March 2020 Issue

Plant Protein Powders
By Ginger Hultin, MS, RDN, CSO
Today’s Dietitian
Vol. 22, No. 3, P. 16

These supplements are taking the category by storm, but are they all they’re cracked up to be?

There are many types of protein powders lining the shelves in grocery, drug, and health food stores. They’re sold in different flavors, formulations, and nutrient profiles, and their protein can come from a variety of sources, such as collagen, whey, egg, casein, and even beef. But while these animal-based protein powders remain popular, an extensive number of plant-based options, often labeled as vegetarian or vegan, are commanding more shelf space in an already crowded category.

Plant-based protein powders currently trending include pea, hemp, soy, algae, and brown rice varieties; pumpkin, sunflower, and chia seed–based products; the more exotic sancha inchi; and blends of plant sources for those desiring a more varied nutrient profile. But are these plant-based protein powders necessary? Are they safe? And how should dietitians counsel clients on what to buy? This article explores the different types of plant-based protein powders on the market, their safety considerations, and how to educate clients who want to purchase them.

Driving the Trend
Vandana Sheth, RDN, CDE, FAND, a spokesperson for the Academy of Nutrition and Dietetics and author of My Indian Table: Quick & Tasty Vegetarian Recipes, has noticed the growing trend in plant-based protein powders and mentions some of the reasons why consumers are interested in these products. “I see plant-based protein powders along with all things plant based trending. There are a variety of reasons for this—health, the environment, sustainability, animal cruelty/compassion, ethics, and religion. Plant-based foods and products are here to stay.”

According to Fortune Business Insights, globally, the plant-based supplements market, under which protein powders fall, was $4.16 billion in 2017, with expected growth to $7.38 billion by 2025. Industry insight analysts suggest the driving factors include the continued growth of the vegan diet trend, demand for sustainability, and the high nutritional value of plant-based foods.1

Taylor Wolfram, MS, RDN, LDN, a Chicago-based dietitian and consultant in private practice, says there are other reasons why plant-based protein powders are becoming more popular. “Protein has been a hot macronutrient for a while; most notably since the low-carb fad diet craze in the 1990s and 2000s. Plant-based protein in particular has been booming in the last decade.”

According to Wolfram, the Plant Based Foods Association substantiates the fact that the plant-based protein market is skyrocketing. She says the organization’s research has found that consumers are more interested in plant-based alternatives, including meat and milk, and sales of these plant-based products have soared in recent years. For example, the association projects that plant-based protein will represent one-third of all protein intake by 2054 and says this sector is growing fast. Plant-based foods recently have grown 20% in retail sales compared with only 2% growth for all foods.2

Wolfram agrees with Sheth that environmental concerns are helping to drive the trend in plant-based protein powders. “Consumers are increasingly concerned about the environmental impact of animal foods and the resources it takes to produce animal protein, as well as animal welfare issues,” Wolfram says. The Plant Based Foods Association cites research that this trend could encourage the responsible use of land, water, fuel, and fertilizer; lower people’s personal greenhouse gas emission footprint; help meet US greenhouse gas reduction targets; and free up US cropland.2-6

Plant Protein Blends
While there are hundreds of plant-based protein powders available, the majority contain a blend of plant sources. These blends may satisfy some consumers who believe they must consume a variety of plant proteins simultaneously to get the full range of essential amino acids at once. Some plant-based proteins don’t contain all of the essential amino acids in adequate amounts (sometimes referred to as “incomplete proteins”). Soy, chia, and quinoa, for example, contain all of the essential amino acids, while pea, bean, and lentil proteins are low in methionine and rice and most seeds are low in lysine.

However, guidelines don’t suggest it’s critical to consume all essential amino acids in one sitting; the Academy of Nutrition and Dietetics’ position paper on vegetarian diets states that using the terms “complete” and “incomplete” to describe proteins is misleading, as protein from a variety of plant foods can be consumed throughout the day to supply all necessary essential amino acids.6

The following are some of the more common ingredients found in plant-based protein powders:

Brown rice: Considered a good allergy-friendly protein powder, it’s gluten-free and mild in flavor. Lysine is a limiting amino acid in rice.

