Fibre Food

                                Eat more Fibre” is a familiar advice when you visit your doctor for difficult bowel movement. Your diet, according to nutritionists, may not be well balanced if the intake of roughage or bulk — which are the colloquial terms for fibre — is not met. Fibre in the diet is just as important as the other nutrients like proteins, vitamins and minerals and is an integral part of a healthy diet.

                              What is dietary fibre? Fibre is a food component from plants and is present chiefly in fruits, vegetables, whole grains and legumes. Our Indian pulses like rajma, red gram (Toor), black gram (Urad) and bengal gram are particularly high in fibre.

There are many types of fibre, and they are generally classified as soluble fibres and insoluble fibres, depending on their solubility in water. The insoluble fibres are found in the cell walls of plants. Some insoluble fibres are cellulose, hemicellulose and lignin. These are found in plenty in green leafy vegetables (like agathi leaves, curry leaves and drumstick leaves), other vegetables like French beans, fruits like sapota and guava, whole grains including millets, pulses and nuts. Refined cereals like maida and raw rice contain less fibre than whole grains. On the other hand, soluble fibres like beta-glucan, psyllium, pectins and gums, are generally found inside the plant cells. Foods containing significant amounts of soluble fibre include oatmeal, oat bran, fruits like apple, figs, guava, and vegetables like ladies fingers, brinjal and guar.

                                Unlike other nutrients like the proteins and carbohydrates, fibre resists digestion by the enzymes present in the human digestive tract. So it passes unchanged through the stomach and the small intestine and into the colon where it is fermented by the bacteria that reside there.

                               Why are health experts concerned about your dietary fibre intake? Because, fibres have a wide range of abilities. The “Fibre Hypothesis” suggests that consuming an unrefined, high-fibre diet could protect against diabetes, cancer, heart disease, and obesity and helps in maintaining bone and digestive health.

Gastro-intestinal health

                                Soluble fibres such as Pectin, Guar gum, and Oat gum are also called prebiotic fibres. They promote the growth of good or beneficial bacteria in the colon. They undergo bacterial fermentation to form products such as hydrogen, methane, carbon dioxide, and short chain fatty acids. These free fatty acids are important sources of energy for the intestinal mucosa. They also protect the health of the colon. This will also produce an acidic medium in the bowel that will prevent the growth of pathogenic bacteria.

There is a strong association between fibre, especially insoluble fibre, and laxation. Fibre increases faecal weight and volume and alters the consistency of the stool and promotes a regular bowel habit. Fibre makes the stools soft, bulky and easy to eliminate.

Fruits

Pectin is an important antioxidant, and protects the gastrointestinal mucosa from damage causing free radicals. Increase your fibre intake to reduce the risk of colorectal cancer.

Heart health

                                A study in 2005 also suggested that intake of fibre may contribute to the prevention of hypertension. Soluble fibres reduce the absorption of cholesterol, increase cholesterol excretion and thus lower serum concentrations of cholesterol.

The aggressive promotion of oats and its products such as oat meal and oat bran as cholesterol lowering agents is due to the presence of Beta-glucans, a water-soluble dietary fibre present in this cereal. Beta-glucans, which are also present in barley, have also been shown to lower low-density lipoprotein (LDL) cholesterol.

 A significant protective effect against cardiovascular disease requires the intake of at least 25g of dietary fibre per day. However, one must aim for a daily fibre intake of 35-40g.

Diabetes

                              Diets high in whole grains and dietary fibre can protect against diabetes and pre-diabetic states. Enhancing the fibre content of a meal lowers the insulin requirement in patients and improves diabetic control. This is achieved through the promotion of satiety and weight loss. Body weight reductions can favourably impact serum glucose levels. Besides, soluble fibres themselves produce a reduced glycaemic response. To state it simply, it has a slow and a low impact on blood sugar — glucose is released gradually and slowly into the blood. Such a response controls the blood glucose levels, provokes less insulin demand and lessens the possibility of hypoglycemia. Habitual consumption of foods that elicit low glycemic responses may help to reduce the risk of CVD, type II diabetes.

Body weight

                              If you are aiming at weight reduction, opt for fibre rich foods. Before a meal, indulge in a big plate of salad.

Available evidence suggests that fibre could potentially play a useful role in weight reduction both in adults and children. Firstly, fibre fills the stomach (bulking agent), delays gastric emptying and provides increased satiety — a feeling of fullness — and therefore one eats less of other calorie-dense foods. Secondly, unlike fats, that give 9 kcal/g and proteins and carbohydrates like starch and sugar that give 4 kcal/g, fibre itself provides very little energy (0 to 2 kcal/g, depending on the level of fermentation in the colon).

Recent studies also maintain that fructooligosaccharides, a type of soluble fibre, increases both calcium and magnesium absorption. This could have long-term implications on bone.

Research data suggest the beneficial effects of fibre intake on chronic respiratory symptoms and lung function in adults. There is also evidence for the immune-enhancing effects of dietary fibres.

How much fibre?

                               Traditional Indian diets consisting of whole grains, pulses, vegetables and fruits contain adequate fibre. The National Institute of Nutrition makes a recommendation of 40g of fibre per day for adults while the National Academy of Sciences Institute of Medicine suggests that adult men 50 years and younger consume 38 grams of total dietary fibre daily and women 50 years and younger consume 25 grams of fibre daily. Suggested intakes for older persons are slightly lower. By including 3 to 4 servings of whole grains, 2 servings of pulses and about 5 servings of fruits and vegetables, one can generally meet these requirements. For diabetics, 25 to 50 g of fibre daily would certainly help in glycemic management.

Too much fibre?

                                 Adequate intake of water is a must with a high fibre diet. In some, such diets could also cause flatulence and gastric irritation and therefore it is wise to increase the fibre intakes gradually.

But when should you avoid too much fibre?? If you have an irritable bowel syndrome, diverticulosis or ulcers, then you may be required to restrict the intake of fibre. Fibre is also known to interfere with the absorption of some dietary nutrients like vitamins and minerals.

Supplements

                                Fibre supplements are available for the elderly and populations whose fibre intakes through the diet are chronically woefully inadequate. Psyllium seed husks are high in fibre and are marketed as Isabgol. Guar gum is also used as a source of fibre.

Clear public health messages based on the growing knowledge of dietary fibre is long overdue and needs to be promoted. So, what is the take-home message? Most often fibre is our good friend and therefore ensure adequate intake from various sources.

 - Excerpt from Hindu Magazine