Chapter 12 Diet Physical Activity and Cancer Prevention

Question 1

discuss the connection between body weight and the risk of cancer

Answer 1

overweight (BMI >25) and obesity (>30 kg/m2) are associated with increased risk for many but not all common cancers

Question 2

describe the relationship between intake of fruit and vegetables, whole grains, dietary fibre,
12.4,

Answer 2

epidemiological investigations have shown that vegetables and fruits provide protection against cancer. recommendations do not include recommendations for starchy vegetable such as potatoes, yams etc.
Non starchy veggies protect against cancers of the mouth, pharynx, and larynx, esophagus and stomach. limited evidence also shows that they may protect against nasopharynx, lung, colorectal ovary and endometrium.
Fruits probably protect against cancers of the mouth, pharynx and larynx and those of the esophagus, lung and stomach. also a possibility that fruits may also protect against cancers of the nasopharynx, pancreas, liver and colorectum. These studies however have their limitations because they were conducted I’m populations with relatively homogenous diets… and with self reporting people often tend to over report intake

Question 3

discuss the relationship between alcohol intake and risk of cancer 12.8

Answer 3

alcohol itself is classified as a human carcinogen.
increases risk of cancers and is probably a cause of liver cancer as well as colorectal cancers in women.
can increase risk for mouth, pharynx and larynx cancers as well as esophagus and colorectum cancers (in men) and breast cancer.
Alcohol is oxidized in the liver to acetaldehyde which is the most toxic metabolite of alcohol and is damaging to cells.

Question 4

Discuss the evidence associating the intake of meat and cancer risk 12.7

Answer 4

increased meat intake and processed meat may be causally related to increase in colorectal cancers...but it is important to realize that increased meat intake will have the  same effect on everyone. 
the effects may be due to the increased intake of carcinogens ingested with the meat. and increased intake of meat leads to increased body weight.
Plus carcinogens (e.g. HCA) are formed when meat is charred.
HCA is linked to Ca of the breast, colorectum, prostate, lung and pancreas.
Nitrates and nitrites also have been shown to interact with dietary substances to produce compounds which are carcinogens.

Question 5

Discuss the relationship between dietary fibre intake and cancer risk. 12.6

Answer 5

most studies have showed a decreased risk of cancer with increased fibre intake but link between dietary fibre and colon cancer remains inconclusive.

Question 6

Discuss the relationship between intake of selenium and cancer risk 12.5.2

Answer 6

possible protective association for lung and prostate cancer but not overly convincing for other cancers including breast and colon and rectum.

Question 7

describe the relationship between intake of micronutrients and phytochemicals, and the risk of cancer 12.5

Answer 7

phytochemicals include salicylates, phytoesterols, saponins, glucosinolates, polyphenols, protease inhibitors, monoterpenes, phytoestrogens, sulfides, indoles, isothiocyanates, terpene and lectins

Some have been shown to be protective against cancer