However, not all dietary fibers are created equal. For example, there are soluble and insoluble fibers, which work in different ways to offer different benefits.
Looking to increase your fiber intake and get the best of both worlds? The good news is that there are plenty of foods that include both types of fiber, making it much easier to diversify your diet (and therefore your gut) with a two-for-one deal. We asked Megan Rossi, PhD, RDdietitian, gut health researcher at King’s College London, and author of How to eat more plantsto share the best foods that contain both, as well as some key facts about fiber sources.
The benefits of different types and sources of fiber
In simple terms, soluble fiber dissolves in liquid while insoluble fiber does not. What Dr Max Pitmangastroenterologist and medical director of Salvo Health, previously said Good + Good, the former slows down digestion and can be helpful for diarrhea, bloating, and abdominal discomfort, while the latter can speed up digestion and is therefore more helpful for constipation. Still, she explained that eating both types of fiber can offer a variety of benefits, “including stabilizing blood sugar, promoting digestive regularity, lowering cholesterol, and even reducing the risk of developing heart disease and many cancers.” .
But before delving any further, Dr. Rossi points out that it may be more appropriate to classify fiber under different terms. “Interestingly, over a decade ago, the Food and Agriculture Organization of the United Nations recommended that we stop using the words ‘soluble’ and ‘insoluble’ to describe fibres, as there are close to a hundred different types and not they fit neatly into these categories,” says Dr. Rossi. Instead, he notes that we’re better off prioritizing fiber sources and their unique properties.
For example, Dr. Rossi mentions psyllium husk fiber and inulin fiber, both of which are soluble by definition. “Psyllium husk is a really great fiber for things like constipation,” he shares. “We know that bacteria aren’t very good at digesting them, so it’s more beneficial for gut symptoms rather than fertilizing the bacteria, so to speak.” On the other hand, he continues, inulin is a fiber that works “like a fertilizer and is fermented by bacteria, producing a variety of anti-inflammatory chemicals.” As beneficial as inulin itself can beDr. Rossi warns that this soluble fiber can actually trigger problems in people struggling with IBS. (If you are one of them, you may want to refrain from chewing specific foods rich in inulin.)
In any case, prioritizing fresh, plant-based foods in your diet is always a good option to load up on a variety of nutrients to support your gut and better health. “Whole [plants] they contain multiple types of fibers, all of which have different functionalities”, reiterates Dr. Rossi. “Different fibers can feed different gut bacteria, and therefore you get a more diverse range of gut bacteria with more fiber diversity.” From there, he mentions that each bacterium offers different abilities, which together can ultimately promote a thriving gut microbiome and a cascade of benefits for digestion and beyond.
5 foods that contain soluble and insoluble fiber
This list of foods that offer soluble and insoluble fiber is not exhaustive; in fact, Dr. Rossi says that most fibrous plant-based foods actually contain a combination of both. (Good date: Leave the skins of fruits and vegetables whenever possible to load even more fiber). That said, if you need some inspiration before you make your next fiber purchase, consider stocking up on the following items.
1. chickpeas
Mediterranean chickpea salad or fresh hummus, anyone? “Half a can of chickpeas equals about 10 grams of fiber,” shares Dr. Rossi, which is more than a third of the FDA recommended daily value of 28 grams. “One of the types of fiber in chickpeas is galactooligosaccharides, a prebiotic that feeds anti-inflammatory gut bacteria like bifidobacteria,” he adds.
2. oatmeal
Whether you enjoy classic oatmeal, mix your oats overnight, or prefer to bake them into a treat, rest assured that oats provide both soluble and insoluble fiber (plus plenty of other micros and macros that can produce impressive benefits for your better health). “Forty grams of oatmeal contains four grams of fiber. Oats also contain beta-glucans, which can help lower blood cholesterol,” says Dr. Rossi.
3. almonds
Almonds are not just a star source of heart-healthy fats and plant-based protein. According to Dr. Rossi, they also contain about 3.5 grams of dietary fiber per 30-gram serving (equivalent to about 20 almonds), making them a great snack to have in your pantry to enjoy by the handful, on top of a salad or soaked and tossed into your favorite smoothie.
4. Firm Tofu
Dr. Rossi says that firm tofu is an excellent source of plant-based protein, making it a worthy substitute for animal proteins. Additionally, he shares that 125 grams (nearly 4.5 ounces) of firm tofu contains three grams of fiber in total. “It also contains phytoestrogens, which have been linked to reduced risk of breast cancer,” he adds.
5. Tomatoes
Lastly, Dr. Rossi recommends loading up on tomatoes if you’re looking for the best whole food sources that contain both soluble and insoluble fiber. “One tomato contains 1.5 grams of fiber and lycopene, a type of plant chemical that can help protect skin from UV damage,” he says. He can get his tomato fix in so many ways, from sauces and dips to any number of creative salad combinations. Consider cooking this Mexican chickpea and tomato stew— which happens to be one of my favorite plant-based recipes — to go the extra mile when it comes to soluble fiber, insoluble fiber *and* protein.
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