Undaria pinnatifida: power of seaweed in skincare

Undaria pinnatifida or Wakame seaweed is one of the six essential actives that make our centess+complex range so powerfully potent. Wakame is a brown seaweed that is consumed at a rate of 1.6 kilograms per person per year in Japan1 and also enjoyed worldwide.

Thanks to an almost unparalleled portfolio of nutritional and bioactive properties, the inclusion of wakame and other brown seaweeds in the Japanese diet is thought to contribute to the societies’ longevity and relative low incidences of common diseases. Why wouldn’t we want to reap the naturally effective benefits of this kelp in our skincare?

Introducing Undaria pinnatifida

Undaria pinnatifida
Undaria pinnatifida: the brown kelp wakame
Photo: Te Ara, Encylopedia of New Zealand

In Western society seaweed is mainly associated with coastal culture or traditional farming and dyeing processes, however the popularity of seaweed in Asian culinary culture is well known. Marine algae such as Undaria pinnatifida (U. pinnatifida) is gaining increased attention as a valuable food source and nutritional supplement. Nutritional analyses of seaweeds show them to contain high levels of carbohydrates and proteins as well as a diverse array of beneficial minerals, vitamins, proteins and trace elements like iodine.

Wakame is an edible seaweed with a sweet flavour often served in soups and salads, particularly in Japanese cuisine. The sea vegetable has been cultivated and harvested by sea farmers in Japan and Korea since the Nara period, AD 710-794. In old Japanese, me meant ‘edible seaweed’ with waka meaning ‘young’ though for a long time the term wakame was widely used to describe all seaweeds that were edible. In English it’s also known as ‘sea mustard’ and the French ‘fougère des mers’ describes it as the ‘fern of the sea’ due to its leaf-like appearance.

Though the seaweed has been used as a food, medicine and fertiliser for thousands of years it wasn’t until 1873 it was scientifically catalogued and its taxonomy defined by Harvey Suringar.2 Centuries on, Japan and Korea remain the main producers and consumers of wakame though wild grown wakame seaweed is sustainably harvested in Australia and New Zealand and cultivated crops are maintained in sea fields off the coast of France. The harvested seaweed is then either supplied fresh to restaurants or freeze dried for retail or consumer products.

A thriving species in its indigenous cold water temperate coastal region around Japan, Korea and China, U. pinnatifida has earned itself a reputation as one of the worlds’ most invasive species thanks to its highly fertile nature and humankind unintentionally spreading the organism around the planet through shipping and marine harvesting methods.3 Owing to rapid fertilisation and global spread, U. pinnatifida can now be found in abundance in temperate regions globally including the USA, Europe, Australia and New Zealand and Central and South America.4

Traditional uses of Vitis vinifera

As early as 100BC Greek farmers would feed their livestock with fresh seaweed, a practice that is still utilised today in coastal farmland around the world. Available in abundance on nearby shores, farmers would use seaweed mulch as a soil improver and plant feed due to its high mineral and trace metal content. Enjoyed as a food for the very same reasons, its marine origin provided an iodine and salt rich sea vegetable for consumption. Oriental medicine believed seaweeds improved the health of the endocrine and nervous systems and as such features heavily in the diets of Japanese and Korean diet.

Historically seaweed was regarded as a high value luxury item with some species even more expensive than others due to logistical difficulties in collecting and processing the algae. Japanese law documents from 701AD and 927AD indicate that marine algae was used as payment for taxes or used as currency, such was its value and status. Many shrines also used algae as offerings, giving further insight into the importance of these marine resources in Japanese culture.5 The consumption of wakame and other luxury seaweeds were once reserved for the noble classes in Japan however enjoyment of the delicacy was opened up to the common masses in the 17th century.

Wakame is still considered a luxury edible seaweed compared to the likes of Nori or Kombu (the most widely sold seaweed in Japan) which are much more easily propagated and therefore more widely available and so commonly used in making sushi. Traditionally and to this day, the main market for wakame in Japan is in the food industry however a small percentage (15%) is processed to extract agar or alginates which are used as starting materials in the pharmaceutical, food and manufacturing industries.6

General Health Benefits and Uses

In Asia the centuries-long tradition of using sea vegetables in traditional medicine for health maintenance and the prevention and treatment of chronic disease were largely regarded as folkloric remedies. However modern scientific research into their medicinal properties has indeed shown that a diet rich in sea vegetables reduces the risk of chronic illnesses such as cardiovascular and chronic inflammatory diseases and some cancers and people live longer, healthier lives as a result.7

