In the grain: Know your fiber

What makes it unique in the food pyramid (proteins, carbohydrates, fats, etc.) is that the human body cannot digest fiber without outside help.

The might flax seed (photo credit: Wikimedia Commons)
The might flax seed
(photo credit: Wikimedia Commons)
Everyone has heard that dietary fiber is good for you and it is, but not everyone knows why and not everyone knows that there are different types of fiber that behave and affect the body differently. In this article I am going to explore some of fiber’s wonders and benefits.
The term “fiber” conjures up a picture of some kind of solid, tough, stringy substance. Most people know that you won’t find any fiber in a can of soda! This instinctive perception is correct; fiber is mostly found in “fibrous” foods that we need to chew and not in foods that “melt in the mouth.” But that descriptor is insufficient, because not all foods that are “fibrous” have fiber, for example, we might think meat has fiber, but you don’t get any fiber from a steak and conversely, there is fiber in some foods that are not “fibrous,” like oatmeal porridge. In fact all the fiber in our diet comes from the plant kingdom, lentils, grains, fruits and vegetables.
What makes it unique in the food pyramid (proteins, carbohydrates, fats, etc.) is that the human body cannot digest fiber without outside help (which I will discuss shortly). If not for this “outside help,” fiber would pass unaltered through our systems (like the time your kid swallowed a button).
There are two main types of fiber – the kind that dissolves in water (soluble) and the kind that doesn’t (insoluble).
When soluble fiber dissolves in water, it swells and forms a kind of a gel. Since a gel flows slower than a liquid, it slows down digestion and because it swells in your stomach, it gives a sense of being full. Foods that have soluble fiber include oatmeal, legumes, apples, bananas, white rice and nuts, and the effect on your digestion is a constipating effect, slowing things down.
There are numerous benefits of soluble fiber. It swells and makes you feel satiated so you end up eating less and consuming fewer calories. It also lines your digestive tract, forming a “barrier” between the food and your blood stream, which slows the absorption of nutrients, like sugars for example, reducing “sugar spike” after eating a carbohydrate-rich meal, thus protecting your pancreas and preventing diabetes. It also prevents heart disease by slowing the absorption of bad (LDL) cholesterol.
Insoluble fiber, on the other hand, does not dissolve in water and does not form a gel, and it has the opposite effect on your digestive system – it makes things move along quicker, i.e. a laxative effect. Foods with insoluble fiber include whole grains, whole rice, broccoli, cabbage, onions, grapes, raisins, ground flax seeds, etc. Aside from adding bulk and making you feel more satiated, insoluble fiber is indispensable in preserving the health of your colon.
As I said before, the body cannot digest fiber without help. It gets this help from the billions of bacteria in your colon. Whenever you step on the scale, at least 2 kg. of your body weight is from the bacteria in your gut! There are two types of bacteria: friendly and unfriendly. You want to steer clear of the unfriendly kind that can give you an upset stomach (e.g. E. coli) by maintaining hygiene when preparing uncooked food. The heat of cooking destroys most of these bacteria. The friendly kind, which many call pro-biotic, helps to digest the fiber using fermentation. This fermentation process is a veritable factory for manufacturing vitamins in the body, including the B-complex vitamins. It is also considered by scientists to be a factory for producing antibodies and boosting the immune system. Experiments with rats show that a sterile diet that totally eliminates intestinal bacteria makes them more prone to disease.
Maintaining a balance between soluble and insoluble fiber helps to preserve colon health. The soluble kind slows things down at the beginning of digestion while the insoluble kind tends to move things along at the end of the colon and prevent clogging, thus preventing colon cancer. Each person needs to achieve this balance between soluble and insoluble fiber, by adding or reducing the various types – to ensure a smooth flow.
The only drawback with adding fiber to your diet is that it increases the fermentation in your gut and thus increases intestinal gas and flatulence. This can be alleviated by adding fiber gradually to your diet until you become used to it, or by supplementing things that reduce flatulence like caraway seeds, fennel, pumpkin, chamomile, turmeric or cloves. Increased soluble fiber intake also requires that you drink more water to keep things running smoothly.
The average fiber requirement per day is 25 gr. for women and 38 gr. for men. Read food labels or check online to see the fiber content of the foods you are eating. Play around, adding/reducing the different types until you achieve a good equilibrium in your digestive flow. The idea is neither to be constipated nor to have a running stomach but rather something in the middle.
The sources of fiber are many, inexpensive, easily obtained and can significantly impact your health.
The writer, a master baker originally from Johannesburg, South Africa, lives in Karnei Shomron with his wife Sheryl and four children. He is CEO of the Saidel Jewish Baking Center (, that specializes in baking and teaching how to bake healthy, traditional Jewish bread. He also manages the Showbread Institute ( which researches the biblical showbread.
Flax Seed Bread
2½ cups of whole grain flour
1½ cups of water
2 tsp. salt
2 tsp. instant dry yeast
½ cup ground flax seeds
Mix and knead dough for 10 minutes by hand (seven minutes in the mixer). Leave to rise for one hour. Punch down and shape into an oval loaf and place in a baking tin. Leave to rise for another 90 minutes. Bake at 180 degrees centigrade for 20 to 25 minutes until golden brown.