Week 7 Flashcards
What is cancer?
The name for the group of diseases that are characterized by loss of normal control over cell growth/ division, death and differentiation
What type of cancer are women most at risk for?
Breast cancer
What type of cancer are men most at risk for?
Prostate cancer
- typically the earlier the cancer is detected and treated the greater the chances of survival
What are some factors that cause cancer?
- both genetic and epigenetic factors influence gene expression controlling cell growth, death and differentiation
- some changes that occur along the path of cancer development can be influenced by environmental factors such as diet
What is a genoprotective diet?
- a diet that is low in potentially harmful substances
- diet low in carcinogens= cancer causing substances
- diet should be sufficient in protective dietary factors like vitamins, minerals, and possibly photochemical components
- B vitamin folate has genoprotective effects. (aka folate acid)
- goal of genoprotective diet is to also delay the age of cancer onset
What are some functions of folate (B Vitamin)
Produces T (thymine) base of DNA so it is important in DNA synthesis
List the reasons of why the role of nutrition in the cancer process is no well understood.
A) cancer is a complex group of diseases and it has many different steps (a multi step process) so it is difficult to relate those steps of cancer development to diet. The chronic nature of cancers except early childhood make it hard to distinguish the relationship
B) The human diet is also complex. Most diets contain factors that may promote or protect against some of the processes that contribute to cancer. Not a single diet that protects against cancer. Therefore it is difficult to isolate specific dietary factors
C) it is difficult to relate the results from laboratory experiments and animal model experiments to human cancer prevention
For example isolated dietary substances substances may be tested upon animals in the laboratory, but those substances are typically consumed along with many other substances as a part of the food that makes up the human diet
Explain the process of carcinogensis (cancer development)
- this process involves genetic mutations perhaps 5 to 10 different mutations which result in a metastatic cancer which is difficult to treat
1. Initiation: mutation and inactivates tumour suppressor gene
2. Cells proliferate (multiply/ increase in numbers)
3. Mutations inactivates DNA repair gene
 4. Mutation of proto- oncogene creates an oncogene
5. Mutation inactivates several more tumour suppressor genes
6. This leads to cancer
Initiation: DNA mutations
Promotion: mutation established and passed on.. growth promotion of mutant cells
Progression: metastasis or spreading of cancer cells throughout the body 
What is metastasis?
It is the spreading of cancer cells from the primary site in the body to other sites
What are polyaromatic hydrocarbons?
They are potential carcinogens that may contribute to cancer risk. some can act at initiation face and others act mainly in the promotion phase of cancer cell growth
What are some of the symptoms of metastases in different parts of the body?
- Brain: headaches, seizures, vertigo
- Respiratory: cough, hemoptysis, dyspnea
- Lymph nodes: lymphadenopathy
- Liver: hepatomegaly, jaundice
5. Skeletal: pain, fractures, spinal cord, compression
Process of cancer pathology at the molecular level///
Specific cancer promoting events:
a) damage to the genetic material DNA (mutations)
- reactive chemical species or oxidative damage
-non-oxidative would be folate deficiency or decrease efficiency of repair enzymes
B) changes in the expressions of genes that influence cell growth
- Increased oncogene expression or decreased tumour suppressor gene expression
c ) inability of the immune system to identify or destroy the abnormal cancer cells
-for example the abnormal cancer cells are not destroyed by the immune system many nutrient deficiencies can lower immunity
- dietary factors can be involved in the specific events for example deficiencies of vitamins such as folate vitamin a niacin biotin and others can influence all of these basic processes
What is the relationship between genetic factors and environmental factors related to cancer?
- diet is an environmental factor. So low intake of protective nutrients such as folate and excessive intake of potentially harmful dietary factors like carcinogens can both influence cancer risk in the context of a persons genetic background
For example if a person has a genetically determined efficient DNA repair system they may be able to tolerate a greater deficiency of folate or greater exposure to dietary carcinogens compared to another person who either has a less efficient repair system or increase genetic susceptibility to cancer
What are the relative contributions of genetic and environmental factors to cancer?
- For adulthood cancers that occur later in life it has been estimated that the environmental contribution may be about 2/3 of the risk
- diet is a part of these environmental factors for example nutrient deficiencies and possible food carcinogens
What are the major contributors to cancer risks according to the WHO?
