Inulin: 14 Foods That Naturally Contain This Weight-Loss-Friendly Prebiotic Fiber

Written by Kayleigh Roberts

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Eating your vegetables might make you feel responsible, even a little grown up, but actively prioritizing something like, say, fiber? Now that feels like a sure sign of adulthood. But it turns out it's something we should all be doing.

Increasingly, we're learning that fiber is pretty darn amazing for boosting satiety, improving digestion, and keeping our population of good gut bacteria happy and plentiful—which comes with its own slew of head-to-toe health benefits.

But did you know there are different types of fiber, beyond just soluble and insoluble? One variety of soluble fiber that's gotten a lot of attention lately is inulin, and in addition to good digestion, it may be particularly beneficial for weight loss and stable blood sugar levels.

Here, learn everything you need to know about inulin fiber's health benefits, where it’s found naturally in food, and how to incorporate more into your diet.

What is inulin?

Inulin is, as we said above, a kind of soluble fiber. It's found naturally in certain plants (more on those in the next section), and it's indigestible by your small intestine. This allows inulin to continue riding the digestive tract train down to the large intestine, where it really works its magic.

The reason inulin can't be digested by the small intestine? Because it's a "fructan," which means it's comprised of fructose molecules that are linked together in a special, digestion-proof way. When it makes its way down to the large intestine intact, inulin is able to act as a prebiotic, meaning it's a source of food for the beneficial probiotic bacteria in your gut.

The gut bacteria that feast on (and get strength from) inulin help keep your body healthy by fighting off pathogens (aka "bad" bacteria), preventing infection, stimulating the immune system, and promoting healthy nerve function, among other things.

Now that you understand a little about inulin's role in the body, let's look at some inulin-containing foods you can incorporate into your diet.

14 foods that naturally contain inulin.

Nestled in plant foods from around the world, some inulin-rich foods are probably already a regular or semi-regular part of your diet. Either way, this can serve as inspiration for your shopping list if you decide to make an effort to increase the amount of inulin in your diet.

  • Leeks
  • Asparagus
  • Dandelion greens
  • Chicory root
  • Yacon root
  • Jerusalem artichokes (also known as "sunchokes")
  • Garlic
  • Onions
  • Wheat
  • Oats
  • Soybeans
  • Bananas
  • Wild yams
  • Jicama

One very important note: Anyone following a low-FODMAP diet should be sure to steer clear of inulin-containing foods. Inulin is a fructan, and fructans are part of the oligosaccharides group in the FODMAP acronym and can cause digestive distress for some people with IBS.

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Health benefits of inulin.

Beyond feeding the good bacteria in your gut, increased inulin intake may have several other perks. Many potential benefits of this fiber have been studied, with varying results. Here's an overview of the most promising potential benefits of inulin so far:

1. Inulin promotes a healthy digestive tract.

Directly related to its function as a prebiotic fiber, inulin plays a natural role in promoting digestive health. Like other dietary fibers that can't be broken down by the enzymes in the small intestine, inulin enters the large intestine and colon ready to work. In the gut, inulin works to increase the number of several different kinds of good bacteria, but particularly Bifidobacteria and Lactobacilli.

The probiotics that inulin supports are among those responsible for regulating digestion and keeping the immune system strong. By helping keep the balance of good and bad bacteria in check, inulin helps overall gut and digestive health immensely.

2. Inulin may promote weight loss.

In addition to maintaining the balance of good and bad bacteria and promoting healthy digestion, inulin may also help promote weight loss, according to some studies.

The first way that inulin helps promote weight loss is by helping you feel fuller longer—making you less likely to overeat. Inulin is a soluble fiber, which means that, upon ingestion, it absorbs liquid and swells into a gelatinous substance. This makes you feel full right away and also slows down the digestive process, making that full feeling last even longer.

In one study, a group of overweight and obese adults took 21 grams of inulin daily, and the supplement was shown to decrease their hunger hormone levels (and increase their fullness hormone levels). At the end of the study, which lasted for 12 weeks, the participants who had been taking inulin supplements lost over 2 pounds, on average, compared to a control group whose members gained a pound during the same time period.

Another study tracked the weight of people with prediabetes who took either inulin or another form of fiber called cellulose. At the end of the 18-week study, the inulin group lost 7.6 percent of their body weight, while the cellulose group lost just 4.9 percent.

