What Is Dietary Fiber?

Dietary fibers are indigestible components in plant-based foods that aid digestion and make us feel full for longer. They play an important role in maintaining a healthy and balanced intestinal flora and can help reduce the risk of various diseases.

Dietary fiber is either excreted practically unchanged in the stool or serves as food for certain gut microbiota.

Good to know: Dietary fiber is only found in plant-based foods such as cereals, vegetables, fruit, legumes, and nuts. Animal products do not contain dietary fiber. [1,2, 3]

How Do Dietary Fiber Foods Work in the Body?

Dietary fiber binds water and increases stool mass in the intestine, promoting bowel movement. It also serves as a source of food for important microbiota that initiate fermentation and produce short-chain fatty acids when eating and digesting the dietary fiber.

As dietary fibers are not broken down, they provide a good feeling of satiety. They have binding properties, stabilize blood sugar, and lower cholesterol levels. Fiber is therefore important for healthy sugar management and as a preventative measure against type 2 diabetes. [1]

Why Are Dietary Fiber Foods So Healthy?

Dietary fiber is extremely valuable due to its many positive effects on our health: it aids in digestion, promotes healthy intestinal flora, and reduces the risk of cardiovascular disease, diabetes, and even certain types of cancer. Dietary fiber foods contribute to weight control through their long-lasting feeling of satiety and help regulate blood sugar and cholesterol levels, which overall leads to improved general well-being.

We will now take a closer look at these individual positive effects on our health.

Intestinal Health

Dietary fiber foods are primarily known for their supportive effect on the intestines. Improving bowel movement and increasing stool mass can prevent constipation and counteract diarrhea. [4]

As dietary fibers swell and remain in the digestive tract longer, they leave us feeling full after eating dietary fiber foods. Dietary fiber also serves as "food" for the important intestinal bacteria, which keeps our gut flora healthy and balanced.

Prevention of Type 2 Diabetes

In the small intestine, soluble fiber forms a gel-like substance. This slows down glucose absorption into the bloodstream, resulting in fewer high blood sugar spikes and a more stable insulin release. Good satiety and slowed glucose uptake together support sustainable weight control and protect against type 2 diabetes [5,6,7].

The above-mentioned gel-like substance binds bile acids, which are important for fat digestion and consist mainly of cholesterol. When bound, they are excreted, forcing the liver to use additional cholesterol from the bloodstream to produce bile acid. This leads to a certain reduction in cholesterol levels and means that fiber is important not only for our sugar metabolism but also for our fat metabolism. [8]

Arterial Health

Dietary fiber foods can also improve arterial health by lowering LDL. They lead to an optimized regulation of blood flow and can, therefore, help lower blood pressure. Stable blood sugar and improved insulin sensitivity (and the associated weight reduction) are also very helpful in lowering blood pressure.

But the little superheroes can do even more - dietary fiber foods can also reduce the risk of a stroke, even if we only eat low amounts of them. [9,10]

Protection Against Cancer

Studies also indicate that dietary fiber can protect against cancer because improved bowel movements and optimized intestinal activity mean that potentially carcinogenic substances are removed more quickly, thus reducing contact with the intestinal mucosa—which, incidentally, also means protection against leaky gut syndrome. [1]

Anti-inflammatory Properties

In addition, the fermentation of intestinal bacteria produces butyrate (fatty acid), which has anti-inflammatory properties and can inhibit the growth of cancer cells. And: dietary fiber can bind toxins in the intestine, including potentially carcinogenic substances. A high intake of soluble fiber is, therefore, also said to protect against breast cancer, both in peri- and postmenopausal women. [11,12]

Bone Health

Dietary fiber also has an impact on bone health. Soluble fiber can promote calcium absorption, which has an influence on both the structure and density of bones. One study showed that men benefit slightly more (and differently) from dietary fiber than women at an older age. Interestingly, fiber from cereals, legumes, or nuts, unlike vegetables, is said to have no effect on bone density in either women or men. [13]

Summary of the health benefits of dietary fiber:

• They aid digestion.
• They prevent constipation.
• They support a healthy gut microbiome.
• They regulate blood sugar and insulin sensitivity.
• They reduce cholesterol levels.
• They lower blood pressure.
• They reduce inflammation.
• They protect against cardiovascular disease.
• They protect against strokes.
• They protect against breast cancer.
• They increase the feeling of satiety.
• They help you lose weight.
• They bind toxins.
• They promote a healthy intestinal mucosa.
• They have a preventive effect against cancer.
• They promote bone health.

