What are Probiotics? Foods, Supplements, and Best Practices

Written by: Ryah Nabielski, MS, RDN

Over the last decades, probiotic research has exploded. We’ve discovered many connections between probiotics and human health. However, we may only be at the tip of the iceberg in understanding the complex relationships between humans and all the microorganisms that inhabit us. 

As we understand more about beneficial microorganisms called probiotics, we have more tools to optimize gut health, promote overall health, and prevent disease. One tool is the use of probiotic supplements. 

Are you confused about all the probiotic choices? This article will walk you through what you need to know, including:

• What are probiotics? 
• A history of probiotics in food
• The 411 on probiotic supplements
• Health benefits of probiotics
• Best practices for using probiotics and maintaining a healthy microbiome 

Let’s get started! 

What Are Probiotics? 

Probiotic comes from Latin, meaning “for life.” Probiotics refer to live bacteria and other microorganisms that are beneficial to human health.

We have a mutually beneficial relationship with probiotics, called a symbiotic relationship. We provide them with a cozy living environment and food, and they provide us with whole-body health.  

The microbiome refers to all the microorganisms, including probiotics, that live in and on the body. You’ll find most of the human microbiome in the large intestine and in the gut. Microorganisms also live on the skin, mucus membranes, eyes, ears, and so on. 

Learn more about the microbiome and how it develops and changes throughout life here. 

Probiotics rely on a fuel source called prebiotics, including specific types of fiber and polyphenols that we eat in our diet. 

When probiotics metabolize prebiotics, they produce beneficial compounds that support health, called postbiotics. 

Postbiotics include:

• Vitamins, such as B vitamins
• Short-chain fatty acids, such as butyrate 
• Enzymes
• Amino acids
• Antioxidants
• Anti-inflammatory compounds
• Immune-modulating compounds

Postbiotics improve gut function and health. We get many nutrients and health-promoting compounds by feeding our probiotics, not just from food itself.  

Probiotic Food Sources

Humans have a long history of consuming probiotics by eating fermented foods. Fermentation is a form of food preservation found in cultures worldwide. Humans have been consuming these probiotic-rich foods since long before we had microscopes and knew about microorganisms. 

Examples of traditional fermented foods and beverages containing probiotics include: 

• Beer
• Wine
• Sourdough bread
• Kefir
• Yogurt
• Cheese
• Sauerkraut
• Kimchi 
• Kvass
• Miso 
• Olives
• Pickles 
• Tofu
• Natto and other fermented beans pastes
• Tempeh
• Fish sauce
• Soy sauce
• Vinegar
• Poi
• And so many more

Note that traditional versions of these foods are fermented and contain live cultures. Modern versions might be pasteurized or canned, killing the natural probiotics. (Although there is some evidence that even dead probiotics benefit the microbiome). 

Fermented foods typically contain high concentrations of many probiotic strains, meaning individual species of beneficial bacteria. 

Probiotic Supplements

Probiotic supplements have been available for a few decades, and the science behind them is evolving rapidly. Probiotic supplements may include a single strain or several individual bacterial strains. 

Examples of probiotic strains include: 

Lactobacillus acidophilus

Lactobacillus brevis

Lactobacillus casei 

Lactobacillus plantarum

Lactobacillus rhamnosus 

Lactobacillus helveticus

Lactobacillus gasseri

• Lactobacillus salivarius
• Lactobacillus bulgaricus
• Lactobacillus paracasei

Bifidobacterium lactis

Bifidobacterium bifidum

Bifidobacterium longum 

• Bifidobacterium breve
• Bifidobacterium infantis
• Bacillus coagulans
• Bacillus subtilis
• Akkermansia muciniphila
• Clostridium butyricum
• Streptococcus thermophilus
• Saccharomyces boulardii (a probiotic yeast)

Probiotics doses are in CFUs (colony-forming units) or AFUs (active fluorescent units). Dosages range anywhere from a couple billion CFUs or AFUs to a couple hundred billion CFUs or AFUs. 

Some probiotic supplements are called synbiotics because they contain both probiotics and prebiotics. 

Health Benefits of Probiotics

Aspects of modern life, including antibiotics, toxin exposures, water treatment, etc., can kill probiotics and alter the microbiome. Replacing probiotics provides an opportunity to reestablish health after medical treatments or environmental exposures and prevent disease. 

The gut microbiome influences health, not only in the gut but throughout the body. Improving probiotic numbers and balance may improve:

• Digestion
• Metabolism
• Immunity
• Oral health
• Skin health
• Hormonal balance
• And more!

Research suggests probiotics may help with prevention of specific diseases or conditions. These include:

• Metabolic syndrome and diabetes
• Depression 
• Inflammatory disease, such as inflammatory bowel disease
• Irritable bowel syndrome (IBS) 
• Constipation 
• Antibiotic-associated diarrhea
• Autoimmune disease
• Infections such as C. difficile, H. pylori, urinary tract infections, food poisoning, etc.
• Cavities

Most probiotic studies look at specific conditions or disease states. However, probiotics may still have benefits for healthy people, including supporting a healthy immune system, gut, and genitourinary tract. In addition, certain probiotic strains are safe for infants and children (ask your pediatrician). Probiotics also support reducing inflammation and protecting gut health in athletes. 

