Many fibrous plants contain organic acids that bind minerals such as calcium, magnesium, zinc and iron. Although this has caused some concern in the past, there is no evidence that people who eat natural high-fibre diets (such as vegetarians) have low mineral levels, probably because this type of diet is particularly rich in vitamins and minerals. Including about 40g dietary fibre a day in your diet is regarded as being perfectly safe. However, where caution is necessary is in the taking of fibre extracts.
One of the lesser-known effects of fibre-rich diets is an increase in flatulence. When fibre ferments in the large intestine it produces odourless gases, which are not dangerous to health but can cause concern in some people. (Incidentally, offensive odour is caused by gases which are produced as result of the breakdown of other substances in the large bowel - such as sulphur-containing proteins - which have escaped digestion in the small intestine.)
Fibre extracts - handle with care!
If a natural high-fibre diet does not solve the problem of constipation, try taking not more than three tablespoons (9-12g) of digestive bran, divided into three dosages, on a daily basis. (If you don't like the taste of bran au nature], you can improve the flavour by baking it for three hours at 100 °C.) At the same time, increase your fluid intake to at least two litres per day and decrease excessive fat intake. This ensures adequate hydration of the 'extra' fibre.
Beware of over-enthusiatic dosage with fibre extracts or concentrates, as this can be harmful. As a general guideline, a third of the prescribed dosage should be taken for a week and two thirds for another week before the whole amount is taken.
The 'fibre message'
All in all, then, there is agreement that fibre forms an important part of a healthy, balanced diet. High-fibre diets are easy to follow and inexpensive if natural foods are eaten in their unrefined forms.
Guidance from and education by dietitians, nutritionists and doctors, as well as increased advertising of high-fibre products, have brought the 'fibre message' to some sections of our population.
Sadly, however, in other sections the situation is in reverse. As South Africa's rural black people grow increasingly urbanized, so their diets are becoming lower in fibre and higher in fat - and more and more, the so-called 'diseases of affluence' are being seen among them. For the 'fibre message' to have any significant effect on the health of the majority of our population, it must therefore also reach the very people whose diets once gave them natural protection against the degenerative diseases of Western civilization.
When all is said and done, education is only worthwhile when put into practice. So unless you, the consumer, choose high fibre, unrefined foods in preference to refined ones and unless pressure is put on manufacturers to produce the healthier alternatives, medical research and nutrition education will be of little use. Ultimately it is up to you to make your voice heard and to combat the influences of society, lifelong nutritional habits and perhaps simple apathy, in order to put the fibre message into practice.
Worthwhile Sources of Dietary Fibre (Food Cereals & Fibre rating)
- Bread, brown: Fair
- Bread, wholewheat: Good
- Wheat bran: Excellent
- Pronutro: Excellent
- Kelloggs All Bran Flakes: Excellent
- Kelloggs Cornflakes: Good
- Oats: Good
- Oat bran: Excellent
- Weet-Bix: Good
- Maize meal, white: Fair
- Maize meal, unsifted: Good
- Popcorn, plain: Good
- Rice, brown: Fair
- Ryvita, Ryeking: Good
- Provita: Good
