WARNING!
This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.
By Dr. Mercola
Inulin is a type of water-soluble prebiotic fiber found in onions, leeks, garlic, asparagus, Jerusalem artichoke and many other foods. Prebiotics are indigestible to you, but they help nourish beneficial bacteria in your body.
These beneficial bacteria in turn assist with digestion and absorption of your food and play a significant role in your immune function. Inulin is a fructan, which means it is made up of chains of fructose molecules.
In your gut, inulin is converted into short-chain fatty acids (SCFAs) that are then converted to healthy ketones that feed your tissues. SCFAs may also nourish colon cells and produce more appetite-controlling hormones in your body.1
As such, inulin has multiple benefits to your health, although there are some risks you should be aware of as well.
Inulin May Lower Your Risk of Diabetes
Among obese women, consuming inulin beneficially changed their gut microbiota composition in a way that might help promote weight loss or lower the risk of diabetes.2
Further, among women with type 2 diabetes, those who took inulin had improved glycemic control and increased antioxidant activity.3 It’s thought that inulin may work to improve diabetes by positively modifying gut microflora or due to a direct antioxidant effect.
Prolonged exposure to excess insulin causes oxidative stress, which is thought to play a key role in type 2 diabetes and its complications. Inulin may help to counteract this with its antioxidant effects.
In addition, a high-performance type of inulin was found to decrease liver fat in people with pre-diabetes.4
Women with type 2 diabetes who took 10 grams of high-performance inulin a day also had decreases in fasting blood sugar (by 8.5 percent) while A1c levels (a measure of long-term blood sugar control) dropped by 10.5 percent.5
Inulin Promotes Weight Loss
A number of studies have shown the potential for inulin to help with weight loss. Among overweight and obese adults, those who took 21 grams of inulin a day had decreases in their hunger hormone and increase in satiety hormones.
Further, they lost more than two pounds while the control group gained one pound.6,7 Among people with prediabetes, meanwhile, those taking inulin for 18 weeks lost 7.6 percent of their body weight compared to the control group’s 4.9 percent.8
A study in mice also showed the potential for inulin to help with weight loss.
Mice fed a high-fat diet with or without inulin or beta-glucan (another prebiotic) experienced lower body weight gain, significantly less total body fat and an increase in the numbers of beneficial bacteria, including Bifidobacterium and Lactobacillus-Enterococcus.9 According to the researchers:
“… [T]he lower body fat content induced by inulin may be metabolically advantageous … Differential effects of fermentable carbohydrates open new possibilities for nutritionally targeting appetite regulation and body composition.”
How ‘Fermentable Fibers’ May Be Protective to Your Health
One way that a high-fiber diet may be protective against obesity and diabetes has to do with your intestinal bacteria’s ability to ferment fibers.
Inulin is one such fermentable fiber, which the bacteria in your intestines ferment into butyrate and propionate — SCFAs involved in sugar production. As reported by Medical News Today:10
“The researchers explain that glucose has certain elements that are detected by nerves located in the vein that collects blood from the intestine — known as the portal wall. A nerve signal is then transmitted to the brain.
The brain then activates a series of defenses against diabetes and obesity in response to the signal. The defenses include increased satiety, increased energy expenditure during periods of rest and less glucose production from the liver.”
In an animal study, mice fed a diet rich in fibers gained less weight and had protection against diabetes, unlike mice fed a diet without fiber supplementation.11
When mice engineered to not produce glucose were used in the study, they gained weight and developed diabetes even when fed a high-fiber diet. Medical News Today continued:12
“These findings suggest that it is the glucose-producing activity of the intestines as a result of propionate and butyrate, and intestinal bacteria, that cause fermentable fibers to protect against obesity and diabetes.”
What Else Is Inulin Good For?
