Nutrition and cancer risk

Cancer research limitations

Cannot separate components of diet well. Data based on FFQ and diet hx intake is not extremely valid/reliable. Development of cancer is multifactorial, difficult to see nutrition picture clearly.

Reflux

Causes chronic inflammation and Barrett's Esophagus which predisposes to adenocarcinoma of the esophagus.

Cross-sectional study

Compares rates of cancer in a group with a key difference, i.e. comparing breast cancer in a state with high and low physical activity levels.

Case control study

Compares something about the case subject to a control subject. I.e. fruit in vegetable intake in a 62 y.o. white woman with cancer to a 60 y.o. white woman without cancer.

Brassica vegetables

Consumption is linked with reduction in breast cancer risk.

Animal studies

Control and experimental animals in the study. Inject substance that causes cancer into experimental, or use a transgenic animal bred to develop cancer. Then, provide different diets.

Fiber

Convincing evidence of a decreased risk for colo-rectal cancer according to a large epidemiological study.

Processed meat

Convincing evidence of increased risk for colo-rectal and gastric cancer. Limited suggestive increased risk for esophageal, lung, and prostate cancer.

Obesity

Convincing evidence that ____ increases risk for esophageal, pancreatic, kidney, liver, gall bladder, endometrial, post-menopausal breast, and colon cancer.

Alcohol

Convincing increased risk for mouth, pharynx, larynx, esophageal, breast, liver, and colo-rectal cancer. May protect against kidney cancer per 2015 data.

Obesity

Creates a systemic inflammatory environment. Adipocytes in central fat release pro-coagulant factors and adipocytokines that may increase risk for cancer.

American institute for cancer research

Recommends 5 portions (14 oz) non-starchy veg & fruits/d Eat relatively unprocessed cereals/legumes with each meal Limit refined grains No more than 18 oz red meat/wk, very little processed Limit salt

American Cancer Society

Recommends to eat at least 2.5 c. F & V/d, choose whole grains vs refined limit consumption of processed and red meats

Iron

Serves as a pro-oxidant, may facilitate cancer development.

Framinham Cohort Study

Showed that obesity and high waist circumference increased risk for cancer. Stronger effect in men than women.

Benefits of physical activity

-Promotes a healthy wt -Improves immune fxn -Positive influence on levels of sex hormones, insulin, and prostaglandins

Red meat

Convincing evidence of increased risk for colo-rectal cancer. Limited suggestive increased risk for esophageal, lung, pancreatic, endometrial cancer.

Fat intake

Could affect secondary bile acid content in the bowel and increase risk for cancer.

Initiation

Damage to DNA

Fruits

Limited suggestive decreased risk for nasopharynx, pancreatic, liver, and colo-rectal cancers. Probable decreased risk for mouth, pharynx, larynx, esophageal, and lung cancer.

Alcohol

May increase permeability of oropharynx tissues to carcinogens. May also increase circulating levels of estrogen and decrease folate levels which could influence development of breast cancer.

Vitamin D and calcium

4 yr RCT found that consumption of both was associated with improved survival free from cancer for a longer period of time.

Meet nutritional needs w/ diet vs supplements

AICR recommendations in regards to supplement use.

Molecular/cellular studies

Administer a substance to a specific type of cancer cells, then test for RNA, protein, or cell growth.

1. Maintain healthy wt and choose foods and bvgs to achieve/maintain healthy wt 2. Adopt physically active lifestyle 3. Consume healthy diet with plant sources. 4. Limit ETOH consumption

Advice to the public (4 main items).

Vitamin D

Associated with reduced risks of colorectal cancer but results are inconsistent. Unclear if associated with risk of other cancers. Not recommended for or against supplement to reduce risk of colorectal or any other type of cancer.

Promotion

Environment enhances reproduction of mutated cells

Indole-3-carbinol and sulforaphane

Exist as glucosinolates in brassica family vegetables and are hydrolyzed to these, which are anti-oxidants and natural detoxifying enzymes.

Omega 3 FAs

Fishermen on the coast had less cancer than farmers living inland possibly d/t consumption of this. However, conclusion is that dietary supplementation of this is not likely to reduce risk of cancer.

Soy

Incidence of breast cancer lower in Asian women who consume this regularly.

Women's Health initiative

Increased risk for invasive breast cancer in post menopausal women with a BMI >35.

Metabolic stress

Increases ROS, insulin levels, and adipokine secreation, along with gut permeability. R/t obesity.

Vegetables

Limited suggestive decreased risk for nasopharynx, esophageal, endometrial, ovary, colo-rectal cancer. Probable decreased risk for mouth, pharynx, larynx, and esophageal.

1. Achieve and maintain a healthy wt. Wt loss may be beneficial after treatment if over wt/obese. 2. Be physically active (esp for breast, colo-rectal, prostate, and ovarian cancer). 3. Eat a healthy diet, emphasize whole grains, fruits, and veg.

MNT for cancer survivors.

Progression

Mutated cells multiply rapidly, forming a tumor

Vitamin D and calcium

No effect on colorectal cancer in postmenopausal women according to the Women's Health Inititiative.

Vitamin C and Vitamin E

Physician's health study found no cancer benefit or harm from supplementing these 2 nutrients.

6 mos

Recommended time for breastfeeding to reduce cancer risk per AICR.

CPS II by Amer Cancer Society

Study showed that the heaviest men and women more likely to die from cancer.

Fruits and vegetables

Systematic review showed some decreased risk for lung cancer but not all data is convincing (some studies with no observed benefit).

Cohort study

Takes a population (group) and following them start to finish to identify who gets cancer and then look at difference in diet of those with and without cancer.

IGF-1

Thought to promote cell proliferation and survival, increased in obesity.

Tobacco, obesity, and physical inactivity

Three key lifestyle influences on risk for cancer. Over half of cancer deaths in U.S. in 2011 were caused by one of these risk factors.

Supplements

Until further research, it is wise to encourage public to reduce cancer risk by eating a variety of foods that provide many vitamins/minerals vs using these to reduce risk of cancer.

Physical activity

_______ has convincing evidence to decrease risk for colo-rectal cancer (15% of colo-rectal cancer can be attributed to lack of this!!!).