What Is a Prebiotic? Your Guide to Gut Health Essentials

Prebiotics Overview

Prebiotics are foods or dietary supplements that promote the growth of healthy bacteria in the human gut. In other words, prebiotics are a food source for helpful bacteria. They help good bacteria grow in the digestive system. 

The human gastrointestinal tract contains trillions of bacteria. In healthy people, there is a balance between good gut bacteria and bad gut bacteria. This is vital for overall health and well-being. Prebiotics provide nutrition to beneficial intestinal bacteria and help them grow. This keeps the numbers of harmful bacteria in check and has other beneficial effects. 

Prebiotics were first identified in 1995 by two scientists called Gibson and Roberfroid. They found that plant-derived carbohydrates called oligosaccharides promoted the growth of healthy bacteria, such as Bifidobacterium and Lactobacillus, that live in the gastrointestinal tract, by providing nutrients to them. 

While prebiotics and probiotics may sound similar, they are two different types of supplements. As mentioned, probiotics improve the “good” bacteria flora in the body by providing live microorganisms. On the other hand, prebiotics are intended to promote the balance of these microorganisms. 

Are Prebiotics and Dietary Fiber the Same Thing?

Many people think that all high-fiber foods are prebiotics. However, only certain types of dietary fiber function as prebiotics. These include carbohydrates (oligosaccharides) containing inulin, pectin, resistant starch, fructose, galactose, lactulose, isomaltose, xylose, polydextrose, and vegetable protein hydrolysates. Non-carbohydrate sources of prebiotics include polyphenols. Find out “How Much Fiber Should You Have a Day?”

What Happens When You Start Taking Prebiotics?

When you start eating foods or taking supplements that contain prebiotics, it stimulates the growth of helpful bacteria like Lactobacillus and Bifidobacterium in your gut. These bacteria are linked to a range of benefits for human health, including improved digestion, less constipation, increased nutrient absorption, regulation of cholesterol levels, and strengthening of the immune system.

The Difference Between Prebiotics and Probiotics

Probiotics are fermented foods like kefir and sauerkraut that contain live microorganisms that already live in the human digestive system. You can also take a probiotic supplement to add to your existing population of good gut bacteria and maintain a healthy microbiota. Taking probiotics has beneficial health effects in many organ systems of the body, including boosting immune system functions.

As mentioned above, prebiotics function as a food source for microorganisms (healthy bacteria) in your gut. These microorganisms metabolize and ferment the prebiotics and use them as food to grow. The process of breaking down the prebiotics also leads to the production of other substances that are helpful for gut health. For example, when bacteria break down prebiotics, different short-chain fatty acids are produced, which provide energy to digestive system cells, stimulate mucus production, and have anti-inflammatory and immunity-boosting effects.

Is It Better To Take a Prebiotic or Probiotic? 

The key difference between probiotics and prebiotics is that probiotics are live cultures of beneficial bacteria and prebiotics are food for these beneficial bacteria. One is not better than the other. Prebiotics and probiotics work best together. 

Benefits of Combining Prebiotics and Probiotics

Research suggests that prebiotics and probiotics work best in tandem for gut health. In other words, for them to work well, you need to eat both probiotics and prebiotics. Some of the health benefits of combining prebiotics and probiotics include:

• Enhancing the protective barrier function of colon cells.

• Supporting immune system functions.

• Preventing overgrowth of bad gut bacteria.

• Make neurotransmitters (natural chemicals) involved in the gut-brain axis (communication channel between the digestive system and nervous system).

• Regulating bowel movements.

• Stimulating the formation of hormones that promote appetite suppression.

• Helping the body absorb nutrients like calcium and phosphorus that increase bone density and are important for bone health. 

• Reducing inflammation.

Prebiotic Foods

Prebiotic foods are usually high-fiber foods that contain fermentable soluble fiber. The three most common types of prebiotics are: 

Resistant Starches

Resistant starches are starches that resist digestion by stomach acid and thereby become the main food source for gut bacteria. Butyrate, a byproduct of the breakdown of resistant starches, has beneficial effects like increased absorption of water and electrolytes in the colon as well as immunity-boosting and anti-inflammatory effects. 

Inulin

Inulin is a plant-based prebiotic fiber that helps you feel full longer. It prevents overeating and can aid in weight loss. Other health benefits of inulin include regulation of bowel movements, lowering of LDL (low-density lipoprotein) or the “bad” cholesterol, stabilization of blood sugar levels, reduction in insulin resistance, and maintenance of a healthy population of good gut bacteria. These beneficial effects are associated with a lowered risk of cardiovascular disease and gastrointestinal disorders. Eating foods containing inulin is also linked to a reduced risk of colon cancer. 

Pectin

Pectin is found in many fruits, especially raw apples. It has antioxidant properties and can lower your risk of many types of cancer. Pectin also makes the cells lining your intestines stronger, preventing germs from entering your body. By providing food to good gut bacteria, pectic improves the diversity of microorganisms in the gut microbiota. 

Best Sources of Prebiotics

Certain foods are good sources of prebiotics.

