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Power of Sour – 5 Fermented Foods for Gut Health

GTs Synergy Kombucha is a popular commercialized kombucha that has increased the awareness of this health fortifying beverage

Fermentation has brought us some of our most beloved foods and drinks


Sourdough’s trademark sour taste is due to lactic acid that is produced by fermenting bacteria in the dough

Fermented foods have been a part of world cultures for thousands of years. The most commonly known of these foods/beverages include yogurt, bread, coffee, pickles, beer, cheese and soy sauce.

Fermented foods are produced using a process called fermentation. Fermentation utilizes certain bacteria and yeasts. These friendly microorganisms have the ability to impart that bubbly / fizzy characteristic to beverages as well as leaven bread through the production of carbon dioxide. Fermentation also often yields lactic acid that gives certain products a more sour or acidic taste; the lactic acid also acts as a preserving agent that allows these foods to be stored longer. Historically, the ability to increase shelf life was one of the most important advantages of fermented foods.

A natural source of probiotics

Eating fermented foods, that contain live cultures, introduce friendly bacteria to our digestive tract that significantly aids our health. We could not live without these friendly bacteria. Our gut is chalk full of bacteria both good and bad. It’s important to eat plenty of good bacteria sources to keep the bad bacteria at bay. Allowing bad bacteria to flourish can cause a cascade of ill health effects.

Good bacteria also provide us nutrition and vitamins, aid in digestion, are big players in our immune system and are able to help fight against and prevent a wide range of ill health effects from cancer to arthritis. Good bacteria also help you stay regular and can help treat as well as prevent constipation. Learn more about probiotics by reading my article on gut health.

Documented scientific evidence

Scientific evidence from highly respected publications corroborates the amazing health benefits of these 5 fermented foodsIn case you, a friend or a colleague has a healthy dose of skepticism in regards to the health benefits of these 5 amazing fermented foods, I have taken the time to document the claims with scientific evidence from studies published in highly respected medical and nutritional journals and encourage you to read them and dig further. It’s a fascinating area of nutrition.

Without further ado!…

List of 5 great fermented foods for great health


Sauerkraut is fermented cabbage and contains many health enhancing compounds and organismsSauerkraut is fermented cabbage and is a popular side dish and condiment. You often see it available as an extra fixing on hot dogs. Cabbage in and of itself is a very nutrient rich food but lacto-fermenting it into sauerkraut actually enhances its nutrient profile. You’ll be happy to know sauerkraut is a low calorie food while providing high amounts of vitamins C and K, magnesium, calcium, potassium, copper, manganese, iron, folate and dietary fiber.

Addtional health benefits of sauerkraut:

  • Antioxidants – Antioxidant rich, containing lutein and zeaxanthin [1]
  • Cancer – Contains isothiocyanates which inhibit cancer cells [2]
  • Canker sore remedy – Place on canker sore for 1 minute then eat (3x daily) [3]
  • Ulcers – Stomach ulcer treatment and soothes digestive tract [4]
  • Bowel flora – Promotes healthy bowel flora

To achieve the best health benefits from sauerkraut, it should be uncooked and unpasteurized. Sauerkraut is one of the easiest foods to ferment yourself. There are many easy sauerkraut recipes online.

Caveats: May contain appreciable levels of sodium which may be of importance to certain individuals with health-related sodium restrictions. Also, if you eat an ungodly amount of sauerkraut you may experience bloating and flatulence from the accumulation of a compound called raffinose that can’t be digested by the small intestine. As long as you abide by the mantra of moderation in all, this should not be a concern.


Kefir is a powerful superfood made by fermenting milk with "kefir grains" that contain Lactobacillus kefiranofaciensKefir is a fermented beverage / yogurt that is said to have originated somewhere in the Caucasus Mountains. It is a drink that uses milk from a ruminant animal such as a cow, goat or sheep and is fermented with “kefir grains,” a collection of fermenting bacteria and yeasts inoculated in a nutrient medium. Kefir grains aren’t actually grains but a collection of nutrients that look like congealed Cream of Wheat or cauliflower. A unique healthy bacteria found in kefir is Lactobacillus kefiranofaciens.

The beverage contains some carbonation, can contain a very low level of alcohol and has a tart taste very similar to yogurt. Kefir has a consistency like “thin yogurt.”

It contains a good amount of vitamins A, B1, B2,  B6, D, K2, folic acid, nicotinic acid, calcium and phosphorous.

More health benefits of kefir:

  • Cancer – A study demonstrated significant tumor reduction in mice  [5]
  • Immune system – Antibacterial and antifungal [5]
  • Allergy – Inhibits allergy induced inflammation  [6, 7]
  • Inflammation – Decreases pain / inflammation in colitis patients [8]

As the popularity of kefir increases it can be found in more and more local grocery stores. I recommend reading Chris Kresser’s article for more information on kefir which also lists commercial products available at the end. You can learn to make your own kefir at home by buying kefir cultures available online.