You may have noticed that there are two types of dietary fiber - soluble and insoluble fiber. We will explain this in the next chapter.

Soluble Fiber – Prebiotics

Soluble fiber dissolves in water and is also known as prebiotics. Our intestinal bacteria love prebiotics - they serve as food for them. The bacteria ferment the soluble fiber. This produces short-chain fatty acids, which positively affect the intestinal mucosa. [3]

The best-known soluble fibers include pectin, inulin, fructo-oligosaccharides (FOS), beta-glucans, psyllium, and galacto-oligosaccharides (GOS).

Pectin: apples, pears, oranges, grapefruits, berries, plums, damsons or quinces

Inulin (+ fructo-oligosaccharides (FOS)): found in chicory roots, Jerusalem artichokes, garlic, onions, leeks, asparagus, (green!) bananas. Inulin and FOS are prebiotic fibers with similar health benefits that differ in their chemical structure and chain length, but are often found in the same foods such as vegetables and whole grains.

Beta-glucans: found in oat products and barley products, shiitake and maitake (mushrooms).

Psyllium: psyllium husks

Galacto-oligosaccharides (GOS): are found in pulses, green beans, cabbage, broccoli, artichokes, onions, leeks, and carrots. Baby food is also often enriched with GOS to support the changes in the intestinal microbiome between the 6th and 12th month of life.

Insoluble Fiber

Insoluble fiber does not dissolve in water but can absorb water and thus swell. Therefore, it is important to drink enough when eating a high-fiber diet. Insoluble fiber provides bulk and thus loosens the stool, leading to a corresponding relief and balancing of both constipation and diarrhea. [2]

The most important insoluble fibers include cellulose, hemicellulose, lignin, and bamboo fibers.

Cellulose: Wheat bran, whole grains, celery, broccoli, and the skins of some fruits (apples, pears, grapes, cherries, kiwi (can be eaten with skin)

Hemicellulose: Whole grain products, nuts, legumes

Lignin: Whole grain products and in the skins of fruits and vegetables such as carrots, zucchini, or tomatoes

Bamboo fibers: Bamboo shoots

Which Are the Best Dietary Fiber Foods?

Foods such as whole grains, legumes, nuts, seeds, berries, green leafy vegetables, root vegetables, and fruits with peel are particularly high in fiber because they are unprocessed or minimally processed parts of plants that aid digestion and provide numerous health benefits. [1,2,3]

Whole Grain Products

Whole grain products such as whole grain bread, whole grain pasta, and oatmeal are rich in soluble and insoluble fiber. These dietary fiber foods promote digestion and can help to lower cholesterol levels. The fiber they contain ensures a long-lasting feeling of satiety, which can help with weight control. They also provide important nutrients such as B vitamins, iron, magnesium and selenium.

Pulses

Lentils, beans, and peas are legumes, which are excellent sources of fiber. They contain both soluble and insoluble fiber, which supports intestinal health and can reduce the risk of heart disease. Pulses are also rich in plant protein, making them an important source of nutrition for vegetarians and vegans.

Nuts and Seeds

Chia seeds, linseeds, and almonds are particularly high in fiber. In addition to soluble fiber, which can help you lose weight, they also contain healthy fats, proteins, and various micronutrients. These nuts and seeds can promote heart health and stabilize blood sugar levels thanks to the fiber they contain.

Berries

Raspberries and blackberries are delicious and rich in fiber and antioxidants. The fiber they contain can aid digestion and help prevent disease. Antioxidants protect cells from free radical damage and support overall health.

Green Leafy Vegetables

Spinach, kale, and other green leafy vegetables are good sources of fiber and contain important vitamins and minerals such as vitamin C, K, iron, and calcium. These nutrients support blood health, bone strength, and the immune system.

Root Vegetables and Tubers

Carrots, sweet potatoes, and other root vegetables are rich in fiber, vitamins, and minerals. They contain beta-carotene, an antioxidant that converts into vitamin A in the body and is important for healthy eyes, skin, and the immune system.

Fruit with Peel

Apples, pears, and oranges are fruity sources of fiber, especially when eaten with their peel. The soluble fiber they contain can help to lower cholesterol levels and promote heart health. They are also rich in vitamins and minerals that support various bodily functions.

How Can You Recognize Dietary Fiber Foods?

You can look out for a few characteristics when shopping for the highest fiber foods.

The texture: Rough, pithy – if you can eat the skin, the vegetables or fruit are usually high in fiber.

The degree of processing: Wholemeal products are always higher in fiber than white flour products.

