Obtained from different types of algae, agar is often used as a thickening agent in foods because of its gel-like consistency. Because agar is entirely a plant-based substance, people following vegan diets can enjoy agar as a substitute for gelatin in recipes. Agar works well as a soup thickener and in jellies.
Agar is a fairly low-calorie food. The U.S. Department of Agriculture (USDA) National Nutrient Database reports that 1 tablespoon, or 7 grams, of dried agar provides about 21 calories. This is good news if you're seeking a vegan plant-based thickening agent, but want to avoid adding extra calories to your recipe. Other ingredients sometimes use as thickeners -- such as corn starch, potato starch, and flour -- contain more calories than agar.
Protein, Carbs, and Fat
Agar contains a small amount of protein and carbohydrates, but is fat-free. A 1-tablespoon portion of dried agar provides just over 5 grams of carbohydrates -- including about 0.5 grams of fiber -- and less than 1 gram of protein, according to the USDA.
Vitamins and Minerals
Dried agar provides a small amount of essential vitamins and minerals -- including calcium, iron, zinc, potassium, magnesium, and folate. While agar isn't an extremely rich source of any of these mircronutrients, getting a little bit here and there does help you meet daily nutritional needs.
Agar vs. Gelatin
Agar and gelatin are both used as food thickening agents, but these two thickeners are different nutritionally. Unlike plant-based agar derived from algae, gelatin comes from the collagen of animals -- such as poultry, fish, pigs, and cattle. Gelatin powder contains 23 calories per tablespoon, which is similar to the 21 calories in dried agar. While agar isn't nutrient-dense, it does provide more vitamins and minerals than gelatin. However, unlike low-protein agar, 1 tablespoon of gelatin powder provides 6 grams of dietary protein.
An experienced health, nutrition and fitness writer, Erin Coleman is a registered and licensed dietitian and holds a dietetics degree from the University of Wisconsin-Madison. She also has worked as a clinical dietitian and health educator in outpatient settings. Erin's work is published on popular health websites, such as TheNest.com and JillianMichaels.com.