- smoking - obesity - alcohol consumption -infections -UV light exposure or sunlight - WHO also provides information on early detection in major symptoms of the most common cancers
Explain the findings of population level studies or epidemiological studies
- population level studies have suggested a role for environmental factors in cancer risk
- migration of Japanese to the US has resulted in a change from the Japan risk pattern to the USA risk pattern for some but not all types of cancers
- For example after about two generations in the USA stomach cancer rates are in the lower and prostate cancer rates higher among Japanese Americans compared to cohorts in Japan
Explain the rating system developed by American cancer society
- A1 Rating is given to those factors that are judged to be best established in terms of Lowering cancer risk
- A2: there is a probable benefit for a dietary factor that receives an A2 rating
- this rating system is established to estimate the contribution of dietary factors to cancer prevention
What are the examples of ACS ratings
A1: The best established is given for limiting alcohol intake to decrease the risk of cancers of the mouth and oesophagus and another A1 rating is given in terms of avoiding overweight to decrease the risk of Colorectal and breast cancers
A2: A lower level rating is given for the possible decrease in risk of colorectal, lung, oral, and, esophageal cancers with increased fruit and vegetable intake
- another example of an A2 rating is the possible reduction in colorectal cancer by limiting consumption of red meats
Explain the example of nutrition research related to cancer risk: beta- carotene and lung cancer
- this study test whether beta-carotene supplements can lower the risk of lung cancer among smokers
- this lead to a hypothesis which indicates that that beta- carotene a component of any fruits and vegetables is a powerful antioxidant
- In the placebo controlled intervention studies results found that beta kidney pills did not lower the risk of lung cancer among smokers relative to the placebo group in fact it increases lung cancer risk among those taking the supplement
- The conclusion of the study is the beta carotene in the pill form does not provide protection against lung cancer and may increase the risk of cancer instead however this study does not disprove a potential beneficial effect of beta carotene when consumed as a part of fruits and vegetables that contain it because those fruits and vegetables contain a lot of other nutrients that can be beneficial
Explain the correlation between energy balance, fat, and cancer
- High BMI is considered with increased risk of breast; colon, and endometrial cancers
- increased physical activity has been reported to lower the risk of breast and colon cancer
- Adults who consume most fat especially omega six are at an increased risk of colon, breast and prostate cancer
Explain association between protein and cancer
- increased consumption of red meats and processed meats resolved an increase risk of colon cancer

What must be considered about co-incidentals?
- With population level studies one Hass to consider related factors which are also known as co- incidentals
- for example in the reported relationship between fat intake and cancer risk one should examine if the studies have properly controlled for other factors: is it the fat directly that’s contributing to increase cancer risk or is it the possible higher caloric intake of those who consume more fat
- is it the exercise itself or a healthier diet by those who exercise more
Consumption of fruits and vegetables and cancer
- Lower risk of some types of cancers has been reported in the majority of the studies for adults to consume more plant foods
Why is there arelationship between fruit and vegetable consumption and the risk of some types of cancers later in life?
- This could be because of the higher content of dietary fibre or other Phytochemicals who is health benefits or not yet well established 
- Higher nutrient density for vitamins and minerals
-possible lower consumption of animal products or alcohol or lower rates of smoking among those who consume more fruits and vegetables
some co-incidentals such as possible lower red meat or fat consumption
What are some health benefits of phytochemicals?
- they can have many effects in the body like in the cells that may influence some of the pathological processes in cancer development
- prevent oxidative damage: some Phyto chemicals have strong antioxidant activity and may Lower DNA damage= vitamin E OR flavonoids
- others may lower the formation or increase elimination of possible cancer-causing chemicals/ carcinogens = isothiocynates
- They can affect hormone action metabolism and levels like Phyto oestrogens= phytoestrogens
What are phytoestrogens and what a dew the 3 main dietary sources ?
- they are plant-based compounds that mimic estrogen in the body
- - they can be found in isoflavons, abundant in soy foods, the coumestans, abundant in some types of beans, and the lignans, especially abundant in flax and sesame seeds - they are not directly phytoestrogenic but can be converted into phytoestrogens through the action of bacteria in the large intensities
How do phytoestrogens decrease risk of cancers
- some studies have reported lower risk of breast and prostate cancers which are to hormone related cancers among people with a relatively high intake of phytoestrogens
- Mini cellular activities can be influenced by Phyto oestrogens like hormone related activities or anti-inflammatory activities may be responsible for a potentially lower risk of some cancers with increased Phytoestrogen intake
- For some women that have already been diagnosed with breast cancer May not be recommended to have high intakes of Fido oestrogens because some breast cancer cells subtypes maybe stimulated by Phyto oestrogens
What are some carcinogens and cancer promoters?
- One key thing to keep in mind when assigning carcinogenicity to foods is that there are genetic and metabolic differences among people that can influence such risk= risk not equal for everyone
-  also keep in mind that risk is often determined and experimental systems that may not be fully relevant to human metabolism
- Risk is also often determined using purified compounds ( out of food context , food contains complex mixtures of many compounds)
- alcohol is a carcinogen when consumed at high levels which is above one or two servings per day. This causes increased risk of cancers of the mouth throat and oesophagus and also increased breast cancer risk. Needs to be considered the malnutrition is also very common among heavy drinkers so deficiencies in folate and other B vitamins are common

What can possible food carcinogens arise from?
