Probiotics vs prebiotics: which is better for gut health?

There has been a recent explosion in research that shows that our gut flora is linked to so many diseases-- cancer, autism, diabetes, heart disease, Alzheimer’s-- and the list goes on and on.

The microbes that inhabit our guts consist of about two million genes compared to only about 22,000 genes humans have, and they’re constantly affecting our health. 

You can think of our gut microbiome as a rainforest. The more variety and number of species that inhabit our guts, the healthier the ecosystem of our intestinal flora will be. 

Each person's gut microbiome is as unique as our fingerprint and is greatly affected by our diet, environment and lifestyle. Our microbiome is first acquired at birth and continues to develop and mature until we are about two or three years old. 

For this reason focusing on gut health has become trendy lately, but it can be hard to know what’s the best course of action to keep your gut healthy. 

Probiotics and prebiotics have been gaining a lot of attention lately, but what exactly is the difference between the two and how can they help you maintain a healthy gut?

What are probiotics

According to the World Gastroenterology Organization, “probiotics are live microbes that can be formulated into many types of products, including foods, drugs, and dietary supplements...Strictly speaking, however, the term "probiotic" should be reserved for live microbes that have been shown in controlled human studies to impart a health benefit.”

Contrary to popular belief, probiotics are transient passengers in the gut and do not change the gut microbiota composition. These live microbes, which include mostly bacteria and some beneficial fungi like Saccharomyces boulardii exert their health benefits as they pass through the intestines and interact with immune cells in the gut, dietary components and other microbes in the gut. 

Probiotics are best taken for specific conditions that have been proven to improve symptoms such as antibiotic associated diarrhea, colic in infants and digestive discomforts. For example, Lactobacillus strains have been shown to maintain a healthy vaginal flora. Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 have been shown to protect pregnant women from Group B Streptococcus (GBS) infection.

Another probiotic supplement that has been researched a lot is VSL#3, which contains a potent mixture of four Lactobacillus strains, three Bifidobacterium strains and one Streptococcus strain. VSL#3 has been shown to improve digestive function and gut flora and can also reduce inflammation in a number of digestive and non-gastrointestinal diseases such as liver disease, obesity, allergies, female reproductive diseases and more.

Although fermented foods are a rich source of probiotics, they’re also high in histamine and are therefore not recommended in high quantities for people who have an intolerance to histamine. Therefore, taking a probiotic is recommended in place of consuming foods that naturally contain probiotics. Drinking a lot of kombucha, which is high in sugar, also isn’t recommended for people who suffer recurrent yeast infections or those who suffer from small intestinal bacterial overgrowth (SIBO).

It’s also important to note that not all supplements are created equally due to a lack of quality control and poor manufacturing practices. Some probiotics that aren’t made with an enteric coating don’t usually survive your stomach acid and therefore never make it to the intestines and colon where they exert their health benefits. Additionally, the effect probiotics have on your digestive and overall health depend on your unique gut microbiota composition.

A high quality probiotic should contain on the label:

• the genus, species and strain names

• quantity (most common is colony forming units or CFU)

• expiration date

• storage recommendations

• company contact information

• all health claims should be supported by studies performed in humans

Should everyone take a probiotic?

Unfortunately, the research on the benefits of taking a probiotic is still in its infancy, and manufacturing practices vary. As a general rule, if your gut and overall health are in good shape, there's likeñy no need to take a probiotic supplement.

If your gut and overall health is good, what else can you do to support your overall gut health?

Consider eating prebiotics.

Probiotics vs prebiotics

Prebiotics can be a type of indigestible fiber, polyphenols or polyunsaturated fatty acid that act like fertilizer for your good gut bacteria, which beneficial substances like short chain fatty acids like butyrate that have anticancer and anti-inflammatory properties. Prebiotics basically act like fertilizer for your gut flora.

Beyond digestive health, other benefits prebiotics exert in humans include increasing the production of immune cells, preventing pathogenic infections, improving blood sugar levels, reducing allergic symptoms, improving lactose intolerance and mineral absorption, and possibly improving skin and mental health.