Grains: A variety of whole grains, such as amaranth, quinoa, and millet, are found in protein powders. Many are gluten-free, and some, such as quinoa, contain all of the essential amino acids. Most have a limited amount of lysine.

Pea/lentil/bean: Legume-based protein powders often are made from yellow split peas, lentils, and a variety of beans including adzuki and garbanzo. Peas contain good amounts of all the essential amino acids, while other legumes are limited in methionine.

Seeds: Many seeds, such as hemp, flax, chia, pumpkin, sunflower, and sesame, are included in protein powder blends. Hemp can be found on its own in several products. Seeds high in omega-3 fatty acids, such as hemp, chia, and flax, are an added benefit in protein powders. Some seeds are limited in the amino acid lysine, but chia and pumpkin seeds contain higher levels of this amino acid.

Soy: Different types of soy protein, such as soy protein isolate and soy protein concentrate, can be found in powders. Isolate is made from soybean flakes that have had the fat, carbohydrate, and fiber removed. Concentrate contains more fiber than isolate and is made from soy flour that has had the fat and some of the carbohydrate removed. Soy contains all of the essential amino acids.

Sancha inchi: These are large seeds that originate from South America. They’re often dry roasted and commonly consumed like a nut. They contain omega-3 fatty acids and good amounts of all of the essential amino acids.

Algae (chlorella): Blue-green algae powder also is found in some protein powders. It’s a source of protein and omega-3 fatty acids that contains vitamins, minerals, and antioxidants. Note that adding this as an ingredient will turn the product a deep bluish-green color, depending on how much is included. Lysine can be a limiting amino acid in algae.7

Blends: Many plant-based powders are blends of rice, grains, legumes, and seeds. If a client has any food allergy or intolerance, it’s important to read labels to understand what protein sources are being used. Blends often have added fruit and vegetable powders, sweeteners, and flavors. Limiting amino acids in blends are harder to assess because of the variety of ingredients. Beans usually are limited in methionine, and grains commonly are limited in lysine. However, there’s no need to worry about limiting amino acids in plant-based diets as long as the diet generally has variety. The body has stores of amino acids and can make what it needs.

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Benefits of Plant-Based Protein Powders
Protein powders may be appropriate and beneficial for some clients. People with increased protein needs such as older adults, athletes, or those with certain illnesses such as cancer, HIV/AIDS, lung diseases including COPD, and heart failure, or anyone with hypermetabolism, could benefit from an added protein source.8,9 “Protein powders have always been big among athletes, both professional and recreational,” Wolfram says. “While it’s true that protein powders aren’t necessary to get enough protein, they can be helpful when life gets busy. I find that pregnant people, especially vegans, also take an interest in protein powder, as protein needs increase in the second and third trimesters. Especially if a pregnant person has food aversions, sometimes a smoothie with protein powder is all they can stomach.”

Protein powders also can be useful for patients interested in general health and wellness. Just one or two scoops of protein powder, depending on the serving size and type of protein blend, can contain more than 20 g. Using the Dietary Reference Intake of 0.8 g of protein per kg of body weight, a 150-lb person needs about 54 g protein per day. Using protein powder in a breakfast smoothie or as a snack could meet about one-third of their needs for the day. “Plant-based protein powders can help people meet their protein needs in a convenient way,” Wolfram says. “For instance, if someone struggles to eat a balanced breakfast, or struggles to eat breakfast at all, a smoothie with calcium-fortified plant milk, fruit, greens, and plant-based protein powder can be a nutritious and convenient option.”

Drawbacks of Plant-Based Protein Powders
While there are benefits to consuming plant-based protein powders, there are some concerns. Many products are sold at high price points; they can contain plant protein blends and a variety of added sweeteners, vitamins, minerals, antioxidants, and herbal formulations. Clients will need to read labels carefully to ensure they’d get the amount of protein they need and that the product meets their health goals without overconsuming any ingredient that could interact with a medical condition, medication, or supplement.