- man-made industrial or agricultural chemicals that are used in food production
- contaminants from the air or soil that become incorporated into plant food
- chemicals that were added during food processing
- cooking depending on method
- may naturally be present in some foods
 there are government regulations on what substances can be used in food production and processing which have to be tested for safety and approved but different countries have different standards
How can cooking produce potentially carcinogenic chemicals?
- this is a problem when food comes in contact with smoke or the food is exposed to very high temperatures such as prolonged high temperatures of frying or grilling in which the flame contacts the food
- most of the potential carcinogens are formed in protein rich animal products such as meats and fish
- meats and fish that are burned or fried to a dark brown colour often contain potential carcinogens known as polyaromatic hydrocarbons or heterocyclic amines (HA)
- The longer the food is exposed to temperatures in the higher the temperature of the greater the levels of PAH and HAS
- acrylamide is another example of a possible dietary carcinogen that has been detected in some foods at high temps Like fried potatoes or potato chips
- nitrites are present in smoking often added to cured meats such as sausages cured ham and other processed meats. In the acidic environment of the stomach nitrates can react with other food components to produce nitrosamines which are potentially carcinogenic
What are some major diet related recommendations that may lower the risk of some types of cancers
- decrease caloric intake to help achieve and maintain a healthy body weight along with his Physical activity
- decrease intake of alcohol
- decreased intake of fats from animal products - Increase intake of fruits and vegetables and other plant foods
- decrease intake of red meats and processed meats
-lower intake of nitrite preserved meats as well as burnt smoked or fried meats
-Iimit sun and UV exposure - Avoid smoking
- prevent infection like HPV through vaccination
What are some side effects of cancer therapies?
- nausea and vomiting
- taste alterations
- inflammation of the lining of the mouth and GI tract
What is cachexia?
- common problem in the advanced stages of cancer
- involves extreme loss of muscle mass, and body weight
-Anorexia and anemia - this happens because there is an overall breakdown of muscle protein through a complex regulation involving many different factors like body enters a catabolic state, and it is not very responsive to nutritional support
Explain the nutritional care of cancer patients
- one problem is that almost 1/2 of patients are already in their advanced stage exhibiting weight loss and poor nutritional status
- major goal is to try to identify and correct nutrients deficiencies and slow or prevent weight loss
- does enhanced nutritional support increase survival? There is evidence for this if the support is started early after diagnosis but is not very strong results
List the side effects of cancer therapies with dietary recommendations to help manage those problems
- nausea and vomiting: have light, low fat foods and cold liquids
- inflammation of mouth (stomatisis): recommended to have liquid or soft foods that are non-acidic
- dry mouth (xerostomia): due to low salivation may be managed by high moisture foods, soups and broths, and by avoiding dry tough foods
- hypoguesia (low taste sensation, most foods are bland and lack flavour): recommended to increase flavour with spices and other additives that the patient likes and tolerates well
- dysgeusia: happens when foods cause a bad taste sensation, such foods should be identified on individual basis and avoided if possible. Foods like chocolate, coffee, red meats are often reported as bad tasting by cancer patients under chemo
- early satiety is a problem, after small amounts of food the patient no longer wants to keep eating: recommended to choose calorie dense foods that are well tolerated
- immunodeficiency: decreased immune function and inflammatory reactions- food safety is of major importance for cancer patients and often includes avoiding raw foods
What are food aversions in cancer patients?
- food aversion can develop in cancer patients especially an aversion in foods that are consumed shortly after chemo.
- to avoid these minimize possible I:pact on the cancer patients diet, uncommon foods may be given as the first foods after chemo
Implantation of nutritional management goals?
- try oral nutrient if the pt is able to eat
- can be done through enteral nutrition where a nutrient solution is pumped into the stomach through a nose tube or parenteral nutrition is required if the patient is not able to eat by mouth
- if oral nutrition possible:
- health care provided to work with pt to identify optimal flavours and food textures
. - identify problematic foods - determine the best mealtimes for patient
-if vomiting or Emesis occur deal with it through a combination of food selection and anti- emetic drugs
- health care provided to work with pt to identify optimal flavours and food textures
Entral nutrition
- tube into nose down the gut
- milk based diets
- soya based diets
- elemental/ predogested food diets
Parental nutrition
- IV with glucose, amino acids, fatty acids, albumin, minerals, vitamins
- used in non function GI tract
- used with more aggressive chemo or GI surgery
What happens if all treatments have been tried and have not been successful?
- patient is recommended palliative care
- intention of this care is to minimize pain for pt and try to maximize quality of life for them and their families
- pt sometimes wants to try other therapies that usually don’t have any scientific evidence so the provider should advice the pt on their options especially if they are more harmful
T/F typically the earlier the cancer is detected, the greater the chance of survival
True
T/F when a cancer is metastatic it is very difficult to treat and mortality is high
True
What food is most likely to become carcinogenic
Protein rich meals like brined or dark brown coloured fish or meats
