(2) According to Fales the hypothetical germ of beriberi can only live in body fluids deficient in potassium carbonate. The high content of potash in potatoes made him greatly increase the amount of this vegetable in the dietary he recommended. Fales noted scurvy as well as beriberi in the Bilibid prisoners on a diet deficient in potash.
(3) Deficient fat. (4) Deficient phosphorus.—It was Schaumann’s idea that the phosphorus contained in the outer layers of the rice grain was essential in the prevention of beriberi. While it is now known that the beriberi-preventing substance does not contain phosphorus, yet the idea has proven of practical value as giving an index of beriberi-producing power of rice.
P2O5 Index of Beriberi-producing Rice.—If a rice contain under 0.4% of phosphorus pentoxide it is liable to produce beriberi.
Schaumann now considers that the antineuritic substance in rice polishings acts as an activator in the metabolism of phosphorus.
Vitamine Deficiency.—Grijns was the first to insist that beriberi was due to the absence in the diet of some substance essential to proper metabolism of the peripheral nerves. His views were along the line of our present vitamine deficiency ones. There are undoubtedly many different vitamines, varying as to nature of protective power, temperature at which destroyed, solubility, etc. McCollum emphasizes the importance of a fat soluble A and a water and alcohol soluble substance B for proper metabolism. This latter, usually designated “Water soluble B,” is generally considered the same as the anti-neuritis vitamine but there is recent evidence that this may not be the case. The antiscorbutic vitamine is water soluble C.
Food Poisoning as Cause.—There are other theories as to intestinal parasites causing the disease and in particular views as to relation of fish eating to the disease, which are (1) that it is caused by the ingestion of raw fish, or again (2) from the eating of certain poisonous fish.
Miura, who is the great advocate of a fish intoxication, believes that this comes about from eating fish belonging to the Scomberidae family. As proving this, he cites the absence of beriberi in prisons in Japan, where no fish is allowed. He does not recognize that it is the diet of barley 6 to rice 4 parts which is the prophylactic factor. Barley is rich in vitamines.
Rice and Beriberi
There are a few points in connection with rice which should be understood. The larger part of the rice grain is starch and covering this central starch core we have the rather thin aleurone layer containing the proteid and fat constituents of the grain. Externally there is an adherent layer, the pericarp, which varies in color from red to white according to the kind of rice. The pericarp contains the salts. The grain is covered by the husk which is always removed to render the rice suitable for food. Unhusked rice is called padi in India and palay in the Philippines. In the process of removing the husk (milling) the pericarp and more or less of the aleurone layer may be rubbed off the grain. When the milling process is carried to the extent that but little remains except the starch the rice is termed polished, highly milled, or white rice. A process of parboiling causes the husk to be more easily detached and the pericarp to adhere more firmly to the grain and when milled there is less loss of the anti-neuritis principle, which is contained in the outer layers. Such rice is called cured rice. The embryo also contains the anti-neuritis vitamine as well as the fat soluble A one. It is also lost in milling. The scale-like dust is termed rice polishings and has curative value for those who have developed beriberi under a diet of polished rice. When the milling process is less complete the rice so treated is called undermilled rice or red rice. Polished, highly milled or white rice contains as a rule less than 0.4% of phosphorus pentoxide while the beriberi-preventing rices contain more than 0.4% of this compound for which reason legislation has required rice to have more than 0.4% phosphorus pentoxide.