Microorganisms live all over and inside your body. There are bacteria on your skin, in your mouth, throat, and vaginal tract in females. Though you may not realize it, the human gastrointestinal tract is home to most of them with around 100 trillion live bacteria. But there’s no need to worry because most of the bacteria are actually good for your health. In fact, beneficial bacteria can not only help improve your digestion, but they can also support your immune and urogenital systems.
1. What are probiotics and how do they work?
Probiotics are live microorganisms, usually beneficial bacteria (but can be a probiotic yeast like Saccharomycess boulardii), which have a number of health benefits when eaten or taken as a dietary supplement. The GI tract is a delicately balanced ecosystem, with many beneficial microorganisms, or probiotics, in your gut and intestines. These probiotics have been proven to have a number of health benefits.
Gastrointestinal health: Numerous studies have been conducted to show how probiotics support digestive health. Probiotics may support healthy stomach acid levels and help support more regular bowel movements. Lactobacillus and Saccharomyces boulardii probiotics have been shown to reduce the duration of diarrhea[1] while Bifidobacterium lactis and Lactobacillus casei probiotics improved symptoms for chronically constipated patients[2].
The mechanisms by which probiotics work is still not thoroughly understood. We do know that when probiotic populations are killed off by antibiotic use, diarrhea is a common result. Taking probiotics helps repopulate the gut with healthy probiotics that reduce the duration of diarrhea and support normal bowel movements.
Constipation is more complicated. In some constipated people, an increase in fiber intake is all that’s needed to normalize bowel movements. In others with irritable bowel syndrome with constipation predominance, also known as IBS-C, constipation is a chronic problem. People with IBS-C have lower levels of serotonin which is known as the “happy neurotransmitter”.[3] Certain probiotic bacteria are known to produce serotonin such as:
- Lactococcus lactis subsp lactis
- Lactobacillus plantarum
- Streptococcus thermophilus
A review article (study featuring data from multiple studies) published in the British Medical Journal’s Gut publication found that taking a probiotic supplement with multiple probiotic strains may be helpful for more normal bowel movements.[4]
Immune Health
The majority of your immune system is within the lining of the gut because this is where the body is exposed to microorganisms. In fact, the number of microorganisms living in the gut exceeds the number of human cells in your body. Because of the sheer number of bacteria, probiotics, and potentially bad organisms inside the gut, much of the immune system is centered around the gut and a large part of a proper immune response is to know what is bad and what is pathologic. Gut associated lymphoid tissue (GALT) accounts for 2/3 of the human immune system.[5]
There is still a lot we don’t know about probiotics and the development of the immune system. What we do know is that there are differences in the composition of gut microbiome of infants born in countries with less autoimmune diseases and allergies. Children in countries with lower incidences of allergies and autoimmune diseases have more Bifidobacterium and Lactobacillus probiotics and less Clostridia organisms living in their gut.[6] Accordingly, researchers are still trying to prove that Bifidobacteria and Lactobacillus supplementation reduces the development of allergies.
Moreover, babies that are born via cesarean section have a higher incidence of asthma and allergies compared to babies born vaginally[7]. A casaerean birth compared to a vaginal birth does not allow the infant to be colonized by probiotics present in the mother’s birth canal. Furthermore, maternal probiotic supplementation during pregnancy and breastfeeding reduces the risk of eczema. One study of mother-infant pairs found that mothers who took a probiotic supplement while pregnant and while breast feeding had babies that were less likely to develop eczema.[8]
According to a review article that analyzed the results from a number of other studies, supplementation with probiotics may be helpful in achieving the following:[9]
- Decreasing IgE-associated eczema
- Decreasing atpic dermatitis
- Lower IgE-associated diseases and eczema
- Lowering SCORAD scores
- Decreased allergy development
- Decreased long-term incidence of allergies
- Amerliorate cutaneous and allergic symptoms
- Decreased level of allergic rhinitis
Indeed, probiotics have many benefits for the immune system and there are still many more to be discovered.
Urogenital/Vaginal Health
Probiotics normally found in the vagina produce lactic acid (particularly Lactobacillus probiotics) that cause it to have a low, acidic pH. This acidic environment in the vagina makes it harder for urinary-tract infection pathogens like E. coli to grow. E. coli is the most common cause of Urinary Tract Infections (UTIs) and normally travels from the vagina, through the urethra, and beyond. The presence of Lactobacillus probiotics in the vagina keep E. coli bacteria at bay. Some women develop UTIs after taking antibiotics because most antibiotics cause the death of lactobacillus
The presence of Lactobacillus also deters the growth of yeast-infection causing Candida albicans. There are studies that show orally consumed probiotics will colonize the vaginal tract and support a healthy vaginal microbiome and pH[10].
2. What are prebiotics?
Prebiotics are forms of indigestible fiber that are not absorbed by your body, but are used to fuel probiotic bacteria. Natural sources include raw garlic, dandelion greens, flax, raw onion, and wheat bran. You can also take prebiotics as a supplement. Supplemental forms of prebiotics include inulin, digestion resistant maltodextrin, and chicory root.