Inulin offers a number of additional potential benefits, including:13
- Heart Health: Inulin may lower blood triglycerides and cholesterol.14
- Bone Health: Inulin improves absorption of calcium and magnesium, leading to improved bone density and bone mineralization in children.15,16
- Colon Cancer: There is research showing inulin may reduce precancerous colon growths, lead to less inflammation and fewer precancerous cell changes in animal studies, and support a less favorable environment for colon cancer development in humans.17
- Inflammatory Bowel Disease (IBD): Research isn’t definitive, but it appears inulin may help reduce symptoms of ulcerative colitis and reduce inflammatory markers in Crohn’s disease.18
- Constipation: Daily supplementation with 15 grams of inulin improved constipation and quality of life in elderly people with constipation.19
In addition, by feeding and enhancing beneficial bacteria in your gut, inulin helps to stimulate and support your immune system.
Risks of Inulin If You’re FODMAP-Intolerant
Unfortunately, like antibiotics, inulin is indiscriminate and it not only feeds beneficial bacteria but may also fuel the growth of disease causing bacteria like klebsieilla a bacteria implicated in ankylosing spondylitis and leaky gut.
FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols) are short-chain carbohydrates that are difficult for some people to digest. Instead, they’re fermented by your gut bacteria, causing gas, pain, bloating and diarrhea.
FODMAPs are found in many foods and include lactose in some dairy, fructose, galactans (found in some legumes), polyols (found in sweeteners like xylitol, sorbitol, maltitol and mannitol) and fructan (i.e. inulin).
Most people digest FODMAPs with no problem, but if you have gut problems, particularly irritable bowel syndrome (IBS), FODMAPs may be problematic for you.
Ragweed Allergies Are Another Sign of Potential FODMAP Intolerance
A low-FODMAP diet was found to be as effective as drug treatment in relieving IBS symptoms,20,21 and FODMAPs may also be involved in other gastrointestinal conditions and may pose a risk to people with ragwood allergies. As reported by Authority Nutrition:22
“ … [P]eople who are intolerant to FODMAPs are likely to experience significant side effects. Those who are allergic to ragweed may also have worsened symptoms after taking it.
Additionally — and very rarely — people with a food allergy to inulin may experience an anaphylactic reaction, which can be dangerous. If you take more than a small amount, then you’re likely to experience some side effects in the beginning …
For example, oligofructose (a type of inulin) has been shown to cause significant flatulence and bloating for people taking 10 grams per day.
Inulin from chicory root can generally be taken at higher dosages, but some people reported slight stomach discomfort at 7.5 grams a day. You can minimize your risk of discomfort by slowly increasing your intake over time, which helps your body adjust.”
What Are the Best Food Sources of Inulin?
Eating foods that are rich in inulin is a safe way for most people to experience the benefits of inulin without side effects. Some of the best food sources include:
If you choose to take inulin in supplement form, start with a small amount to be sure it’s well tolerated, then gradually increase the dose. Authority Nutrition continued:23
“If you decide to supplement, begin with no more than 2 to 3 grams a day for at least 1 to 2 weeks. Then, slowly increase your intake by 1 to 2 grams a week until you’re taking 5 to 10 grams a day. Most of the studies used 10 to 30 grams per day, gradually increasing over time.
The side effects should also improve with continued use. However, not everyone may be able to tolerate the amounts listed here.”
If you experience some bloating or gas when taking inulin, it could also be a sign that your gut bacteria ratio is not properly balanced. Whether you have IBS or not, an unhealthy gut can contribute to FODMAP intolerance, whereas introducing inulin to a healthy gut is likely to promote beneficial processes.
Inulin Is Only One Part of a Healthy Gut
Inulin is by no means a “cure-all” for gut problems. Rather, it represents one piece of the puzzle. Only by putting together all of the pieces will your gut health truly flourish. The best way to optimize your gut flora is through your diet. A gut-healthy diet is one rich in whole, unprocessed, unsweetened foods, along with traditionally fermented or cultured foods.
But before these powerful foods can work their magic in your body, you have to eliminate the damaging foods that get in their way. A good place to start is by drastically reducing grains and sugar and avoiding genetically engineered ingredients, processed foods and pasteurized foods. Sugar promotes the growth of pathogenic yeast and other fungi.
Grains containing gluten are particularly damaging to your microflora and overall health. This would be a good time for you to review the table below that lists foods, drugs and other agents that harm your beneficial microbes — so that you can avoid as many as possible. By avoiding harmful agents and introducing beneficial ones, i.e. inulin and beneficial bacteria, your gut health, and your overall health, will thrive.