Tofu contains the proteins that build the liver and the nutritional constituents that enhance liver function.

As an ethnic group, the Japanese are said to have weak livers. Although alcohol is broken down in the liver, the acetaldehyde that is formed when alcohol is broken down has ten times greater toxicity than alcohol, and the enzyme that breaks down acetaldehyde is deficient in Japanese people. Consequently, they are more prone to becoming sick from alcohol, and the burden on the liver is greater. 70% of European and American patients suffering from hepatitis, an inflammatory disease of the liver, have alcohol-induced hepatitis, while 80% of Japanese patients have viral hepatitis. The fact that the percentage of Japanese patients with alcohol-induced hepatitis is so low even with low alcohol tolerance shows just how vulnerable Japanese livers are against the hepatitis virus.

The liver weighs approximately one fiftieth of body weight, so in comparison to Europeans and Americans, the physically smaller Japanese have smaller livers. Liver volume decreases with age, and this loss of volume is greater in the Japanese than in Europeans and Americans. This also means that the Japanese liver is more prone to over burdening, and liver dysfunction can easily occur.

An abundance of builder proteins and function enhancing vitamins and minerals are needed to fortify the liver. Approximately 90% of the liver is regenerated in one month. As the liver accounts for one fiftieth of body weight, the liver in a person weighing 60kg (132 pounds) is 1.2kg (2.6 pounds). In other words, a person weighing 60kg needs 40g (about 1.4oz) of protein every day just to regenerate the liver. This is the amount needed to maintain a normal liver. To fortify the liver, 50g (about 1.8oz) a day (25% more) is recommended.

Tofu has good digestive efficiency, is easily absorbed and is a low energy food that can be eaten in quantity. For these reasons tofu is currently the center of attention as a source of protein for a healthier liver.