Last updated on 5 August 2010

Consumers advised not to eat hijiki seaweed

hijiki seaweed contents

The Food Standards Agency is reminding people of its advice not to eat a type of seaweed called hijiki because it contains high levels of inorganic arsenic. Inorganic arsenic is known to increase people’s risk of getting cancer.

This reminder follows a notification from the European Commission to the Agency about a brand of hijiki seaweed, Clearspring, which was found to contain high levels of arsenic. The Agency is advising people to avoid all hijiki on sale in the UK.

We are advising people not to eat hijiki seaweed and to choose alternative types of seaweed instead. However, if you have eaten hijiki occasionally it is unlikely that you have raised your risk of developing cancer significantly.

The Agency also carried out a survey in 2004, which found that hijiki contains inorganic arsenic – a form that occurs naturally in some foods. The survey also tested arame, kombu, nori and wakame but no inorganic arsenic was found in these types of seaweed.

Hijiki is a distinctive, almost black, shredded seaweed, that is used mainly as an appetiser or starter in some Japanese restaurants. It is not used in sushi or in Chinese restaurants.

Hijiki is also sold for use in soups and salads and some vegetarian and vegan dishes where seaweed is an ingredient. It is sometimes found in the specialist food sections of some supermarkets and department stores and in health food shops and specialist shops selling Asian and Far Eastern food.

The Agency has contacted the European Commission to establish if they intend to take action on hijiki, which is also on sale across the European Union (EU).

Science behind the story

Arsenic is widely distributed in the environment. It occurs in soil, water – both sea and fresh – and in almost all plants and animal tissues. As a result, arsenic occurs naturally at very low levels in many foods and it is not possible to avoid it completely.

How harmful the arsenic is depends on the chemical form in which it is present. The inorganic form can cause cancer by harming our genetic material (DNA). Rice and rice products together with hijiki seaweed have higher levels of the inorganic form of arsenic compared with other food. The Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) (an independent scientific committee that provides advice to the Food Standards Agency) has concluded that people should consume as little of this form of arsenic as reasonably practicable. The organic form is less harmful.

Current regulations
There are no EU-wide regulations for arsenic levels in food. In the UK, there is a general limit of 1 mg/kg (milligram per kilogram) for arsenic in food, though seaweed is not included. Separate limits apply to certain food categories. For instance, ready-to-drink non-alcoholic beverages have a limit of 0.1 mg/kg. The UK regulations were set in 1959 before it was known that inorganic arsenic can cause cancer.

In September 2009, the European Food Safety Authority (EFSA) published its opinion on the risk to human health associated with arsenic in food. EFSA concluded that it was not appropriate to identify a tolerable daily or weekly intake for arsenic and recommended that dietary exposure to inorganic arsenic should be reduced. Following this, it is possible that EU-wide regulations will be set for arsenic levels in food.