High Costs
When compared with whole food–based protein options, plant-based protein powders can be expensive. For example, a block of tofu costs approximately $1.79 ($0.13/oz); one serving (84 g) contains 80 kcal and 9 g protein. Many plant-based protein powders cost more than $1 per oz. Instead of buying a plant-based protein powder, Wolfram suggests clients consider adding soymilk, peanut butter, and ground flaxseeds to a smoothie.

Possible Contaminants
Another consideration about plant-based protein powders is their safety profile. “Some folks have expressed concern over arsenic in rice-based protein powders,” Wolfram continues. In 2018, the Clean Label Project conducted a protein powder study of 134 top-selling animal and plant-based protein powders from 52 brands. They found that organic products contained more than twice the amount of heavy metals, including lead, arsenic, and cadmium, than nonorganic products tested. They also concluded that the plant-based products tested generally were more contaminated, while those containing egg as a protein source had much fewer contaminants.10

Recent studies on arsenic in rice have caused consumers to question the use of brown rice protein in protein powders. The World Health Organization has set maximum tolerable levels for arsenic in drinking water at 10 mcg/L. Arsenic content of raw rice can range from 0.1 to 0.4 mg/kg of dry mass—a higher arsenic level than other grains. The arsenic is concentrated in bran layers, so it’s higher in brown rice than white rice, though levels vary widely based on cultivation location and processing.11 Arsenic in protein powder may be a concern depending on how clients consume it, their overall diet quality, and exposure to this element.

Other consumers continue to fear the safety of soy. Some studies show that soy supplements contain higher levels of the isoflavones genistein and daidzein than whole soyfoods.12 However, it’s unclear that these cause any negative effects. A review of 92 randomized, controlled trials (n=9,692) concluded that phytoestrogen supplements don’t have unsafe side effects, and incidence of vaginal bleeding, endometrial hyperplasia and cancer, and breast cancer weren’t significantly increased in participants using phytoestrogens in these studies.12,13

A small study done on 12 male volunteers taking 56 g soy protein powder for 28 days found that serum testosterone decreased by 19% (p=0.021) and increased again within two weeks of discontinuing the product. Note that the serving size for many protein powders is about 30 g, so the amount these participants consumed was larger than what many people would consume with daily use. These researchers also noted that most studies done on various soy formulations in men haven’t documented a significant reduction in testosterone, though a couple of studies using high concentrations of soy isoflavones have indicated such.14 Research isn’t entirely clear on the effects of soy supplements in men and women, but it appears to be generally safe.

Another potential issue is phytate content. Most plant-based protein powders derived from foods contain phytates, which are naturally occurring compounds found in nuts, seeds, grains, and legumes that can inhibit absorption of minerals such as iron, zinc, calcium, magnesium, and manganese.15 While this generally isn’t a concern for people following a plant-based diet, consuming high levels of concentrated sources of phytates can become problematic depending on an individual’s nutrient needs and health concerns such as gastrointestinal problems.6 However, the process of soaking and/or sprouting can reduce phytic acid content. In fact, many popular plant-based protein powders market their ingredients as “sprouted.”

Recommendations for Clients
Protein powders can be a part of clients’ diets if they want to include them. Athletes, older adults, and people with certain illnesses may benefit from adding more protein to their diets via powders. Dietitians can discuss the pros and cons of using plant-based protein powders with clients. Cost may be an issue, but RDs can offer suggestions for food-based options that are more affordable and offer additional fiber as well as natural sources of vitamins, minerals, and antioxidants.

To get more protein into the diet without the added cost of powders, Wolfram suggests clients pick up some single-serve packets of plant-based protein powders and see which ones they like before investing in a big tub of the product. She says protein powders aren’t meant to replace food; they’re supplements. “Meeting as much of your protein needs through food should be the goal,” Wolfram continues. “When it comes to plant-based protein, legumes are king. Folks eating a plant-based or vegan diet should eat at least three servings of legumes per day. One serving comprises 1/2 cup of beans, lentils, tofu, or tempeh; one serving of soy-based plant meat; two tablespoons of peanut butter; or one cup of soymilk.”

