Getting Seaweed back on our Plates

By Eilish Blade

Welcome ocean lovers!

Whether it’s surfing the waves, open water swimming, kayaking to secluded coves or walking our beautiful coastal paths on a glorious sunny day, we can all appreciate the magic of the sea and it’s beguiling ways. As well as feeding our minds and our soul the sea has long been a bountiful provider of a nutritious and health giving food. As an island nation we are abundant in the maritime magic which is seaweed; a nutrient dense sea vegetable regularly consumed until roughly 50-100 years ago and also used for medicinal properties and as a fertiliser on the land.

A lot has changed in our dietary habits in the last 50 or so years and seaweed has certainly not been on the menu in most households as we have moved to a highly A functional food ‘delivers additional or enhanced benefits processed and more meat based diet. over and above their basic nutritional value’. Most of us will have heard, or possibly tried laver seaweed (Porphyra Umbilicalis) in the As a Registered Nutritional Therapist living on the beautiful form of laverbread which was traditionally coast of Pembrokeshire I advocate for a rich and varied eaten in Ireland, Scotland and Wales as a diet especially with a background of locally grown and healthy and accessible food in coastal sustainably produced. Seaweed has the ability to become communities. Welsh laverbread (Bara Lawr) part of the Holy Grail of sustainable nutrition which we are was given the prestigious name of Welsh espousing as part of our commitment to both feed the caviar and there are records of laver being planet and preserve our environment. So let us take a deep harvested and used to make laverbread dive into the nutritional and functional qualities of seaweed near St David’s, Pembrokeshire around to unravel it’s mysteries and acknowledge it’s power. 1693. Outside laverbread our only other culinary connection with seaweed is possibly in the form of sushi, a food strongly associated with Japanese culture and high- end restaurants. Seaweed also risen to the ranks of a superfood and celebrity status through the likes of Jamie Oliver and Heston Blumenthal, but where does it fit into a normal diet for the majority of us and what of its’ role as a nutritional and functional food?

Minerals and vitamins The recommended iodine intake for adults (>12 years) is 150 µg/day. However, during pregnancy and lactation, the Some seaweeds have 10 to 100 times more requirement for iodine rises from 150 to 250 µg of iodine per minerals and vitamins per unit of dry mass day. The safe upper limit for iodine is approximately 600 than any other plants or animal foods. µg/day for adults (>12 years) and pregnant women but There really is an incredible range of there is a red flag in the case of those who are chronically nutrients from the fat soluble vitamins A, D, iodine deficient as they may react adversely to levels lower E, K to the water soluble vitamins C, B1, B2, than this if the thyroid has adapted to low iodine levels. It is B9, B12 plus minerals such as calcium, iron, also not advisable to consume a lot of seaweed or iodine, magnesium, phosphorus, potassium, supplement with kelp when taking thyroid medication. zinc, copper, manganese, selenium. The available content of vitamins and minerals The background to determining how much seaweed we in seaweed will vary though by species and can eat will also be dependant on the inclusion of other environmental factors. iodine rich food in our diet; so if we eat a lot of shellfish, fish, milk, dairy and eggs then we are likely to require less iodine The first health claim often touted is the in food from seaweed and should apply more caution. abundant supply of iodine in seaweed. To However, for vegans and vegetarians who avoid these understand how to use seaweed as part of foods then seaweed can be a really beneficial form of our diet we really need to address this iodine to supplement their diet. In this respect I am talking potent mineral and how it can bring health about a wholefood source and not a supplement. but also recognise how it can be a potent Seaweed also has a delayed release of iodine so it can inhibitor of thyroid function. So what are the remain available in the body longer for continuous use. This things we need to consider to get the can be beneficial when the body needs it but it is also why balance right? prolonged use at high levels can cause toxicity.

Seaweeds can be a good dietary source of It is important that products have adequate labelling to iodine but they can also be a source of demonstrate iodine content or to provide information to excessive iodine. Iodine is an essential estimate iodine content. Much like other food we should micronutrient which is required for the get into the habit of understanding the nutritional content synthesis of thyroid hormones and this is of the food we eat so we can inform ourselves about particularly important during pregnancy meeting our dietary requirements. Applying the guidelines when production of thyroid hormones are for recommended daily allowance and recognising the needed for the neurodevelopment of the safe upper tolerance levels, plus acknowledging if we have baby. The UK has traditionally been a background risk e.g. Thyroid disease can inform our considered iodine-sufficient but there is choice to eat seaweed in a safe and healthy manner. now concern that iodine insufficiency may Once we have a handle on this then we are free to enjoy be present particularly in pregnant women the other amazing nutraceutical applications of seaweed! and women of childbearing age. Furthermore, a recent survey in the UK Protein found that iodine deficiency was found in more than two-thirds of schoolgirls aged 14- Researchers have demonstrated seaweeds can contain 15 years. between 5%–47% protein as dry mass. Red seaweeds such as dulse (Palmaria palmata) and laver (Porphyra aver) may present a great opportunity as a low-cost, nutrient- dense option to compete with protein crops such as soya. Healthy, alternative protein sources are important for

vegans and vegetarian and a more sustainable option to soya.

