Fiber is an important type of carbohydrate and the recommended intake is 14 grams per 1,000 calories of total food intake. Based on typical daily calorie intakes, this works out at approximately 38 grams for men and 25 grams for women.
Sometimes people with a low fiber intake from their diet may consider using fiber supplements such as psyllium, but is this a good idea?
In this article, we examine the findings from scientific research and what they show on the potential benefits and drawbacks of common fiber supplements. As part of this, we will focus on their effects on digestive health and regularity as well as their impact on risk markers like LDL cholesterol (LDL-C), which is sometimes referred to as “bad cholesterol.”
Table of contents
Common Types of Fiber Supplements
There are numerous fiber supplements available and they can come in the form of pills, capsules, and powders. Some of these are soluble fibers while others are insoluble.
Related: Learn about dietary fiber and the differences between soluble and insoluble fibers
Here is an overview of the main fiber products used in supplements, whether they are soluble or insoluble, and which supplements they are in. We’ll also categorize them as either natural fibers, which are found in food, or synthetic fibers that have been produced in a lab.
| Type of fiber | Solubility | Supplements found in | Natural or synthetic |
|---|---|---|---|
| 1. Acacia gum | Soluble | Numerous | Natural |
| 2. Calcium polycarbophil | Insoluble | FiberCon | Synthetic |
| 3. Flaxseed | Soluble and insoluble | FiberSmart | Natural |
| 4. Inulin | Soluble | Fiber Choice | Natural |
| 5. Methylcellulose | Soluble | Citrucel | Synthetic |
| 6. Psyllium | Soluble and insoluble | Metamucil | Natural |
| 7. Wheat dextrin | Soluble | Benefiber | Plant-derived but altered |
1. Acacia Gum
Acacia gum, which is also known as acacia arabic, consists of hardened sap extracted from Acacia tree species.
It is a soluble fiber with a sticky texture, and it dissolves well in water. It is commonly sold as either acacia fiber powder or in capsules.
In addition to its use in fiber supplements, the food industry uses acacia gum as an emulsifier (E414) for its thickening and bulking properties.
Benefits
- Gut microbiota: A randomized crossover trial found that 10-15g acacia gum over ten days resulted in an increased number of beneficial gut bacteria. There were no statistically significant side effects at doses under 30g.
- IBS symptoms: A randomized, controlled trial fed 130 patients with IBS (irritable bowel syndrome) a daily yogurt containing acacia fiber, or a plain yogurt as a control. After 8-weeks, the improvements in IBS symptoms was “significantly higher”in the acacia fiber group.
- Health markers: One study suggested that a daily 10–40g dose of acacia fiber may reduce inflammation in patients with chronic kidney disease.
Drawbacks
- Gastrointestinal side effects: While daily acacia fiber intake appears to be well-tolerated up to 30 grams per day, some studies have shown potential side effects, such as flatulence, at doses higher than 30g.
2. Calcium Polycarbophil
Calcium polycarbophil is a synthetic fiber supplement aimed at relieving the symptoms of digestive issues such as constipation.
Benefits
- Digestive health: In a clinical trial involving 57 patients, calcium polycarbophil led to either “very good” or “good” improvements in 91% of chronic constipation cases. Only 9% of cases saw no effect.
Drawbacks
- Gastrointestinal side effects: Although calcium polycarbophil is thought to have minimal adverse effects, there have been cases of gastrointestinal distress, including symptoms like bloating, fullness, and flatulence.
3. Flaxseed
Flaxseeds are a whole food form of fiber.
Most notably, flaxseeds are not just a source of isolated fiber; they also provide a range of essential nutrients, particularly magnesium, copper, selenium, and manganese.
Flaxseed is the primary ingredient in the ‘Fiber Choice’ supplement, and flax powders are available in capsule and bulk powder forms.
Benefits
- Digestive health: In a randomized controlled trial, flaxseed significantly lowered constipation symptoms in 53 patients with type 2 diabetes without having adverse effects.
- Health markers: A 2021 systematic review of 31 randomized controlled trials found that flaxseed may have a positive impact on lipid (cholesterol) profiles, lowering LDL-C and inflammation in patients with high cholesterol.
Drawbacks
- Research limitation: While a 2025 review noted that flaxseed appears to be safe and effective at doses of up to 30–40g per day, the authors noted that there is limited long-term research on such doses, and that research suggests it is safe to use for 2–4 months.
- Medical interaction: According to the National Institutes of Health, flaxseed may potentially interact with medications, such as blood thinners.
Nutritionist’s Note
It is worth taking a moment to understand the potential drawbacks listed above.
