You need both, and if you eat a range of whole plant foods you are already getting both without tracking either. Soluble fiber dissolves in water and forms a gel that slows digestion; insoluble fiber does not dissolve and adds bulk that speeds things through. Almost every plant food contains a mixture, in different ratios, which is why the split matters far less than the total for most people.
The distinction becomes worth understanding in two situations: when you are chasing a specific effect such as lowering cholesterol, and when you are trying to read a label and cannot find the information. The second problem has a regulatory explanation that almost no consumer guide mentions, and it is below.
What each type does
| Soluble fiber | Insoluble fiber | |
|---|---|---|
| Behaviour in water | Dissolves, forms a viscous gel | Does not dissolve, stays intact |
| Main effect | Slows gastric emptying and nutrient absorption; binds bile acids | Adds bulk and holds water in stool; speeds transit |
| Most associated with | Blood cholesterol and blood sugar response | Regularity and stool consistency |
| Fermented by gut bacteria | Largely yes | Partly, varies by type |
| Common sources | Oats, barley, psyllium, beans, apples, citrus, carrots | Wheat bran, whole grains, nuts, the skins and stalks of vegetables |
Two of the six ingredients in a SaladPower pouch, apple and carrot, are among the better-known sources of soluble fiber, largely as pectin. The leafy greens and broccoli contribute more on the insoluble side. A whole plant is rarely one or the other.
Why the label usually will not tell you
If you have turned a package over looking for the soluble and insoluble breakdown and found only "Dietary Fiber", the label is not defective. Under 21 CFR 101.9(c)(6)(i)(A), declaring soluble fiber is voluntary. A manufacturer only has to declare it when a claim about soluble fiber is made on the label or in labeling. The same applies to insoluble fiber.
That single regulatory fact explains most of the frustration people have with this question. The split exists in the food and in the laboratory analysis. It is simply not required to appear in front of you.
What legally counts as fiber in the first place
The FDA definition has two tracks, and the difference between them is the most useful thing to know when comparing a vegetable with a supplement.
Track one: intrinsic and intact. Non-digestible soluble and insoluble carbohydrates with three or more monomeric units, plus lignin, that are naturally present and intact in plants. This counts automatically. It is the fiber in a carrot, a bean or a slice of whole grain bread.
Track two: isolated or synthetic. Non-digestible carbohydrates that have been extracted or manufactured count as dietary fiber only if the FDA has determined they have physiological effects beneficial to human health. The agency has approved a closed list of seven.
| Approved isolated or synthetic fibers | Typically from |
|---|---|
| Beta-glucan soluble fiber | Oats and barley |
| Psyllium husk | Plantago ovata seed husk |
| Cellulose | Plant cell walls, wood pulp |
| Guar gum | Guar bean |
| Pectin | Fruit, especially citrus and apple |
| Locust bean gum | Carob seed |
| Hydroxypropylmethylcellulose | Synthetic, modified cellulose |
An added non-digestible carbohydrate outside that list can be in a product without counting toward the fiber declared on the label. This is the mechanism behind the wider comparison in SaladPower vs. fiber powders.
The health claims the FDA has actually authorized
Fiber is unusual in that the FDA has authorized specific health claims involving it, with the wording and the qualifying conditions written into the regulation. These are claims about diets, not about any single product, and they are worth quoting because they show exactly how far the evidence has been judged to go.
Soluble fiber and heart disease, 21 CFR 101.81
This is the narrow one. It applies only to a defined list of eligible sources, and the daily amounts are specific.
| Eligible source | Daily intake associated with reduced CHD risk | Minimum per serving to bear the claim |
|---|---|---|
| Beta-glucan soluble fiber from whole oats or barley | 3 g or more per day | 0.75 g per serving |
| Soluble fiber from psyllium seed husk | 7 g or more per day | 1.7 g per serving |
Vegetables are not on that list. The soluble fiber in a carrot is real soluble fiber, but this particular authorized claim was built on oats, barley and psyllium, and it does not extend beyond them.
Fruits, vegetables and grains, 21 CFR 101.76 and 101.77
Two older authorized claims do name vegetables directly. The model wording, which appears in the regulation itself, is:
"Low fat diets rich in fiber-containing grain products, fruits, and vegetables may reduce the risk of some types of cancer, a disease associated with many factors." (21 CFR 101.76)
"Diets low in saturated fat and cholesterol and rich in fruits, vegetables, and grain products that contain some types of dietary fiber, particularly soluble fiber, may reduce the risk of heart disease, a disease associated with many factors." (21 CFR 101.77)
Both come with conditions a food must meet before it may carry the claim.
