Probiotics: Good Bacteria Fighting For Your Digestive Health

What are probiotics? How does it benefit our health? And why should we take them?

Probiotics are beneficial bacteria that help fight against harmful bacteria in the gut. This helps prevent infections and other diseases.

A healthy digestive system is essential to overall good health. The human body has a complex ecosystem of microorganisms living within it. These microbes play important roles in digestion, immunity, and metabolism.

According to the World Health Organization (WHO), probiotics are “live microorganisms, which, when administered in adequate amounts, confer a health benefit on the host.”

What Are Probiotics?

Also referred to as friendly or good bacteria, probiotics help maintain the natural balance of organisms (microflora) in the intestines. They are live, microscopic living organisms – such as bacteria, viruses, and yeasts – that play a vital role in the fermentation and digestion of carbohydrates, and aid in the digestion of fats and proteins.

Probiotics help prevent bloating, gas, and yeast overgrowth because they maintain intestinal acidity at a healthy pH level. They generate certain vitamins and nutrients, support the immune system, and help prevent disease by depriving bad bacteria of nutrients, so that they aren’t able to thrive in the intestinal tract.

Good bacteria will also recycle and metabolize hormones such as estrogen, phytoestrogens, and thyroid hormones. That will help to foster hormonal balance and help minimize menopausal symptoms. 

Bacteria populations that live in the gut are a combination of both good and bad bacteria; a proper balance between the two is necessary for an optimal state of health.

While each person’s mix of bacteria varies, friendly bacteria are crucial to the digestion and absorption of food and nutrients. A properly functioning immune system responds effectively to potential allergens, and protection against disease-causing microorganisms. 

Bad bacteria include those that cause diseases such as Clostridium, Salmonella, and others. The bad bacteria can grow into large numbers and become uncontrollable compared to the good bacteria. Even yeast, such as Candida, is healthy and normal in small amounts.

Good bacteria include Bifidobacterium bifidum, Lactobacillus bulgaricus, Lactobacillus acidophilus, and others. They help us digest our food, keep our guts healthy, give us nutrition and vitamins, and ward off bad bacteria. Some fermented foods will contain the good bacteria, as well as probiotic supplements.

As a rule, probiotics – available in foods and dietary supplements – are bacteria similar to those naturally found in our gastrointestinal (GI) tracts. These bacteria are usually obtained from two groups, Lactobacillus or Bifidobacterium.

Within each group there are many different species, and numerous strains within these species. Probiotics are different from prebiotics, which are non-digestible food ingredients that stimulate the growth and/or activity of beneficial bacteria already living in the human digestive system.

Symptoms of Gut Flora Imbalance

When the gut microflora becomes imbalanced, an incredible variety of symptoms can result.

Probiotics have been found to be helpful in easing numerous symptoms and conditions:

  • Abdominal pain
  • Acne, rosacea (chronic)
  • ADD (attention deficit disorder)
  • Allergies (environmental)
  • Asthma
  • Autism
  • Autoimmune disease
  • Bad breath
  • Bloating, flatulence, and gas
  • Chronic fatigue syndrome
  • Constipation
  • Cold sores (herpes)
  • Diarrhea
  • Dyslexia
  • Ear infections (chronic)
  • Eczema
  • Emphysema
  • Endometriosis
  • Fatigue
  • Fibromyalgia
  • Food allergies, such as gluten, sucrose or fructose intolerance
  • Gum disease
  • Headaches, migraines
  • Hyperactivity
  • Infant dermatitis
  • Increased PMS (pre-menstrual syndrome) and menopausal symptoms
  • Infertility
  • Intestinal tract inflammation (chronic enteritis)
  • Irregular bowel movements
  • Irritable bowel syndrome (What is IBS Definition?)
  • Irritability
  • Joint aches
  • Lactose intolerance
  • Learning disabilities
  • Lyme disease
  • Nail problems (tinea)
  • Patchy white areas on skin (vitiligo)
  • Prostate inflammation
  • Psoriasis
  • Sinusitis (chronic)
  • Stuffy nose, increased mucous
  • Thrush
  • Upper respiratory infections (chronic)
  • Urinary tract infections (chronic)
  • Viral infections (i.e. hepatitis, herpes, human papillomavirus [HPV])
  • Yeast infections

What Causes Probiotic Imbalance?

The balancing act required to keep friendly and unfriendly bacteria levels in check can be disrupted in various ways. Medications such as antibiotics can kill both good and bad gut bacteria in one fell swoop. Unfriendly, disease-causing bacteria, fungi, yeasts, and parasites can then flourish and overpopulate, leading to increased intestinal distress with bloating, gas, abdominal cramping or diarrhea.

Intestinal upset such as diarrhea brought on by food poisoning can lead to a decrease in good microflora. Age, illness, and stress can also cause microflora imbalance. Poor diet is one of the most serious contributors – good bacteria love fiber; bad bacteria thrive on refined sugar and animal fat. Starvation, low-calorie dieting, and excessive alcohol consumption can all cause a microflora disruption.

When a microflora imbalance occurs, the population of Lactobacilli (a good bacteria) in the small intestine decreases, giving bad bacteria and yeasts (such as Candida albicans) the opportunity to occupy the space left by the reduction of good bacteria. The bad microflora begin to proliferate, overpopulating the GI tract, and this can persist for months and/or years leading to chronic gastrointestinal complaints.

