Mark Messina: Hello! I am Mark Messina. I am an Adjunct Associate Professor at Loma Linda University. And on behalf of The Soyfoods Council I will be talking about the role of soy in Asian diets.
For a food that has been consumed for centuries, there is a surprising amount of confusion about the role of soy in Asian cuisines. In many respects, soy foods play a similar role in the Japanese diet as dairy does in the United States. We get about 16 grams of protein per day from dairy foods, which represents about 20% of our overall protein intake. In Japan, older individuals consuming a traditional diet get about 10-12 grams of soy protein per day. Those individuals in the upper 25% of intake get about 15-20 grams of soy protein per day. Since one serving provides about 7 grams of protein, that translates to about 1.
5-3 servings of soy per day. In Shanghai, intake is a bit higher than it is in Japan. Information about soy intake comes from studies involving thousands of individuals, sometimes as many as 50,000. Subjects in these studies are asked how often, how much, and what types of soy foods they consume. There are many different types of soy foods consumed throughout Asia, but these foods are usually divided into two different categories; fermented and unfermented soy foods. Fermented soy foods were the first forms of soy consumed, but historical records indicate that unfermented soy has been consumed for at least a 1,000 years. In Shanghai, most of the soy consumed is in unfermented form, primarily as tofu and soymilk. In contrast, in Japan about half of the soy consumed is unfermented and about half fermented, primarily in the forms of miso and natto.
In the United States, although soy foods are becoming more popular, the average person consumes only about two grams of soy protein per day. Americans consume about 80 grams of total protein per day. So soy makes a rather negligible contribution to total protein intake. Nevertheless, soy protein is found in a wide range of foods commonly consumed in the United States. That's because the food industry uses soy protein for its functional properties, such as to enhance shelf life and increase the amount of moisture in a food.
However, because the amount of soy protein added to these foods is so small, the average American consumes very little soy. A century ago Americans consumed about 50% of their protein from plants and about 50% from animals. Today about two-thirds of our protein intake comes from animals. The 2010 Dietary Guidelines calls for Americans to incorporate more plant protein into their diet. An excellent way to do that is to eat about two servings of soy foods everyday.