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Review of Synbiotic 365 from United Naturals

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5 out of 5 stars/ 5
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Improving Digestive Health and Boosting Energy
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Review Summary of Synbiotic 365

In the more than nine years that I've been reviewing supplements and probiotics, I've had the opportunity to test many products and talk with any number of company owners and product formulators.

I believe that both the rationale for developing Synbiotic 365 and the research that goes into the ingredients and selection of probiotic strains are highly compelling.

For the consumer with digestive issues, Synbiotic 365 offers one of the most considered selections of probiotics, prebiotics and B vitamins available on the market. In fact, I know first hand that as part of an ongoing quest to deliver the best solution for digestive health, the developers have changed and/or updated their choices of probiotic strains more than once.

Each Synbiotic 365 capsule is packed with a blend of 14 probiotic strains delivering 20 billion CFU of beneficial bacteria. In addition, the probiotics are nurtured by a plant-based prebiotic of chicory root inulin.

And because people struggling with poor digestive health often are deficient in B vitamins, Synbiotic 365 contains at least 200% of the minimum daily value of eight different B vitamins (including 1000% of the all-essential B12).

Since its founding in 2017, Canadian-based United Naturals has been committed to producing products designed to improve digestive health. Synbiotic 365 is their first--and most popular--product.

United Naturals' Inspiration for Synbiotic 365

Sometimes it takes a very special inspiration to deliver an exceptional product, and Synbiotic 365 is no different. According to the company's founder, he first became aware of the serious nature of poor digestive health through his girlfriend's problems.

He witnessed the devastating and potentially life-destroying issues associated with her poor digestive health, including low energy and vitamin B deficiencies. His research led him to probiotics. And since his girlfriend had difficulties digesting vegetables (natural prebiotics) he opted to include easily digested, plant-based chicory root inulin to nurture the probiotics.

Dr. Vincent Pedre's Contribution to the Synbiotic 365 Formula

Although the initial selection of probiotics, prebiotic and B vitamins gave his girlfriend relief and improved her digestive health, United Naturals' founder set a high goal for his formula. He wanted to produce the optimal digestive health supplement.

He invited Board-Certified Internist Dr. Vincent Pedre to collaborate. As a specialist in internal medicine with more than 16 years of clinical experience, Dr. Pedre helped refine the formula.

The result is Synbiotic 365, which may be one of the best probiotics for digestive health available today.

Synbiotic 365 Ingredients

Blend of 14 Probiotic Strains

Lactobacillus gasseri BNR17®

L. gasseriis one of more than 150 lactobacillus strains in the lactic acid bacteria group. Although isolated from human breast milk, it is naturally found in the digestive and urinary tracts. Significantly, L. gasseri is one of the low-histamine probiotics that help increase the body's histamine intolerance and support the bacteria that boost digestive health.

The strain of L. gasseri BNR17 has been widely studied for it's potential to reduce hyperglycemia, and decrease blood sugar control and reduce the problems associated with polydipsia, polyphagia, and polyuria.1

In 2013, Jung et al, conducted a randomized, double-blind clinical trial of LG BNR17 in 62 obese humans that suggested a tendency towards lower weight.2 Kim's study in 2017 found more statistically significant weight loss.3

Of particular importance to the our examination of the the ingredients in synbiotic 365 are the studies of LG BNR17 as a treatment of irritable bowel syndrome (IBS). Shin et al (2017) found that L. gasseri BNR17 reduced diarrhea and improved quality of life for IBS patients significantly.4 The following year, Kim documented significant improvements in the symptom scores of IBS patients.5

While findings are encouraging, we anticipate more studies by a more diverse set of research and author groups.

United Naturals is one of a few exclusive partners in the world that can include this clinically studied strain in their product.

Lactobacillus plantarum UALp-05™

L. plantarum is a gram-positive, lactic acid bacteria commonly foud in fermented foods that is often identified as beneficial for helping relieve diarrhea and ulcerative colitis.

As for the UALp-05 strain, Polewski showed that it inhibited E. coli bacterial adhesion to the bladder wall.6 Vemuri et al showed that this strain demonstrated significant anti-inflammatory activity in the aging gut, downregulating inflammatory cytokines and upregulated interleukins.7

Bacillus subtilis DE111®

Also known as the grass bacillus, B. subtilis is a robust bacterium found not only in the soil but also in the GI tract of both humans and ruminants. Its benefits include contributing to gut health and survivability in the intestinal tract.

