What is Gut Health? (Part Two)

If you’ve read part one of our gut health series, you know that nutrition and gut health go hand in hand. If you haven’t read it, get yourself over there and get to reading! Part 2 will make much more sense if you’ve read Part 1. I’ll wait … Are you back? Great! Let’s get on to our next two topics regarding gut health: food additives and probiotics.

First, food additives.

Food additives are a broad category which encompass a very wide—like 10,000 plus—variety of compounds added to foods. They can be directly added, like salt as a preservative, or indirectly added from packaging or processing. Many food additives are harmless substances that preserve the color, texture, or flavor of our food. However, issues with government oversight of food additives in the U.S. has led to many substances being allowed in our food that are associated with scary health concerns (think cancer and endocrine disruption.) Check out the EWG’s Dirty Dozen Guide to Food Additives for more info here. A potential health issue that has more recently caught attention is the effect of food additives on our gut microbiome. In general, information on this is lacking, however, I’ve scoured my sources and pulled information on a few specific compounds that may have a negative effect on your gut microbes.

  • Maltodextrin.Maltodextrin has been associated with dysregulation of your intestine’s defense against bacteria and it is speculated that this may play a role in the development of Inflammatory Bowel Disease (IBD) in those who have the genes for it. (1)
  • Artificial sweeteners. Artificial sweeteners have been shown to cause gut dysbiosis and blood sugar regulation issues, which is often the issue the person is trying to avoid by using them. (2)
  • Carboxymethyl cellulose(found in dairy products, processed meats, and bread) and polysorbate 80 (found in ice creams, whipped cream, condiments, and dill pickles) are common emulsifiers that have been associated with dysbiosis, as well as leaky gut. (3) I’ve seen these on the ingredient list of several probiotic supplements—kinda defeats the purpose, right?

These are just a few of the many food additives that are deemed safe to add to our food, but we have little or no information on less obvious negative health effects. This is why I continue to recommend reading food labels and eliminating products that have ingredients that you recognize as harmful or do not recognize at all. Despite the need for more research, the giant question mark surrounding many of these food additives leads me to continue to recommend that we limit them as much as possible.

Should I take a probiotic?

The official definition of probiotics is “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.” (4) Which basically means you take a pill that has some good bacteria and it helps you. We have pretty strong scientific evidence on treating certain health conditions with probiotics—conditions like antibiotic-associated diarrhea and IBD. However, the evidence is less compelling for prevention. What I can say is probiotic supplements have a low risk of side effects and many folks report some sort of benefit.

Their potential to treat certain diseases points me to the conclusion that they can have an impact on our gut microbiome. However, whether this leads to an improvement in health is still up in the air for me. If you do choose to take a probiotic, I suggest following the guidelines below. I also recommend keeping your expectations reasonable. Most people report symptom improvements that are mild and not any miracle overall improvements in health.

How to choose a probiotic:

  1. Scope out the strains of bacteria in the supplement. Look for a supplement that contains five or six-plus strains, including a combination of both Lactobacilli and Bifidobacteria strains which are the types that have the most research. Specific strains associated with gut health include Lactobacillus acidophilus (abbreviated as L. acidophilus), L. fermentum, L. brevis,  L. bulgaris, L. casei, L. plantarum, L. rhamnosus, L. reuteri, Bifidobacterium animalis (B. animalis), B. breve, B. infantis, and B. longum. The strain Streptococcus thermophilus has also been associated with gut health. (5)
  2. Look for a supplement containing 10-45 billion units per capsule. The most common reported side effect associated with the supplements is gas, so a lower dose may be wise if you are prone to this. (5)
  3. Check out the ingredient list. If it contains any ingredients that you do not recognize or any of the additives discussed above, look for another brand.
  4. Research the company that makes the supplement. Most probiotics are classified as dietary supplements which are not strictly regulated like medicine. This puts them at risk of not containing what the label says, so you want a brand that has a good reputation. See Sarah’s piece below for some RD-approved brands or ask your primary care provider to help you choose a trusted brand.

Taking a probiotic supplement daily seems to be safe for healthy populations. However, there are no specific guidelines on taking probiotic supplements for prevention. Keep in mind the advice from Part 1 about eating fermented foods. If you eat fermented foods every day, taking a probiotic supplement is likely not necessary. Fermented foods are the best source of probiotics and also contain the added bonus of prebiotics which the bacteria can use for food.

I want to end by saying that much is still unknown about the gut microbiome and how we can influence it. The research is currently limited to those strains of bacteria that can actually be cultured (grown) outside of the human body, which is only a handful of the estimated thousands. That means there are many strains that cannot yet be studied to see if dietary or other habits affect them. It’s also difficult to say whether or not the microbiome of modern day humans has recently changed due to lack of information regarding microbiome composition of pre-modern day humans.

