Week #5 Healthy Habits Challenge – Nurture Your Gut, Eat Probiotic- and Prebiotic-Rich Foods

Welcome to Week #5 of the 12-Week Healthy Habits Challenge!

The health of our gut not only affects our digestion of foods and absorption of nutrients.

Scientific research has discovered the critical roles that gut and gut microbiota (i.e., an ecological community of microorganisms in the gut – bacteria, viruses, fungi, etc.) play in the healthy functioning of the rest of the body including immune health, metabolic health, brain/neurological/mental health, cancer risk, hormonal balance, liver & detox function, skin health and sleep.

The health of our gut depends in large part on the composition of our gut microbiota, i.e., the balance between good (beneficial) and bad (disease causing) microorganisms.

It may be quite commonly understood that eating probiotic-rich foods (e.g., fermented foods, probiotic supplements) is good for gut/gut microbiota health because such foods supply the gut with live beneficial bacteria/microorganisms, thus resulting in a healthier gut microbial composition.

However, it may be lesser known that consuming probiotic-rich foods alone is not sufficient if you don’t continue to feed the beneficial microorganisms in the gut with the right foods, so that these microorganisms can continue to thrive and colonize in the gut.

Certain dietary fibers and resistant starch in whole plant foods (i.e., whole fruits, vegetables, legumes, whole grains, nuts and seeds) called prebiotics serve as foods to gut microorganisms. Prebiotics are not digestible by human small intestine. They are passed on to the colon and fermented by gut microbiota.

Scientific research has found that while the consumption of probiotic-rich foods or supplements can provide transient or short-term enhancement to the gut microbial composition, on-going or sustained consumption of prebiotic-rich foods is needed to maintain healthy gut microbiota in the long run. Diet is the dominant factor shaping the gut microbiota composition.

Therefore, ideally, we want to incorporate both probiotic- and prebiotic-rich foods into our diet. Please continue reading the next sections for more details and tips.

(For more information on the importance of probiotics and prebiotics to gut/gut microbiota health and the relevant scientific research, please check out my previous article: Prebiotics versus Probiotics: Is One Better Than the Other?)

(For more information on the importance of gut health to our overall health and tips to promote healthy gut, please check out my previous articles:

Why Your Gut Feeling Matters

You are What You Eat? Not Quite

Tips to Promote Gut Health for a Healthy Body & Mind)

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Probiotic- and Prebiotic-Rich Foods – Diversity Matters

Research has found the positive correlation between gut microbial diversity and the health of the human host as different species of beneficial gut microorganisms exert different health-promoting biological functions.¹

Prebiotic-Rich Foods

Diet plays an important role in shaping not only the gut microbiota composition, but also diversity. A diet rich in a wide variety of prebiotic foods contributes to improved gut microbiota composition and diversity.²

A study comparing individuals eating more than 30 different types of plants per week to those eating less than 10 per week, showed that the formers have significantly increased beneficial microorganisms and reduced pathogenic microorganisms.^2,3

Therefore, we want to diversify the whole plant foods we eat as much as possible.

In general, whole plant foods rich in fibers and resistant starch are prebiotic-rich foods. Some examples include:

• Foods rich in inulin and fructooligosaccharides (FOS): asparagus, Jerusalem artichoke (or sunchoke), garlic, onion.
• Foods rich in pectin: apples, berries, peaches, peas, green beans, sweet potatoes.
• Foods rich in resistant starch: whole grains (e.g., rice, wheat, sorghum, millet, oats), legumes, starchy fruits and vegetables (e.g., root vegetables, plantain, banana), nuts, seeds.

For a more comprehensive list of prebiotic-rich foods, please check out the Table in my previous article: Prebiotics versus Probiotics: Is One Better Than the Other?

Probiotic-Rich Foods or Supplements

One can consume probiotics through naturally fermented foods and/or by taking probiotic supplements.

Fermented Foods

Fermentation process involves the action of different beneficial microorganisms, namely bacteria, yeasts, and fungi.

Fermented foods not only provide live beneficial microorganisms (in case of uncooked fermented foods) to the gut, but these foods also have other health-promoting compounds and properties not found in their non-fermented counterparts, due to metabolic and enzymatic actions of microorganisms. The health-promoting compounds and properties found in different fermented foods include:^4,5

• • Increased antioxidant content and activity.
  • Vitamins B12 and K2.
  • Predigested carbohydrates and proteins, which are easier to digest and absorb and help to alleviate indigestion, food intolerance and sensitivity.
  • Blood pressure lowering effect.
  • Anti-diabetic effect.
  • Anti-blood clotting effect.

Ideally, we want to consume a wide variety of fermented foods to increase probiotic diversity (thus gut microbiota diversity), as well as to garner the various health-promoting compounds/properties of fermented foods as described above.

