not replace cancer-fighting foods
 Exercise moderately (30 minute daily walk, for example)
 Maintain desirable body weight
 Selenium is found in whole grains and has the same antioxidant effects as vitamin C and beta carotene.
 Caution is advised in supplementing selenium, which is toxic in large doses.

Foods That Contain Cancer Preventing Substances

 Broccoli
 Brussels sprouts
 Cabbage
 Cauliflower
 Carrots
 Red peppers
 Tomato
 Sweet potato
 Collard greens
 Green Tea
 Kale
 Spinach
 Apricot
 Cantaloupe
 Grapefruit
 Orange
 Papaya
 Peach
 Plum
 Watermelon
Recommendations for Cancer Prevention
 Do not smoke or chew tobacco
 Be sun smart
 Avoid sugary drinks and energy dense foods. Eat a variety of vegetables, fruits, whole grains and legumes
 Limit red meats and avoid processed meats
 Don’t use supplements to protect against cancer
 Breastfeed exclusively to 6 months
 After treatment, same guidelines apply to cancer survivors.

Foods Can Fight Cancer

Directly

 Individual vitamins, minerals and phytochemicals have anticancer effects

 Synergy of compounds in overall diet that have the biggest protective effect

Indirectly

 Excess body fat increases the risk of seven cancers

 Vegetables and fruits are low in calories
 Whole grain and beans are rich in fiber and moderate in calories
 Fill 2/3 of you plate with vegetables, fruits, whole grains and beans

Cancer Prevention and Diet

 ADD Cancer protective foods
 SUBTRACT foods that increase risk
 REPLACE large portions of calorie dense foods

Phytochemicals – the Cancer Fighters in our Foods

 Flax seed provides all the nutrients from this small brown Flax seed or golden hard-coated seed. It is an excellent
source of dietary fiber, omega 3 fat (as alpha-linolenic acid), and lignans.
 Ground flax seeds have been studied for its effect on cancer, including its lignan fraction reduced the established
tumor load (both in number and size of tumors); and the flax seed also reduced metastasis.
 In an animal model using mice, Lin et al. (2002) found that a diet supplemented with 5% flax inhibited the growth and
development of prostate cancer in their experimental mouse model.
 Phytochemicals – naturally occurring plant chemicals
 Provide colour, flavour, odour
 Influence chemical processes in the body
 Thousands have been identified

Phytochemicals can :
 Stimulate immune system
 Block carcinogens
 Reduce inflammation
 Prevent DNA damage and help repair
 Reduce oxidative cell damage
 Slow the growth of cancer cells
 Trigger death of damaged cells
 Regulate hormones
Foods that Fight

 Apples
 Blueberries
 Broccoli and cruciferous veg
 Cherries
 Coffee
 Cranberries
 Flaxseed
 Grapefruit
 Legumes (dry beans, peas, lentils)
 Soy
 Squash (winter)
 Walnuts
 Whole grains
 Berries
 Dark leafy greens
 Garlic
 Grapes and grape juice
 Green Tea
 Tomatoes

Herbs, Spices and Tea

 Turmeric
 Ginger
 Saffron
 Tea

Incidence of Malnutrition
 Up to 80% of cancer patients experience malnutrition during their illness Why?
 Increase in energy expenditure
 Changes in carbohydrate, protein and lipid metabolism
 Decreased intake due to treatment side effects

Effects of Malnutrition
 ↑ treatment complications and delays
 ↑ hospitalizations
 ↓ response to treatment
 ↓ quality of life
 ↓ survival rates
Benefits of Eating Well Nutrition Goals During Treatment
 Maintain or improve nutritional status improve immune function to help fight infections
 Maintain or increase current weight Promote healing and recovery after treatment
 Manage symptoms related to cancer and/or treatment Prevent muscle wasting and maintain strength
Provide energy to combat fatigue