Consistency: foods that swell (chia or linseed, lentils) are usually high in fiber.

Color: dark foods often contain more fiber than light ones.

Nutritional information: Read the nutritional information on the packaging. There, you will also find dietary fiber. These are sometimes also labeled as fiber.

How Much Dietary Fiber Foods Should I Consume Per Day?

The Swiss Society for Nutrition (SGE) recommends 30 grams of dietary fiber daily. Based on the assumption that our ancestors, the hunter-gatherers, consumed up to 100 g of fiber per day, this seems quite low. In fact, fiber intake was first significantly reduced with the Industrial Revolution.

The possibility of processing food and switching from coarse wholemeal products to soft white flour products became very popular. As a result, fiber intake fell drastically in the 19th and 20th centuries, and even today, many people find it difficult to get "only" 30 g of fiber a day.

You don't have to weigh your fiber in grams if you eat a healthy diet. Lots of vegetables and salads can be your base, which you can supplement with a few whole grains or pseudo-cereals such as quinoa and pulses, nuts or seeds, and the occasional fruit for dessert. If you stick to these staple foods, you're doing well in terms of dietary fiber and don't have to worry.

What Should You Look Out for When Eating Dietary Fiber Foods?

If you are not used to fiber, you should only increase the amount slowly and pay attention to how you react physically. Fiber can lead to severe bloating and even abdominal pain, so it is worth trying out fiber-rich foods gradually and then steadily increasing the amount.

The most important thing in connection with high-fiber foods is hydration: drink enough water throughout the day.

The correct preparation of some high-fiber foods is crucial. Legumes, in particular, can have very unpleasant effects on your intestines if they are not prepared properly. Pulses must be soaked for at least 24 hours before cooking. The soaking water must be poured away, and the pulses should then be rinsed with fresh water and cooked.

If possible, cereals should be eaten in sprouted form. If you suffer from intolerances, consult a nutrition coach for advice.

Our health coaches at CARE will be happy to support you if you want to optimize your diet or adapt it to your needs.

What Side Effects Can Dietary Fiber Foods Have?

As already mentioned, dietary fiber foods can lead to bloating and abdominal pain. This usually only happens if the food is not prepared properly or if the intestines are only used to very little fiber.

Dietaryiber is also available as a supplement, in powder or capsule form. It is quite easy to get a little too much fiber from these supplements. So, start with small amounts and wait for your intestine to react before increasing your dietary fiber intake.

Dietary fiber helps against constipation, but if you consume too little liquid throughout the day, too much fiber can lead to constipation in the worst case.

Tips and Tricks – How to Increase Your Dietary Fiber Intake

Try to estimate how many grams of dietary fiber you get every day. You'll probably barely make it to 30g. Pay close attention to food rich in dietary fiber for a while so that you can increase your daily intake a little. [2]

Breakfast

• Sourdough bread or fermented bread not only tastes great, but it also contains a lot of dietary fiber. Ask your baker for bread with a long resting time (at least 20 hours).
• Do you like muesli? Look for wholemeal mixtures and add some oat bran or linseed.
• Mix tiger nuts flakes into muesli - the insider tip par excellence! Tiger nuts are gluten-free and taste slightly sweet. They are perfect if you want to slowly but surely eliminate sweeteners from your muesli.
• Have you ever tried chia pudding or overnight oats? Both are easy to prepare the evening before, and they can be topped with fresh blueberries or blackberries and nuts.

Lunch & Dinner

You can easily replace individual foods for your main meals with fiber-rich options. Experiment and get used to the new flavors this creates.

• Instead of white rice: cauliflower rice, brown rice, quinoa, konjac rice
• Instead of wheat flour: wholemeal flour
• Instead of pasta: wholemeal, lentil, pea, fresh zucchini or konjac pasta
• Instead of potato chips: Kale chips, vegetable chips made from beetroot, parsnips or sweet potatoes, roasted chickpeas
• Instead of tortilla wraps: Wholemeal wraps or spinach wraps

Snacks

It's best not to snack at all - if you can't go without it, then make sure it's a "good" high-fiber snack:

• Nut mixes, sunflower and/or pumpkin seeds
• Edamame
• Raw vegetables with hummus for dipping
• Roasted chickpeas (mix olive oil with oriental spices, drizzle over chickpeas and bake in the oven until crispy)

Fiber is one of the most underestimated nutritional components that we know about, but which still receives too little attention.

With foods high in fiber diet, you also consume larger amounts of antioxidants, vitamins, and other nutrients. This has a significant impact on your health in the medium and long term.