This is the second column in a series based on “Nourish, The Definitive Plant-Based Nutrition Guide for Families,” by Stanford-based pediatrician Reshma Shah, M.D., MPH, and registered dietitian Brenda Davis. Last week’s column was about carbohydrates and today’s is about protein — next week’s will be about the third and final macronutrient, fat.

Proteins are complex macronutrients that have multiple functions in the body. They are made up of amino acids, some of which our body cannot produce, which are called essential amino acids, and others that our body can produce. There are two questions that lay people have regarding protein and childhood nutrition: 1) Can growing children get enough protein from plants? 2) Is the quality of plant-protein adequate?

QUANTITY OF PROTEIN

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The RDA (recommended daily allowance) of protein for adults is 0.8 grams per kilogram (1 kg = 2.2 pounds), which translates into 46 grams a day for the average American female and 56 grams for the average male. However, in the following situations additional protein is needed: growing infants, children and adolescents; pregnancy; and breast feeding. For example, growing infants require almost twice the protein per kilo as do adults.

Following is a comparison of protein content of a few common foods: 3 ounces of beef or chicken, 25 grams of protein; 1 egg, 6 grams; ½ cup of firm tofu, 22 grams; 1 veggie burger patty, 11 grams; 1 ounce of hemp seeds, 10 grams; 12 ounces of almonds, 6 grams; ½ cup of beans or lentils, 7-9 grams.

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One issue with protein-containing foods is digestibility. Fiber — a carbohydrate — is not digested and feeds the bacteria in the gut microbiome. With high fiber, protein-containing foods such as legumes, up to 10 percent of the protein is lost in the stool. Although kids should eat some fiber in order to have a healthy gut microbiome, it’s important that they also eat some highly digestible protein-rich plant foods, such as tofu, soy milk, veggie “meats,” and nut butter. If cell walls are removed, as happens, for example, when soybeans are processed into tofu, the protein digestibility ranks about the same as meat.

“Nourish” notes that “a recent review reported protein intakes in plant-exclusive eaters (vegans) ranging from 62 to 82 grams of protein per day — well above the RDA.” Studies of vegetarian and vegan children show that they exceed the RDA for protein and have normal growth and development compared to omnivorous children.

Eating too much protein is problematic. Several studies have shown that high protein intake is associated with abnormally rapid growth, overweight and obesity. Shah and Davis note that “children in Western nations get two to four times more protein than they need.” For this reason, protein powders are not recommended, plus they often contain environmental contaminants, sweeteners, fillers, preservatives and thickeners.

QUALITY OF PROTEIN

In the 1970s there was a theory that not all plant foods contained all nine of the essential amino acids that the body can’t make. This was proven in the 1980s to be false— all plant foods have been shown to contain all nine essential amino acids.

How about health benefits of plant versus animal protein? Shah and Davis note that “plant protein significantly reduces mortality and risk of chronic disease [for example obesity, hypertension, diabetes, heart disease, chronic kidney disease] when it replaces meat.”

CONCLUSION

Don’t make this too complicated (don’t eat your meals with a calculator!). As Shah and Davis say in their book, “If we meet recommended intakes for protein and consume a reasonable mix of plant foods over the course of the day, protein and individual amino acid needs will … be easily met.” For further information, read “Nourish,” which has some specific suggestions about how to ensure adequate protein for kids on a plant-predominate or plant-exclusive diet.

Dr. Feinsinger is a retired family physician with special interest in disease prevention and reversal through nutrition. Free services through Center For Prevention and The People’s Clinic include: one-hour consultations, shop-with-a-doc at Carbondale City Market and cooking classes. Call 970-379-5718 for appointment or email gfeinsinger@comcast.net.