38Tera Fiber Supplement: Scam or Legit? What You Need to Know.

There are plenty of fiber supplement companies which cherry-pick ingredients and have deceptive marketing that overshadows scientific evidence. How about we subject these companies and claims to a "peer review"? 

In the world of academia, this is when a research paper is evaluated and approved by other experts in the same field before being published in a journal. Link to my own articles. My own commentary critiquing paper on AI. 

Starting with a blog post, lets discuss  38Tera. 

• The founder is Dr. Will Bulsiewicz who is a GI doctor himself and has written Fiber Fueled and the The Fiber Fueled Cookbook. I think he does a great job through his books and interviews stressing the importance of fiber in diet (more to come in another post). 
• On PubMed, I found one peer reviewed review article about the importance of dietary fiber. He is also a principal investigator for a trial sponsored by Zoe Global Limited aiming to assess if an increase in fermented food intake improves bloating, mood, hunger, or energy levels. 
  
  • His website touts "Daily Microbiome Nutrition (DMN) is designed to be a simple, effective daily habit to fuel your digestive wellness". "Your gut microbes are straving"...This type of wordage is common in the black box of fiber supplements. It sounds great... kind of like when a politician gives a speech. But I don't really know what it means. 
  • "Your gut microbes are straving". Again, what does this mean? 
  • The product seems to cherry pick a number of ingredients with low level evidence and then puts them together to make a powder.  
  • He states "evidence first and claims second". He does not actually provide any evidence for the product that he sells. He instead links to individual studies that make up the 6 "core ingredients" of his product. OK. Lets go through each of them.
    • Potato in the form of Solnul (RS2 Resistant Starch) 
      • Who actually paid for this study? It was MSP Starch Products Inc., who is the the developer of Solnul®. Will they start cherry picking results? 
        • Let's focus on the 3.5 g RPS that is used in 38Tera and referenced in the paper. In the abstract they state that "the number of diarrhea- and constipation-associated bowel movements were both significantly lower in the 3.5 g RPS arm compared to the placebo group." 
          • The authors employ a "self reported Bristol scale" to help assess for improvement in constipation or diarrhea. Self reported leads to potential for bias. 
          • Four week trial duration. What happens beyond 4 weeks? 
          • The Bristol Stool Chart has 7 types of stool consistency ranging from Type 1 (seperate hard lumps) to Type 7 (liquid consistency and no solid pieces). The only statistically significant comparisons with a P value < 0.05 were when they lumped together differences between: 
            • "Type 1 or 2" and "Not Type 1 or 2" as well as when comparing "Type 7" and "Not Type 7". 
              • So those who had harder stools at week 4 and those with everything else. We have no clue if those who "improved" past 1 or 2 have full blown loose stools or a normal stool.
              • The absolute numbers of Type 1, 2, and 7 stools are low across both groups. Such small event counts can lead to their statistical test picking up significance. 
              • The study examines multiple stool types (Types 1 through 7) across different groups. The more comparisions you test for, the more likely it is you will have a false positive. 
                
    • Green Kiwifruit 
      • Lets start with this 2022 paper that helped bring Kiwifruit into vogue in the GI world. The abstract reports that "Consumption of green kiwifruit was associated with a clinically relevant increase of ≥ 1.5 CSBM per week (FC; 1.53, P < 0.0001, IBS-C; 1.73, P = 0.0003) and significantly improved measures of GI comfort (GI symptom rating scale total score) in constipated participants (FC, P < 0.0001; IBS-C, P < 0.0001)."
        • Scrolling down to conflicts of interest. "Zespri International Ltd. is the principal sponsor and reviewed, approved, and funded the study design". Zespri's website notes that "Eating just one Zespri™ Organic SunGold™ Kiwifruit a day provides 100% of your daily Vitamin C needs." Let's repeat this study without a Kiwi company as the principal sponsor. 
      • OK now back to the powder form used in 38Tera. (Actazin 600mg (proven dose) – New Zealand)
        • 38Tera's cited paper. Again this trial is sponsored by the company who makes the product actually being tested. I unfortunately can not access the actual data, perhaps because the journal is so obscure, but the paper does note that " Both Actazin and placebo showed improvements of >1 complete spontaneous bowel movement per week over baseline (p < 0.05). 
    • Below are the other ingredients in 38Tera. I was going to do a deep dive into each of them but frankly my time can be better spent elsewhere. If you are interested I would encourage you to see what evidence you can find for the following substances.  
      • Baobab  
      • Acacia 
      • Ligonberry  
      • Beetroot  
      • Mango