What is dietary fiber? Soluble and insoluble fibers can lower your cholesterol level by limiting cholesterol absorption & regulating bile acid.
Dietary fiber cannot digest or absorb by the body. However, it can help reduce the risk of heart disease additionally good for the digestive tract and overall health.
You cannot avoid dietary fiber unless you are 100% carnivore. Your ancestor’s diet is mostly fruits, nuts and vegetable containing lot of fibers.
Lower cholesterol with fiber foods
Broadly, there are two kinds: soluble (acts like a sponge) and insoluble (doesn’t act like a sponge). There are two main types of cholesterol-lowering fiber foods, they are:
- Insoluble fibers
- Soluble fibers (or viscous fibers)
Both fiber types have health benefits; however, only soluble fiber can reduce the risk for heart diseases by help lowering LDL cholesterol. Distinguish between these two types of fibers based on how they go through the digestive tract.
Insoluble fibers are incapable of dissolving; therefore, known as “roughage” and helps the colon to function properly. It has a laxative effect and adds bulkiness to the diet, which helps to prevent constipation (but not diarrhea). It is mainly available in many whole-grain foods, fruits (with the skins), vegetables, and legumes.
Sources of insoluble fiber are whole wheat, whole grains, wheat bran, corn bran, seeds, nuts, brown rice, bulgur, zucchini, celery, broccoli, cabbage, onions, tomatoes, carrots, cucumbers, green beans, dark leafy vegetables, raisins, grapes, fruit, and root vegetable skins.
Soluble fiber goes largely dissolved into a gel-like substance in the intestines. This fiber helps to block cholesterol and fats from being absorbed through the wall of the intestines. Additionally, it emulsifies fat, binds & remove bile acids, and inhibit bile acid absorption. Liver requires more cholesterol to produce required bile acids, thus reducing the blood cholesterol level.
Furthermore, eating foods rich in fiber can help to feel fullness with fewer calories, which makes it a good choice of food, if you need to lose weight.
Sources of soluble fibers are barley, oats, psyllium, apples, bananas, berries, citrus fruits, nectarines, peaches, pears, plums, prunes, Brussels sprouts, dry beans, peas, soy products (such as tofu, miso).
Barley reduced both LDL and non-HDL by 7%. Reference: A systematic review and meta-analysis of randomized controlled trials of the effect of barley β-glucan on LDL-C, non-HDL-C and apoB for cardiovascular disease risk reduction. Published in European Journal of Clinical Nutrition, 2016; DOI: 10.1038/ejcn.2016.89.
Psyllium fiber can help those suffering from constipation, diarrhea, or high cholesterol; appropriate daily intake can help improve these conditions.
Dietary supplement psyllium husk swells up to ten times of its weight with water. If you add 30grams of fiber in your diet, you would have an extra 300gram in your digestive system that bulks up and help pass on your stool. Thus, resulting in less pressure for intestinal movement or loose stools.
Psyllium husk fiber can help improve digestion; furthermore, clinical studies show that it is beneficial in lowering high cholesterol. A daily intake of 10 grams psyllium lowered cholesterol levels by 5% and LDL cholesterol by 9%.
8 Health Benefits of Fiber
Dietary fiber may boost your health, some of its potential benefits include:
- Bowel health: Fiber help increases water absorption in the intestine, regulate bowel movement, stool formation, proper defecation, and reduces risk towards colon cancer. Moreover, it regulates the absorption of nutrients. Insoluble fiber may lower your diverticulitis risk (inflammatory intestinal polyps) by 40 %. High fiber intake may lower your hemorrhoids risk. Fiber may provide some relief from IBS.
- Blood sugar control: Soluble fiber may slow down carbohydrate digestion and absorption of glucose thus help regulate blood sugar.
- Blood cholesterol control: Soluble fiber emulsifies fat, binds & remove bile acids, and inhibit absorption. Liver requires more cholesterol to produce bile acids, thus reducing the blood cholesterol level.
- Heart health: Research shows fiber intake has an inverse association with a heart attack by up to 40%.
- Stroke: Research shows every 7 grams more fiber per day found to have decreased in stroke risk by 7%.
- Weight loss: Fiber ingestion provides a sense of fullness. Thus it enhanced weight loss among obese people.
- Skin health: Fiber ingestion improves gut health by removing bad microbes and increase good microbes. If there are a high bad microbe, then the skin require expelling its toxin that affects its health. Thus, skin not requires to expel toxins; also good microbes provide additional nutrient for healthy skin.