A study by Toohey on the effects of this strain on strength and body fat in female athletes showed significant impact on weight loss, but no effect on strength gains.8 A study by Townsend on the effects of this strain on immune function in athletes showed no effects.9

Bifidobacterium bifidum UABb-10™

B. bifidum is another in the family of lactic acid bacteria that are commonly found in the intestinal and urogenital tracts of mammals, including humans. It helps relive GI disorders (diarrhea, constipation and stomach pain) and IBS.

A study by Sergeev10 used this strain in combination with three other probiotic organisms to study weight loss. Noted a decrease over time in body mass, BMI, waist circumstance, and body fat mass.

Bifidobacterium lactis UABla-12™

The B. lactis probiotic bacteris has many benefits for the body, including helping improve digestion, which in turn can help boost the body's general immunity.

A study by Gerasimov looked at using this strain to prevent or shorten acute respiratory infections in kids.11 Results suggest that while B. lactis didn't prevent infections but did shorten duration.

In a separate study, Martoni (who works for UAB labs) found that this organism significantly reduced symptoms of IBS.12

Bifidobacterium longum UABl-14™

This gram-positive, catalase-negative bacterium is among the 32 species in the genus Bifidobacterium. Its benefits include improving gut health, reducing symptoms of Celiac Disease and boosting immunity.

A study by Greany using this strain along with two others measured their effect on lipids.13 Patients had normal lipids to begin with; there was no effect.

However, a study by Martoni (who works for UAB labs) found that this organism, in combination with three other probiotics, significantly reduced functional constipation.14

Lactobacillus casei UALc-03™

Among other things, L. casei compliments L. acidophilus. However, for the purposes of this review, we found no human studies of this strain.

Lactobacillus paracasei UALpc-04™

L. paracasei has any number of benefits; one in particular is its role in helping to maintain the balance of microflora in the intestine. We found no human studies of the UALpc-04 strain.

Lactobacillus rhamnosus GG

Fong et al performed in vitro analysis of L. rhamnosus GG on markers of immunomodulatory properties on antigen-presenting cells (APCs).15 Results showed modulation of immune function markers.

A study by Näse look at the impact of this strain on pediatric dental health.16 The findings showed an overall reduction in dental caries.

A cool study by Pedersen17 compared a low FODMAP (Fermentable Oligo-, Di-, Mono-saccharides And Polyols) diet to this organism in treating symptoms of IBS. L. rhamnosus GG Worked as well as restrictive diet.

Lactobacillus reuteri UALre-16™

Although we found no human studies of this strain, L. reuteri generally is described as beneficial to gut health, reduced abdominal pain, weight loss, and general wellness.

Lactobacillus salivarius UALs-07™

L. salivarius can be found in virtually every part of the body and is identified as beneficial for digestive health, dental health and immunity. However, we have not identified any human studies for this strain.

Streptococcus thermophilus UASt-09™

Vemuri et al showed that this strain demonstrated significant anti-inflammatory activity in the aging gut, downregulating inflammatory cytokines and upregulated interleukins.18 It was used as a comparator against a human-derived probiotic (this one is plant derived) to show that human-derived probiotics are superior.19

Lactobacillus fermentum SBS-1™

Lactobacillus fermentum is a gram-positive, rod-shaped bacterium that is commonly found in and on the human body. While it has powerful probiotic properties in the gut generally, we know of no human trials available on this strain.

Saccharomyces boulardii

Saccharomyces boulardii is a yeast organism frequently used as a probiotic. The goal of probiotic therapy is to introduce beneficial organisms into the GI tract, adding protection against more pathogenic organisms. S. boulardii, like other probiotic organisms, produces proteins and chemicals that inhibit the growth of pathogens. This allows healthy bacteria and yeast to flourish in the gut. These proteins inhibit pathogenic bacterial adhesion to the intestinal wall.

The potentials for using S. boulardii in the treatment and even prevention of antibiotic-associated diarrhea20 have been heavily researched and the findings encouraging. This includes diarrhea associated with serious and life-threatening conditions, including:

  • Clostridium difficile21,22
  • HIV/AIDS23
  • H. pylori24,25
  • Viral gastroenteritis26

The Cochrane Review further reports that S. boulardii is safe and efficacious for children as well as adults.


United Naturals paired Synbiotic 365's probiotics with a highly researched, plant-based prebiotic--chichory root inulin. Chicory root has been shown to boost beneficial bifidobacteria in the large intestines.27

B Vitamins

B vitamin deficiencies are very common among people with impaired digestive health. And because these deficiences can lead to a wide range of health issues--ranging from weakness and fatigue to nerve damage and impaired mobility--I'm particularly impressed with United Naturals' decision to pack Synbiotic365 with the beneficial Bs.

