At the time, beriberi was a serious problem on warships and was affecting naval efficiency. Takaki knew that beriberi was not common among Western navies. He also noticed that Japanese naval officers, whose diet consisted of various types of vegetables and meat, rarely suffered from beriberi. On the other hand, the disease was common among ordinary crewmen, whose diet consisted almost exclusively of white rice. Many crewmen from poor families, who had to send money back home, often tried to save money by eating nothing but rice. In 1883 Takaki learned of a very high incidence of beriberi among cadets on a training mission from Japan to Hawaii, via New Zealand and South America that lasted for 9 months. On board, 169 men out of 376 developed the disease and 25 died. Takaki made a petition to Emperor Meiji to fund an experiment with an improved diet for the seamen that included more meat, milk, bread and vegetables. He succeeded, and in 1884, another mission took the same route, but this time only sixteen beriberi cases among 333 seamen were reported. This experiment convinced the Imperial Japanese Navy that poor diet was the prime factor in beriberi, and the disease was soon eliminated from the fleet. Takaki's success occurred ten years before Christiaan Eijkman, working in Batavia, advanced his theory that beriberi was caused by a nutritional deficiency, with his later identification of vitamin B1 earning him the 1929 Nobel Prize in Physiology or Medicine. Although Takaki clearly established that the cause was due to nutritional issues, this conflicted with the prevailing idea among medical scientists that beriberi was an infectious disease. The Imperial Japanese Army, which was dominated by doctors from Tokyo Imperial University, persisted in their belief that beriberi was an infectious disease, and refused to implement a remedy for decades. In the Russo-Japanese War of 1904–1905, over 200,000 soldiers suffered from beriberi — 27,000 fatally, compared to 47,000 deaths from combat. In 1905, Takaki was ennobled with the title of danshaku under the kazoku peerage system for his contribution of eliminating beriberi from the Imperial Japanese Navy, and also awarded the Order of the Rising Sun. He was later affectionately nicknamed "Barley Baron". Takaki founded the Sei-I-Kwai medical society in January 1881. In May, 1881, he founded the Sei-I-Kwai Koshujo, now the Jikei University School of Medicine. Takaki's school was the first private medical college in Japan, and was the first in Japan to have students dissect human cadavers. Takaki was posthumously honored by having a peninsula in Antarctica at named "Takaki Promontory" in his honor. It is the only peninsula in Antarctica named after a Japanese person.