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3. Inulin may help balance blood sugar levels.

Inulin's role in controlling blood sugar is tied to the same attributes that make it a potential weight loss aid. Remember, inulin slows the digestion process—this means it slows down the digestion of carbohydrates. Since blood sugar levels rise as carbs are broken down, digesting them quickly can lead to dangerous spikes for people with diabetes, prediabetes, or other blood-sugar-related health issues. As inulin slows digestion, it slows the release of sugar into the bloodstream, which in turn promotes healthy, stable blood sugar levels.

Research into the effects of inulin on blood sugar levels has centered on participants with diabetes and prediabetes, for obvious reasons. And that research shows promise, with several studies demonstrating that inulin helps control blood sugar levels for these groups.

Furthermore, there's evidence that one kind of inulin in particular, high-performance inulin, may reduce levels of liver fat in patients with prediabetes. This could have huge implications for diabetes treatment since reducing liver fat can also reduce insulin resistance and even possibly help reverse type 2 diabetes.

4. Inulin may help treat IBS and constipation.

Since inulin plays such a key role in digestive health and spends so much of its time in the colon, it's no surprise that its benefits extend to promoting healthy bowel movements.

Increasing the amount of inulin in your diet has been shown to increase the frequency and improve the consistency of bowel movements, particularly among older adults. For people who suffer from IBS, inulin supplements could offer some release. Several animal studies suggest that insulin can help reduce the inflammation associated with IBS. There have also been human studies that suggest inulin can help reduce symptoms of ulcerative colitis and inflammation related to Crohn's disease. But doctors don't yet recommend inulin as a treatment for these conditions.

Also keep in mind, people with these digestive conditions who are also sensitive to FODMAPs may actually experience worsened symptoms when they consume inulin-containing foods. So it's important to listen to your body.

5. Inulin may help prevent colon cancer.

Among inulin's most impressive benefits is as a potential preventive measure against colon cancer. During its time in the colon, inulin ferments into the short-chain fatty acid butyrate, which is thought to protect colon cells with its powerful anti-inflammatory and antioxidant properties.

Most of the research that's been conducted on inulin and colon cancer to date has focused on animals. But it's still promising. For instance, in one notable review of a dozen animal studies, 88 percent of the mice that received inulin supplements had fewer precancerous colon growths than the mice that did not receive inulin.

One human study looking into the relationship between inulin and colon cancer found that inulin made the colon a less favorable environment for cancer development. But these findings aren't yet conclusive.

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How much inulin should you be consuming?

Most people can get enough inulin in their diet by incorporating plenty of the foods on the above list and aiming for 25 to 30 grams of total fiber in your diet per day.

Out of that fiber total, try to aim for 5 grams of fiber from prebiotic or inulin foods a day, suggests Dr. Bindiya Gandhi, M.D., American Board Family Medicine–certified physician. Shifting your diet to contain more vegetables, fruits, and whole grains in general will go a long way toward increasing your inulin intake. "There are additional inulin prebiotic supplements you can take," she says, "but I always encourage getting your nutrition through your diet first."

If you do decide to supplement, the most popular forms of inulin are powders and capsules. With inulin, it's particularly important to start slow and work your way up, as the side effects are significantly more severe if you take too much too soon. A good general guideline: Start with 2 to 3 grams of inulin per day for one to two weeks, then slowly increase by 1 to 2 grams each week, and do not exceed 10 grams per day.

Not everyone needs to take (or can even tolerate) larger doses of inulin. So listen to your body and talk to your doctor if you need guidance, especially if you're using inulin to help manage a health condition.

Side effects of inulin supplements.

Taking inulin supplements is generally considered safe, and allergic reactions to inulin are extremely rare. That said, however, there are some side effects associated with inulin that many people may experience. The most common side effects associated with inulin are flatulence, bloating, abdominal discomfort, and loose stools or diarrhea. People who are intolerant to FODMAPs tend to experience more intense side effects and should avoid inulin.

If you are pregnant, have a chronic health condition, or currently take a prescription medication, consult your doctor before starting inulin to ensure it's safe and that you're taking an appropriate dose.

Ready to learn more about how to unlock the power of food to heal your body, prevent disease & achieve optimal health? Register now for our FREE web class with nutrition expert Kelly LeVeque.

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