- Kelin M
What Are Probiotics (All You Need to Know in 2021)
Updated: Oct 26, 2021
The network of microorganisms living on every surface of your body is known as the microbiome. It's so important to your health that it's known as a "supporting organ". We inherit a specific set of microorganism species from our mothers (both at birth and while breastfeeding) but as we grow we accumulate more types of microbes (a process known as "colonization"), both good and bad, from what we eat.

The good (health-promoting) and bad (potentially disease-causing) microorganisms generally exist in harmony. However, once the balance of good and bad bacteria is disturbed (because of overuse of antibiotics, a poor diet, or prolonged illness, for example) our body can be thrown into what's called "dysbiosis" and become susceptible to disease.
There are specific strains of bacteria that will benefit particular health concerns (vaginal health, digestive health, immunity, etc.). so we'll show you how to choose a probiotic that's targeted for your concern and actually does what it claims.
Maintaining Harmony
While it's never a bad idea to support the "good" bacteria in your microbiome, it's especially important for the very young or aging whose microbe colonies may not be as robust.
It's also important to give your microbiome extra support if you suspect it's out of balance, either because you've been putting strain on it (for example, antibiotics, stress, poor diet, traveling) or because you're experiencing a bout of digestive or bacterial health problems (such as a urinary tract infection).
There are two ways to maintain the balance of your microflora: prebiotics and probiotics. Prebiotics feed the healthy yeast, fungi, and bacteria in your gut and probiotics are healthy yeast, fungi, and bacteria that add to the number in your system.
Prebiotics
Prebiotics are a special type of fiber or resistant starch (found in plants) that your body can't digest. You can think of them as the fertilizer for your microbiome that helps the healthy bacteria grow.
Simple sugars are quickly absorbed by the small intestine, but since they can’t be digested, more complex carbohydrates move into the large intestine. They then become food for the “good bugs”; the microbiota help break their fibers down and produce short chain fatty acids (SCFA). These SCFA can help prevent and treat certain cancers and bowel disorders like Crohn's disease.
SCFAs lower the pH of your colon making it inhospitable to many types of harmful bacteria that thrive in a less-acidic environment. They also stimulate your immune system and maintain healthy blood sugar and cholesterol levels.
You can find prebiotic fibers in supplements, but there are prebiotics abundantly available in plant foods. These fibers go by the names inulin, resistant starch, fructooligosaccharides, gum, or pectin.
It's important to eat a varied diet rich in plant foods as different types of prebiotics will feed different bacteria. Some of the best sources of prebiotic fibers include:
raw garlic
raw onion
raw leeks
raw asparagus
raw Jerusalem artichokes
raw dandelion greens
bananas
raw seaweed
Other good sources include whole grains, fruits and vegetables, and beans.
It's important to note that sudden increased intake can lead to flatulence and indigestion, especially in those with irritable bowels, so gradually increase intake to allow your tolerance to improve.
Probiotics
Probiotic foods are live microorganisms that directly increase the quantity of healthy microbiota in your gut.
Most people have around 1000 species of bacteria in their gut. Regular consumption of probiotic foods can improve not only the diversity but also the quantity of healthy species.
Just like it's important to consume a variety of prebiotic foods to feed various types of bacteria, it's important to consume varied probiotic foods as these foods each contain different strains (species) of microorganisms. These foods include kefir, kimchi, sauerkraut, yogurt, kombucha, and many other fermented and cultured products.
A dearth of certain species will lead directly to specific health concerns. Lactobacillus, for example, is a genus (or family) that prevents Candida overgrowth. Candida is a harmful family of fungi whose overgrowth is responsible for yeast infections. You can find certain strains of lactobacillus in yogurt.
The two most abundant genus are Lactobacillus and Bifidobacterium (from which most probiotic supplements are made). Lactobacillus is found primarily in the vagina and small intestine, whereas Bifidobacterium is mainly in the large intestine/colon.
Within each genus there are several species with particular functions (like Bifidobacterium longum, which is associated with digestion and immunity). Within these species there are unique strains, each of which has a very specific benefit.
How to Choose a Probiotic Supplement?
When looking for a probiotic, here are a few things you should consider:
Research
It’s important to ensure the company is using strains that have studies behind them. Incorrectly mixed strains can work against each other or be ineffective, so check that the strains have been tested and proven (the best companies will link the studies they base their formula on).
Purchase a probiotic supplement that’s specific for the condition you wish to treat.
2. Strength
A good rule of thumb is to choose a probiotic with at least a billion colony forming units (CFU) overall.
3. Stability
Ensure that the probiotic you choose has strains from the most studied genus (like Lactobacillus), and stay away from those that consist solely of Bifidobacterium which is delicate and may not survive the stomach’s acid.
Choose a probiotic in a form that is encapsulated and delayed-release or otherwise protected, so that it survives to populate the large intestine.
4. Other ingredients
Check that the other ingredients work for, and not against, the condition you’re trying to treat. For example, if you’re experiencing gastrointestinal discomfort, too much prebiotic fiber at once may exacerbate the condition.