#559: Skin Health & Nutrition – Thivi Maruthappu, PhD
Sigma Nutrition Radio
Danny Lennon
4.8 • 633 Ratings
🗓️ 8 April 2025
⏱️ 45 minutes
🧾️ Download transcript
Summary
The intersection of nutrition, dermatology, and skin health is an area of growing interest, yet one that remains riddled with misinformation and oversimplified claims.
The influence of dietary patterns, specific nutrients, and lifestyle factors on conditions such as acne, eczema, psoriasis, and skin aging has been widely debated, with varying levels of evidence supporting different interventions.
While some nutritional strategies may play a role in optimizing skin health, the challenge lies in distinguishing practical, evidence-based approaches from overstated or anecdotal claims.
A significant issue in this space is the naturalistic fallacy—the belief that diet alone can replace medical treatments, or that conventional dermatological interventions should be avoided in favor of "natural" approaches. This has led to widespread vilification of certain foods, such as dairy, gluten, and sugar, despite a lack of strong supporting data.
Similarly, supplements and probiotics are often promoted with broad claims, while their actual efficacy is highly context-dependent—varying based on individual nutrient status, disease severity, and baseline dietary intake.
In this episode, Dr. Thivi Maruthappu, a consultant dermatologist and researcher in nutritional dermatology, joins Danny Lennon to explore the current state of evidence in this field.
Guest Information
Dr Thivi Maruthappu MA PhD FRCP ANutr is a consultant dermatologist, nutritionist and leading researcher. As the UK's first and only dual-qualified dermatologist and nutritionist, her pioneering expertise bridges the gap between diet and skin health. Dr Thivi continues to work in the NHS and has her own practice based at London's renowned Cleveland Clinic.
Dr Thivi studied Medicine at Oxford University and completed Dermatology training in London. She undertook a PhD to understand the links between our skin and internal health and this research featured in top tier scientific journals. She is one of a handful of dermatologists to have completed training in severe eczema and psoriasis during a fellowship at St John's Institute of Dermatology, London and achieved a Certificate in Nutrition Science from Stanford Medical School, USA.
Timestamps
- [02:52] Start of interview
- [03:37] Dr. Maruthappu's background and expertise
- [05:57] Sunscreen and skin health: myths and facts
- [12:15] Effective skincare ingredients
- [16:07] The role of nutrition in skin health
- [20:25] Dairy and skin conditions
- [24:10] Collagen supplements: do they work?
- [27:45] Probiotics for skin health
- [31:35] Research outcomes and challenges
- [35:20] Practical applications in clinical practice
- [43:05] Key ideas segment (premium-only)
Related Resources
- Join the Sigma email newsletter for free
- Subscribe to Sigma Nutrition Premium
- Enroll in the next cohort of our Applied Nutrition Literacy course
- Dr. Maruthappu's website
Transcript
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| 0:00.0 | Hello and welcome to Sigma Nutrition Radio. This is episode 559 of the podcast. You are very welcome. |
| 0:07.5 | My name is Danny Lennon. Today on the podcast, we're going to be talking with Dr. Therhi Marathupu, |
| 0:13.8 | who is a consultant dermatologist, a researcher as well as being a qualified nutritionist. |
| 0:20.8 | And she is going to walk us through some of |
| 0:23.2 | the controversies that relate to diet and skin health area that is notorious for a lack of high |
| 0:30.4 | quality studies that we can call upon to make some clear and confident conclusions. |
| 0:35.2 | And oftentimes this is at odds with what we may hear in various places, |
| 0:39.2 | whether they are anecdotes from people or information people are putting online or various products, |
| 0:44.6 | supplements, diets and so on that are promoted as being beneficial for the skin or indeed |
| 0:50.7 | treating specific skin conditions. So we're going to try and look at what the evidence |
| 0:55.2 | currently says on a number of these topics. And in the areas where we don't have clear answers from |
| 1:00.5 | research yet, what has Dr. Marathupu done within the clinic setting and what is she found to be |
| 1:08.2 | working and applying some of these principles in the real world with patients. |
| 1:13.1 | And so we're also going to take a look at some of the controversies that end up finding the way into health science discussions broadly online. |
| 1:20.5 | For example, various claims people make about sunscreen and potential health effects there. |
| 1:26.8 | And so hopefully by the end of this conversation, |
| 1:29.2 | you are more clear on a number of the topics we are going to get into. If you wish to get |
| 1:34.0 | detailed study notes to accompany this episode, as well as our previous episodes, you can do |
| 1:38.8 | so by being a subscriber to Sigma Nutrition Premium. Our subscription not only gives you these resources like |
| 1:45.2 | detailed study notes and transcripts for all our episodes, but you also get a number of |
| 1:50.0 | premium exclusive episodes that cover a range of other topics, not on the public feed, as well |
| 1:56.0 | as Q&A episodes as well. So I will link to Sigma Nutrition Premium in the description box where |
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