Irritable Bowel Syndrome and Dietary Fiber: What You Need to Know

Irritable Bowel Syndrome and Dietary Fiber: What You Need to Know
  • Dietary fiber helps the body move waste through the gut and can improve common symptoms of IBS, including both diarrhea and constipation.
  • There are two main types of fiber: soluble and insoluble. Soluble fiber can help with diarrhea and constipation, while insoluble fiber is best for constipation only.
  • Regardless of your symptoms, we all need dietary fiber, as it helps regulate blood sugar, lower cholesterol and keep us feeling full.

When considering treatment for irritable bowel syndrome (IBS), you’ll hear a whole lot about fiber. No matter if you have IBS with diarrhea (IBS-D), IBS with constipation (IBS-C) or mixed, the resounding advice is as follows: eat more fiber. Indeed, this essential carbohydrate is good for everyone, but why? How can it be so beneficial to both seemingly opposite types of IBS? In this guide, we’re covering everything you need to know about IBS and dietary fiber so you can learn how to use food to build an IBS diet plan that works for you.

What Is Dietary Fiber?

Found in whole grains, legumes, fruits and vegetables, dietary fiber is a pillar of the human diet. Unlike other nutrients, fiber passes through the system relatively unchanged because it’s resistant to digestion, in part because our bodies don’t make the right enzymes to break it down. Dietary fiber has the ability to stabilize the gastrocolic reflex and intestinal muscles — which form the part of the digestive tract responsible for moving food through the system — so it is especially valuable to people who suffer from IBS.

Because fiber has such a measurable impact on the way food passes through the body, it can cause both positive and negative effects for many people. If you feel that consuming fiber has a tendency to trigger your IBS symptoms, you’re probably onto something because it can certainly worsen the condition, particularly for those with IBS-D. However, fiber can also have the opposite effect, and it’s crucial to your overall health and well-being, so you need to find ways to safely include it in your diet. That’s what we’re here for!

How Much Fiber Should You Eat?

So how much fiber are you supposed to eat? The recommendation for adults is about 22 to 30 grams of fiber per day. For people  19 to 30 years old, the recommendation is 28 grams per day for women and 33.6 grams per day for men. For people  31 to 50 years old, the recommendation is 25.2 grams per day for women and 30.8 grams per day for men. For people who are 51 and older, the recommendation is 22.4 grams per day for women and 28 grams per day for men.

How Much Fiber Should You Eat

For reference, a cup of black beans contains 15 grams of fiber, a cup of oatmeal contains five grams of fiber and a cup of green peas contains nine grams of fiber.

Seems attainable, right? Surprisingly, research shows that on average, most American adults only consume about 10 to 15 grams of fiber per day. It’s often recommended that those with IBS increase their fiber intake to between 20 to 35 grams per day, but because different types of fiber can elicit different gut responses, you need to be strategic about how you get those grams. But don’t worry because we’re covering all of that below!

How do you get fiber? Luckily, dietary fiber is found in abundance in a healthy diet, and many people are able to achieve their daily intake through diet alone. However, dietary fiber supplements — found in powder and capsule form — can help you reach your daily goals if you’re having trouble getting enough through food. 

Fiber rich foods

Soluble and Insoluble Dietary Fiber

There are two primary kinds of fiber: soluble and insoluble. Both types are found naturally in our foods and can help improve digestive performance, though they have very different effects. Most plant-based foods contain a combination of soluble and insoluble fiber, but many foods are especially rich in one or the other. Knowing which kind to eat at any given time can help you better manage your IBS symptoms.

  • Soluble Fiber: Dissolves in Water — Soluble fiber attracts and absorbs water, which helps make you feel full, slows down digestion and lowers blood sugar. Foods high in soluble fiber include starches like rice, potatoes and yams, as well as oats, black beans, chia seeds and Brussels sprouts. As soluble fiber travels through your system, it softens and breaks down food, turning it into a more easily digestible substance. This is beneficial in preventing both diarrhea and constipation. 
    • Diarrhea — When your stool is mostly liquid, the muscles in the bowels don’t have anything to grip onto, so the food passes through the intestines quickly, causing diarrhea. Since soluble fiber absorbs excess liquid, it can help slow the digestive process and firm up stool. 
    • Constipation — At the same time, soluble fiber can help people with constipation because it draws in more water, which can soften and break apart hard stool, allowing you to pass it more easily. People with constipation may also want to add more insoluble fiber to their diet (more on this below) because it helps speed up the transit of food.
  • Insoluble Fiber: Repels Water — Unlike soluble fiber, insoluble fiber doesn’t absorb water. Instead, it adds bulk to your stool and helps it move through the intestines more quickly. Foods high in insoluble fiber include those that are rough, stringy or have tough skin, such as seeds, legumes, greens, celery, zucchini and nuts. Due to the fact that it triggers a powerful gastrocolic reflex, a diet high in insoluble fiber is beneficial to people who suffer from constipation, but not recommended for those with diarrhea.  

