Colon cancer update
Some recent findings to do with the prevention of colon cancer (one of the most common cancers) are heartening. Studies on human beings have shown that including less fat and more fibre in one's dietprobably lessens the presence of `mutagens' (substances which can promote the development of cancer) in the bowel contents.
A recent four-year study in the USA also produced interesting results. The subjects of the research were a series of patients with 'familial adenomatous polyposis'. This refers to a segment of the population with bowel polyps which are particularly prone to become cancerous. (Polyps are growths with a pedicle or stem which usually develop on mucous membranes.) These patients were put on a high fibre diet (about 22g of fibre daily compared with the usual daily intake of about 12g), the extra fibre being provided by commercial bran cereal. In all the patients, a regression or shrinking of the polyps resulted - an outcome which was regarded as very promising by the US National Cancer Institute.
Also interesting is the fact that elderly blacks examined in the Department of Gastroenterology at Baragwanath Hospital, Soweto, showed no evidence of polyps; indeed their bowels had the appearance and elasticity of that of white teenagers! Among old rural blacks, colon cancer is extremely rare and even among urban dwellers, its occurrence is only a tenth of that found in elderly whites. The significance seems to be that the diets of these people are generallymuch higher in fibre and lower in fat than those of their white counterparts.
Eating to combat cancer - a day's sample menu**
* Breakfast: Cereals (such as All-Bran flakes or Weet-Bix), or oatmeal porridge, with milk and sugar
* Orange juice, a poached egg on brown (preferably wholewheat) toast and a couple of slices of tomato
* Lunch: 2 or 3 slices of brown or wholewheat bread with margarine,cottage cheese, salad (eg lettuce, celery, raw carrot), an apple or a banana
Dinner: Fish or chicken (not fried), brown rice, baked or newpotatoes, a green vegetable, baked beans, gem squash and a brown roll
Stewed or canned fruit (eg pineapple) and yoghurt
**This suggested menu provides about 30% of energy from fat and about 20-25g dietary fibre.
The alcohol/cancer link
Too much alcohol is a risk factor for the development of several cancers, especially of the liver, oesophagus, lung, pancreas and rectum. But here again, little notice has been taken of calls to cut down and levels of consumption are still rising, not only in many Western populations but in all Third World urban populations as well.
What is a reasonable or safe alcohol intake? For the majority of consumers there is no health problem, since it is considered that the majority of people who drink do so moderately and never experience any harmful effects. The crucial question is: What is a sensible limit? The liver burns up one standard drink (a half pint of beer, a glass ofwine, a measure of whisky) in an hour. With this in mind, the following safe allowances have been put forward:
For men, four to six standard drinks, two or three times a week. Or, at most, from 18 to 20 standard drinks weekly. For women, two or three standard drinks, two or three times a week or, at most, 9 to 13 standard drinks weekly.
These recommendations (endorsed by World Health 1985) were set out by the London Health Education Council in a booklet titled 'That's the Limit: a Guide to Sensible Drinking'. The reason why the limits for women are lower than for men is twofold: firstly, in men, water makes up 55-65°/o of body weight and in women, 45-55%, therefore alcohol is more diluted in men than in women; secondly, alcohol is potentially more noxious in women than in men.
Smoking and cancer
Smoking is believed to be responsible, directly or indirectly, for about a third of total cancers. It increases the risk of certain diet-related cancers such as breast cancer, but appears to have little influence with others, such as cancer of the prostate. In many Western populations there has been a major decrease in cigarette smoking among men, although far less so among women. In the USA, current frequencies are 32% for men, but 26% for women. Nowadays more young women than young men smoke, and today's female smoker is a heavier onethan yesterday's!
In Third World countries, tobacco use is rapidly increasing - in African populations, consumption has doubled in the last 10 years. So the dismal view is that all tobacco-related cancers, especially lung cancer, will almost certainly increase in the years to come.
