While true tamari or shoyu is an aged product, most of the commercial soy sauce sold in the United States is a nonfermented synthetic product made from defatted soybean meal and grains mixed with chemicals. Real aged tamari or shoyu has a different flavor than commercial, synthetic soy sauce. In Japan, synthetic soy sauce is not recognized by the government, which allows five different types of soy sauce to be labeled as shoyu. Among the synthetic brands, reduced-sodium soy sauce is available.
Soy sauce is a condiment, used sparingly to flavor dishes. Use it in stir-fried dishes, or to prepare marinades for meat or vegetables. It can also be used in place of salt in soups and stews.
Soy sauce is not a good source of isoflavones (phytroestrogens). Isoflavones are compounds thought to be largely responsible for many of the health benefits associated with eating soy. Therefore, eating soy sauce should not be expected to contribute to the potential health benefits derived from eating other soy foods, such as miso, tofu, and tempeh, which contain higher levels of these compounds.