This makes it hard to say if modern diseases coincide with gut dysbiosis. What I can say is the disorders associated with gut dysbiosis are a modern phenomenon, which leads me to think modern diet and lifestyle may be related. We know that diet can influence the composition of your gut microbiome and because of this, it has great potential to impact our health. So while the research has its issues, the changes recommended are safe for healthy people and have a potential to positively impact your health. Go with your gut. – Lindsey

A note from Sarah:

Brilliant information, Lindsey! Selecting the right probiotic, or any supplement for that matter, can be overwhelming to say the least. While I’m sure there are several high quality, legit brands circulating the shelves, I can attest to these three brands being high quality picks: Garden of Life RAW Ultimate Care is probably my fave as it contains a robust amount of the highly-researched strains Lindsey mentioned above. Additionally, Klaire Labs and CLEAN probiotic seem to offer effective, potent options for those seeking to improve their gut health.

P.S. If you like this post, you’ll love our entire Ask A Dietitian series. And you can get even more info from Lindsey and Sarah in our cookbook, Weekday Weekend

Credits // Authors: Lindsey Kelsay with contributions from Sarah O’Callaghan. Photo: Emma Chapman.
References: 1. Chassaing, B., Vijay-Kumar, M., & Gewirtz, A. T. (2017). How diet can impact gut microbiota to promote or endanger health. Current Opinion in Gastroenterology, 33(6), 417–421. http://doi.org/10.1097/MOG.0000000000000401 2.Caricilli, A. M., & Saad, M. J. a. (2014). Gut microbiota composition and its effects on obesity and insulin resistance. Current Opinion in Clinical Nutrition and Metabolic Care, 17(4), 312–8. http://doi.org/10.1097/MCO.0000000000000067 3. Serban, D. E. (2015). Microbiota in Inflammatory Bowel Disease Pathogenesis and Therapy: Is It All About Diet? Nutrition in Clinical Practice, (5). http://doi.org/10.1177/0884533615606898 4. Sanders, M.E. (2008). Probiotics: Definition, Sources, Selection, and Uses.Clinical Infectious Diseases, 46(2), S58–S6. https://doi.org/10.1086/523341 5.Harvard Institutes of Medicine (n.d.). The Benefits of Probiotics [Brochure]. Boston, MA: Harvard Health Publishing.
  • The artificial sweeteners above were no clarified, and I wanted you to touch on what you meant a little more, only because many natural sweeteners also get lumped into this category.

    What are your feelings on natural no/low calorie sweeteners like erythritol, xylitol, monk fruit, and stevia?

    • Hi Laura – you make a good point. The article I was referencing (https://www.nature.com/articles/nature13793) was specifically looking at saccharin, sucralose, and aspartame. In my research, I did not find anything specifically on the gut microbiome and the other sweeteners you listed. I will say that what is being found is the sweet taste (calories or no) seems to set off a metabolic response in our body that may lead to negative health effects. Because of this, I will continue to recommend using as little added sugar or sweetener as possible. I would also caution you to look at the food label and see what other ingredients are included. I often find that with stevia and monk fruit especially, they are not even the first ingredient in the product.

  • I love how informative this series is!


  • I love these kinds of posts, I really want to know more about what is good for my body and what is not good!

  • Great to see more focus on this important area of health. A lot of research is continuing, but it needs articles like yours to get the public attention. We all need to learn more. I follow Dr Bruce Lipton’s studies, the possibilities in this time of Global Upheaval demand inner healing and unity.

    • You make a good point, Phoebe! I’ll have to check out Dr. Lipton!

    • That’s a really good question. I have been able to find no consensus on this, probably because it is not well represented in the literature. One study (https://www.ncbi.nlm.nih.gov/pubmed/22146689) found that taking the supplement 30 minutes before or at the beginning of the meal improved probiotic survival. However, it must be considered that the study was done using a model of the human intestinal tract which just means they used a man-made digestive tract, not an actual person. Until we have clinical trials on humans performed, I think this question will remain unanswered. I might suggest that you take the supplement whatever time of day is easiest for you to remember. Thanks for reading!

  • I really enjoyed this post! It’s always nice knowing more about our body and how to keep it healthy. 🙂

    Charmaine Ng | Architecture & Lifestyle Blog

  • Another awesome article on health! I’ve been wanting to take a probiotic for some time but I get migraines from fermented/aged foods and worry that if I take the wrong one I could face worse migraines in the short term. It’s probably better for me to consult a stomach doctor before I try anything, but I’m curious if there are “gut bacteria” doctors yet. Maybe that’s something we’ll see in the future. Thanks for sharing!!

    Eva | www.shessobright.com

    • Thanks! I know gut health is certainly getting attention from physicians and is definitely an area of interest for many healthcare providers. I’m sure there are specialists out there, but I only know of those in the research world!

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