Like most rice-cultivating cultures, the Japanese have put their staple food to use in many forms, ranging from starch to sake.
In the latest use of one of the world’s most beloved grains, scientists and corporations in Japan are applying advanced technology to develop rice with a variety of medical benefits.
Professor Hiroshi Kiyono and his team at the University of Tokyo’s Institute of Medical Science have used genetic engineering technology to produce an oral rice-based cholera vaccine. When this MucoRice is consumed the body produces antibodies that enable it to combat the real toxin.
There are numerous benefits to an oral cholera vaccine compared with existing injected ones, says Prof Kiyono. Pathogens can invade the body through the skin, the nose, the mouth and rectal cavities, and infect the mucosal surface that lines the digestive, respiratory and reproductive tracts.
“Injection cannot provide immunity at the mucosal area,” which is equivalent in surface area to one and-a-half tennis courts, he says.
“Injection-type vaccines provide protection like a policeman inside a house where the door and windows are not locked, so a burglar can invade the house. But if we could induce mucosal immune responses as well, it would be like locking the door and windows as well as having a policeman inside.”
An added benefit is that an oral vaccine does not require disposable syringes and needles, and it is possible to administer in tablet or capsule form.
Crucially such a vaccine would not require refrigeration either, a big problem for developing countries.
Prof Kiyono’s studies showed that monkeys that were fed MucoRice produced antibodies that presented neutralising activity against toxins, which they maintained for six months.
What is more, several doses of MucoRice did not induce allergic reactions.
Prof Kiyono’s team is working with Nippon Paper Industries to grow MucoRice in a closed harvesting facility so as not to affect the natural environment. The group is also working with regulators to draw up rules for growing and marketing “rice as a new vaccine product, and a new vaccine storage and delivery vehicle”, he says. “This is no longer food. It is medicine.”
Nippon Paper is also developing rice to treat other conditions, ranging from cedar allergy to diabetes and influenza. “The idea is to orally consume the [cedar] allergen. That way, if the body recognises cedar pollen as something that it consumes, it won’t react to it as an alien element,” by having an allergic reaction, says Saori Endo-Kasahara, research manager at the company’s forestry science research laboratory.
Nippon Paper, which developed advanced genetic engineering technology through its work with trees, was commissioned by the ministry of agriculture, forestry and fisheries to develop rice that could help alleviate cedar allergy, similar to hay fever and widespread in Japan.
The idea was that oral consumption of the cedar allergen could offer a better solution than injection.
The cedar allergen has to be injected in small portions to prevent the body from going into shock and so it takes many years to inject a sufficient amount to have an effect.
But Nippon Paper has been able to develop rice containing the cedar allergen, which when consumed orally will, theoretically, not cause the body to have an allergic reaction, says Ms Endo-Kasahara.
Rice is a convenient carrier because it acts like a capsule, preventing the allergen from being decomposed before it reaches the intestines.
One difficulty is in ensuring stability of the commercial product because the modified rice must contain the same ratio of allergen. This is crucial since the rice is considered a drug rather than food.
Nippon Paper is using water rather than soil to grow the rice, which makes it easier to control the ratio of what goes into the rice.
It expects to start clinical trials on humans within five years.
Meanwhile, Kameda Seika, Japan’s leading rice confectionery group, is taking a different approach to developing rice with various health benefits.
Yume Gohan, which means dream rice, has only a fraction of the amount of protein found in ordinary rice and is therefore suitable for people who suffer from renal failure and require dialysis treatment.
Their reduced ability to digest protein means they must restrict their protein intake without reducing their overall calorie intake.
Kameda developed equipment that exposes the rice to protease, an enzyme that dissolves the protein in the rice without breaking down the rice itself.
“If this rice is consumed three times a day, the consumption of protein can be reduced by about 15 grammes and that allows the patient to eat other foods, such as fish,” says Takehisa Kumagai, manager of Kameda Seika’s rice research centre.
Kameda is also developing rice with a lactic acid bacterium to alleviate the symptoms of atopic dermatitis and cedar allergy. It also hopes to develop rice with fewer calories to help diabetes patients.
Copyright The Financial Times Limited 2010.
