5 things to know before buying a fiber supplement
Fiber seems so simple. In fact, ask almost anyone above the age of 12 what fiber is, and at the very least, they will know it has something to do with food. In large part, this is because fiber content is listed on the back of every food label, included as part of the total carbohydrates.
However, much like the vagueness of the standard American nutrition facts label, most nutrition and medical professionals cannot explain the nuances of fiber either. Our collective lack of specificity around fiber means we aren’t using it to its full potential to optimize our health, including in the supplement form. This lack of understanding may be sabotaging our health goals.
Here are five common misconceptions about fiber supplements and the role fiber plays in our nutrition and overall well-being.
Misconception: Fiber is fiber, no need to get specific
All fibers are not the same. The most basic difference between fibers is whether it is insoluble or soluble.
Insoluble fibers give plants their structure and are responsible for making your carrots crunchy. These fibers are good for us in many ways: They help us to feel full without extra calories, they keep things moving in the digestive tract, and they bulk up our stool.
Soluble fibers, on the other hand, absorb water. These fibers feed the healthy microbes in our digestive tract and expand in our stomach to help us feel full. Soluble fibers can be either highly viscous or non-viscous (more on that below!).
Misconception: Taking any fiber supplement is better than taking none at all
If you’re going to spend money on a fiber supplement, it should help you feel better! Unfortunately, not all fiber supplements improve health outcomes. Many people are taking fiber to improve digestive, metabolic, or heart health.
However, drug store brands are often single ingredient fibers made from inulin or wheat dextrin. These fibers are not shown to improve bowel movements, heart health or metabolism. Worse, wheat dextrin and inulin have been shown to commonly cause stomach pain, bloating, gas and problems with bowel movements.
Misconception: All fiber supplements help to lower cholesterol and improve heart health
Highly viscous soluble fibers that are gel-forming, such as b-glucan, chia, psyllium, guar gum, and glucomannan, have been shown to reduce LDL cholesterol and triglycerides. Viscous soluble fibers bind to bile salts (which are made from cholesterol in your liver) as well as dietary cholesterol (cholesterol in your food) and carry it into your toilet. This is why regular consumption of (viscous) soluble fiber has been shown to reduce cholesterol.
Non-viscous fibers such as inulin and wheat dextrin have only been shown to lower lipids in rodents in doses exponentially higher than what would be possible in humans = 3,750-15,000g/day. These benefits are not replicated in humans because we cannot consume that quantity of inulin or wheat dextrin.
Misconception: All fiber supplements help to regulate blood sugar levels
Fiber is thought to help regulate blood sugar levels and is commonly suggested to patients aiming to lose weight and drop their risk of diabetes. However, much like cholesterol and triglycerides, glucose lowering effects are directly related to the viscosity of the soluble fiber.
Soluble fibers that are non-viscous are typically inulin, FOS, wheat dextrin, and acacia. Soluble fibers that are viscous include guar gum, psyllium, glucomannan and chia.
Research continues to suggest that viscous soluble fibers reduce the spike in blood glucose levels that occurs after eating. A potential indirect benefit may happen after consumption of large amounts of non-viscous fiber because it helps you feel more satiated so you may eat less food at each sitting, resulting in lower blood glucose spikes. However, non-viscous fibers do not directly impact the post-meal glucose spike. For regulation of blood glucose levels, viscous fibers can be beneficial to consume with meals.
Misconception: Fiber is only for better bowel movements
Not only is fiber great for satiety and the aforementioned health concerns, but it is often thought to be the “gamechanger” for better poop. However, once again, not all fiber is created equally so if you’re aiming for bathroom benefits, make sure you’re focused on the right fiber.
Only two fiber-related mechanisms improve bowel movements:
1. Insoluble fiber improves regularity by irritating the gut mucosa in the colon wall, stimulating water and mucous secretion for smoother movements.
2. The high water-holding capacity of gel-forming (viscous) soluble fiber improves the consistency and motility of stool.
Because of these mechanisms, some people may experience gas, bloating and lower abdominal discomfort when increasing insoluble fiber, although the increase in viscous soluble fibers can improve bowel movements without irritating the gut. While gel-forming soluble fibers are superstars when it comes to healthy poop, non-viscous soluble fibers have their place in gut health as well. Although they don’t directly impact the consistency of stool, these fibers are food for the microbes in your gut which can improve the health of the microbiome and increase short chain fatty acid production, leading to better colon health overall.
It's important to consume a diversity of fibers. Not all fibers are created equally, and some fibers show their strengths better than others depending on what you’re aiming to accomplish.
What to look for in a fiber supplement
- Find something organic and look for the seal of the certifying source. This ensures your fiber is "clean." It also ensures what's in your fiber is what the packaging indicates. The supplement industry is unregulated by the FDA, and organic certification provides peace of mind for consumers by ensuring ingredients are as stated.
- Make sure there are no additives, dyes or sugars. Ideally your supplement contains only functional ingredients.
- Look for a blend. This ensures you are getting a diversity of fibers that can work together inside your body to support all the different ways fiber can benefit your body. Soluble fiber is much harder to find in food, so soluble fibers should be a key part of any blended supplement.
- Avoid wheat dextrin and inulin. While these are included in fiber supplements all the time, they are frequently cited as gut irritants. Fructooligosaccharides (FOS) are sometimes listed as prebiotic fibers, but in fact they are a resistant starch and not a soluble fiber at all. They can also be irritating to the gut.
Stick to this list, and your colon (and entire body, for that matter) will thank you!
Why I created Florasophy
I couldn't find a soluble fiber supplement that was "clean" and diverse to reflect the range of fibers you would get in an optimal diet. I knew soluble fiber had the power to do amazing things for my patients, but the options I found had inorganic ingredients tainted with pesticide residue, inflammatory fillers and additives, and fiber blends that contained ingredients known to irritate the intestinal wall. So I began blending organic fibers for my patients, and the results were phenomenal. Happy, healing patients was the reason that Florasophy came to be, and it has remained an invaluable tool in my clinical practice.
About Megan Barnett, MS, CNS
Megan Barnett is a functional medicine practitioner in Portland, Oregon. In her clinical practice, she helps patients identify the root cause of their health problems, then designs individualized and evidence-based approaches to alleviate symptoms and help their bodies heal. She has a Bachelor of Science in Dietetics from Kansas State University and a Master of Science in Nutrition and Functional Medicine from University of Western States.