A balanced diet, II Give us our daily fibre

Press, 19 December 1981, Page 12

A balanced diet, II Give us our daily fibre

Is chaff the staff of life? Indeed, no!

’ In part one we looked at a wholesale basic food plan that supplies a “natural” balance of a wide variety of nutrients.. This approach to food. selection is the “safe” choice amidst our current bombardment by clever food advertising. Looking at foods in terms of single nutrients is a popular trend but it masks the importance of the combination of nutrients. Because some substances are lost during food processing (cleaning, grinding, extracting, adding, mixing, cooking) a new concept is that “natural” foods are best. Fibre is only one of many constituents found in the foods we eat. The idea that our richest source of dietary fibre, coarse uncooked bran, is the "ideal” fibre food conflicts with the idea of balanced whole foods. Bran or chaff is natural but it is not a wholefood. What is fibre? And do we need a daily quota of chaff or bran, along with the rough and tough grits and bits our grandmothers know as “roughage”? Yes, but bran is only one of the dietary fibres that we eat regularly. Our modern concept of fibre or “dietary fibre” is that not all fibre is tough and stringy. Gel and gum-type fibres found mainly in fruits and vegetables are soft, easy to eat and absorb. “Dietary fibre” is the plant material that is not digested by the secretions produced in our intestines. Some fibre is fermented by intestinal bacteria arid used to a certain extent without digestion. Our individual ability to digest or ferment fibre differs from person to person. . Fibre is the key to the regular elimination of wastes from the bowel. It is the only food constituent that has a marked effect on our bowel movements.

Different types of fibre have different effects. If the outer husk or “chaff” of cereals grains is left in our

diets, as wholeflour foods or corn or whole breakfast cereals, the time that food takes to pass through the intestines is shortened. Bran also absorbs water; making bowel movements more frequent and softer. Dried beans, lentils and peas (legumes) have gel-type fibre which slows down the absorption of nutrients into the blood stream so that the normal body mechanisms can more easily cope with their disposal throughout our bodies. They are useful for the regulation of sudden surges of- sugar or fat into the bloodstream.

Fruit pectin, oat bran and legumes have all been shown to lower blood cholesterol levels by holding bile acids in the intestines. These bile acids are then excreted from our bodies rather than being absorbed into the blood stream and subsequently manufactured into more cholesterol.

Crunchy or crisp green vegetables may help promote weight loss because they give the . stomach a feeling of fullness. They contain a lot of water and take a lot of chewing, which allows the brain time to register that the stomach is filling. We can eat a greater volume of food for less calories, if vegetables take a prominent place in our meals.

The grinding of cereal into flour allows better access to the food for our digestive juices, making indigestible whole cereal foods more nutritious. Pureeing, grinding or liquidising does not alter the fibre content of a food so long as it is not strained or sifted out. But when easily absorbed foods such as vegetables or fruits are crushed into juice, the natural barrier to overeating is destroyed although the fibre content remains.

Starch is not easily digested unless it is cooked (if we eat raw flour, subsequent bloating is due to gas production of our intestinal bacteria). Cooking alters the tex-

ture of fibre but not the content. How much fibre should we have? There is no set level for everyone. The aim is for soft bulky motions, and this factor is the marker for how much fibre we need. For most people, 30 to 50 grams of dietary fibre each day will achieve this result. (Some foods are labelled with the content for “crude” fibre which is an old measurement that underestimates the total “dietary fibre” content of foods.)

Many New Zealanders consume a diet largely of milk and dairy products, eggs, fats, meat, poultry, fish, white bread, biscuits and cakes made from white flour, sugar, and less than one serving breakfast cereal each day; vegetables only once a day in small quantity; and little fruit. Such a diet will supply only 10 to 15 grams of dietary fibre each day. Inactive and overweight people need proportionately more high fibre food and less low fibre food than highly active people. Each of these wholefoods supply more than 5 grams of fibre:- 2 medium slices wholegrain bread, 1 cup puffed wheat, % cup corn, 2 weetbix, 1 cup carrots, cooked; 1 cup of berry fruits (except strawberries); average serving of broccoli, spinach or watercress; 1 cup of broad or green beans; Vz cup of cooked lentils, soy, haricot or kidney beans; small serving of peas. For 3 to 5 grams of fibre:large servings of strawberries; bean sprouts, turnips, leeks, celery, cabbage, cauliflower, beetroot, green beans, parsnip or one banana; 1 cup porridge, 14 cup of nuts. For 2 to 3 grams per serving:— most stoned, cored or citrus fruits; potatoes (skinned), onions, silverbeet, tomatoes, pumpkin, 3 crispbread biscuits, 2 slices brown bread.

Five grams of fibre is supplied by 4 tablespoons of unprocessed branflakes, 4 dried apricot halves, 4 prunes, Vz to % cup processed bran cereal.

Avoid too many low fibre foods. There is no fibre in meat, fish, chicken, eggs, cheese, milk, most drinks, sauces (unless high fibre foods are added), sugar, fats, oil, butter, margarine, icecream, jelly, boiled lollies. These are low in fibre: cornflour, white flour and foods made from white flour such as cakes, fancy biscuits, white rice, white pasta, rice bubbles.

To increase fibre intake, choose wholemeal breads, and pastas; eat vegetables with their skins on; make breakfast cereal a habit; have fruit and or vegetables at every meal; inclue dried beans, peas or lentils more frequently; have more salad type sandwich fillings;' try brown rice in preference to white rice.