Just above the shoreline on the island of North Ronaldsay, the northernmost of
the Orkney Islands, roams a rare and ancient breed of dishevelled-looking
sheep. These creatures yield some of the finest wool in the world and suffer
exceptionally low levels of disease. The secret of their robust health is
believed to lie in their unusual diet, which is composed almost entirely of
seaweed.
For years farmers have understood the nutritional benefits of seaweed in
animal fodder. It is added to poultry feed to produce thicker eggshells and
yellower yolks and is fed to some farmed mink as a fur conditioner.
Most people associate seaweed with the crispy, salty appetisers served at
Chinese restaurants, yet there is a strong tradition of seaweed consumption
in Celtic areas such as Scotland, Ireland and Brittany. In some parts of
Scotland seaweeds such as carrageen and dulse (see Yo! Seaweed) are
still eaten in the traditional way — carrageen boiled with milk to make a
kind of pudding and dulse as seaweed soup. Dulse is still popular in
Ireland, where it is often mixed with butter and potato and fried in little
round cakes.
Japanese nori, the small red seaweed Porphyra umbilicalis, which is
used in many sushi dishes, also grows in this country, where it used to be
known as sloke. The plant is boiled and eaten as a jelly in South Wales and
is also used to make laverbread. In Cornwall it used to be eaten cold with
vinegar.
Researchers have started to investigate seaweed’s nutritional qualities and
have discovered that it is a rich source of antioxidants, such as
beta-carotene, and the vitamins B1 (thiamine, which keeps nerves and muscle
tissue healthy), B2 (riboflavin, which helps the body to absorb iron and is
therefore good for anaemics) and vitamin B12. It also contains trace
elements, such as chromium, which affects the way insulin behaves in the
body, and zinc, which helps with healing.
In the past seaweed was used by herbalists to cure ailments from ulcers to
cuts and grazes. Legend has it in Brittany that the earliest seaweed farmers
never worried about the cuts they sustained while handling the knotted
tangles of seaweed and kelp they were harvesting to make pain d’algues
— seaweed bread — because they knew that the wounds healed with little or no
treatment. Today, NHS nurses still use certain dressings which are
impregnated with seaweed to promote rapid healing.
Now it seems that seaweed may yet emerge as a leading player in the field of
cancer-fighting foods. A US study out in February indicated that a diet
containing kelp lowers levels of the sex hormone oestradiol (a form of
oestrogen) in rats and bringing hope that it might also decrease the risk of
oestrogen-dependent diseases such as breast cancer in human beings. The
results, published in the American Journal of Nutrition, shed new
light on the Japanese diet — 10 per cent of which comprises seaweed. It may
also explain why Japanese women have such a low incidence of
oestrogen-dependent cancers such as breast, ovarian and endometrial cancer.
The study showed that Japanese women have longer menstrual cycles and lower
oestradiol levels than their Western counterparts and it has long been
accepted that longer menstrual cycles are linked to lower risks of
female-specific cancers.
The type of seaweed used in the US study was Fucus vesiculosus, or
bladderwrack — the sort of brown seaweed so common on the beaches of Wales
and the South West coast of England. It is closely related to its Japanese
cousins wakame and kombu. “The most profound discovery was that women with
endometriosis and severe menstrual irregularities experienced significant
improvement in their symptoms after three months of taking 700mg of seaweed
capsules a day, ” says Dr Chris Skibola, an assistant research toxicologist
at the School of Public Health at the University of California. “In the past
soya has been cited as the key player in why Japanese women have such low
rates of breast cancer. However, this new study suggests that it could be
the seaweed which plays a protective role,” she says.
For 20 years Japanese scientists have run more than 500 clinical trials to
discover whether there are elements in seaweed that could suppress the
growth of tumour cells. In 1996, researchers at the Japanese biomedical
group Takara Shuzo discovered the polysaccharide known as fucoidan which
causes cancer cells to self-destruct. Their research showed that when a
small amount of fucoidan, was added to a culture of colon cancer cells, half
of them died within 24 hours and the rest were eliminated after 72 hours.
However, scientists at Cancer Research UK are cautious. “On the face of it,
the evidence is quite compelling but there are so many potentially active
compounds which can do funny things to cells in a lab that there needs to be
more research before we would consider funding,” says Henry Scowcroft,
Cancer Research UK’s science information officer.
But there is plenty of evidence to support seaweed’s many other qualities.
Recent Canadian research suggests that certain types of seaweed may inhibit
the absorption of lead, cadmium and strontium which could have applications
for patients undergoing chemotherapy.
The author Mary Beith, who wrote Healing Threads (Polygon, £7.99), a
book describing the traditional medicines of the Highlands and Islands of
Scotland, believes seaweed maybe undergoing a renaissance. “Dulse has long
been used in childbirth and to cure ulcers,” she says. It might even have a
role in the fight against obesity as the iodine it contains can affect your
metabolic rate.
Dr Skibola, however, sounds a note of caution. “The high levels of iodine in
kelp means that it is not recommended for people who are pregnant, nursing
or who have hyperthyroid conditions. We are working to isolate the active
compounds in kelp which affect oestradiol levels to avoid the possible
toxicity of iodine and metals,” he says. Watch this space.
Yo! Seaweed
- Seaweed is no longer confined to the shelves of sushi specialists and health
food stores. Sainsbury’s sells a dried variety of seaweed and Tesco
sells it in its Nutri Centres.
- Seagreens, a British organic seaweed company, makes an alternative to salt
from the Norwegian seaweed Arctic wrack. It is baked into loaves at
Artisan Bread, in Whitstable, Kent (artisanbread.ltd.uk). For more
information, visit seagreens.com
- Combine romance and economy by foraging for seaweed along the British
coastline. The best places to indulge in a bit of pick-your-own are in
western Ireland, Wales and the Scottish isles. Hunt away from polluted
areas and wash seaweed thoroughly. Martin Catt runs seaweed-foraging
courses in Devon (e-mail martin.catt@btinternet.com).
WHAT TO LOOK FOR
Sea lettuce is found year-round in high-tide zones but it is
tastiest in spring.
Sea beet flourishes between May and December. It has green,
fleshy laurel-shaped leaves and makes a hearty spinach substitute.
Dulse has dark-red fronds and grows from spring to autumn on
rocks on the middle shore between the tides.
Carrageen seaweed, or Irish moss, is found in rock pools off
the west coast of Ireland where it is sometimes used in a bramble flan.
Its russet antler-shaped fronds are high in roughage and make a good
antiseptic gel when boiled with water.
Samphire, a great crispy salad ingredient, is best in early summer
and is found on sandy mud in salt marshes. Cheat by buying it from your
local fishmonger.
Laverbread, a Welsh speciality, is made from laver, a purple
seaweed found around the rocky shores west of Swansea. After washing and
then boiling for up to six hours until a gelatinous pulp, it is mixed
with oatmeal, formed into cakes, fried and served with bacon. Buy tins
from wales-direct.co.uk
NICK WYKE
