By Betsy Keller, MS, RD
I entered the vitamin store at our local strip mall in hopes of finding a simple protein powder to boost the calorie intake of my very thin teen son. I am a Registered Dietitian and this should have been easy. I was directed to the powdered protein wall which was no less daunting than a first glimpse of the Great Wall of China. After 45 minutes grilling the store manager and a personal guided tour of rice powder, soy isolates and whey protein supplements, I was dizzy with marketing hyperbole. There were protein powders for body builders, weight loss, weight gain, lactose intolerance and vegans.
What Type of Protein Do We Need?
I was very confused. The last time I checked my basic nutrition reference book, our bodies recognized protein as just that….protein made up of 20 different amino acids which are digested and used to replace the protein lost in our bodies. Whether the protein comes from a steak, rice and beans or a powdered supplement, it will all be digested and used by the body or stored. A scoop of typical protein powder contains about 20 grams of protein, which is the same amount found in a 3 oz. chicken breast or a veggie burger with a cup of baked beans. But are these food sources providing all 20 amino acids? In 1993, The Food and Drug Administration adopted the Protein Digestibility Corrected Amino Acid Score (PDCAAS) to provide a measurement of protein quality in food and food ingredients- does it have all 20 amino acids our bodies need and can we digest it. Dietitians, scientists and apparently vitamin store managers agree, as long as your dietary protein sources are varied, you will consume complete and adequate protein.
How Much Protein Do We Need?
I was certain what I had learned during grad school still rang true- most people can easily achieve their protein needs (see chart below) through a healthy and balanced diet. The store manager vigorously agreed. While there may be a few circumstances which warrant additional protein intake (endurance athletes…do you exercise for more than 90 minutes every day?), most Americans are eating enough protein. In fact, over consumption of protein (from food or powder) just results in weight gain as our bodies store the unused calories.
According to the PDCAAS chart below, I take comfort knowing that I can serve healthful and sustainable complete proteins for breakfast by frying a local egg (25 cents)and serving it with a glass of hormone-free organic milk (55 cents)- skipping the manufactured soy powder for $27.99 a container. Or if I am really intent on sneaking some extra protein calories into my son’s diet, I can add nonfat dry organic milk powder (17 cents) and it retains all the protein, calcium and other nutrients of a glass of milk.
A PDCAAS value of 1 is the highest and 0 the lowest. The table shows the ratings of selected foods.
|1.00||casein (milk protein)|
|1.00||whey (milk protein)|
|0.59||cereals and derivatives|
How much protein do I need?
Maybe you’ve wondered how much protein you need each day. In general, it’s recommended that 10–35% of your daily calories come from protein. Below are the Recommended Dietary Allowances (RDA) for different age groups.
|Recommended Dietary Allowance for Protein|
|Grams of protein
needed each day
|Children ages 1 – 3||13|
|Children ages 4 – 8||19|
|Children ages 9 – 13||34|
|Girls ages 14 – 18||46|
|Boys ages 14 – 18||52|
|Women ages 19 – 70+||46|
|Men ages 19 – 70+||56|
Examples of amounts of protein in food:
1 cup of milk has 8 grams of protein
A 3-ounce piece of meat has about 21 grams of protein
1 cup of dry beans has about 16 grams of protein
An 8-ounce container of yogurt has about 11 grams of protein
|Protein Content of Selected Vegan Foods|
|Soybeans, cooked||1 cup||29||9.6|
|Lentils, cooked||1 cup||18||7.8|
|Black beans, cooked||1 cup||15||6.7|
|Kidney beans, cooked||1 cup||13||6.4|
|Veggie burger||1 patty||13||13.0|
|Chickpeas, cooked||1 cup||12||4.2|
|Veggie baked beans||1 cup||12||5.0|
|Pinto beans, cooked||1 cup||12||5.7|
|Black-eyed peas, cooked||1 cup||11||6.2|
|Tofu, firm||4 ounces||11||11.7|
|Lima beans, cooked||1 cup||10||5.7|
|Quinoa, cooked||1 cup||9||3.5|
|Tofu, regular||4 ounces||9||10.6|
|Peas, cooked||1 cup||9||6.4|
|Textured Vegetable Protein (TVP), cooked||1/2 cup||8||8.4|
|Peanut butter||2 Tbsp||8||4.3|
|Veggie dog||1 link||8||13.3|
|Spaghetti, cooked||1 cup||8||3.7|
|Soy milk, commercial, plain||1 cup||7||7.0|
|Soy yogurt, plain||6 ounces||6||4.0|
|Bulgur, cooked||1 cup||6||3.7|
|Sunflower seeds||1/4 cup||6||3.3|
|Whole wheat bread||2 slices||5||3.9|
|Almond butter||2 Tbsp||5||2.4|
|Brown rice, cooked||1 cup||5||2.1|
|Spinach, cooked||1 cup||5||13.0|
|Broccoli, cooked||1 cup||4||6.8|
|Sources: USDA Nutrient Database for Standard Reference, Release 18, 2005 and manufacturers’ information.
The recommendation for protein for adult males vegans is around 56-70 grams per day; for adult female vegans it is around 46-58 grams per day .
Betsy Keller, MS, RD is a nutrition marketing and communications consultant specializing in sustainable food, nutrition and health-related issues. She is a freelance writer and also lectures in Fairfield County, CT.