The Lure of the Seaweed

Seaweed is known as a highly nutritious, natural and tasty food source which has been utilised for millennia around the world with multiple health benefits.  This traditional food is seeing a resurgence of interest for food and health, owing to its often unique nutritional profile, taste and sustainability.

Of the approximately 10,000 seaweed species globally, there are estimated to be 600 species around the UK.  No seaweed is considered toxic, and when you know what you are looking for, there is a vast array of incredible seaweeds that taste great and can be eaten for flavour and to provide many health benefits.

In the UK, seaweed is harvested either by hand or by vessel, and which ranges from small scale artisan harvesting to larger scale commercial activities.  Even at the largest scale, the sustainability of harvesting wild seaweed is well-known, with the largest UK company (Hebridean Seaweed Company) working in partnership with the regulators and also winning numerous awards for their approaches (

The environment in which seaweeds thrive is a harsh environment.  For example some plants will be covered by seaweed at high tide for part of the day, and then exposed to drying out or fresh rainwater at low tide.   To survive, seaweeds have many protective adaptations, and it is often these adaptations, such as high levels of antioxidants, that provide the health benefits of seaweeds within the entire human food chain.

Seaweeds provide all essential dietary minerals. No land plant approaches seaweeds as sources of minerals required by human metabolism. Seaweeds can provide minerals often absent from food crops grown on mineral-depleted soils, and seaweeds are often added to compost and some organic farmers are even starting to use seaweed tea sprayed directly onto leaves for foliar feeding through the stomata as ways to therapeutically keep plants plague-free and to get trace elements into their fruit and vegetable crops.

For examples of mineral levels, an 8 g portion of Ulva lactuca (sea lettuce, pictured above) provides 260 mg of calcium, equalling approximately 37% of the RNI of calcium for an adult male.  In comparison, the same portion of cheddar cheese provides just 5% of the RNI.  In relation to iron, there is more iron in an 8 g serving of dry Palmaria palmata (Dulse/Dillisk,pictured left) than in 100 g of raw sirloin steak (6.4 mg versus 1.6 mg, respectively).

A mineral commonly associated with seaweed is iodine.  With the UK now considered iodine deficient (66% of adult females and 76% of girls of school age), there is a dire need to utilise seaweed as natural safe source of iodine, which helps prevent thyroid issues and breast cancer and supplement iodine from other sources (e.g. dairy) which are increasingly being displaced by pollutants in our food and environment.

Other properties of seaweed include antibacterial activities, which are partly due to their iodine and polyphenolic contents. Sulphated polysaccharides such as carrageenans, fucoidans and rhamnogalactans from marine algae have substantial antiviral activity against enveloped viruses, such as herpes, Human Papilloma Virus (HPV) and HIV.

Furthermore, the balance of minerals and peptides derived from seaweed are proven to have hypotensive effects in the human circulatory system. Hypertension is one of the major, yet controllable, risk factors in cardiovascular disease (CVD). CVD is the main cause of death in Europe, accounting for over 4.3 million deaths each year. In the United States it affects one in three individuals. Hypotensive peptides derived from marine and other sources have already been incorporated into functional foods such as beverages and soups.  This concept of using seaweeds as food ingredients to address heart health is receiving huge interest in terms of salt replacement, as well as the range of other health benefits.

There is a plethora of information on seaweed for food and health, and for that reason, the Seaweed Health Foundation and its members have developed courses to train and educate on the benefits and uses of seaweed.

The Seaweed Health Foundation is an independent and not-for-profit forum for research, and to raise awareness of the benefits of human food quality seaweed for food and health.   For its members and wider stakeholders, the Foundation is further developing the seaweed industry to meet market place concerns on food and health such as salt reduction, nutrition and weight management, as well as issues of sustainability of foods.

The Foundation provides expertise and training to its members and external stakeholders, and has developed and delivered courses on seaweeds for organisations and individuals, including their BANT accredited seaweed for food and health course (  Furthermore, in the past few months alone, the Foundation has raise over £53,000 in research funding to support the seaweed industry, and their previous work on salt reduction was highlighted this year as a “Big Idea for the Future” in the Research Council’s UK report (  – see page 58 for seaweed).


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