Bowl of seaweed, overlayed with title "Adding Seaweed to your menu"

The health benefits of seaweed (& why you should add it to your menu)

Seaweed has undergone something of a rags-to-riches rise in the UK food scene recently. What was once considered a slimy, smelly annoyance on the shores of Bognor Regis and Scarborough is now being served up in some of Britain’s plushest restaurants. Most supermarkets even stock it. And for good reason, too.

These marine algae have been used across the world for thousands of years, featuring prominently in Asian food — especially in Japanese, Korean and Chinese cuisine. With a savoury, salty, umami taste, seaweed blends effortlessly into dishes as diverse as udon noodle soup and vegan paella.

As for the health benefits of seaweed, consider this: the Japanese, who eat seaweed religiously, have one of the highest life expectancies in the world. Coincidence? We’ll let you decide.

In this guide, we look at why you should be getting some nori nourishment and wakame wonderment in your diet, as well as why chefs are starting to embrace it in their kitchens.

What is edible seaweed?

Edible seaweeds (also referred to as sea vegetables) are algae which are harvested from the sea to be eaten or used in food prep. A rich source of fibre that can be used in all types of cooking, this sea vegetable is a versatile addition to any meal.

There are thought to be over thirty edible species of seaweed — containing various nutrients, health benefits and potential risks. These species are commonly divided into three categories: red, green and brown seaweeds.

Some of the most popular types of seaweed include nori (which is dried in sheets and used to make sushi), hijiki, spirulina, kelp, wakame, dulse and kombu. If variety is the spice of life, then no wonder that this nutrient-rich option is a red-hot food trend.

Just a word of warning: if you plan to forage seaweed yourself, it’s worth noting that only marine algae species are edible. Most freshwater seaweed is toxic, so don’t go looking for an alternative to kale in your garden pond.

What are the health benefits of seaweed?

As you’ve probably established from our gushing overview of this edible marine marvel, having seaweed in your pantry is a great way to provide diners with a wide range of important vitamins and minerals. High in protein and low in fat, it also provides a valuable array of non-animal nutrients — helping to lower cholesterol and reduce blood pressure in the process.

Seaweed contains traces of the antioxidant vitamins A, C, E, as well as vitamin K, zinc, sodium, calcium, copper, folate and magnesium. It’s also a great source of omega-3 fats and vitamin B12. 100 grams on nori makes up 65% of your recommended dietary intake (RDI) of vitamin C. Hijiki has ten times the calcium content of milk, while spirulina is high in amino acids that are necessary for brain function and help to improve memory.

Algae absorb concentrated amounts of iodine from the sea that is crucial for thyroid health. The thyroid gland is necessary for your body to function properly, and so getting enough iodine in your diet is important. With so many different species of seaweed, the amount of iodine content depends on the type of seaweed. Kelp is a particularly good source.

Seaweed is also something of a godsend for gut health, providing essential fibre and polysaccharides (a type of carbohydrate). Fibre is actually thought to make up 25% to 75% of seaweed’s dry weight — giving it a higher fibre content than most fruit and veg.

The fibre in seaweed is mostly soluble fibre, which turns into a gel, slows down the digestive process and then stops the absorption of sugars and cholesterol. Meanwhile, certain types of polysaccharides found in seaweed are thought to boost immunity and cardiovascular function.

Finally, there’s also some evidence that seaweed may reduce the risk of heart disease and Type 2 diabetes (though this is up for debate among nutritionists). There’s even evidence it may help weight loss. No wonder that humble seaweed is being labelled a superfood.

Some potential doubts around the benefits of seaweed

The high concentration of certain nutrients in different types of seaweed can be problematic for some. The overconsumption of vitamin K, for example, can interfere with blood-thinning medicines. Meanwhile, high potassium levels can cause issues for people with pre-existing kidney problems. When serving your seaweed, make sure you provide information about the potential risk for your customers.

There’s also an ongoing debate among scientists about whether your body can actually absorb the B12 in seaweed — so take any claims about B12 with a pinch of salt.

Why you should add seaweed to your menu

In this increasingly health-conscious age of dining, seaweed is becoming more of a fixture on the modern chef’s order list. In fact, seven out of ten of the world’s best restaurants have seaweed on their menu. Consumer demand for the stuff is as high as ever, and given the health benefits we’ve discussed, it’s not hard to see why.

Seaweed can vary in texture from chewy to papery, while the taste can be described as anything from briny to slightly fishy — making it a perfect option for classic Asian dishes like pad thai or phở. Seaweed offers a great nutritional alternative to traditional seafood, especially fishes at the top of the food chain such as salmon and tuna

Globally, seaweed is big business. The value of nori alone is estimated to be as much as $1bn. But in Europe, consumers only eat a paltry 100 tons of seaweed per year (for context, over 170,000 tons are consumed every year in China and Japan alone). Though it’s hardly a surprise that dining preferences vary in different regions of the planet, the global food crisis means it’s up to restaurants to turn to sustainable options.

And when it comes to sustainability, seaweed sure is hard to beat. It doesn’t need soil, fresh water, fertiliser or farming. It grows quickly and is nutrient-dense. And it absorbs CO2 and releases oxygen into the atmosphere. Given that 90% of the world’s global fish stocks are seriously depleted, introducing algae as a staple of the European diet can really make a positive difference to the marine ecosystem.

The tide is changing. Heston Blumenthal has helped popularise the ingredient with his steak, ale and kombu pie for Waitrose — one of the supermarket’s best sellers. Seaweed has also appeared as an experimental ingredient in well-known British restaurants such as The Greenhouse in Mayfair and Jamie Oliver’s Fifteen Cornwall in Newquay.

Much of the seaweed consumed in the UK comes from Asia, but with over 20 species of edible growing along Britain’s 11,000-mile coastline, the British seaweed renaissance seems inevitable. Traditional seaweed and sea moss harvesters operating around the rocky islands of Scotland and Ireland are starting to see business boom. And for struggling coastal fishing communities that have long relied on ever-depleting fishing stocks, seaweed harvesting offers a vital seasonal employment alternative.

If you want to explore the full potential of different kinds of seaweed, your nearest Asian market is a good place to start. For popular species such as nori or hijiki, you shouldn’t have much difficulty finding it in your local Tesco or Sainsbury’s. If you’re after the best in British, it’s hard to look beyond suppliers such as The Cornish Seaweed Company, whose seaweed is sustainably harvested from the coast of West Cornwall.

Wherever you source your seaweed, it’s clear that it’s a hot trend right that experimental chefs should look to add to their menu.

Leave a comment below to let us know how you use seaweed in your menu!

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