The omnipotent bioactive profile of U. pinnatifidia8 has shown wakame extract to have a diverse array of natural properties:

Anti-oxidant popular in anti-ageing skincare and is also the basis for its anti-cancer activity through reduction of oxidative stress in tissues

Anti-inflammatory an increased intake of seaweed has been linked to lower incidences of chronic inflammatory diseases

Anti-microbial and anti-bacterial activity against food-borne pathogenic bacteria

Anti-cancer active against many types of cancer and carcinoma

Research suggests that an increase in the incidences of adult diseases such as diabetes, hypertension, hyperlipidemia correlates with a decrease in the dietary intake of fish, shellfish and sea vegetables such as seaweed.9

The nutritional and medicinal properties of wakame and other types of brown kelp seaweeds are related to their rich mineral content with high levels of iodine, amino acids, alginate and mannitol (the sugar that gives wakame its ‘sweetness’). Its ability to store water also makes it an excellent source of hydration. 10

Scientists have also discovered that sea vegetables have anti-biotic and anti-tumour properties, with lower risks of colon and rectal cancer reported. A reduction in blood pressure and cholesterol are also reported. As a result of discovering the wide-ranging and significant medicinal properties of seaweeds, new medicines have been developed for example laminin which is now prescribed to reduce blood pressure.6

Scientists continue to research the potential applications of seaweed extract in different therapeutic and commercial areas such as use as an anti-inflammatory medicine or a food and cosmetic preservative.

Botany and Grow it Yourself

Undaria pinnatifida, botany of wakame
Undaria pinnatifida, botany of wakame
Photo:Fisheries and Aquaculture Department, Food and Agriculture Organization of the United Nations

A brown kelp, Undaria pinnatifida can grow up to a mature length of 2-3 metres in a year with a growth rate of 1 cm a day.11 The arrangement of feather-like fronds, typically in pairs opposite each other on the central midrib, is known as pinnation.12

The latin name Undaria pinnatifida actually translates as ‘pinnated cleft’ describing the alternating, almost symmetric feathered algal fingers found on this seaweed. Another excellent example of pinnation can be found in the common fern. This is in contrast to palmation where the leaves radiate out from a common point.

U. pinnatifida can be found in the intertidal and subtidal zones on the coast in native saltwater habitats, mostly in sheltered reef areas, away from tidal activity. Wakame can also be farmed or cultivated on ropes and rocks in non-native habitats such as the sea fields off the coast of France. The algae is harvested using long hooks in spring and early summer (February-June) before washing in fresh water and either shipping fresh or the thalli (leaf-like fronds) removed from the central midrib, cut into small pieces for freeze-drying and transportation to specialist food suppliers.

A highly invasive species, wakame has potential to overgrow and exclude native seaweeds in local ecosystems and so poses problems for marine farms due to contamination of other farmed algal pecies.

Cook Your Own Kelp

In Korea wakame is known as miyeok with a traditional soup prepared with the dried seaweed known as miyeok guk. In Korean culture miyeok guk is served served on birthdays to give thanks to their mothers for nourishing them through pregnancy with the iodine and calcium nutrients miyeok provides and in symbolism of motherhood.13 Ensuring you get adequate levels of trace metals in your diet is important for everyone at any time, though especially during pregnancy!

Wakame became a popular addition to the Western diet in the 1960s as the dried seaweed became available in Asian-American food stores due to the popularisation of the macrobiotic diet, and spreading even more widely with the introduction of Japanese cuisine to the USA and Europe.

Wakame seaweed salad
Wakame seaweed salad
Photo:splendidtable.org

The easiest way to incorporate seaweed into your diet is to seek inspiration from Asian dishes like seaweed salads and soups, or incorporate into stir frys or sushi. With the average wakame seaweed serving size of 8g providing the same amount of fibre as brown rice and exceeding the recommended nutrient intake of vitamins A and B9 at over 150%,14 it’s a nutritious and smart health choice!

Bioactivity and associated components of the plant

The use of marine algae in development of naturally effective cosmetic skin care is rapidly advancing, with France the largest consumer using 5,000 tons of wet algae to meet demand. The use of marine algae in the cosmetics industry becomes an even higher potential industry with a growing body of research available highlighting the effects of topically applied products on ageing and sun-damaged skin thanks to its significant anti-oxidant and anti-inflammatory properties.