Firstly, what the review found on flaxseed was that the existing evidence suggests it is safe and effective for a short to moderate time period — 2–4 months. However, this doesn’t necessarily mean it isn’t safe to supplement with flaxseed for longer than this; it just means that there isn’t enough long-term data to state with confidence.
Additionally, flaxseed may interact with certain medications (such as anticoagulants), but so might other supplements. For this reason, it is always advisable to consult with your healthcare provider before starting any new supplement.
4. Inulin
Inulin is a soluble fiber naturally present in many fruits and vegetables. It has prebiotic properties, which means that gut beneficial microbes in the human gut can ferment it for energy.
Many fiber supplements contain inulin, and this includes the supplement brand ‘Fiber Choice.’
Benefits
- Digestive health: A 2025 randomized controlled trial involving 39 individuals found that 12g of inulin per day improved symptoms of constipation over four weeks. Pain symptoms were reduced and stool frequency increase, and this was accompanied by a shift in the gut microbiota to a profile thought to better support health.
- Health markers: A 2024 systematic review of 55 randomized controlled trials looked at the impact of inulin on cardiovascular risk markers. The study found that inulin supplementation may lower LDL-C, but the certainty of evidence was low, and more rigorous research is necessary to confirm this.
Drawbacks
- Gastrointestinal side effects: As with other fiber supplements, inulin supplementation has been associated with adverse gastrointestinal effects like bloating, cramps, and flatulence.
5. Methylcellulose
Methylcellulose is a synthetic fiber produced from plant cellulose. It is a common type of soluble fiber and features in products by the brand name ‘Citrucel.’
Benefits
- Digestive health: A clinical trial found that methylcellulose was an effective laxative when used in daily doses of 1 gram.
- Gastrointestinal side effects: Methylcellulose is non-fermentable in the gut, so there may be a lower risk of gastrointestinal side effects like bloating.
Drawbacks
- Gut microbiota: While methylcellulose being non-fermentable lowers the risk of side effects, it also means that it doesn’t feed and support the gut microbiota in the same way some types of fiber do.
6. Psyllium
Psyllium, or psyllium husk, comes from the outer layer of seeds produced by the Plantago ovata plant.
The outer layer of these seeds are a significant source of soluble fiber.
Psyllium husk is a primary ingredient in many fiber supplements, including brands such as Metamucil, and it is also available as a bulk fiber powder. As a powder, it can be mixed into drinks and smoothies.
Benefits
- Digestive health: A 2022 systematic review of randomized controlled trials found that psyllium supplementation significantly improved constipation symptoms over four weeks at doses above 10 grams per day.
- Weight management: A 2023 systematic review of six clinical trials found that psyllium supplementation before meals was effective for weight loss. This was potentially due to the impact it had on satiety levels (reduced appetite).
- Health markers: Systematic reviews published in 2024 and 2025 found that psyllium supplementation significantly decreased systolic blood pressure and lowered LDL-C.
Drawbacks
- Potential side effects: Since psyllium is bulk-forming and absorbs water as it passes through the gut, it is important to consume it with sufficient liquids. This case study of an intestinal obstruction believed to be from psyllium intake highlights the importance of this.
Related: Learn more about psyllium husk here
7. Wheat Dextrin
Wheat dextrin is a fiber produced from modified wheat starch. While it comes from a natural food product, it is altered through a process called partial hydrolysis, which involves being treated with hydrochloric acid.
It is a soluble fiber used in numerous fiber supplements, including those under the brand name of ‘Benefiber.’
Unlike other fiber supplements, there is very little research on the efficacy of wheat dextrin
While wheat dextrin is highly processed and is thought to be gluten-free, Beyond Celiac notes that it may contain small traces of gluten. For this reason, individuals with celiac disease or non-gluten sensitivity may wish to discuss this supplement with their healthcare provider.
Which Fiber Supplement is Best?
If you’ve decided to try a fiber supplement and are pondering which is the best option, then it’s a difficult question to answer with certainty due to the differences between products and potential for individualized responses from person to person.
However, here are some factors to consider:
- Clinical evidence: While several types of fiber have shown benefits in randomized controlled trials, psyllium husk arguably has the most clinical evidence supporting it. Multiple systematic reviews of clinical trials found that it has demonstrated benefits for digestive health as well as improving markers of cardiovascular risk like LDL-C.
- Soluble or insoluble: Individuals who experience gastrointestinal side effects from fiber like bloating may prefer an insoluble fiber supplement, which is less likely to cause gas and abdominal pain.
- Listen to professional guidance: It is important to consult with your healthcare provider for individualized guidance from a professional who understands your personal situation.
Overall, there are many fiber supplements on the market, often with bold marketing claims behind them. However, it is most important to focus on understanding which one is the right fit for you.
