DR ADITYA NARAYAN SEN
ROLE OF NUTRITION IN CANCER PREVENTION
Around in 1980 prominent epidemiologists estimated that about 30% of all cancer cases are attributable to dietary habits.more than 25 years later American Institute of Cancer Research came to the similar conclusion.
About one third of the most common cancers in higher income countries and about one fourth in lower income countries could be prevented through eating healthily,being physically active,and maintaining a healthy weight.
Overweight is one of the most important risk factors for cancer: it convincingly increases the risk of colonic cancer,breast cancer, endometrial, oesophageal, pancreatic and kidney cancers.
It is not simply overweight,but the distribution of fat mass which appears to influence the risk.
Abdominal fat and possibly visceral fat is convincingly associated with a 70% increase in risk of colon cancer and probably increases the risk of postmenopausal breast cancer,pancreatic cancer,and endometrial cancer.
The risk of cancer attributable to excess body mass index(BMI).
AICR advises to be as lean as possible within the normal range of body weight.
A healthy weight is best achieved by choosing diets based on foods with low energy density,avoiding sugery drinks,and being physically active throughout life.
Independently of the effect on body fatness, physical activity convincingly decreases the risk of colon cancer, probably protects against post menopausal breast cancer and endometrial cancer.
Being moderately physically active means 30 minutes of active walking,biking,and or gardening perday.when overweight is already present 60 minutes physical activity is advised.
Most diets that are protective in nature are from plant origin.Consumption of non-starchy vegetables protects against cancers of mouth, pharynx,larynx,oesophagus and stomach.
Allium vegetables probably protect against stomach cancer.
Garlic probably protects against cancers of colon and rectum.
Fruits decreases the risk of mouth, pharynx,larynx,oesophagus lung and stomach cancers.
The beneficial effects of vegetables and fruits could be due to dietary fibre,specific vitamins or other bioactive compounds.
AICR recommends to eat at least five portions(400 gms) of a variety of vegetabls and of fruits per day,and to consume unrefined grains and pulses at each meal.
RED MEAT AND PROCESSED MEATS
Consumption of red meat( beef,pork, lamb,horse) and processed meat(red meat preserved by smoking,curing,salting and by adding preservatives, such as ham,bacon,salami,sausages,etc.) convincingly increases the risk of colorectal cancer.
Increasing the consumption of red meat by one intake per week increases the risk of colorectal cancer by about 40%, for processed meat the risk of colorectal cancer increases by about 20% with each 50gm per day.
It is the heam iron content of red meat , which irritates the colonic mucosa may laed to carcinogenesis.
Other compounds responsible are heterocyclic amines,N –nitroso compounds and poly clyclic aromatic hydrocarbons.
AICR recommends to limit the consumption of red meat to 500 gms per week.
Alcoholic drinks are a cause of several cancers,ie.cancer of oral cavity,breast,colorectal cancers in men is convincing.IN western Europe 10% of cancers in men and 3% of cancers in female are estimated tobe attributable to alcohol consumption.
However the modest amount of alcoholic drinks are likely to protrct against coronary heart diseases,the AICR recommends one drink for female,two drinks for men per day when alcohol is consumed.
PRESERVATION<PROCESSING,AND PREPERATION OF FOOD.
Some methods of food preservation,processing and preparation affect cancer risk.Salt and salt preserved foods are probably a cause of stomach cancers.
Foods contaminated with aflatoxins, such as cereals and pulses are a cause of liver cancer.
Aflatoxins are produced by moulds when foods are stored too long at warm temperatures.
AICR recommends to avoid salt preserved, salted or salty foods to ensure an intake of less than 6 gm(2.4gms sodium) aday.
The main risk factors for cancer associated with food,nutritions,and physical activity are known and recommendations to decrease ones risk of cancer are available.
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