Active dry yeast is one form of baker's yeast used to leaven, or expand, bread before baking. It is sold in pre-measured ¼ oz. single-use envelopes, with three envelopes connected and sold as one unit. It is also available in 4-oz. jars and for bulk use in large bags. You can find at least one form of active dry yeast on baking aisles in most grocery stores. In spite of its tiny form, grains of yeast pack a powerful punch, with as little as 7 grams of yeast able to create a light, airy loaf of bread.
Active dry yeast has 21 calories per 7 grams or ¼ oz. envelope. Because most single loaf bread recipes call for one envelope of active dry yeast which equals 2 ¼ teaspoons, yeast does not contribute significantly to the caloric content of the final bread product.
One envelope of active dry yeast contains 4 milligrams of sodium, which is a fraction of the 2,300 milligrams daily limit established by the Institute of Medicine. The Centers for Disease Control and Prevention note that consuming excess sodium can lead to high blood pressure, which is a precursor for stroke and heart attack.
One ¼ oz. envelope of active dry yeast contains 140 milligrams of potassium. Since this amount of yeast is worked through one loaf of bread, active dry yeast makes a small contribution to your overall daily consumption of potassium.
Carbohydrates are comprised of sugars and dietary fibers. Sugars are a source of quick energy for the body, while dietary fiber adds bulk to your digestive system and helps reduce blood cholesterol levels. One envelope of dry active yeast contains 2.67 grams of carbohydrates, with 1.5 grams coming from dietary fiber.
Protein acts as a building block for the body's cells. The Institute of Medicine recommends that men ages 19 and up consume 56 grams of protein daily. Women of the same ages should eat 46 grams daily. Because they are maintaining their own bodies and feeding the growth of an embryo and baby, pregnant and nursing women should eat 71 grams of protein daily. One envelope of active dry yeast contains only 2.68 grams, and is not a significant source of protein.
A ¼ oz. package of active dry yeast contains .32 grams of fat. The saturated fat content of active dry yeast is .042 grams, but the bulk of the fat content comes from monounsaturated fat, at .179 grams. Polyunsaturated fat contributes a trace amount at .001 grams.
The only vitamin or mineral provided by active dry yeast is iron. One packet has 6 percent of the Recommended Daily Value of iron.