VSL#3 Probiotic Protects Against Weight Gain

Obesity VSL3 1


In my review of VSL#3 Probiotic, I touched on a paper published in the Obesity journal, this October 2015 titled:

Probiotic Supplementation Attenuates Increases in Body Mass and Fat Mass During High-Fat Diet in Healthy Young Adults

They concluded that:

VSL#3 supplementation appears to have provided some protection from body mass gain and fat accumulation in healthy young men consuming a High-fat and high-energy diet.

This of course made me curious.  Some questions that immediately popped into my mind included: How did they run this experiment?  How much VSL#3 did they use?  How long did they supplement for?  What else did they test?

Luckily, this paper can be accessed for free, so I set aside some time and read through it.

The authors do a wonderful job in the introduction providing the background to their project.  I learned quite a few interesting things about the relationship between gut bacteria and our metabolism:

High-fat, high-energy diets cause a shift in gut bacterial communities and a modest increase in circulating endotoxin concentrations…

This modest elevation in circulating endotoxin, termed “metabolic endotoxemia”, has been implicated as a cause for the low-grade systemic inflammation observed in obesity and related metabolic diseases.

Elevated circulating endotoxin has been shown to initiate obesity and insulin resistance in rodent models. In addition, elevated endotoxin concentrations have been associated with insulin resistance and increased risk for incident type 2 diabetes in humans.

Essentially, what they’re saying is, our diet can alter our gut bacteria which can then cause endotoxin to leak into our blood stream, which then causes systemic inflammation, leading to obesity and insulin resistance.

This is sort of related to one of the theories behind high cholesterol that Rhonda Patrick has been espousing lately which goes something like: inflammation in the gut causes bacterial endotoxin to leak into the circulation, which then binds to LDL particles, preventing them from being absorbed, therefore causing high LDL.



This was a randomized, double-blind placebo-controlled study, which is pretty much the gold standard of scientific experiments.

They took 20 healthy yet sedentary males and fed them a diet consisting of 55% carbs, 30% fat, and 15% protein for 2 weeks, at a maintenance level of calories.

For someone eating 2000 calories, this would look like:

  • Carbs: 275 gm
  • Fat: 66.7 gm
  • Protein: 75 gm

The subjects were then randomized into a control group receiving placebo and a test group receiving VSL#3.  For the next four weeks, the diets of both groups were converted to 55% fat, 30% carbs, and 15% protein (the percentages of carbs and fats were reversed), which for someone eating 2000 calories would look like:

  • Carbs 150 gm
  • Fat: 122 gm
  • Protein 75 gm

On top of that, the caloric content was increased by 1000 calories.

So if our hypothetical test subject a 2000 calories for the first 2 weeks, the subject would now be eating 3000 calories for the next 4 weeks.  They really were trying to fatten these guys up.

How much VSL#3 did they give?

They mixed two sachets of VSL#3 (each sachet contains 450 billion bacteria for a total of 900 billion) into a shake composed of ice cream and coconut milk, and gave it to the test group.  The control group received two sachets of cornstarch as placebo.

This actually sounds like a milk shake I’d like to drink…

What did they track?

  • Body weight
  • Serum endotoxin
  • Insulin sensitivity via an IV glucose tolerance test
  • Skeletal biopsies to measure various metabolic enzymes
  • Stool samples to measure gut bacteria

What did they find?

There were no differences in the two groups with regard to serum endotoxin levels, insulin sensitivity, or the various metabolic enzymes they measured.

Both groups gained weight and gained fat, however the group taking VSL#3 experienced overall LESS weight gain and LESS fat gain.

Obesity VSL3 2

Looking at the data:

  • The control group gained on average 2.4 kg of weight and 1.4 kg of fat.
  • The VSL#3 group gained on average 1.1 kg of weight and 0.6 kg of fat.

They concluded:

The major finding of the present study was that VSL#3 treatment attenuated body mass and fat mass gain following a high-fat diet compared with placebo. However, neither the high-fat diet nor VSL#3 treatment altered circulating endotoxin concentrations, proinflammatory cytokines, insulin sensitivity, or skeletal muscle substrate metabolism.

In the discussion they propose some mechanisms for how this happens based on prior research.

  1. VSL#3 supplementation alters gut bacteria to decrease the amount of energy absorbed through diet, leading to less weight and fat gain.
  2. VSL#3 supplementation alters gut bacteria which decreases the amount of fat the gut absorbs via decreased pancreatic lipase activity.
  3. VSL#3 supplementation increased the body’s metabolism via mechanisms like increased angiopoietin-like protein-4, GLP-1 secretion, and increased sympathetic activity to white and brown fat.

It’s important to note that none of these things have been proven and some of these theories are only supported by preliminary animal models.

Did VSL#3 change their gut biome?

When it comes to probiotics, I’ve always wondered how much of it actually makes it through the gut.  There are a lot of claims out there stating that the majority of probiotics are bogus and don’t even make it through the acid and digestive enzymes of the stomach to reach the small and large intestines.  That’s why I was glad that this was something they measured.

Here is what they found:

Obesity VSL3 3

Streptococcus thermophiles was significantly enriched in both groups (P=0.002); however the magnitude of change in fecal bacterial enrichment was greater (P=0.02) in VSL#3 compared with the placebo group.

Similarly, Lactobacillus acidophilus was enriched over time (P=0.041); however there was a significant time 3 treatment interaction (P=0.40), indicating that the VSL#3 group had greater fecal bacterial enrichment compared with the placebo group following the high-fat diet.

Meaning, they found more of these two bacteria (which are 2 of the 8 strains in VSL#3) in the stool of the VSL#3 group.  There is a clear difference between the control group and the VSL#3 group.

The next question I have is how long do these changes persist after supplementation is stopped?  Do the changes take hold without continuous supplementation?  Or will the gut bacteria return to baseline?

Mainly I want to know, do I need to keep taking this in perpetuity to experience the effects?  Or is it just a one time thing, and boom, we’re done?

Final Thoughts

This probiotic isn’t cheap.  You can see that on Amazon:

Pack of 30 VSL#3 Sachets for $94.91 = 142 billion bacteria per dollar.

To replicate the amount they gave for this study, it would require 60 packs over 4 weeks which comes out to $190!!!

On the other hand:

Bottle of 60 VSL#3 Capsules for $56.49 = 119.5 billion bacteria per dollar

I’ve found capsules are more convenient to take compared to powders, but now that I’ve run the numbers, I’m not entirely sure the convenience is worth it.

The benefits that this probiotic confers and the fact that it stands up to the rigors of a randomized study really legitimizes it as a supplement for me.  It’s something that I’ll definitely consider taking regularly… or at the very least semi-regularly depending on how much my wallet allows.

(Here’s a link to the pdf or the paper with all of my highlights in case the original link breaks)

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