| Condition | 101.76 (cancer) | 101.77 (heart disease) |
|---|---|---|
| Food type | Is or contains a grain product, fruit or vegetable | Is or contains a fruit, vegetable or grain product |
| Fat limits | Meets "low fat" | Meets "low saturated fat", "low cholesterol" and "low fat" |
| Fiber requirement | "Good source" of dietary fiber without fortification, which is 10 to 19 percent of the Daily Value | At least 0.6 g soluble fiber per serving without fortification |
| Label requirement | None specific to fiber | Soluble fiber must be declared on the nutrition panel |
| Hedging language | Must say "may" or "might", and must use "some types of cancer" | Must say "may" or "might" |
Notice what the regulation itself insists on: "may", "might", and "a disease associated with many factors". Even in a claim the FDA has authorized, the agency requires the sentence to concede that diet is one factor among many. That is a useful calibration for any bolder claim you encounter elsewhere.
We do not carry either claim on SaladPower. Whether a given product qualifies is a labeling determination rather than an arithmetic one, and the 101.77 route additionally requires a declared soluble fiber figure, which our panel does not carry. We are describing these claims here as facts about US food labeling, not asserting them about our own pouch.
So which one should you be looking for?
| If your goal is | Lean toward | Practical version |
|---|---|---|
| Regularity and bulk | Insoluble | Whole grains, vegetable skins and stalks, nuts |
| Blood cholesterol | Soluble | Oats, barley, beans, psyllium, apples, citrus |
| Steadier blood sugar response | Soluble | Legumes and whole fruit rather than juice |
| Feeding gut bacteria | Both, and variety above all | More different plants, not just more grams |
| Simply hitting 28 g a day | Whichever you will actually eat | See the daily target below |
For the target itself and how far most people are from it, see how much fiber you need a day. For the gut-bacteria question specifically, see probiotics or fiber and how many different plants you should eat in a week.
Where SaladPower sits
An 8 oz pouch contains 5 grams of total dietary fiber, 18 percent of the Daily Value, all of it intrinsic and intact in the six whole organic ingredients: spinach, kale, carrot, broccoli, apple and lemon. Nothing is added to raise the number. Like the vegetables it is made from, it carries a mixture of both types, with apple and carrot contributing on the soluble side.
We do not publish a soluble and insoluble split, for the reason set out above: that analysis is voluntary and we have not commissioned it. Stating a figure we have not measured would be worse than saying so plainly. The pouch is commercially processed, sealed and shelf-stable, and delivers 2x the USDA daily recommended vegetable intake.
Frequently asked questions
Do I need more soluble or more insoluble fiber?
Both, and there is no official separate target for either in the United States. The Daily Value of 28 grams applies to total dietary fiber. Eating a range of whole plant foods delivers a mixture without any need to track the split.
Why does my food label not show soluble and insoluble fiber?
Because declaring them is voluntary under 21 CFR 101.9(c)(6)(i). A manufacturer is only required to declare soluble fiber when a claim about soluble fiber is made on the label or in labeling.
Which fiber lowers cholesterol?
Soluble fiber is the type associated with blood cholesterol, and the FDA has authorized a health claim for two specific sources: 3 grams a day or more of beta-glucan soluble fiber from whole oats or barley, and 7 grams a day or more of soluble fiber from psyllium seed husk. That claim does not extend to vegetables.
Do vegetables have soluble fiber?
Yes. Carrots, apples and citrus are well known for pectin, a soluble fiber, and most vegetables contain a mixture of both types. The authorized soluble fiber heart claim is limited to oats, barley and psyllium, which is a fact about that specific claim rather than about the fiber in vegetables.
Does added fiber in a processed food count the same?
Only if the FDA has approved it. Fiber intrinsic and intact in plants counts automatically. Isolated or synthetic non-digestible carbohydrates count only if they appear on the FDA's approved list, which currently holds seven: beta-glucan soluble fiber, psyllium husk, cellulose, guar gum, pectin, locust bean gum and hydroxypropylmethylcellulose.
Sources
- 21 CFR 101.9(c)(6)(i), definition of dietary fiber, the approved isolated and synthetic fiber list, and the voluntary declaration of soluble and insoluble fiber. eCFR.
- 21 CFR 101.81, health claim for soluble fiber from certain foods and risk of coronary heart disease. eCFR.
- 21 CFR 101.76, health claim for fiber-containing grain products, fruits and vegetables and cancer. eCFR.
- 21 CFR 101.77, health claim for fruits, vegetables and grain products that contain fiber, particularly soluble fiber, and risk of coronary heart disease. eCFR.
- 21 CFR 101.54, nutrient content claims including "good source" and "high". eCFR.
- US Food and Drug Administration. "Daily Value on the Nutrition and Supplement Facts Labels." fda.gov.
- Callahan A. "Are You Eating Enough Fiber?" The New York Times, September 15, 2026. Read the original article.
- SaladPower Nutrition Facts panel, 8 oz pouch.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
