Soy protein powder is made by removing much of the fat and carbohydrates from dried, ground soybeans. The result is a protein-rich supplement popular with bodybuilders and other performance athletes. Many brands of soy protein powders come enriched with other nutrients. However, the following nutrition facts are for simple, unenriched protein powder. Consult your doctor before beginning any supplementation regimen.
Serving Size and Calories
The US Department of Agriculture lists nutritional information based on a serving on 1 ounces of soy protein powder. This is typically mixed with water or another drink, or sprinkled as a topping on other food. One ounce of soy protein powder contains 95 calories. Eight of these calories come from fat, eight more come from carbohydrates. The remaining 78 calories are proteins.
One serving of soy protein powder, about 28 grams, contains 0.9 g of total fat. This breaks down to 0.1 g of unhealthy saturated fats and 0.8 g of heart-healthy unsaturated fats. The ratio of good to bad fats is the most important factor when considering the fat content of a given food, Harvard nutritionist Walter Willett writes in his book "Eat, Drink and Be Healthy."
A serving of soy protein powder contains 2.1 g of carbohydrates, split between 1.6 g of dietary fiber and 0.5 g of complex carbohydrates. Dietary fiber helps your body's natural cleansing process and contributes to dietary and circulatory health. Complex carbohydrates deliver steady energy over time, a useful feature in a supplement for athletes.
Protein is, perhaps unsurprisingly, the key contribution of soy protein powder. One serving contains 22.6 g of protein, nearly half your daily requirement in every ounce. Unlike most plant proteins, soy protein is complete: It contains all the amino acids your body needs for building and maintaining muscle.
Soy protein powder contains 12 percent of your daily recommended intake of folate and between 1 and 3 percent of your requirements for thiamine, riboflavin, niacin and vitamin B6. Oregon-based fitness coach Ben Cohn recommends taking soy protein powder with a vitamin C supplement. Vitamin C is vital to the recovery and growth that accompanies aggressive athletic training.
One serving of soy protein powder delivers nearly one quarter of your daily requirement for copper, phosphorus, iron and manganese. It contains between 1 and 8 percent of your calcium, magnesium, potassium and zinc requirements. However, this comes at the cost of 281 mg of sodium per serving, about 12 percent of your daily allowance.