Pomegranates Flashcards
What is pomegranate referred to as?
a superfruit
- has potent antioxidant properties
- high polyphenol content - containing some unusual ones
- antioxidants are bioavailable
Why was pomegranates considered to be protective against hepatocarcinogenesis?
because they cause up regulation of genes such as Nrf2
What is the polyphenol content of pomegranates like ?
contain normal ones such as gallic acid and ellagic acid
also contain unusual ones such as punicalins and punicalagins which are semi-polymerised forms that have lots of hydrophobic components - this means they are able to more easily cross the cell membrane
How was pomegranate consumption linked to prostate cancer?
in a phase 2 clinical trial they linked oral consumption of pomegranate juice with a significant prolongation of prostate specific antigen doubling time, this lengthening of time is a good thing
What experiment was carried out in rats in relation to pomegranates?
observing the developments and growth of macroscopic hepatocyte nodules induced by DENA-PB (carcinogen)
3 groups
- just administered the carcinogen
- administered carcinogen and 1 dose of pomegranate
- administered carcinogen and high dose of pomegranate
those given the high dose of pomegranate had significantly less nodules and less cancer incidence
it is thought that it may be beneficial by up regulating cytoprotective enzymes
What is interesting about the polyphenols ellagitannins and urolithins?
metabolise them into more bioactive components
urolithin is produced by the breakdown of punicalagins by intestinal bacteria
ellagitannins produced by gut microflora
urolithins antioxidant activity is dependent upon amount of hydroxyl groups and the lipophilicuty of the molecule- detect its levels in the blood
What cancer are urolithins suppose to reduce?
considered to reduce colon cancer
- have a dose-response graph which is good
- studying pomegranates showed that 29% of their polyphenol reach colon and they are able to inhibit CYP1 activity (inhibiting phase 1 activity)
continuous consumption could be sufficient for preventing colon cancer development but currently no epidemiology demonstrating reduced risk
Why are plant foods good?
protect us against cancer but their ability to do this is unknown
Why is killing off cancer cells not as good as we think ?
because some of the cells are resistant due to mutations and therefore these ones will continue to divide making it more difficult to treat the cancer
Is cancer inevitable ?
NO
Why is cancer not inevitable ?
- different countries show different rates of incidence for different cancers
- epidemiology suggests that food and lifestyle can modify risk
- migrating populations can change their cancer risk
- evidence from animal studies
- evidence from in vitro biochemical studies
- support from studies that provide plausible mechanism
How is food involved in cancer mainly ?
its role is predominantly protective however there are carcinogens and pro carcinogens in food
Why is it beneficial to eat more fruit and veg ?
protective role which may be a consequence of years of exposure
may modify the role of phase 1 and 2 enzymes, stimualtion of apoptosis, inhibition of tumour development and optimisation of DNA repair
not just the nutrient content of fruit and veg which is important, its the idea of phytochemicals that are being increasingly recognised
What is an important aspect of food consumption that has yet to be touched on ?
in general food consumption optimised for cancer protection has hardly been touched on
but also the interactions between different foods
furthermore food processing is not necessarily a bad thin- processing of food that people want to eat is almost certainly a way to go
What are key factors about food consumption that we need to determine?
the relevant compounds within food
how to optimise our ingestion of food components
how to optimise absorption
how to optimise bioavailability
how to optimise delivery to target cells
dont know enough about the metabolism of food
What is cancer research still predominantly looking into ?
about treatment not prevention
looking into development of drugs which is expensive rather than promoting lifestyle changes which are cheap
What lifestyle factors have been demonstrated so far to contribute to cancer risk ?
exposure to some industrial hazards- soot, radium dials, asbestos
intake of real carcinogens like cigarette smoke and aflatoxins
lifestyle factors such as meat consumption, butter and fat intake- their effects are too low in impact to give clear answers
What are the non-genetic factors that increase risk of human carcinogenesis?
tobacco occupational exposures diet- high fat and low fruit and bag sexual behaviour lifestyle- exercise and caloric intake
How much do poor diet costs the NHS each year?
£6 billion a year this is significantly higher than 1.5 billion for smoking
thought to contribute to a 1/3 of all cardiovascular diseaea, diabetes and cancer
What is evident in low income countries ?
their populations and total cholesterol increase rapidly as the national income of poor countries rise
4 out of 5 deaths from chronic diseases are in low income and middle income countries
