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Sigma Nutrition Radio

#607: Gut Health & Microbiome Testing: What Evidence Do We Actually Have? – Emily Leeming, PhD

Sigma Nutrition Radio

Danny Lennon

Health & Fitness, Nutrition

4.8 • 633 Ratings

🗓️ 26 May 2026

⏱️ 51 minutes

🔗️ Recording | iTunes | RSS

🧾️ Download transcript

Summary

Gut health has become a major focus in nutrition, medicine, and consumer wellness, but the term is often used loosely. Claims about microbiome testing, probiotics, fermented foods, fibre, and "boosting" the gut microbiome are now common, yet the evidence behind these claims varies substantially.

In this episode, Dr. Emily Leeming examines what gut health actually refers to, why it cannot be reduced to the microbiome alone, and where current microbiome science is being applied before it is ready. The discussion covers the limits of commercial stool testing, the difficulty of defining a healthy microbiome, and the practical strategies most strongly supported by current evidence.

Timestamps:
  • [02:48] Interview start
  • [04:17] Defining gut health
  • [09:03] What is a "healthy microbiome"?
  • [15:25] Microbiome testing - any clinical utility?
  • [24:08] Interpreting microbiome studies
  • [34:39] "30 plants a week" is not evidence-based
  • [39:53] Serotonin and gut brain
  • [45:34] Fiber research frontier

Links/Resources:

Transcript

Click on a timestamp to play from that location

0:00.0

Hello and welcome to Sigma Nutrition Radio. This is episode 607 of the podcast. My name is Danny Lenin.

0:07.9

You're very welcome to the show. Today we're going to be talking about a range of topics that relate to

0:13.7

overall gut health, specifically to the microbiome, and then of course how nutrition interacts with

0:20.0

this and affects health ultimately.

0:22.6

And mainly looking at what evidence we have for a variety of claims that are often made

0:28.7

or things that are presumed to be true at this point.

0:32.7

And what evidence is behind them, what areas we have good quality evidence or not, where exactly the field is at this point, and then ultimately, what can we conclude with some degree of confidence right now and what is still up in the air?

0:48.0

To go through this, I'm going to be talking with Dr. Emily Leaming, who is a researcher at King's College London, is a dietitian and has

0:56.2

published work in this particular area. Dr. Leaming has a PhD in diet and the gut microbiome

1:03.0

from King's College London, and previous to that, she completed her master's in nutrition

1:08.0

and dietetics at Monash University. And she has both published work in this

1:13.3

area, like I mentioned, as well as being one of the people who has tried to disseminate that

1:18.4

information, which can be quite tricky, given as this is one of the areas where oftentimes hype

1:23.7

goes way beyond what evidence we have. And so trying to do that in an accurate way, but that is also understandable and useful

1:31.0

for the general public can be quite the challenge.

1:33.8

So we'll be taking a look at some of these ideas through this conversation.

1:38.4

If you are a premium subscriber to the podcast, remember you can get a set of detailed

1:43.5

study notes that accompanies this

1:45.1

episode as well as a full edited transcript. You'll also be listening to our key idea segment

1:51.1

that follows this particular interview. If you're listening over on the free public feed of the

1:56.0

podcast and want to get more out of your podcast listening and use it to really learn and retain

2:00.7

much more of the information that you hear on these podcasts,

...

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