Natto is a traditional japanese dish made by fermenting soy beans

This traditional Japanese preparation is made by fermenting soy beans with the fermenting bacterial species Bacillus subtilis. It has a very goopy, slimy texture with a powerful smell and taste that many say make it an acquired taste. Natto has all the health benefits of soy beans plus the additional benefits provided in the fermenting process.

Natto’s notable health benefits:

  • Clots– Contains pyrazine and nattokinase which reduce blood clotting
  • Alzheimer’s – Nattokinase has ability to dissolve brain amyloid plaques involved in Alzheimer’s disease [9]
  • Brain – Contains tetramethylpyrazine which has been researched to help post-stroke brain inflammation and reduce memory impairment. It is an anti-inflammtory and nootropic (enhances brain performance) [10,11]
  • Skin and reproductive – Natto contains pyrroloquinoline quinone which is shown to increase reproduction and maintain healthy skin collagen [12, 13]
  • Triglycerides and cholesterol – Was shown to reduce plasma triglycerides and total cholesterol in mice [14]
  • Cancer – A compound found in natto induces apoptosis (cell death) of leukemia cancer cells [15,16]


GTs Synergy Kombucha is a popular commercialized kombucha that has increased the awareness of this health fortifying beverageKombucha is a fizzy fermented beverage made from tea that has a refreshing tart flavor to it. A few popular commercial kombucha products have recently increased the awareness of this tasty and healthy brew. It has only been as of recent that kombucha has been successfully bottled and distributed commercially. Many people are familiar with GT’s Synergy Kombucha pictured above.

Before it became more widely available, people fermented this beverage at home using tea, water, sugar and a SCOBY (Symbiotic Culture of Bacteria and Yeast). It can be manufactured at home fairly easily and aside from being pretty darn tasty it contains probiotics, enzymes good for digestion and is also purported to help detoxify the body.

Early 1900’s Russian research claims kombucha: [17]

  • Cancer – Increases resistance against cancer
  • Heart – Prevents cardiovascular diseases
  • Digestive system -Promotes digestive functions
  • Immune system – Stimulates the immune system
  • Inflammation – Reduces inflammatory problems

Caveats: Kombucha, being derived from tea, does have a small amount of caffeine content. A small amount of alcohol content (around 0.5%) is also usually present having been created during the fermenting process. There is a rumor that fermenting this product at home is dangerous and batches can easily be contaminated and cause severe illness. Read this great article on kombucha myths and truths that dispel this claim.


Yogurt is one of the most known fermented foods and is made from the milk of ruminant animals like cows, sheep and goatsOne of the most widely known fermented foods is good ol’ traditional yogurt. Yogurt is cultured with lactic acid bacteria using cow’s milk (or other ruminant animals) and is an excellent source of probiotics that can help balance our gut flora and provide all the health benefits we’ve spoken of. Yogurt is also rich in protein, calcium, riboflavin, vitamin B6 and vitamin B12

It can be prepared with many other healthy foods, especially fruits. With the explosion of yogurt-based smoothie diets, there are many recipes out their incorporating yogurt with additional healthy foods providing us a  tasty variety of nutrition options.

Additional health benefits of yogurt:

  • Cholesterol – Decreases total serum cholesterol and LDL cholesterol [18]
  • High blood pressure – Yogurt made from lactobacillus helveticus contains peptides that significantly reduced blood pressure in hypertensive mice [19]
  • Yeast infections – Women eating yogurt (with L. acidophilus cultures) had a 3-fold decrease in recurring candida albicans yeast infections [20]
  • Immune system – Increases the production of interferon gamma which fights infection [21]

Honorary mentions that didn’t make the list

If you are looking to incorporate more fermented foods into your diet and promote good gut health it always helps to keep all your options on the table. Other great fermented foods you should look further into are:

  • Kimchi (napa cabbage and vegetables)
  • Tempeh (soy bean)
  • Miso (Japanese seasoning)
  • Fermented vegetables (Pickles, asparagus, etc)
  • Rejuvelac (beverage from grain sprouts)

About Doctor Scott Health

Dr. Scott McLeod, PharmD is an independent researcher, health advocate and author living in Santa Barbara, CA. For more information about Scott and Doctor Scott Health please visit the 'About' section, here.


  1. Good article, I thought yogurt was the only one. I’m curious, is there a way to tell which one has the most probiotics per serving?

    • That’s a great question. Although each of these foods has a unique blend of probiotic cultures in them and probably vary in the amount based on the conditions under which they’re independently produced, it does seems like there should be somewhat of a rough estimate available to compare them. I’ll look into it and see if I can get some numbers or rough estimates to compare. Thanks for the thoughtful / insightful comment!

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