3. Should I take probiotics?
People young and old should be taking probiotics because of the numerous benefits for digestive, urinary, and vaginal health. You should especially consider taking a probiotic supplement if you notice digestive issues, have recently been ill, or are taking a course of antibiotics. As discussed earlier, expecting and nursing mothers should take probiotics to reduce the chances of developing eczema. Infants can also be introduced to probiotics with probiotic drops or probiotic powder that is mixed into their food.
Furthermore, as you age the levels of Bifidobacteria probiotics in your gut decrease. Supplementing your digestive system with probiotics as you age supports healthier and more regular bowel movements. A quality probiotic can also support urogenital health.
4. What are the different types of probiotics?
Not all probiotics are alike. Each probiotic species has a specific niche and function within the ecosystem. Each has evolved different living strategies that confer unique benefits to the host. Here is a short list of the most common strains and their benefits.
Lactobacillus acidophilus
Lactobacillus acidophilus is a probiotic that produces lactic acid which helps to make yogurt sour. The lactic acid produced by this probiotic in the vagina controls the growth of Candida albicans, the yeast that causes yeast infections. Lactobacillus acidophilus also may reduce the effects of lactose intolerance[11] because it is able to breaks down lactose.
Saccharomyces boulardii
Saccharomyces boulardii is recognized for its effectiveness for treating diarrhea related to travel and antibiotic use. This strain of probiotic yeast is helpful for gastrointestinal problems and was used by the natives of Southeast Asia to control symptoms of cholera. The indigenous people there chewed on the peels of the lychee fruit that contained S. boulardii to ward off symptoms of cholera.[12] S. boulardii has been shown to improve symptoms of diarrhea and reduce the reoccurrence of C. diff infections
Streptococcus thermophilus
Streptococcus thermophilus is often used in the manufacture of cheese and yogurt. This probiotic supports the treatment of acute diarrhea. It is often given to infants in hospital to prevent diarrhea[13].
Lactobacillus brevis
Lactobacillus brevis is another species of lactic acid bacteria, which can survive in the human gastrointestinal tract. It is found naturally in fermented food such as sauerkraut and kefir. As part of a probiotic supplement, it may help support the functions of the immune system[14] as well as beneficial for women’s health.
Lactobacillus bulgaricus
More specifically known as Lactobacillus delbrueckii subsp. bulgaricus, L. bulgaricus resides in the digestive tract where it helps in the conversion of lactose to lactic acid. Because of this function, it can be helpful for those with lactose intolerance. This probiotic strain may also be beneficial with liver health and function.
Lactobacillus casei is found in the human intestines and mouth. It is often used in the manufacture of cheese and yogurt and for fermenting green olives. This probiotic improves intestinal functions[15]. It can also support treatment of allergies.
Lactobacillus helveticus is often used to make cheeses. It boosts the function of the immune system with its antioxidant[16] properties. L. helveticus also supports healthy blood pressure[17].
Lactobacillus rhamnosus A Initially, this probiotic was thought to be a subspecies of L. casei, but it was then found to be its own species. L. rhamnosus protects the urogenital tract[18] and may also help support a healthy respiratory tract[19]
Lactobacillus salivarius
This probiotic inhibits the growth of pathogenic bacteria, increases the body’s resistance to infection[20], and helps support oral health[21].
Bacillus coagulans is a lactic-acid forming probiotic, so it can reduce the effects of lactose intolerance. It also promotes healthy vaginal flora[22], improves abdominal discomfort and bloating[23] and supports immunity. B. coagulans also inhibits the growth of bad bacteria in the GI tract[24].
Bifidobacterium bifidum
Increases the acidity of the large intestine, which inhibits the growth of harmful bacteria. It also keeps yeast populations under control.
Bifidobacterium breve
This probiotic makes up most of the gastrointestinal microflora[25] in babies who are breastfed.
Bifidobacterium lactis
Reduces inflammation in the gastrointestinal tract[26], boost the immune system[27], and supports healthy cholesterol levels[28].
Bifidobacterium longum
This probiotic is transmitted from the mother to the infant via breast milk. In adults, it is found throughout the GI tract and in the vagina. It alleviates symptoms of diarrhea and cyclic diarrhea/constipation[29] and supports a healthy inflammatory response.
5. What foods contain probiotics?
You can obtain probiotics from some food sources. These include:
Yogurt: Most yogurts are made with Lactobacillus bulgaricus and Streptococcus thermophilus.
Kefir: This is a fermented milk product that, texturally, can be considered as drinkable yogurt. You can find a variety of different probiotic strain in kefir, including Lactobacillus acidophilus, Streptococcus thermophilus, Bifidobacterium bifidum, Streptococcus thermophilus, Lactobacillus helveticus, and Lactococcus lactis.
Kombucha tea: This fermented tea usually contains the probiotic Gluconacetobacter xylinus and sometimes the yeasts Schizosaccharomyces pombe and Zygosaccharomyces bailii.