On the other hand, a long-term diet low in prebiotics like low FODMAP and low carb diets may result in less beneficial bacteria like Bifidobacterium and Lactobacillus.

Basically if you’re not feeding the “good bugs” in your gut, they will get hungry and die, so you may want to reconsider adopting a trendy restrictive diet. Feed them often, and they will be happy and survive in your intestines to form a healthy, well established gut flora.

The good news is you don’t have to buy expensive supplements or search high and low for exotic ingredients to find prebiotics. You’ll likely find they’ll already in your kitchen.

Foods rich in prebiotics

• Onions

• Leeks

• Asparagus

• Chickpeas

• Lentils

• Oats

• Corn

• Barley

• Rye

• Wheat bran

• Garlic

• Chicory root

• Soy beans

• Jerusalem artichokes

• Apples

• Bananas (especially unripe green bananas)

• Cooked and cooled potatoes

• Nuts and seeds

• Polyphenols which are plant components such as flavonoids, tannins, curcumins, and resveratrol and can be found in cacao, tea and berries. 

• Human breast milk

Although prebiotic supplements exist, a great way to ensure you’re eating enough prebiotics is to simply consume at least the recommended 25-30g of fiber per day as well as a variety of colorful fruits and vegetables that are rich in polyphenols as well as prebiotics. 

What if eating prebiotic foods like beans give you gas?

There may be some truth in the song that calls “beans the magical fruit,” but luckily there are ways to reduce excessive gas production without reducing your prebiotic intake. A great way to increase the digestibility of legumes and grains is to soak them in water overnight or sprout them. It’s also recommended to start incorporating prebiotic rich foods into your diet slowly so that your digestive system and microbiota can adjust.

Ways to incorporate prebiotics in your diet

• Add nuts and seeds to your yogurt and salads

• Add berries to your smoothies

• Drink a cup of green or chicory tea a day

• Swap white bread for whole wheat or rye bread

• Consider eating oatmeal instead of sugary cereal, muffins or doughnuts for breakfast

• Choose dark chocolate over milk chocolate

• Substitute lentils or chickpeas in rice dishes

• Eat an apple or banana for a snack instead of sugary or low fiber options

• Make garlic and onions your new favorite condiment in savory dishes

Take away

For improved gut health, it’s best to consume both probiotics and prebiotics from fruits, vegetables, whole grains and fermented foods since they work synergystically in your intestines. One is not better than the other in terms of digestive health.

Prebiotics act like food for beneficial bacteria and can be found in a variety of foods that may already form part of your diet.

Be careful when taking supplements because not all are created equally and you might just be throwing money down the toilet-- literally. Eating probiotic rich fermented foods may also provide more beneficial microbes and health benefits than supplements alone. 

Since every person’s gut microbiome is unique, some supplements may not produce any noticeable health benefits. On the other hand, following a diet rich in fiber and prebiotics that's low in processed foods and additives may be the most helpful for promoting a healthy gut.

***Note: This article was originally written for Wellness Journey. 

References

1. Hill, C., Guarner, F., Reid, G. et al. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nat Rev Gastroenterol Hepatol 11, 506–514 (2014). https://doi.org/10.1038/nrgastro.2014.66 

2. Gibson GR, Hutkins R, Sanders ME, Prescott SL, Reimer RA, Salminen SJ, Scott K, Stanton C, Swanson KS, Cani PD, Verbeke K, Reid G. Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics. Nat Rev Gastroenterol Hepatol. 2017 Aug;14(8):491-502. doi: 10.1038/nrgastro.2017.75. Epub 2017 Jun 14. PMID: 28611480.

3. Tsai, Y. L., Lin, T. L., Chang, C. J., Wu, T. R., Lai, W. F., Lu, C. C., & Lai, H. C. (2019). Probiotics, prebiotics and amelioration of diseases. Journal of biomedical science, 26(1), 3. https://doi.org/10.1186/s12929-018-0493-6

4. Sanders, M.E., Merenstein, D.J., Reid, G. et al. Probiotics and prebiotics in intestinal health and disease: from biology to the clinic. Nat Rev Gastroenterol Hepatol 16, 605–616 (2019). https://doi.org/10.1038/s41575-019-0173-3