According to Sheth, clients who want to buy protein powders should choose varieties that contain little or no added sugars and should watch out for added fibers such as inulin and sugar alcohols because they can cause bloating and other uncomfortable digestive symptoms if consumed in excess.

Dietitians should explain to clients that studies have found certain contaminants, such as arsenic, lead, and other heavy metals, in popular plant-based protein powders. Review the latest consumer reports to find the best options that have been tested and approved for consumption. Suggest clients rotate between the different types of plant-based protein powders over time, including those containing brown rice, so they limit their exposure to possible contaminants. In addition, RDs should consider their clients’ overall vitamin and mineral intake to determine whether they’re getting too much or too little of certain nutrients and assess whether concentrated sources of phytates from plant-based protein powders could become a problem. After all of these concerns are taken into account, dietitians can assure clients that plant-based protein powders can fit into a balanced diet. However, the ideal goal is to first consume a variety of plant-based proteins from whole foods that can meet their needs and supplement with a plant-based protein powder if needed.

— Ginger Hultin, MS, RDN, CSO, is a nutrition and health writer and certified specialist in oncology nutrition based in Seattle. She’s a past chair of the Vegetarian Nutrition Dietetic Practice Group, past president of the Chicago Academy of Nutrition and Dietetics, and owner of concierge nutrition practice Champagne Nutrition LLC.


1. Plant based protein supplements market size, share and industry analysis by type (soy protein, pea protein & wheat protein), by distribution channel (mass merchandisers, pharmacies/drugstores, specialty stores, online retail & others), and regional forecast 2018-2025. Fortune Business Insights website. Published April 2019. Accessed December 9, 2019.

2. Why plant based. Plant Based Foods Association website. Accessed December 9, 2019.

3. Sranacharoenpong K, Soret S, Harwatt H, Wien M, Sabaté J. The environmental cost of protein food choices. Public Health Nutr. 2015;18(11):2067-2073.

4. Scarborough P, Appleby PN, Mizdrak A, et al. Dietary greenhouse gas emissions of meat-eaters, fish-eaters, vegetarians and vegans in the UK. Clim Change. 2014;125(2):179-192.

5. Harwatt H, Sabaté J, Eshel G, Soret S, Ripple W. Substituting beans for beef as a contribution toward US climate change targets. Clim Change. 2017;143:261-270.

6. Melina V, Craig W, Levin S. Position of the Academy of Nutrition and Dietetics: vegetarian diets. J Acad Nutr Diet. 2016;116(12):1970-1980.

7. Bleakley S, Hayes M. Algal proteins: extraction, application, and challenges concerning production. Foods. 2017;6(5):E33.

8. Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: nutrition and athletic performance. J Acad Nutr Diet. 2016;116(3):501-528.

9. HF: protein needs (2008). Academy of Nutrition and Dietetics, Evidence Analysis Library website. Accessed December 9, 2019.

10. 2018 protein powder study. Clean Label Project website. Accessed December 9, 2019.

11. Hojsak I, Braegger C, Bronsky J, et al. Arsenic in rice: a cause for concern. J Pediatr Gastroenterol Nutr. 2015;60(1):142-145.

12. Watanabe S, Uehara M. Health effects and safety of soy and isoflavones. In: Singh RM, Watson RR, Takahashi T, eds. The Role of Functional Food Security in Global Health. Cambridge, MA: Academic Press; 2019:379-394.

13. Munro IC, Harwood M, Hlywka JJ, et al. Soy isoflavones: a safety review. Nutr Rev. 2003;61(1):1-33.

14. Goodin S, Shen F, Shih WJ, et al. Clinical and biological activity of soy protein powder supplementation in healthy male volunteers. Cancer Epidemiol Biomarkers Prev. 2007;16(4):829-833.

15. Gupta RK, Gangoliya SS, Singh NK. Reduction of phytic acid and enhancement of bioavailable micronutrients in food grains. J Food Sci Tech. 2015;52(2):676-684.