Takaki's navy diet trial against beriberi

Kanehiro Takaki, born in 1849, entered St Thomas's Hospital Medical School in London in 1875 and studied there for five years. When he returned to Japan in 1880, about one in three members of the navy had beriberi. He noted that the disease was less common among wealthier people and that Western navies rarely saw it. Analysing naval meals, he found that sailors' rations held far less nitrogen relative to carbon than the diets of healthy adults, and that the poorest ratios almost always went with beriberi. He concluded that the rations lacked nitrogenous food, which would now be called protein.

The training ship Ryujo had left Shinagawa on 19 December 1882 for New Zealand, Chile, Peru and Hawaii, returning on 15 October 1883. Of its 376 crew, 169 developed beriberi and 25 died, and the ship had to stop in Hawaii, where the sick recovered once meat and vegetables were taken aboard.

Takaki persuaded officials to send the training ship Tsukuba over exactly the same route with a new menu richer in protein, including meat, bread, vegetables and condensed milk. The Tsukuba left Shinagawa on 3 February 1884 and returned on 16 November. Only 14 of the crew developed beriberi and none died, and those 14 had not eaten the new rations. The test compared two voyages in successive years, with the route held constant.

Many sailors disliked the Western food, and from April 1885 the navy mixed barley into its rice instead. Beriberi fell to 0.59 percent of the navy in 1885 and 0.04 percent in 1886, and then disappeared. Takaki became Navy Surgeon General in 1885, and in 1906 he described the two voyages in lectures at St Thomas's that were published in The Lancet.

His explanation was wrong. The missing factor was later identified as vitamin B1, which tends to rise with the protein in a diet, and in 1898 Christiaan Eijkman criticized Takaki's methods. The Japanese Army, whose medical leaders held that beriberi was an infection, kept white rice rations until March 1905. During the Russo-Japanese War of 1904 to 1905 an estimated 250,000 Japanese soldiers developed beriberi, and 27,000 of them died.