Seaweeds have great efficacy as naturally effective skincare products thanks to their high mineral content and diverse profile of vitamins, lipids, minerals, amino acids and other biologically active ingredients. Until recently the highly beneficial properties were only anecdotal as the chemical constituents of U. pinnatifida essential oil (UPEO) weren’t fully described until 2016.15 This research shed some light on the biochemical origins of seaweed extract bioactivity, demonstrating we are yet to see seaweed realise its full bioactive potential.

Let’s take a closer look at some of the compounds identified as responsible for the impressive array of wakame’s natural bioactivity:

Fatty Acids

Making up 59% of UPEO oil extracted from wakame, a number of fatty acids contribute to the anti-microbial and anti-inflammatory properties of U. pinnatifida. The main fatty acid myristic acid (31% of UPEO) is a known anti-microbial and takes its name from another species in which it is also the main component, Myrisitica fragrans or nutmeg.

As well as being a major component in the essential oil of nutmeg, myristic acid can be found in coconut oil, palm kernel oil, butter fat and in smaller amounts in animal fats. The ester of myristic acid- isopropyl myristate- is commonly used in topical cosmetic and medical creams to enhance the products’ absorption properties.

The anti-inflammatory activity of UPEO can be attributed to palmitic acid, the second most abundant compound in UPEO. The most common saturated fatty acid found in animals, plants and microorganisms, palmitic acid is best known as the major constituent of palm oil. The science linking fatty acids and inflammation isn’t yet fully understood but once scientists confirm the role of fatty acids in reducing inflammatory response this may prove groundbreaking in understanding how dietary fats may help reduce the risk or symptoms of a whole range of inflammatory diseases.

Some components of algal extracts work with proteins in the stratum corneum to form a protective barrier on the skins’ surface to assist in retaining moisture.16 Kelp contains fatty acids like omega 3 and 6 oils that are known to promote cell regeneration and improve overall skin health. Kelp extract is also used as a thickener in cosmetics and hair conditioner.

Proteins

Most brown seaweeds contain between 3-15% of their dry weight as proteins, compared with that of green and red seaweeds which contain between 10-47%. At 11-24% protein, U. pinnatifida has exceptionally high protein levels for a brown seaweed and makes it a product of interest in developing ‘functional foods’- foods that aside from nutrition also provide additional benefits to the consumer. Seaweeds are usually marketed based on their mineral content or other benefits but rarely for their protein content, and this could prove a low-calorific alternative in increasing protein in the human diet. 17

For most seaweed species, a large percentage algal protein is made up of the amino acids aspartic acid and glutamic acid. These two acids give seaweed their flavour with glutamic acid isolated from Kombu seaweed (Laminaria digitata) being the original source of flavour enhancer monosodium glutamate (MSG). Ionic salts of glutamic acid are the basis of the fifth distinct taste umami (together with sweet, salty, bitter and sour).

Some seaweed proteins are more digestible than others, meaning varying levels of the proteins are free to be absorbed by the body to impart their therapeutic benefits. The level of bioavailability of these proteins seems to be linked to the amount of soluble fibre in the marine algae, with higher levels preventing absorption of the proteins.14

Polysaccharides

Polysaccharides are the name given to carbohydrates, or long chain molecules made up of many single sugar units (poly= many, saccharide sugar). Some examples of these are starch or cellulose which is the main component in paper and cotton.

There two main types of polysaccharide in seaweeds. Structural polysaccharides like celluloses and xylans help to maintain the cellular structure of the seaweed. More interesting are the storage polysaccharides like carageenans, alginates and agar which are specific to marine algal species and represent the most commercially useful seaweed components. Carageenan and alginates impart textural and stabilising properties on food products, and agar is used as a medium for growing cells in biology labs so much of the kelp harvested is processed to isolate these commercially valuable components.

Research suggests that increasing your intake of alginate– present in both wakame and kobu seaweeds- leads to a decrease in cholesterol levels, has an anti-hypertensive effect and plays a major role as a dietary fibre. Alginate also functions as an anti-cancer active preventing the formation of cancer cells, and acidic polysaccharides also exhibit anti-tumour properties, ensuring cancer cells are unable to aggregate.18

Carageenan, alginate and agar are also used in cosmetic formulations as emulsifiers, thickeners and gelling agents. Alginates make up to 32% of the dry weight of brown seaweeds which makes them excellent ingredients in shampoos, soaps, creams, powders and other formulations.

Two of the most common marine algae-derived skincare ingredients are polysaccharides fucoidan and fucoxanthin. Brown seaweeds get their characteristic colour from pigment fucoxanthin and studies report that fucoidans have significant effects as an anti-coagulant and anti-cancer agent.