- Gallstones and kidney stones: Fiber ingestion may reduce gallstone and kidney stone risk, because of its ability to regulate bile acid.
Dietary fiber helps to prevent coronary heart disease, stroke, high cholesterol, hypertension, diabetes, obesity, and certain gastrointestinal diseases.
Are there any side effects of dietary fiber?
Some who suddenly raise their fiber intake mostly by supplementation may complain to have mild bloating and cramping. Lower daily ingestion of fiber help eliminate these symptoms, and you can raise the fiber intake slowly in steps once your body accepts it.
Fiber feeds the microbe in your gut. You can get a few hundred extra calories a day from the "indigestible" fiber in your food digested by microbes. Excess insoluble fiber (wheat bran) can aggravate heartburn, intestinal gas, and diarrhea.
Sudden increase in fiber ingestion by fiber supplementation instead of more fruits and vegetable consumption can speed up intestinal transit lead to diarrhea, bloating, and malabsorption. Rarely, consuming excess fiber with little water may lead to constipation and even risk of intestinal blockage.
To prevent these side effects, increase your fiber intake slowly over few weeks. Begin fiber intake by adding more fresh fruits and veggies into your diet instead of supplementation. After your body begin accepting it, you can increase fiber intake by supplementation.
Is dietary fiber good during diarrhea? Soluble fiber helps diarrhea by absorbing water and adding bulk to stools. Insoluble fiber provides inert bulking help with constipation but makes diarrhea worse.
How much dietary fiber do I need?
You know, our ancestors used to consume 100-150g of fiber/day that is from fruits and vegetables.
Recommended dietary fiber intake is 16 to 18 g/d for men and 12 to 14 g/d for women. Another rule of thumb is to get 14 grams of fiber for every 1,000 calories of diet.
How much fiber is TOO much? There is no single answer for everyone; every human body differ vastly. Too much fiber can undergo fermentation in your large intestines causing gas, pain, and misery. If your experience these symptoms then lower ingesting fiber.
Fiber help dilutes your food, similar to water dilutes lemonade. We cannot just drink lemon juice and sugar without diluting it with water. However, too much water leaves the lemonade diluted and difficult to get enough nutrition.
Tips to add more fibers in your diet
Some who increase the fiber intake suddenly all at once may experience intestinal gas, abdominal cramps or bloating and other few discomforts. Thus, it is advisable to increase the fiber intake gradually, which allows your body to adapt to it. Soluble fiber absorbs more water and swells, so you should need to drink more water as you increase the fiber intake.
Many people are unknowingly getting more fibers, by preferring certain food items. Some of these food items are as below:
- Choose hot or cold breakfast cereals such as oatmeal & oat-bran that have 3–4 grams of fiber per serving.
- Eat the whole fruit instead of drinking its juice. For example, one orange has six times more fiber than one 4-ounce glass of orange juice.
- Choose whole-grain flours (and products) against refined white flours.
- Prefer high fiber cereals, legumes, seeds, and nuts as snacks.
- Eat vegetable salads.
Research studies on dietary fiber
There are numerous studies on dietary fiber intake and its benefits, below are a list of few studies.
- Cancer: Dietary fiber intake and risk of breast cancer by menopausal and estrogen receptor status. European journal of nutrition 2013 Feb; 52(1):217-23.
- Blood Pressure: Dietary fiber and blood pressure: a meta-analysis of randomized placebo-controlled trials. Archives of Internal Medicine 2005 Jan 24; 165(2):150-6.
- Cholesterol: The Effects of Barley-Derived Soluble Fiber on Serum Lipids. The Annals of Family Medicine 2009; 7:157-163. DOI: 10.1370/afm.917
- Inflammation: Effect of dietary fiber on circulating C-reactive protein in overweight and obese adults: a meta-analysis of randomized controlled trials. International Journal of Food Sciences and Nutrition Volume 66, 2015 - Issue 1.
- Diabetes type 2: Dietary Fiber for the Treatment of Type 2 Diabetes Mellitus: A Meta-Analysis. Journal of the American Board of Family Medicine January-February 2012 vol. 25 no. 1 16-23. What would improve your digestion, bowel movements, and overall health is understanding what a healthy diet is (as opposed to opinion), and following it.
- SIBO: One daily fiber snack bar (containing 21 grams of fiber) for three weeks significantly increased Bacteroidetes bacteria and decreased Firmicutes. Reference: Fiber supplementation influences the phylogenetic structure and functional capacity of the human intestinal microbiome. Published in American Society for Nutrition, November 12, 2014, doi: 10.3945/ajcn.114.092064.