Miso: This Japanese paste is made from soybeans, water, and koji. It contains the probiotic fungus Aspergillus oryzae.
Sauerkraut: This fermented cabbage has been shown to contain Leuconostoc mesenteroides, Lactobacillus plantarum, Pediococcus pentosaceus, and Lactobacillus brevis.
Soy milk: Some brands of soy milk are fortified with the probiotic strain Bifidobacterium animalis.
6. What are the side effects and risks of probiotics?
Side-effects are uncommon, but may include gas or bloating. This can be avoided by taking probiotics on an empty stomach without food.
7. How should people take probiotics?
As well as obtaining them from some foods, you can take probiotics in the form of capsules, powder or chewable gummies. The strength of a probiotic is measured in colony forming units (CFUs), which stands for the number of active bacteria in each dose. A probiotic supplement used for therapeutic purposes such as acute diarrhea should contain at least 10 billion CFUs as that was the amount found to decrease the length and duration of diarrhea in children[30].
Researchers in the United States are currently involved in studying the effects of probiotics and developing new strains. Some specific areas currently being studied in more depth include probiotic adhesion to the intestinal wall and allergy support. More and more discoveries about the relationship between our health and the microbiome of the mouth, throat, skin, as well as the vagina in females are being made.
[1] https://www.ncbi.nlm.nih.gov/pubmed?term=21069673
[2] https://www.ncbi.nlm.nih.gov/pubmed?term=25099542
[3] http://www.sciencedirect.com/science/article/pii/S0166432814004768
[4] http://gut.bmj.com.forward.marian.edu/content/59/3/325
[5] Watson, R and Preedy V. Bioactive Food as Dietary Interventions for Arthritis and Related Inflammatory Diseases: Bioactive Food in Chronic Disease States. October 22, 2012. Academic Press.
[6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2883099/
[7] http://www.webmd.com/allergies/news/20041020/c-section-may-increase-kids-allergy-risks
[8] http://www.sciencedirect.com/science/article/pii/S0091674912014649
[9] https://aacijournal.biomedcentral.com/articles/10.1186/1710-1492-5-5
[10] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2662373/
[11] https://www.ncbi.nlm.nih.gov/pubmed/9925136
[12] https://www.ncbi.nlm.nih.gov/pubmed/10961730
[13] http://www.sciencedirect.com/science/article/pii/S0140673694917086
[14] https://www.ncbi.nlm.nih.gov/pubmed/8829098
[15] https://link.springer.com/article/10.1023%2FA%3A1010611920750?LI=true
[16] https://www.ncbi.nlm.nih.gov/pubmed/24507291
[17] https://www.ncbi.nlm.nih.gov/pubmed/16093403
[18]https://link.springer.com/article/10.1007/s00345-005-0043-1
[19] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC32161/
[20] https://www.researchgate.net/profile/Christian_Riedel/publication/6371765_From_the_Cover_Bacteriocin_production_as_a_mechanism_for_the_antiinfective_activity_of_Lactobacillus_salivarius_UCC118/links/02e7e514c7ff1350c2000000.pdf
[21] https://www.researchgate.net/profile/Christian_Riedel/publication/6371765_From_the_Cover_Bacteriocin_production_as_a_mechanism_for_the_antiinfective_activity_of_Lactobacillus_salivarius_UCC118/links/02e7e514c7ff1350c2000000.pdf
[22] http://onlinelibrary.wiley.com/doi/10.1111/j.1541-4337.2003.tb00017.x/abstract
[23] https://www.ncbi.nlm.nih.gov/pubmed/19332970
[24] http://www.webmd.com/vitamins-supplements/ingredientmono-1185-bacillus%20coagulans.aspx?activeingredientid=1185&activeingredientname=bacillus%20coagulans
[25] https://www.ncbi.nlm.nih.gov/pubmed/11590374
[26] https://www.ncbi.nlm.nih.gov/pubmed/21274375
[27] http://search.proquest.com/openview/906f36b275fd9976d6fa0222ad997a2e/1?pq-origsite=gscholar&cbl=33883
[28] http://www.karger.com/Article/Abstract/203284
[29] http://www.gastrojournal.org/article/S0016-5085(17)35557-9/abstract
[30] http://pediatrics.aappublications.org.forward.marian.edu/content/109/4/678.full
About the Author:
Dr. Bryan Do, D.O. is an osteopathic physician whose research interests include gastroenterology, immunology, and dermatology. He is particularly interested in the role of probiotics in the gut-brain-skin axis and has written many articles on the topic. He graduated from University of California, Los Angeles (UCLA) before graduating from Marian University College of Osteopathic Medicine in Indianapolis, Indiana and becoming a Doctor of Osteopathic Medicine. Osteopathic physicians are taught to take a holistic approach to medicine and to consider mind, body, and spirit when treating a patient. Osteopathic physicians receive training in Osteopathic Manipulative Medicine (OMM) in addition to the standard rigorous medical school curriculum. Both physicians with a Doctor of Osteopathic Medicine (D.O.) degree as well as a Doctor of Medicine (M.D.) can practice medicine.