For the amount of nama shoyu used in normal cooking or as a flavoring and seasoning liquid (which is very little), it contributes very little in calories, carbohydrates and proteins, with no fat, cholesterol or trans fats.

Shoyu also has small amounts of minerals like iron, magnesium, phosphorus, sodium, and manganese but the amounts of these nutrients contributed to the daily diet is very less.

One mineral that is present in very high quantities and contributes to the saltiness of shoyu is sodium. Consuming high amounts of sodium regularly is not healthy as it may contribute to hypertension, heart diseases, etc. But the quantity of shoyu required to add saltiness and flavor to the foods is very little compared to the salt that might be needed to give the same amount of saltiness and flavor. So in that way, the sodium contributed by shoyu may not be that dangerous. But if you are suffering from hypertension or on a sodium-reduced diet or advised by doctor to avoid salt, you should avoid shoyu along with other high salt foods.

Along with saltiness, shoyu also adds other flavors like sweetness, sourness, savory taste, and umami (which is 'fresh taste' in Japanese contributed by glutamic acid naturally present in shoyu). So these complex flavors actually enhance the flavor of the foods with less quantities of shoyu, instead of adding a lot of other spices.

Shoyu also has minor amounts of B-group vitamins like riboflavin, niacin, vitamin B6, and folic acid.

Namashoyu (unpasteurized shoyu) also has live microorganism that are beneficial to the intestinal flora.