In general, multi-strain probiotics tend to be more beneficial than single strains. While many factors go into a healthy microbiome, changes in the diet or the use of probiotic foods or supplements tend to shift the microbiome quickly. 

How to Take Probiotic Supplements – Best Practices

Probiotic supplements work best in the context of a healthy diet and lifestyle. Here are some tips for getting the most out of your probiotic supplements. 

• Include prebiotics in the diet. Prebiotics are the food source for probiotic bacteria. Prebiotics support a robust and diverse microbiome. You’ll find them in a variety of plant foods containing specific types of fiber and polyphenols. Prebiotic foods include:
• Artichokes
• Asparagus
• Green bananas
• Sunchokes
• Burdock root
• Dandelion greens
• Garlic
• Onions
• Leeks
• Jicama 
• Apples
• Berries – blueberries, raspberries, cranberries
• Grapes
• Plums
• Cacao and dark chocolate
• Olives 
• Oats
• Beans
• Nuts
• Flaxseeds 
• Coffee
• Tea

• Eat a diverse diet. A diverse diet supports a healthy, diverse microbiome. Choose a variety of foods each week instead of eating the same foods each day. A goal can be to eat 30 to 40 unique plant foods each week, including whole grains, beans, nuts, seeds, vegetables, fruits, herbs, and spices. Be sure to include protein and fats with meals for balanced blood sugar. 

• Include fermented foods in the diet. Fermented foods are an effective and affordable source of probiotics, containing many diverse probiotic strains. Consider fermented foods as a condiment and enjoy a tablespoon or two with meals. 

Choose fermented foods found in the refrigerated section of grocery stores. Shelf-stable options likely don’t contain live probiotics. 

• Take probiotic supplements with food. Take probiotic supplements with a snack or meal to mimic having a fermented food with the meal. With food in the stomach, the pH is less acidic, and the bacteria are more likely to survive through that part of the digestive tract. 

• Go slow. If you don’t eat many fermented foods or much fiber, start with small portions and slowly increase. The same advice applies to probiotic and prebiotic supplements; you can open capsules and begin with a small dose mixed into food. 

• Consider probiotics as a long-term wellness tool. Probiotics from food and supplements are part of a long-term strategy for health. As the microbiome shifts quickly with the introduction of probiotics (and prebiotics), the gut also shifts when you reduce or stop probiotics (and prebiotics). 

• Consider a synbiotic. A synbiotic supplement is a synergy between probiotics and prebiotics. Twenty2 Nutrition Probiotic contains seven unique probiotic strains at a dose of 60 billion CFUs per dose, along with a fiber blend and prebiotic FOS and beta-glucans. 

• Spend time in nature. The microbiome shifts when we interact with the natural world. We spend much more time indoors and experience more cleanliness and disinfection than our ancestors. Gardening, camping, playing outside, and other interactions with nature support a healthy microbiome as we contact probiotics in the earth. 

• Get personalized guidance. Work with your doctor or dietitian for personalized advice about probiotic strains and dosages specific to your needs and health goals. 

While trying probiotics for wellness is likely safe, if you take medication or have a medical condition, please discuss all supplements with your provider. Probiotics may be contraindicated for those undergoing cancer treatment, who have an organ transplant, or otherwise weaker immunity. Please consult with your provider. 

We all want a quick fix and a magic pill, and a probiotic supplement supports many aspects of health. Get the most out of your probiotics by implementing these diet and lifestyle tools for a healthy, robust, and diverse microbiome that serves you well over time. 

This article is for educational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or another qualified healthcare provider with any questions regarding probiotics, supplements, and your health. 

Ryah Nabielski, MS, RDN is a Registered Dietitian, functional nutritionist, writer, and recipe creator. Ryah helps clients use a natural, food-as-medicine approach to improve fertility, pregnancy, hormone balance, autoimmunity, and discover a healthy relationship with food and body. Learn more about Ryah and her private practice at econutrition.co. 

References

1. https://www.sciencedirect.com/science/article/abs/pii/S221479932030014X 
2. https://pubmed.ncbi.nlm.nih.gov/25576593/ 
3. https://pubmed.ncbi.nlm.nih.gov/19584499/ 
4. https://www.jmb.or.kr/journal/view.html?doi=10.4014/jmb.1906.06064 
5. https://pubmed.ncbi.nlm.nih.gov/30009996/ 
6. https://pubmed.ncbi.nlm.nih.gov/31480656/ 
7. https://pubmed.ncbi.nlm.nih.gov/31356353/ 
8. https://pubmed.ncbi.nlm.nih.gov/32451960/ 
9. https://pubmed.ncbi.nlm.nih.gov/29581563/ 
10. https://pubmed.ncbi.nlm.nih.gov/30597307/ 
11. https://pubmed.ncbi.nlm.nih.gov/33231600/