Tips for Working Fiber Into Your IBS Meal Plan

So now that you know which type of fiber is best suited to your specific situation, it’s time to formulate a plan for how to get the right amount of it. A well-designed IBS meal plan must take fiber into account, whether it’s consumed via food or supplementation. Here are some quick and easy tips for how to boost your fiber intake.

  • Focus on Hitting Your RDA Physicians recommend that patients with IBS shoot to consume about 20 to 35 grams of dietary fiber per day to help regulate digestion and reduce pain. For many people, that falls in line with the recommended daily allowance (RDA). Since most people are only getting about half of the fiber they need, the RDA can serve as a great benchmark for people with IBS who want to try increasing their fiber intake for gut health. Remember: There is definitely such a thing as too much fiber, and excessive amounts can actually leave you in a worse place than where you started.
  • Consider a Low-FODMAP Diet Following a low-FODMAP meal plan can do wonders for people with IBS because it drastically reduces or even eliminates the consumption of highly fermentable carbohydrates that tend to trigger symptoms like diarrhea, constipation, gas, bloating and stomach pain. Despite the fact that it removes some foods from your diet, the low-FODMAP plan is still rich with high-fiber foods. We’ve listed some of the best high-fiber, low-FODMAP foods below. 

 Best high fiber low fodmap foods

  • Keep the Skin On — When you’re aiming to increase your daily fiber consumption, remember that many vegetables store a lot of their fiber power in their skins. This is certainly true with foods like potatoes, green beans, carrots and eggplants. In fact, studies show that unpeeled fruits and veggies may contain as much as 33 percent more fiber than those that have been peeled. Even seemingly inedible skins can be worked into your diet for a bit more fiber. For example, citrus peels can be grated into a zest for a pop of fiber (and flavor)! 
  • Be Careful with Insoluble Fiber — There are a few important rules you need to know about insoluble fiber to ensure that it doesn’t toss your belly into an explosive state. Because it’s such a powerful gastrocolic reflex stimulator, eating too much insoluble fiber or eating it at the wrong times can mean bouts of diarrhea, cramping and discomfort. Follow these rules for the best results:
    • If your stomach is empty, be sure to eat a bit of soluble fiber before you consume insoluble fiber for the day. Eating insoluble fiber on an empty stomach can cause diarrhea and discomfort.
    • Always pair insoluble fiber with an equal or larger serving of soluble fiber. It’s also a good idea to pair fat, which also has a powerful effect on the gastrocolic reflex, with an equal or larger serving of soluble fiber.
    • Always spread out your insoluble fiber consumption throughout the day. Too much in one sitting could lead to gastronomic distress.
    • Never drastically increase your fiber consumption. Work your way up to your recommended daily allowance in increments.
  • Don’t Be Afraid to Try Supplements The truth is that you can definitely get your recommended daily amount of fiber through food alone, but if you’re finding it difficult to reach your daily goals, taking a daily fiber supplement can help. Luckily, there is no evidence that daily use of a fiber supplement is harmful, but it can reduce the absorption of some medications, including aspirin and carbamazepine. With that said, the best way to get your daily fiber is through your diet because high-fiber foods tend to be rich in vitamins and minerals.

Vitamins And Supplements

Other Benefits of Dietary Fiber

As you can see, high-fiber foods can serve as an incredible tool for digestive health. They can be leveraged to suit a wide variety of IBS types and symptoms, no matter if you struggle with diarrhea, constipation or a mix of the two. However, that’s not all fiber’s good for! The stuff is crucial to our overall health and well-being, providing an array of benefits to help keep us healthy and stave off disease. That’s why it’s so important to find space for it in your diet.

  • It Lowers Cholesterol — Got high cholesterol? You might want to consider increasing your fiber intake. This key nutrient reduces the absorption of cholesterol into your bloodstream and helps lower levels of low-density lipoprotein (LDL) cholesterol, otherwise known as “bad” cholesterol. 
  • It Helps Control Blood Sugar — Soluble fiber, in particular, is known to help delay the rate at which sugar absorbs into the blood, which can help your body control blood sugar. This may reduce your risk of diabetes.
  • It Helps Maintain Gut Bacteria — The good bacteria in your gut can help regulate digestion and, since it helps stave off the bad strains of bacteria, can keep you safe from many serious health conditions. Good bacteria feed off fiber, which helps you maintain a healthy balance of microbiota.
  • It May Help You Lose Weight — Fiber is amazing because one of its core functions is to expand in your stomach and make you feel full. This can help you reduce your calorie consumption and lose weight. Be sure to integrate plenty of fiber into your diet if weight loss is an ultimate goal.

Try Our IBS Meal Plan Delivery

Try Our IBS Meal Plan Delivery

From calculating fiber intake to figuring out your trigger foods, creating an IBS-friendly diet can be surprisingly stressful. Want an easier option? Try ModifyHealth’s low-FODMAP meal delivery options to help you take and maintain control over your IBS symptoms. Featuring delicious, perfectly calculated meals with ample nutrients and the right amount of fiber, our system can help you discover what’s causing your digestive woes or set you off on a path of trigger food-free eating.

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