It is used mostly in traditional Japanese restaurants, mainly as an appetiser or starter, but not in sushi. Nor is it used in Chinese restaurants. Hijiki is also sold for use in some soups, salads and vegetable dishes.

Besides minor use in Japanese restaurants, hijiki is found in shops specialising in products from Asia and the Far East and can sometimes be found in the specialist food sections of some supermarkets and department stores. This seaweed is sold in packets weighing from 12 to over 100 grams, and some may have recipes on the packets.

The FSA is advising people not to eat hijiki following a survey, prompted by Canadian concerns about the food, that showed that it contains high levels of inorganic arsenic.

Inorganic arsenic, which can occur naturally in some foods, is known to add to the risk of people developing cancer. International experts say that the intake of this type of arsenic in food should be reduced so that it is as low as is practical. The Agency’s expert advisers, the Committee on Toxicity, has said that the levels of inorganic arsenic found in hijiki could add significantly to how much inorganic arsenic people take into their bodies.

If you have eaten hijiki occasionally it is unlikely that you will have raised your risk significantly of getting cancer. However, the Agency is advising that you stop eating it.

No, the risks are similar for everyone.

The FSA survey looked at levels of inorganic arsenic in four other types of seaweed: arame, kombu, nori and wakame. None of these were found to have any inorganic arsenic, whereas all the hijiki did contain it.