What’s the deal on Fiber?

There is a lot of hype about boosting protein intake but how many of us pay attention to adequate intake of fiber everyday? Many of us fall far short of the recommended daily intake of at least 25 grams for women and 35 grams for men. Paleolithic man was getting more than a 100 grams of fiber per day! A good rule of thumb is to add 5 to our age to get the right amount of fiber in our diets everyday. Therefore a 40 year old should ideally be eating 45 grams of fiber everyday and a 10 year old 15 grams.

So what is fiber?

Fiber is the stringy substance that holds fruits and vegetables together and is found solely in plant foods. It is also found in seeds and in the outer covering of grain called bran. Bran is the part of the grain that is ground and found in whole wheat flour and whole grain cereal, but is removed from white flour. Fiber is found in the flesh of whole, fresh, natural foods and plays a very important role in our body. There are two kinds of fiber, soluble and insoluble.

Soluble fiber dissolves in water, turning the food into a gel like substance from which nutrients can be absorbed at a slow, steady rate. This also keeps us full for a longer time. Soluble fiber is found in dried beans and peas, oat bran, apples, citrus fruits, carrots and barley. This type of fiber may also cause intestinal gas and bloating because it ferments in the gut. If this happens, back off from fruits, vegetables and legumes for a bit and reintroduce them slowly.

Insoluble fiber holds water like a sponge and does not dissolve in water. It keeps food soft as it moves through our intestines and helps in the easy elimination of waste products from our body. Insoluble fiber is found in the stringy parts of plant leaves, the hard covering on the outside of grains, nuts and many vegetables.

So why should we care about fiber? Here are some of the key benefits of consuming a fiber rich diet.

Weight control.  Fiber adds bulk to food without adding extra calories. To illustrate, let’s compare a  bottle of cold pressed apple juice to whole apples. A bottle of 450 ml of apple juice,( which is basically apples with the fiber removed), can be chugged down in a matter of minutes. To get the same number of calories as the juice, we would have to eat nearly 5 cups of sliced apples! Obviously eating the whole apples would fill us up much more. Why is that? One of the reasons for this is that we would have to chew every apple slice. High fiber foods require much more chewing. This  slows down eating rate which makes the food far more satiating.  It also leads to increase in the secretion of saliva and gastric juices. These foods also stay in the stomach longer, helping us keep full and curbing overeating. The feeling of fullness that comes after eating a bowl of oatmeal for instance,  is because the fiber in the oatmeal pushes against the walls of our stomach.  Our stomach has nerves with stretch receptors that can send fullness signals directly to our brain. Our brain then directs our stomach to stop eating.

Studies show that people who eat an extra 5 grams of fiber a day ( equal to one serving of fiber-rich cereal) eat fewer calories throughout the day.

Steady blood sugar. Fiber steadies and slows the rate at which sugar is digested by our bodies. This prevents blood sugar spikes and dips that can affect mood and behaviour. The apple juice from the previous example would get rapidly absorbed as soon as it comes out from our stomach into our small intestine and spike blood sugars, whereas the sugar trapped in the apple slices would be absorbed more slowly along the length of our intestine. The fiber in the apples act as a barrier to dilute and even eliminate the sugars from out of our body.

Heart friendly. Soluble fiber helps carry dietary cholesterol out of our bodies, lowering blood cholesterol.

Good bacteria . Fiber fosters the growth of good bacteria in our gut  The gut flora, which weigh more than one of our kidneys and are more metabolically active than the liver, have sometimes been called the ‘forgotten organ’. As the good gut bacteria ferment the fiber in our digestive tract, substances called short chain fatty acids (SCFA) are released. These can then be absorbed from our colon into our bloodstream, circulating throughout our body finally ending up in our brain.The  SCFAs have wide ranging positive effects on our body  from enhanced immune function and balanced  inflammation to regulating  appetites, metabolism and body fat.

Antidepressant.  The short chain fatty acids (SCFA) that are released when fiber is fermented in our gut may have beneficial effects on our brain. When the intestinal bacteria are disrupted, either by eating an unhealthy diet or by the use of antibiotics, depression is more likely to occur. Having plenty of fiber in the digestive tract helps the good bacteria to flourish which in turn helps to protect against depression.

Cancer. Just a fiber escorts dietary cholesterol out of our body, it also helps to eliminate unwanted hormones from our bodies. This is particularly relevant for hormone sensitive cancers like breast or prostate cancers. In women, the liver filters excess estrogens out of the blood and sends them into the intestinal tract where the fiber carries them away. The more plant based the diet is, the more efficiently the system works. In Harvard’s Nurses’ Health Study, women who ate 30 grams of fiber each day were 32% less likely to develop breast cancer, compared to women who got relatively less fiber.

Healthier digestive system . A high fiber diet helps in the regularity of bowel movement, keeping stools soft and easy to eliminate.

The best sources of fiber are not fruits and leafy greens as commonly believed . These are in fact the poorest whole food sources of fiber as they are 90% water! In comparison, root vegetables like sweet  potatoes, yams, turnips, beets, Jerusalem artichokes,and carrots have twice as much fiber on a per weight basis, but the champs are whole grains and legumes, which include dried or canned beans, chickpeas, split peas and lentils. By eating a wide variety of high fiber foods everyday, both soluble and insoluble fiber requirements can be met.

 Not sure how to boost your fiber intake? Reach out to me by filling out the submission form at www.rimabhealth.com.