Some examples are fermented foods are given below:⁴

• • Fermented dairy or non-dairy milk, e.g., yogurt, cheese.
  • Fermented beverages, e.g., kefir, kombucha, rejuvelac.
  • Fermented fruits and vegetables, e.g., sauerkraut, kimchi and other lacto-fermented fruits and vegetables.
  • Fermented grains, e.g., sourdough bread, dosa, idli, kishk.
  • Fermented legumes, e.g., tempeh, miso, natto, fermented bean paste.

Probiotic Supplements

Probiotic supplements can be taken as a complementary add-on to eating fermented foods and prebiotic-rich whole plant foods, as part of a gut rebuilding protocol for people with gut dysfunction, or if one’s diet does not contain adequate amount and diversity of fermented foods.

A good probiotic supplement should contain diverse strains of probiotic bacteria (e.g., Lactobacillus, Bifidobacterium, Bacillus species) and yeast (e.g., Saccharomyces boulardii).^6–8

Note that although probiotic supplements provide live beneficial microorganisms to the gut, they do not contain those previously described health-promoting compounds and properties found in fermented foods.

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Tips to Incorporate Probiotic- and Prebiotic-Rich Foods into the Diet

Here are some tips to incorporate a wide variety of probiotic- and prebiotic-rich foods into the diet:

1. Include a wide variety of whole plant foods (i.e., whole fruits, vegetables, legumes, whole grains, nuts and seeds) in the diet, including those rich in prebiotics as described in the previous section. Target to consume more than 30 different types of whole plant foods each week.
2. Include a wide variety of fermented foods in the diet (see examples given in the previous section). Target to consume at least one type of fermented food each day.
3. Probiotic supplements may be taken as a complementary add-on to eating prebiotic- and probiotic-rich foods. Choose a probiotic supplement that contains diverse strains of probiotic bacteria (e.g., Lactobacillus, Bifidobacterium, Bacillus species) and yeast (e.g., Saccharomyces boulardii).

Note that microbial fermentation of prebiotics can produce gas and bloating. If one is not accustomed to prebiotic-rich foods in the diet or has pre-existing gastrointestinal (GI) conditions, it is important to slowly introduce and increment the consumption of prebiotic foods, and avoid/limit those foods that result in GI discomfort.⁹

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Related Articles

Prebiotics versus Probiotics: Is One Better Than the Other?

Why Your Gut Feeling Matters

You are What You Eat? Not Quite

Tips to Promote Gut Health for a Healthy Body & Mind

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References

1. Green M, Arora K, Prakash S. Microbial Medicine: Prebiotic and Probiotic Functional Foods to Target Obesity and Metabolic Syndrome. Int J Mol Sci. 2020;21(8):2890. Published 2020 Apr 21. doi:10.3390/ijms21082890
2. Leeming ER, Johnson AJ, Spector TD, Le Roy CI. Effect of Diet on the Gut Microbiota: Rethinking Intervention Duration. Nutrients. 2019;11(12):2862. Published 2019 Nov 22. doi:10.3390/nu11122862
3. McDonald D, Hyde E, Debelius JW, et al. American Gut: an Open Platform for Citizen Science Microbiome Research. mSystems. 2018;3(3):e00031-18. Published 2018 May 15. doi:10.1128/mSystems.00031-18
4. Melini F, Melini V, Luziatelli F, Ficca AG, Ruzzi M. Health-Promoting Components in Fermented Foods: An Up-to-Date Systematic Review. Nutrients. 2019;11(5):1189. Published 2019 May 27. doi:10.3390/nu11051189
5. Weng Y, Yao J, Sparks S, Wang KY. Nattokinase: An Oral Antithrombotic Agent for the Prevention of Cardiovascular Disease. Int J Mol Sci. 2017;18(3):523. Published 2017 Feb 28. doi:10.3390/ijms18030523
6. Wieërs G, Belkhir L, Enaud R, et al. How Probiotics Affect the Microbiota. Front Cell Infect Microbiol. 2020;9:454. Published 2020 Jan 15. doi:10.3389/fcimb.2019.00454
7. Piewngam P, Otto M. Probiotics to prevent Staphylococcus aureusdisease?. Gut Microbes. 2020;11(1):94-101. doi:10.1080/19490976.2019.1591137
8. Piewngam P, Zheng Y, Nguyen TH, et al. Pathogen elimination by probiotic Bacillus via signalling interference. Nature. 2018;562(7728):532-537. doi:10.1038/s41586-018-0616-y
9. Holscher HD. Dietary fiber and prebiotics and the gastrointestinal microbiota. Gut Microbes. 2017;8(2):172-184. doi:10.1080/19490976.2017.1290756