Synbiotic 365 contains 200% of the daily value (DV) for vitamins:

  • Thiamin (Vitamin B1)
  • Riboflavin (Vitamin B2)
  • Niacin (Vitamin B3) (as niacinamide)
  • Vitamin B6 (as pyridoxine HCl)
  • Folate (as calcium L-5-methyltetrahydrofolate)
  • Biotin (Vitamin B7)
  • Pantothenic acid (Vitamin B5) (as D-calcium pantothenate)

In addition, because B12 deficiencies are particularly problemmatic in people with digestive problems, United Naturals packed Synbiotic 365 with 1000% DV of B12.

Other Ingredients

The other ingredients relate primarily to the Synbiotic 365 capsule. Hypromellose is an inert polymer whose acid-resistant, enteric properties protect sensitive bacterial ingredients from stomach acid, thus enabling them to reach the intestine.

Gellan gum is a water-soluble thickener. Both hypromellose and gellan gun are vegan alternatives to animal gelatin.

Titanium dioxide is a commonly used colorant (white). Although TD has been linked to possible inflammatory 28and immune system problems,29 the amount used in each capsule is miniscule.

Finally, rice hull concentrate--a rice by-product--is used as a natural anti-caking agent to replace synthetic silicone dioxide.

I've looked hard at these ingredients, and while there is always someone who is opposed to virtually every additional ingredient, I have found little to concern me--especially given the tiny amounts being used in each capsule.

Furthermore, I feel that United Naturals has made considered choices with its use of vegan ingredients and a more natural alternative to silicone dioxide.

Does Synbiotic 365 Have Any Allergens or Side Effects?

Another of the things I like about Synbiotic 365 is that since it is formulated specifically for people with digestive issues, United Naturals selected ingredients that are easily tolerated by those with food allergies and sensitivities. Synbiotic 365 is...

  • Gluten Free: I've heard first hand from United Naturals founder that Synbiotic 365 is safe for people with Celiac's disease. They have had zero reports of allergic reactions.
  • Dairy Free: If you are lactose intolerant or allergic to dairy products, you should have NO difficulties with Synbiotic 365. Although some bacteria are cultured in dairy products, only the smallest residual levels remain. Again, I have it directly from United Naturals that they have zero reports of ill-effects or allergic reactions.
  • GMO Free: No GMO (genetically modified organisms) are included in the formulation of Synbiotic 365.
  • Soy, Egg and Nut Free: United Naturals takes careful precautions in its manufacturing process to avoid cross-contamination with common allergens, including eggs, nuts and soy.

As with all United Naturals products, Synbiotic 365 is sourced with the very best ingredients, manufactured in the USA, and tested against the company's strictest quality requirements.

How to Take Synbiotic 365

Whether you are just starting to take Synbiotic 365 or have been taking it for several weeks or months, the dosage is the same. Take one (1) capsule daily. Whenever I take Synbiotic 365, I prefer to take it on an empty stomach along with an eight-ounce glass of water.

Although Synbiotic 365 is safe and well-tolerated, I always recommend that you talk with your nutritionist or health provider prior to starting a regimen--particularly if you are under a physician's care, on medications and/or pregnant or nursing.

Furthermore, if you should experience any uncomfortable side effects, discontinue use and contact your physician.

Does United Naturals Offer a Money-Back Guarantee?

A good guarantee goes a long way toward building trust and confidence in my book. And I'm pleased with United Naturals' 60-day money-back guarantee.

If at any time within 60 days of your purchase date, you are not 100% satisfied with the product and your results, call United Naturals. Customer service is available Monday through Friday at 844-794-7728. They will help you receive a full refund. No questions asked.

If you originally purchased several packages, you are allowed to return up to two empty containers and the remainder of any product that is unused and in a fully sealed, untampered package.

Are There Any Product Complaints or Scams Regarding Synbiotic 365?

I like to test products myself, and Synbiotic 365 is no different. I found the supplement easy to take, the ingredients easily tolerated and the packaging clean. And based on my research and conversations with the people behind this product, I am confident in giving Synbiotic 365 one of our highest ratings.

Leaving nothing to chance, I also regularly scour the Internet for news and reports of problems other people may have. Other than the usual range of personal opinions and preferences for one probiotic over another, I can find no serious complaints.

Similaarly, I know of no scams I should warn you about. That said, you are always safest when you buy directly from the manufacturer. Not only are you assured of getting the freshest product and untampered packaging, but you can take advantage of company discounts and savings on volume purchases.

Is United Naturals a Reputable Company with Good Customer Support?

I've worked with United Naturals for several years and always found the customer support to be excellent--both responsive and helpful.

I've also conducted blind tests by calling the company at odd hours, leaving messages and waiting to see how long it takes to get a response. Invariably, I receive a return call the next morning.

