By Kermit B. Fernander, For The Guardian

A friend of mine once described dietary fiber as nature's broom for sweeping clean the lower bowel. WHATEVER! Fiber happens to be the indigestible parts of plant foods and is found in grains, vegetables and fruits. As fiber passes through our digestive systems, it helps to rid the bowel of toxins and other undesirables. Fiber also encourages bowel evacuation on a regular basis. The pattern of bowel evacuation may of course vary from individual to individual.

While we Bahamians know better, many of us still insist upon eating white bread as opposed to whole wheat bread. We also tend to prefer white rice to fiber-rich brown rice. This is a pity because whole wheat bread and brown rice contain far more dietary fiber and are healthier than their white counterparts.

Fiber is often classified into two categories: Those that don't dissolve in water (insoluble fiber) and those that do (soluble fiber). Insoluble fiber increases the movement of material through your digestive system and increases stool bulk, so it can be of benefit to those who struggle with constipation or irregular stools. Whole-wheat flour, wheat bran, nuts and many vegetables are good sources of insoluble fiber.

Soluble fiber dissolves in water to form a gel-like material. It can help lower blood cholesterol and glucose levels and there are generous quantities of soluble fiber in oats, peas, beans, apples, citrus fruits, carrots and barley. Fiber — particularly soluble fiber — can also lower blood cholesterol levels and slow the absorption of sugar, which for people with diabetes, can help improve blood sugar levels. A high-fiber diet may also reduce the risk of developing type 2 diabetes.

A high-fiber diet may help lower our risk of other disorders, such as hemorrhoids or piles, irritable bowel syndrome and the development of small pouches in your colon called diverticular disease. In addition, a high-fiber diet may also help with weight loss. High-fiber foods generally require more chewing time, which gives our body time to register when we're no longer hungry, so we're less likely to overeat. A high-fiber diet also tends to make a meal feel larger and linger longer, so we stay full for a greater amount of time. And, finally, high-fiber diets tend to be less "energy dense," which means they contain fewer calories for the same volume of food.

The National Academy of Sciences' Institute of Medicine, which provides science-based advice on matters of medicine and health, recommends the following daily fiber requirements for adults. Men 50 and younger need 38 grams daily while men 51 and older require 30 grams daily. Women 50 and younger require 25 grams daily while women 51 and older need 21 grams daily.

If we aren't getting enough fiber each day, we may need to boost our intake by choosing whole-grain products, raw or cooked fruits and vegetables, and dried beans and peas. Refined or processed foods — such as fruit juice, white bread and pasta, and non-whole-grain cereals — are lower in fiber content. The refining process removes the outer coat (or bran) from the grain, which lowers its fiber content. Similarly, removing the skin from fruits and vegetables decreases their fiber content.

The following list shows the amount of fiber in grams in fairly common foods:

1 cup cooked Split Peas,16.3 grams;

1 cup cooked Red Kidney Beans, 13.1 grams;

1 cup whole wheat spaghetti, 6.3 grams;

1 medium apple with skin, 3.3 grams;

1 cup of cooked brown rice, 3.5 grams,

1 slice of whole wheat bread, 1.9 grams.

Whole foods rather than fiber supplements are generally better. Fiber supplements — such as Metamucil, Citrucel and FiberCon — don't provide the vitamins, minerals and other beneficial nutrients that high-fiber foods do. However, some people may still need a fiber supplement if dietary changes aren't sufficient, or if they have certain medical conditions, such as irritable bowel syndrome. Check with your doctor if you feel you need to take fiber supplements.

High-fiber foods are good for your health. But adding too much fiber too quickly can cause intestinal gas, abdominal bloating and cramping. Remember to increase fiber in your diet gradually over a period of a few weeks. This allows the natural bacteria in your digestive system to adjust to the change. Also, remember to drink plenty of water. Fiber works best when it absorbs water because water not only helps to prevent constipation, it also helps to lubricate the lining of the lower bowel.