Plant protein powder selection guide: Differences and precautions between soybean, pea and rice protein

[Health Channel/Comprehensive Report] Many people tend to choose plant protein powder because they don’t eat enough protein. However, they are confused about the differences between soybean, pea, and rice protein. Huang Yijie, deputy director of Ageless Clinic, pointed out that if you want to choose a single source, soy protein is usually the easy choice; if you don’t want to choose soy, pea protein is a common option on the market, but you have to accept that it may have a plant-like or powdery taste. She reminded two things. Some protein powders may add sweeteners, spices, etc., which may cause gastrointestinal discomfort. If you are undergoing treatment for breast cancer or hormone-related diseases, it is still recommended to confirm with your care team.

Huang Yiji shared on the Facebook page "Dr. Huang Yiji's Intestinal Health Diet School" that some people buy plant protein powder, but they are troubled by not knowing the difference between soy, pea and rice protein. Soybean, pea, and rice protein are not the same as the word "plant". In other words, plant protein is not the same thing.

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Huang Yijie explained that protein is composed of amino acids, of which 9 essential amino acids cannot be produced by the human body and need to be obtained from food. The amino acid composition of different protein sources is different, and some amino acids will be relatively insufficient. This is called limiting amino acids. The essential amino acid composition of soy protein is relatively complete and it is a higher-quality source of plant protein; pea protein has good lysine performance, but relatively few sulfur-containing amino acids; rice protein is just the opposite, relatively deficient in lysine, but relatively advantageous in sulfur-containing amino acids.

She further said that this is why the public will see that many products put pea protein and rice protein together. This is not to make the product sound high-end. The point is that the two have complementary amino acids.

Regarding the evaluation of protein quality, Huang Yijie mentioned that PDCAAS is commonly used in the literature to evaluate protein quality. It considers essential amino acid composition and digestibility together, and the highest score is 1.0. In common information, soy protein isolate is usually close to the perfect score; pea protein isolate is slightly lower; rice protein is usually even lower. However, PDCAAS is not a perfect indicator and the actual product will still be affected by raw materials, processing, purity and formulation.

How should people choose plant protein powder? Huang Yijie suggested that when choosing plant protein powder, don’t just look at “soybeans are better” or “mixing them must be better.” If people want to choose a plant protein with a single source and relatively complete protein quality, soy protein is usually the simple choice; if people are not suitable for or do not want to choose soybeans, pea protein is a common option on the market, but they must accept that it may have a plant taste or powdery feel; if it is pea and rice protein, the focus is not on a fixed ratio, but on the overall protein content, amino acid design, ingredient list, and whether the taste is suitable for you.

Huang Yiji reminded that many protein powders will add sweeteners, spices, emulsifiers or thickeners in order to taste better. These ingredients do not mean they are harmful if they are seen. Once people drink it every day, it is best to check each serving of sugar, sodium, total calories, and whether there are any ingredients that may cause gastrointestinal discomfort.

Soy is also often asked about hormonal issues. Huang Yiji emphasized that general soy foods such as tofu, soy milk, and edamame are not the same thing as high-dose soy isoflavone supplements. Many current cancer nutrition materials also believe that most soy foods in the general diet can be used as part of a healthy diet. However, if people are receiving treatment for breast cancer or hormone-related diseases, it is still recommended to confirm with the care team.

Huang Yijie concluded that the essence of protein powder is a supplementary tool. When choosing, it is best for people to confirm how much protein they need in a day, how much they usually eat, and how much protein a serving of protein powder can supplement.