IT'S slimy green fronds are something you'd usually try to avoid on a trip to the seaside. But now Scottish producers claim that the country's native seaweeds are going mainstream, reporting sales into the millions. They claim nutrient-rich varieties – from dulse to kombe, sea lettuce and sugar kelp – are flying off the shelves thanks to an explosion of interest in plant-rich diets, healthy eating and local, seasonal ingredients.

The seaweed revolution has already been championed by celebrity chefs such as Jamie Olivier and Paul Holloway with a growing number of restaurants incorporating the flavoursome sea vegetables into everything from fish dishes to pizza toppings.

Companies now farming seaweed off Scotland's native coastlines are highlighting impressive evidence on the health benefits of seaweed. It's high levels of iron are said to support healthy thyroid function, helping to regulate hormones and fight off everything from fatigue to depression. A rich source of calcium and protein, it's claimed sea vegetables' levels of vitamin A and C are higher than those of broccoli and it boasts antioxidant and anti-inflammatory properties.

Last month sea vegetables featured on Jamie and Jimmy's Friday Night Feast – a Channel 4 cooking show in which Oliver and his best friend Jimmy Doherty teach recipes to celebrities before serving them to invited diners at their cafe on Southend pier. The two visited the nearby coastline to learn about the 650 species available in the UK and were impressed by what they found. Oliver said: "Kelp is very nutritious – per gram it has more iron than spinach, more folic acid than kale and more calcium than milk. I think it's really important that we bring it back. I'm thinking in my head seaweed is going to go nuts."

One of those benefitting is Edinburgh-based Mara Seaweed, which uses sea vegetables harvested from the Fife coastline and has just sold its four-millionth packet of dried weed. The company, which supplies to shops, restaurants and individuals around the country, has also recently started importing to the States.

Rory MacPhee, harvesting manager, said: "When we started up no-one knew about seaweed apart from a few people who got it in the Chinese health food shop. If you'd told me we'd be this big seven years ago when we were selling it at farmers markets I'd have said: 'don't be daft'.

"It is a tough business and we've invested a lot in research and development and worked very hard to get here but it's paying off. Plant-based foods are becoming more and more of a zeitgeist. People are interested in antioxidants like turmeric and seaweed has so much to offer there."

Mara, which farms and dries seven varieties of seaweed, has recently started supplying a pizza shop in Leith which is planning to serve it as an anchovy equivalent topping. Other regular customers include Edinburgh's White Horse Oyster Bar, where chefs use seaweed as a foundation for stocks and other dishes.

As well as packets of dried seaweed, which add a Unami [savoury] hit to everything from soups to smoothies, the company has created seasoning mixes, combining seaweed with chilli and sesame seeds as a topping for avocados and salads. It can also be eaten as a side vegetable, used to wrap fish before cooking or drunk as a slimy tea with bags of health benefits: "Seaweed acts like a magnet, attracting heavy metals and can help detox from the inside," added MacPhee.

Mark Williams, of Galloway Wild Foods which provides information on foraging, said: "Interest in seaweed is certainly booming. Foraging in general – for plants, fruits, fungi – is on the up, but seaweed is coming from a lower start point in terms of being recognised as a food source in the general population, so seems more remarkable."

He claimed seaweed was "the most highly-mineralised vegetable on earth" with some varieties, such as dulse, coming closer than any other food to providing a balanced diet all on its own. He added: "The growth of interest in seaweeds and other plant-based and wild foods comes from many strands: healthier eating, reducing food miles and growing interest in using seasonal ingredients. People are realising that eating any food from anywhere at any time isn't quite so exciting as they once thought. Rather, the taste of their own locale is infinitely diverse and interesting with unique and surprising flavours lurking around every corner – and they don't cost the planet."

Nutritionist and herbalist Angela Baldi MacRitchie agreed that a growing number of people were interested in plant-based diets and looking for new ingredients to add both taste and health benefits. "There is a big drive with veganism as it seems to be quite a trend or fad at the moment," she added. "There are health benefits to increasing vegetables in the diet and this is the first place I go to with a nutrition plan. The aim is 10 portions of vegetables a day in order to get nutrient density from our food as well as alkalising the body to reduce inflammation, which is the precursor for all disease. People are becoming more aware of what they eat and what is in the food – awareness is growing."

2018's top food trends

1. Plant-based diets

Educational charity The Vegan Society say that there are 360 per cent more vegans now than 10 years ago. That means alternatives to dairy, including almond, hemp and rice milk are on the rise along with interesting herbs and spices that bring vegetables to life, from sumac to turmeric, which also boast antioxidants properties. Demand for plant-based protein sources are leading to a rush on everything from tofu burgers to chia seeds to cashew nuts while "steaks" are now thick slices of cauliflower and deserts use aquafaba (chickpea liquid) instead of egg.

2. Healthy drinks

This year it's predicted we're going to embrace teas based around nutrient-rich ingredients, from seaweeds to mushroom powder, which will help break down harmful stress-hormone cortisol (but without the hallucinogenic effects of other fungi-based hot drinks). Good Food columnist Tony Naylor also cites non-alcoholic drinks as a growth area in the food and drink industry, which supermarket forecasters claim will appeal to health-conscious millennials. Look out for botanical infused non-alcoholic mixes and "spirits".

3. Gut-friendly eating

Fermented food is a big thing as we get increasingly interested in gut health, perhaps with good reason as an increasing body of research suggests it is linked to everything from cancer to depression – think probiotics – like kimchi, miso and kefir – and prebiotics such as onions, garlic and, you guessed it, seaweed. Have a go at making your own sauerkraut – it's the new hummus.

4. Lab grown clean meat

This will be another trend, according to the Scotland Food & Drink Partnership's Make Innovation Happen service, driven by global food supply challenges, such as long-term impacts of the industrialised animal agriculture, rising greenhouse gas emissions, limited land and water resources, overfishing and rising animal welfare issues. Welcome to the age of "clean meat".

Silicon Valley start-up Hampton Creek is at the forefront of growing meat in the lab, with plans to bring their version to supermarkets in 2018, while others are attempting to create SuperMeat, made from cells extracted from chickens. US-based Impossible Foods is creating an iron-rich burger by harvesting Heme – a compound found in haemoglobin – from legumes and adding it to its veggie patties to create an authentically meat-like taste.

5. Food without waste

Finally, we're catching on to the devastating effect of food and packaging waste. Food waste cafes – cooking-up past-its-sell-by date food – are popping up all over, while even celebrity chefs are coming up with uses for everything from broccoli stems to fruit skins. Make Innovation Happen also claim this is the year we'll get on top of packaging with biodegradable versions replacing plastics and "food tattoos" on fruit and veg instead of stickers.