Fucoidans: a spotlight on a highly bioactive polysaccharide

Fucoidan’s primary function in algae is to reinforce cell wall structures and protect the seaweed from drying out when exposed at low tide, and its this same property that provides hydrating benefits in topical skincare as it’s great at locking in moisture.

Fucoidans have also shown promise in a number of research studies as an anti-cancer agent that also plays a role in preventing tumour proliferation.19

It does this through multiple pathways including cancer cell apoptosis (cell death), inhibiting cancer cell invasion and metastasis (the secondary spread of cancer). It also interferes with angiogenesis which is the growth of new blood vessels required to ‘feed’ tumours’ growth in addition to disrupting cancer growth signal mechanisms. An all-rounder, fucoidan derived from wakame seaweed was used in a study to prove fucoidan operates by enhancing the immune system.20 Studies on the anti-tumour activity of fucoidan from wakame sources show it to be highly potent against prostate and cervical cancers and lung and liver carcinomas.21

To round out the multitude of bioactive talents of U. pinnatifida, it would be remiss not to mention the origin of wakame’s anti-oxidant properties. Coming mainly from its potent polyphenol portfolio, wakame has many polyphenols in common with some of the other centess+complex actives as they’re found widely in nature in plants with anti-oxidant activity. Polyphenols are discussed in detail in the Centipeda cunninghamii article in this series- why not head over there to find out more? Or learn more about some of the other naturally effective griffin+row ingredients in our active ingredient series.

For further reading on the wonders of wakame, check out some of the Undaria pinnatifida literature at the links below.


1. Fujiwara-Araskai, T et al, The protein value in human nutrition of edible marine algae in Japan, Hydrobiologia, 116/117, 513-516.

2. Suringar, WFR, Illustrationes des algues du Japon, Musée Botanique de Leide 1, 77-90, pls 26-33.

3. Joint Nature Conservation Committee.

4. AlgaeBase Database.

5. Arasaki, M. & Arasaki, T., Kaisou no Hansai (A Story of Marine Algae), Tokai kagau sennsyo, Tokyo 1978, pp 228. In Japanese.

6. Mitoku Natural Products Sea Vegetable Database.

7. Doosan (Korean) Encyclopedia.

8. Bharathiraja, B et al, Environmental Eco-friendly marine resource macro algae (seaweeds): an omnipotent source for value added products and its applications, Int. J. Curr. Microbiol. App. Sci., 5, 7, 19-47, 2016.

9. Murata, M & Nakazoe, J, Production and use of algae in Japan, JARQ, 35, 4, 281-290, 2001.

10. Skriptskova, A et al, Seasonal Changes in growth rate, morphology and alginate content of Undaria pinnatifida at the northern limit in the sea of Japan (Russia), Journal of Applied Phycology, 16, 17-21, 2004.

11. Undaria pinnatifida (Harvey) Suringar 1873 Species Fact Sheet, Fisheries and Aquaculture Department, Food and Agriculture Organization of the United Nations

12. Pinnation definition, Oxford Dictionary

13. Institute of Traditional Medicine.

14. MacArtain, P et al, Nutritional value of edible seaweeds, Nut. Res., 65, 12, 535-543, 2007.

15. Patra, JK et al, Antioxidant and antibacterial properties of essential oil extracted from an edible seaweed Undaria pinnatifia, J. Food Biochem., 41, 1, 2016.

16. Kim, S-K, Marine Cosmoceuticals: Trends and Prospects, CRC Press, Florida 2012.

17. Fluerence, J, Seaweed proteins: biochemical, nutritional aspects and potential uses, Trends Food Sci. Technol., 10, 25-28, 1999.

18. Zhuang, C et al, Antitumour active fucoidan from the brown seaweed umitoranoo (Sargassum thunbergii), Biosci. Biotechnol. Biochem., 59, 4, 563-567, 1995.

19. Senthilkumar, K et al, Brown seaweed fucoidan: Biological activity and apoptosis, growth signaling mechanism in cancer, Int. J. Bio. Macromolec., 60, 366-374, 2013.

20. Maruyama, H et al, The role of NK cells in anti-tumor activity of dietary fucoidan, Planta Med. 72, 15, 1415-1417, 2006.

21. Synytsya, A et al, Structure and anti-tumour activity of fucoidan isolated from sporophyll of Korean brown seaweed Undaria pinnatifida, Carbohydr. Polym., 81, 41-48, 2010.