Marine biologist Dr Craig Rose has spent two decades making the case that seaweed is one of the most nutritionally powerful ingredients on the planet. As founder of Seaweed & Co and the Doctor Seaweed brand, he’s built a business on the conviction that this ancient food is about to have its moment. He spoke to Natural Newsdesk about the science, the opportunity, and how this ‘forgotten food’ is being rediscovered by a new generation of health and wellness motivated consumers. 

What first got you interested in seaweed?
I’m a marine biologist by training and I started working with seaweed around 20 years ago, initially on a project exploring how to turn it into biofuels. There was an opportunity there — but something else was solidifying in my mind. This massive realisation that seaweed is a largely forgotten food. Something that was once eaten commonly right across the world — from Japan to Ireland to the Pacific Islands — had quietly disappeared from Western food culture. And yet the nutritional profile was extraordinary. I could see a commercial opportunity, a sustainability story and a genuine public health angle all converging at once. Biofuels may well happen with seaweed, but they are not as impactful or valuable as the more immediate need for health and nutrition.

“I could see a commercial opportunity, a sustainability story and a genuine public health angle all converging at once”

How did you translate that into a business?
The key question for me was how to get people to understand the importance of seaweed in ways they could actually use — without being preachy about it. It’s easy to talk about sustainability credentials. But ultimately that’s not what sells a product. What sells a product is making clear how it benefits the customer, and offering it in ways that fit into their daily lives.

I started the business after meeting the team at the Hebrides Seaweed Company, who hold the Crown Estate licence for harvesting seaweed around Lewis and Harris in the Outer Hebrides. Their harvesting method is genuinely impressive — specially designed boats that trim the top of the seaweed, essentially mowing it while leaving the plant intact to regenerate. The species, Ascophyllum nodosum, is hugely abundant, which means production is scalable in ways that matter commercially. We installed our own processing equipment at their facility and began producing our seaweed ingredients under the PureSea brand — carefully dried and milled to preserve the full nutritional profile, with complete traceability from sea to shore. We’re certified organic by the Organic Food Federation, and we offer two formats: PureSea Natural and PureSea Protect, a micro-encapsulated version for a flavourless option.

How do seaweed’s health and wellness credentials stack up in scientific terms?
There’s a growing body of robust, peer-reviewed research to support seaweed’s multiple benefits. That’s what serious products developers — and increasingly, regulators — actually demand. 

Brown macroalgae, the variety we use, has decades of credible nutritional and clinical research behind it. The bioactive compounds — fucoidan, alginate, laminarin — are the subject of active peer-reviewed study across immune function, anti-inflammatory pathways and hormonal balance. And there are multiple EFSA-authorised health claims for iodine alone, covering thyroid support, energy and metabolism, skin health and nervous system”.  That’s a claims foundation that means when a brand works with our ingredient, they have a proper scientific story to tell. That changes everything — for retailers, for consumers and for regulatory positioning.

Can you talk about seaweed’s role in addressing iodine deficiency — how significant an issue is this?
It’s more significant than most people realise. Iodine can really only be obtained through fish and dairy in the typical Western diet, and deficiency is now a serious and growing public health concern. A 2024 paper in The Lancet called for much greater vigilance around iodine deficiency and specifically highlighted the UK as having a particularly significant problem. Globally, around five billion people are iodine deficient. That’s not a niche issue — it’s one of the most widespread nutritional shortfalls on the planet. And seaweed is one of the only natural food sources of iodine that exists outside fish and dairy. That alone should be making manufacturers sit up.

You’ve done your own clinical research into how the body processes seaweed iodine. What did you find?
We worked with Glasgow University Medical School comparing how the body absorbs iodine from seaweed versus synthetic potassium iodide — the form used in most fortified products. Both groups ingested the same amount of iodine. What we observed was striking. The synthetic form was absorbed quickly and excreted quickly. The seaweed iodine behaved completely differently — slower, more sustained release, because it’s bound within the food matrix of a high-fibre whole food. The body processes it the way it was designed to process food, not isolated supplements.

That has real implications for formulation. It suggests that seaweed isn’t just a natural source of iodine — it may actually be a superior source. That’s the kind of evidence that gets serious product developers excited, and rightly so.

What were you setting out to do with the Doctor Seaweed consumer brand?
The vision from the start was to enable people to look and feel wonderful with seaweed — but to do that in a meaningful, evidence-led way. So we’ve stayed entirely focused on what seaweed actually does scientifically. We’ve never launched a gut health product, for instance, because that’s not where seaweed’s real strength lies. Every product — Immunity+, Collagen+, Menopause+ — is built around the evidence.

What’s been genuinely exciting is that some of our best ideas have come directly from customers. The menopause product came about because we had so many women contacting us to say our pure seaweed capsule was helping with their symptoms. We looked into why, and built a product specifically around it. Our newest launch, Endo+, developed in partnership with Carla Cressy OBE, founder of The Endometriosis Foundation, followed the same path. She told us she’d been taking our pure seaweed capsule and that it had genuinely helped with her endometriosis symptoms. We dug into the science and formulated something specifically for that community. Health claims matter — but what makes people buy again is how something makes them feel.

Where do you see the biggest opportunities going forward?
Iodine awareness is growing fast and I’d expect that to accelerate — the Lancet paper will filter through into consumer and media consciousness over the next few years. But seaweed awareness is building more broadly too. The fact that seaweed snacks from brands like Itsu are now sitting at the end of the aisle in Tesco tells you something real about where mainstream appetite is heading.

“Seaweed gives you nutritional credibility, a sustainability story that genuinely holds up, and a real point of difference at shelf. It requires no freshwater, no fertiliser, no arable land — it actively improves the marine environment it grows in”

For manufacturers, the opportunity spans multiple categories — nutraceuticals, women’s health, sports nutrition, fortified food and drink. Seaweed gives you nutritional credibility, a sustainability story that genuinely holds up, and a real point of difference at shelf. It requires no freshwater, no fertiliser, no arable land — it actively improves the marine environment it grows in. In a market where sustainability is moving from nice-to-have to must-have, that profile is increasingly valuable.

For more information on PureSea visit www.seaweedandco.com/puresea and for Doctor Seaweed visit www.doctorseaweed.com

Main image: Dr Craig Rose