Healthy Fats Other dietary and lifestyle factors will also impact the incidence of chronic disease but at this time seaweed is Another great benefit from seaweed is the definitely becoming a focal point for scientific research; so contribution of healthy fats. Most lipids in let’s look at why it may be having some a positive impact seaweed are polyunsaturated, composed on weight and chronic disease. of omega 3 fatty acids such as docosahexaenoic (DHA) and In a study looking at the dietary habits of 923 Japanese eicosapentaenoic acid (EPA). The patients who had undergone surgery for colorectal cancer, presence of such healthy fats is associated those who consumed a Western style diet, high in red meat, with benefits for reducing depression in the sugar, carbohydrates and refined oils had a significantly elderly and lowering the inflammatory higher risk of colorectal cancer than those who consumed markers for diabetes and Cardiovascular a traditional diet with seaweeds, vegetables, fruits and fish. disease. When Chinese, Japanese and Filipino women emigrated from Asia to the United States a population based study Benefits for the gut demonstrated a 6 fold increase in breast cancer after approximately 4 years. This may be attributed to other An exciting new area of research is looking lifestyle factors and possibly a move from a traditional diet at the potential of seaweeds to boost the which is more protective against breast cancer. human gut microbiome. What we are talking about is the nutritional benefits for The Okinawans in Japan enjoy the longest life expectancies our gut bacteria from specific in the world and have a high dietary intake of fish, soy, and carbohydrates in seaweeds which are seaweed. Research has shown that some components in called polysaccharides. These can be seaweed such as carotenoids, peptides, and dietary fibres fermented by the gut microbiota to provide may positively impact markers for total cholesterol, blood a prebiotic effect which is beneficial for our glucose levels, lower blood pressure and body weight. This health . suggests that seaweed may have a protective effect against cardiovascular disease but a direct association has Some of these polysaccharides have not been measured. generated a plethora of research due to their potential health benefits. One of the There is also some data which points to bioactive most notable is Fucoidan. Fucoidan is a compounds in seaweed which can positively impact sulphated polysaccharide primarily found in weight. Dietary fibres such as alginate which are isolated brown seaweed. Oral preparations made from the cell wall of brown algae have been promising in using fucoidan to treat mice with IBD such trials for weight management. In a 4 week trial an alginate as ulcerative colitis and Chrons disease drink was reported to significantly reduce energy intake in have shown a significant effect on participants who were overweight and obese and could reducing the inflammatory response. Some help with weight loss as part of a healthy diet. A bioactive of the benefits from other complex compound in seaweed called Fucoxanthin which is a polysaccharides in seaweed may be carotenoid produced by brown algae, was used in achieved through a positive modulation of supplementary form over 4 weeks for obese participants. the gut microbiome and an increase in The results were a reduction in body weight, BMI, and beneficial bacteria. It has to be noted that abdominal fat by acting on both the visceral and the main body of research is in vitro and subcutaneous fat. animal studies but clinical trials are now under way to look at how fucoidan can be Lastly, there may be potential for the use of seaweed for used in the treatment of IBD. those with Type 2 Diabetes. A seaweed supplement containing dried sea tangle and sea mustard 3 times a day Impact on chronic disease with a daily consumption of 48g was given to participants with Type 2 Diabetes over 4 weeks. The results showed a Epidemiological studies comparing positive impact on glycaemic control, lowering blood lipid Japanese and Western diets have markers and increased antioxidant levels. Edible seaweed suggested a lower incidence of obesity are also low in calories and rich in dietary fibre, unsaturated and chronic conditions such as cancer, fatty acids, minerals and vitamins which makes them hyperlipidaemia and coronary heart suitable for helping managing diabetes. disease (CHD) may be linked to the consumption of seaweed.

Conclusion

On a personal note as a practicing Nutritional Therapist, many clients present with inadequate levels of iodine and this is generally in association with low selenium. The basis for this is a 3 day food diary which clients must complete to generate an approximate intake of macro and micronutrients. Therefore, for clients where contraindications do not apply, seaweed as a wholefood can be a great option. Supplements should be used with caution and I would strongly recommend getting professional advice before supplementing.

There is such an incredible wealth of data now on the health benefits from seaweed that hopefully it will change the image of this humble and overlooked sea vegetable. I think it is hard not be taken aback by the lower incidence of chronic disease in Asian countries where seaweed has been a part of their traditional diet. Sadly, this is also changing and when we look at the impact of migration from East to West I would not be championing the West in this scenario!

Changing our dietary habits is critical to a healthier society and eating not just plant based but also sea-based is a very exciting alternative. We have an epidemic of chronic illnesses which are a huge burden on society and the NHS and seaweed is showing incredible potential as low calorie, high fibre, antioxidant rich and nutrient dense food. At this time we also need more research with human trials to identify how to specifically use extracts of seaweed as appropriate nutraceuticals.

We need to connect again with our own indigenous seaweeds and how can we incorporate them into dishes we can enjoy, make it a savoury sprinkle on our meal rather than salt, get fancy with some homemade sushi, use it in a ‘good to go’ early morning smoothie, bake it in our bread or do as Richard Burton and put some Welshman’s caviar with your bacon and cockles or perhaps a crafty seaweed gin!