Soy Nutrition Institute

 

Soyfoods Make It Easy to Eat More Legumes

By Mark Messina, PhD, Executive Director, Soy Nutrition Institute

The United Nations declared 2016 to be the International Year of the Pulses, placing a focus on the role of these foods in healthy diets and sustainable food production.

Pulses are part of the legume family, which includes dried beans, peanuts, and soyfoods. They are important in diets throughout the world and represent an especially easy way to eat more plant proteins. According to a 2017 survey, 40 percent of U.S. consumers say they are eating more beans. But it’s not clear that people actually think of soyfoods in the same way they think of other legumes.

In fact, soybeans aren’t the same as other beans. They are much higher in both fat and protein and are classified as oilseeds rather than pulses. But just like pulses, they are packed with fiber, resistant starch, and an assortment of micronutrients. There is no disagreement among nutrition professionals that legumes are extremely nutritious.1

Boosting bean intake can also help consumers save money on grocery bills. The Median Nutrient Rich Foods Index Score, which ranks foods on the basis of their cost per 100 calories and their nutrient value, found that beans, nuts, and seeds provide the highest nutrient value for the lowest cost.4  Eating beans can also shrink your carbon footprint since bean production requires less water and land and results in less greenhouse gas emissions than the production of protein from animals.5 

However, historically, beans have been perceived as “the poor man’s meat.” That image likely contributes to the marked decline in bean consumption that has taken place in countries such as India and Mexico over the past several decades.6  These changes are part of the nutrition transition that is taking place in many countries around the world. They most likely are part of the explanation for the increase in prevalence of chronic diseases, such as obesity and diabetes, in these countries.7,8 

Legumes are also underutilized in western diets. Although plant protein provides about one-third of the total protein intake of Americans, according to an analysis of the National Health and Nutrition Examination Survey (NHANES) from 2007 through 2010, beans provided only 1.3 percent of  total protein intake.2 

Even among vegans and vegetarians, who typically have higher intakes of legumes than the average American, bean intake is still quite modest. For example, in the Adventist Health Study-2, vegans consumed an average of  84 grams of non-soy legumes per day, or the equivalent of just one serving.3

According to a review in the American Journal of Clinical Nutrition, obstacles to bean consumption include “perceived inconvenience, a negative culinary image, and intestinal discomfort.” 1

Soyfoods may present fewer obstacles in this regard. While soybeans can be cooked and consumed in a similar way to other dried beans, this isn’t their most common culinary use. Whole soybeans are more usually consumed as edamame, which is the fresh green bean, or as roasted soynuts. Soynuts are often used as a snack similar to peanuts, but have a higher protein content.

In Asian countries, soy is most frequently consumed as lightly processed foods tofu and soymilk or the fermented products tempeh and miso. Fermentation eliminates most of the oligosaccharides from the beans, and is a good choice for reducing flatulence that is sometimes associated with legume consumption.9  Tofu, which is also lacking in oligosaccharides,  represents another easy way to increase plant protein in diets because of its versatility. It’s used in main dishes as well as in smoothies or for replacing dairy products in puddings and other desserts.

Finally, soy protein products, such as isolated soy protein and soy protein concentrate, represent an easy way to substantially increase plant protein intake.  The quality of soy protein is similar to that of animal protein and higher than just about all other plant proteins.10  Soy protein also lowers LDL-cholesterol11 and possibly blood pressure.12 It’s used extensively in the food industry to produce everything from veggie burgers to energy bars.

Soyfoods represent an easy and enjoyable way for Americans to eat more legumes.


References

  1. Messina V. Nutritional and health benefits of dried beans. Am J Clin Nutr. 2014;100 Suppl 1:437S-42S.
  2. Pasiakos SM, Agarwal S, Lieberman HR, Fulgoni VL. Sources and amounts of animal, dairy, and plant protein intake of US adults in 2007-2010. Nutrients. 2015;7:7058-69.
  3. Orlich MJ, Jaceldo-Siegl K, Sabate J, Fan J, Singh PN, Fraser GE. Patterns of food consumption among vegetarians and non-vegetarians. Br J Nutr. 2014;112:1644-53.
  4. Drewnowski A. The cost of US foods as related to their nutritive value. Am J Clin Nutr. 2010;92:1181-8.
  5. Sabate J, Harwatt H, Soret S. Environmental nutrition: A new frontier for public health. Am J Public Health. 2016;106:815-21.
  6. Messina MJ. Legumes and soybeans: overview of their nutritional profiles and health effects. Am J Clin Nutr. 1999;70:439S-50S.
  7. Popkin BM. The nutrition transition in low-income countries: an emerging crisis. Nutr Rev. 1994;52:285-98.
  8. Popkin BM, Horton S, Kim S, Mahal A, Shuigao J. Trends in diet, nutritional status, and diet-related noncommunicable diseases in China and India: the economic costs of the nutrition transition. Nutr Rev. 2001;59:379-90.
  9. Calloway DH, Hickey CA, Murphy EL. Reduction of intestinal gas-forming of legumes by traditional and experimental food processing methods. J Food Sci. 1971;36:251-5.
  10. Hughes GJ, Ryan DJ, Mukherjea R, Schasteen CS. Protein digestibility-corrected amino acid scores (PDCAAS) for soy protein isolates and concentrate: Criteria for evaluation. J Agric Food Chem. 2011;59:12707-12.
  11. Tokede OA, Onabanjo TA, Yansane A, Gaziano JM, Djousse L. Soya products and serum lipids: a meta-analysis of randomised controlled trials. Br J Nutr. 2015;114:831-43.
  12. Dong JY, Tong X, Wu ZW, Xun PC, He K, Qin LQ. Effect of soya protein on blood pressure: a meta-analysis of randomised controlled trials. Br J Nutr. 2011;106:317-26.

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