Where to Buy Synbiotics 365

I recommend that you follow any of the links on this page, which will take you directly to the Synbiotics 365 information and order page. When you buy directly from United Naturals, you are assured of the best price, including discounts on larger volume (savings on three- or six-box orders).

Review Rating:

Best for: Improving Digestive Health and Boosting Energy

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Full Reference List

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  2. Jung SP, Lee KM, Kang JH, Yun SI, Park HO, Moon Y, Kim JY. Effect of Lactobacillus gasseri BNR17 on overweight and obese adults: a randomized, double-blind clinical trial. Korean journal of family medicine. 2013 Mar;34(2):80.
  3. Kim J, Yun JM, Kim MK, Kwon O, Cho B. Lactobacillus gasseri BNR17 Supplementation Reduces the Visceral Fat Accumulation and Waist Circumference in Obese Adults: A Randomized, Double-Blind, Placebo-Controlled Trial. Journal of medicinal food. 2018 May 1;21(5):454-61.
  4. Shin SP, Choi YM, Kim WH, Hong SP, Park JM, Kim J, Kwon O, Lee EH, Hahm KB. A double blind, placebo-controlled, randomized clinical trial that breast milk derived-Lactobacillus gasseri BNR17 mitigated diarrhea-dominant irritable bowel syndrome. Journal of clinical biochemistry and nutrition. 2018;62(2):179-86.
  5. Kim JY, Park YJ, Lee HJ, Park MY, Kwon O. Effect of Lactobacillus gasseri BNR17 on irritable bowel syndrome: a randomized, double-blind, placebo-controlled, dose-finding trial. Food science and biotechnology. 2018 Jun 1:1-5.
  6. Polewski MA, Krueger CG, Reed JD, Leyer G. Ability of cranberry proanthocyanidins in combination with a probiotic formulation to inhibit in vitro invasion of gut epithelial cells by extra-intestinal pathogenic E. coli. Journal of functional foods. 2016 Aug 1;25:123-34.
  7. Vemuri RC. Investigation on the utilization of beneficial microbes in modulating the gut microbiota and metabolic profiles in ageing (Doctoral dissertation, University of Tasmania).
  8. Toohey JC, Townsend JR, Johnson SB, Toy AM, Vantrease WC, Bender D, Crimi CC, Stowers KL, Ruiz MD, VanDusseldorp TA, Feito Y. Effects of probiotic (Bacillus subtilis) supplementation during offseason resistance training in female division I athletes. J Strength Cond Res. 2018 Jun 1;10.
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  13. Greany KA, Bonorden MJ, Hamilton-Reeves JM, McMullen MH, Wangen KE, Phipps WR, Feirtag J, Thomas W, Kurzer MS. Probiotic capsules do not lower plasma lipids in young women and men. European journal of clinical nutrition. 2008 Feb;62(2):232-7.
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  16. Näse L, Hatakka K, Savilahti E, Saxelin M, Pönkä A, Poussa T, Korpela R, Meurman JH. Effect of long–term consumption of a probiotic bacterium, Lactobacillus rhamnosus GG, in milk on dental caries and caries risk in children. Caries research. 2001;35(6):412-20.
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  20. Szajewska H, Kołodziej M. Systematic review with meta‐analysis: Saccharomyces boulardii in the prevention of antibiotic‐associated diarrhoea. Alimentary pharmacology & therapeutics. 2015 Oct;42(7):793-801.
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  24. Namkin K, Zardast M, Basirinejad F. Saccharomyces Boulardii in Helicobacter pylori Eradication in children: A randomized trial from Iran. Iranian journal of pediatrics. 2016 Feb;26(1).
  25. Cindoruk M, Erkan G, Karakan T, Dursun A, Unal S. Efficacy and safety of Saccharomyces boulardii in the 14‐day triple anti‐Helicobacter pylori therapy: a prospective randomized placebo‐controlled double‐blind study. Helicobacter. 2007 Aug;12(4):309-16.
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  27. Menne, E., Guggenbuhl, N., & Roberfroid, M. (2000). Fn-type chicory inulin hydrolysate has a prebiotic effect in humans. The Journal of nutrition, 130(5), 1197-1199.
  28. Nogueira C M, de Azevedo W M, Dagli M L Z, Toma S H, de Arruda Leite A Z, Lordello M L, Nishitokukado I, Ortiz-Agostinho C L, Duarte M I S, Ferreira M A, Sipahi A M. Titanium dioxide induced inflammation in the small intestine. World J Gastroenterol. 2012 Sep 14; 18(34): 4729–4735.
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