Foods that contain resistant starches include:

• Potatoes (boiled and chilled)

• Green bananas

• Whole grains like oats and barley

• Rice

• Legumes

• Beans

The best sources of inulin include:

• Jerusalem artichokes

• Asparagus

• Chicory root

• Burdock root

• Leeks

• Onions

• Dandelion greens

• Garlic

• Wild yams

• Soybeans

Foods rich in pectin include:

• Apples

• Apricots

• Peaches

• Raspberries

• Tomatoes

• Potatoes

• Carrots

• Green beans

Prebiotic-Rich Recipes and Meal Ideas

Here are some convenient ways to incorporate both prebiotics and probiotics into your diet:

• Kefir overnight oats with chia seeds and nuts

• Roasted Jerusalem artichokes with olive oil and seasoning

• Berry and kale salad with a kombucha dressing 

• Asparagus, carrots, and green beans sheet pan meal

• Dandelion greens, green banana, oats, and flaxseed smoothie in kefir milk

Benefits and Side Effects of Prebiotics

Benefits of Prebiotics

More research and human studies are ongoing to understand the benefits of prebiotics. Here’s a quick recap of the health benefits and clinical applications of prebiotics that we know of:

• Improves digestion

• Regulates bowel movements

• Boosts metabolism

• Helps with weight loss due to increased fullness

• Stimulates hormones that help with appetite suppression

• Improves absorption of calcium

• Regulates blood sugar and lowers insulin resistance

• Reduces inflammation

• Helps the immune system function properly

• Balances hormone levels

• Lowers cholesterol levels

• Lowers the risk of cardiovascular disease

• Regulates stress hormone levels and mood

• Reduces colon cancer risk

Potential Side Effects

Most people tolerate prebiotics without any problems. However, prebiotics can cause side effects, especially at high doses, such as gas, bloating, stomach pain, diarrhea, and acid reflux.

Recent Scientific Studies on Prebiotics and Gut Health

Some of the latest studies and prebiotic research show:

• Both prebiotics and probiotics have a beneficial effect on the gut microbiota.

• Prebiotics lower the risk of cardiovascular disease through their effect on bile acid synthesis.

• Prebiotics improve bone mineral density and lower the risk of osteoporosis through increased production of short-chain fatty acids, which in turn decrease pH levels in the intestines and improve calcium absorption.

• Ingestion of both probiotics and prebiotics may allow people with lactose intolerance to eat dairy products with less severe symptoms.

When to Take Prebiotics

Optimal Timing for Maximum Benefits

The best time to take prebiotic supplements is in the morning, before breakfast, with a glass of water. This is when your gut is well-rested after overnight fasting. You can eat prebiotic foods at any time of the day. 

How Do You Know If You Need Prebiotics?

Most people who eat a balanced, healthy diet get prebiotics from food sources. The average person therefore does not need to take a prebiotic supplement. However, if you have gut health issues, it may be worth trying prebiotics to promote the growth of good gut bacteria. It’s important to remember, however, that prebiotics and probiotics are not a substitute for a healthy diet and they cannot counteract the effects of an unhealthy diet.

Can Prebiotics Treat IBS Symptoms?

There isn’t enough evidence that prebiotics help with treating digestive issues like irritable bowel syndrome (IBS) or other diseases like Crohn’s disease. In fact, prebiotics can worsen symptoms of irritable bowel syndrome because the rapid fermentation can lead to gas, bloating, and diarrhea. 

Who Should Not Take Prebiotics?

People with certain medical conditions such as small intestinal bacterial overgrowth (SIBO) or FODMAPs intolerance should not take prebiotics.

Safe Use and Dosages of Prebiotics

The recommended dose is 2.5 to 10 grams per day to reap the benefits of prebiotics when taken in supplement form. Some experts advise taking no more than 5 grams of prebiotics. 

How to Incorporate Prebiotics into Your Diet

Dietary Supplements vs. Natural Sources

While you can take probiotics and prebiotics in supplement form (tablets, capsules, gummies, and powder), it’s always preferable to obtain them from natural dietary sources (prebiotic and probiotic foods). Many foods that are rich sources of prebiotics and probiotics also provide additional benefits such as antioxidants and other nutrients. 

Also, there are hundreds of species of healthy bacteria that live in our intestines. Taking one purified prebiotic in supplement form is unlikely to give you the biodiversity you need in your gut microbiome. Experts in digestive health advise that the best way to nourish good gut bacteria is by following a fiber-rich diet with plenty of fresh fruits and vegetables. 

Tips for Increasing Prebiotic Intake

Cooking methods can change the composition of food and affect how much prebiotics are available to your body. For example, baked potatoes have less resistant starch compared to boiled and chilled potatoes.

A great way to ensure that you are getting a large amount of prebiotics is to select foods that are minimally processed and more nutritious. Consider substituting flavored, instant oatmeal packets that are high in sugar and salt for old-fashioned steel-cut oats that are higher in prebiotics. Similarly, it’s best to eat unsweetened fresh or frozen fruits like bananas and blueberries.

Prebiotics in Everyday Foods and Beverages

Here are some meal ideas for getting your daily dose of prebiotic fiber:

• Breakfast: Overnight oats with nuts and seeds

• Lunch: Roasted vegetables (asparagus and Jerusalem artichokes seasoned with onions and garlic)

• Snack: Banana and blueberry smoothie

• Dinner: Leek soup with cold potato salad