Read more about IBS and Yeast Overgrowth.

Probiotic Treatment and Prevention: The Benefits

Understanding the importance of intestinal flora balance, many health care specialists recommend probiotic supplementation as a part of any daily health regimen.

Probiotics can relieve chronic constipation, reduce diarrhea and gas pain, as well as restore beneficial bacteria in the digestive tract to healthy levels.

Research suggests that probiotic supplementation may help prevent or treat conditions such as

  • Antibiotic associated diarrhea
  • Childhood stomach and respiratory infections and eczema
  • Colon cancer
  • Helicobacter pylori (H. pylori) infection (a peptic ulcer and chronic stomach inflammation-causing bacterium)
  • Infectious diarrhea (especially that caused by rotavirus)
  • Inflammatory bowel disease (IBD) (ulcerative colitis and Crohn’s disease including pouchitis)
  • Irritable bowel syndrome (IBS)
  • Lactose intolerance
  • Malabsorption of trace minerals (especially for vegetarians with high phytate diets: i.e. legumes, nuts, and whole grains)
  • Skin infections
  • Tooth decay and gum disease
  • Urinary and vaginal infections like bacterial vaginosis

Probiotics can be helpful in lowering blood pressure, reducing inflammation, shortening the duration of intestinal infections caused by Clostridium difficile, as well as reducing the recurrence rate of other conditions, such as bladder cancer. 

What to Consider When Choosing a Probiotic

A normal part of the digestive system, probiotics are generally considered safe. When choosing a probiotic, it’s important to be aware that only certain kinds of bacteria or yeast work well in the digestive tract.

The effects experienced from ingesting one probiotic species, strain, or preparation won’t necessarily be experienced with another. For this reason, it’s important to choose supplemental probiotics with care.

Microflora varies between the intestines, genitourinary, respiratory, and skin populations. Lactobacillus acidophilis is the dominant strain in the small intestine, whereas Bifidobacterium bifidum is dominant in the large intestine.

Ideally, a probiotic supplement ought to be composed of several beneficial bacteria – such as Lactobacillus acidophilus and Bifidobacterium bifidum.

Choose a probiotic containing strains that are non-pathogenic (harmless) to humans (again, look for species Lactobacillus and Bifidobacterium). A product with microflora species cultured from human strains, capable of colonizing the digestive tract and attaching themselves to the lining of the small intestine, and able to remain within the large intestine is desirable.

Look for a probiotic that contains a prebiotic such as FOS (fructooligosaccharides) or inulin (polysaccharide/fructose). They help the microflora survive the acidic upper GI tract environment, so they can get to where the need to be within the GI tract.

To ensure quality, purity, and safety, choose a product that is GMP-compliant (good manufacturing practice), and certified by the National Sanitation Foundation (NSF) International (Public Health and Safety Company).

Choosing the right probiotic may feel like a daunting task as a result of the sheer mass of information that has been written about them. Your doctor may be able to help give you some guidance.

Fostering Adequate Microflora through Diet

Cheese, chocolate, cider, fermented and unfermented milk, kimchi, miso, pickles, tempeh, sauerkraut, some juices and soy beverages, soy sauce, Yakult, and yogurt are examples of foods and drinks containing probiotics.

Since prebiotics stimulate the growth of friendly bacteria within the human digestive system, consider eating foods that contain prebiotics such as asparagus, bananas, garlic, leeks, oats, onions, and wheat. Some grocery store foods are enriched with prebiotics.

Consider prebiotic supplements if your probiotic does not already contain a prebiotic and you don’t eat many prebiotic containing foods.

And remember, friendly bacteria thrive on fiber; bad bacteria adore refined sugar and animal fat. So when choosing your grocery items, stock up on fruits, legumes, vegetables, and whole grains in order to foster the health of your good bacteria.

Foods such as garlic, ginseng, and green tea contain polyphenols, which also help to encourage long life for the good bacteria.

Probiotics Final Thoughts

The digestive system is an incredibly important – and complex – part of the human body. Many health care providers believe it is the place where health begins and ends. Probiotics offer an exciting new dimension to our understanding of the health of the human body.

As with all medications, the effectiveness of probiotics depends on a variety of factors, ranging from the species and strain ingested, to the age, gender, genetics, health status, and medical history of each individual.

Today, however, there is a mounting body of evidence to support the effectiveness of probiotics in the treatment of an enormous number of health conditions.

Written and Medically Reviewed By

  • Chelsea Cleary, RDN

    Chelsea is a Registered Dietitian Nutritionist (RDN) specializing in holistic treatment for chronic digestive disorders such as Irritable Bowel Syndrome (IBS), SIBO, and Crohn’s disease. She educates patients on how they can heal themselves from their conditions by modifying lifestyle and dietary habits.

  • Julie Guider, M.D.

    Dr. Julie Guider earned her medical degree from Louisiana State University School of Medicine. She completed residency in internal medicine at the University of Virginia. She completed her general gastroenterology and advanced endoscopy fellowships at University of Texas-Houston. She is a member of several national GI societies including the AGA, ACG, and ASGE as well as state and local medical societies.