The Role of Soy in Vegetarian Diets

Abstract

Soyfoods have long been prized among vegetarians for both their high protein content and versatility. Soybeans differ markedly in macronutrient content from other legumes, being much higher in fat and protein, and lower in carbohydrate. In recent years however, soyfoods and specific soybean constituents, especially isoflavones, have been the subject of an impressive amount of research. Nearly 2,000 soy-related papers are published annually. This research has focused primarily on the benefits that soyfoods may provide independent of their nutrient content. There is particular interest in the role that soyfoods have in reducing risk of heart disease, osteoporosis and certain forms of cancer. However, the estrogen-like effects of isoflavones observed in animal studies have also raised concerns about potential harmful effects of soyfood consumption. This review addresses questions related to soy and chronic disease risk, provides recommendations for optimal intakes, and discusses potential contraindications. As reviewed, the evidence indicates that, with the exception of those individuals allergic to soy protein, soyfoods can play a beneficial role in the diets of vegetarians. Concerns about adverse effects are not supported by the clinical or epidemiologic literature. Based on the soy intake associated with health benefits in the epidemiologic studies and the benefits noted in clinical trials, optimal adult soy intake would appear to be between two and four servings per day.

Effects of Soil Applications of Micro-Nutrients and Chelating Agent Citric Acid on Mineral Nutrients in Soybean Seeds

“…Soybean seeds have the highest protein content amongst other plant products, and contain all eight essential amino acids. Soybeans are processed to various soy products namely soy flour, soy milk, cottage cheese like tofu, fermented products like tempeh and miso [3] [4]. Soybean seeds are also a major source of oil, carbohydrates, minerals, and secondary metabolites such as lignin and isoflavones [5] [6].…”

Proximate Composition, Phytoconstituents and Mineral Contents of Soybean (Glycine Max) Flour Grown and Processed in Northern Nigeria

“…Many leguminous crops provide some protein, but soybean is the only available crop that provides an inexpensive and high quality source of protein comparable to meat, poultry and eggs [3]. Historically it is nick-named "meat of the field" or "meat without bones" because it is the only vegetable with a complete protein [4]. The gold standard for measuring protein quality is the Protein Digestibility Corrected Amino Acid Score (PDCAAS) and by this criterion soy protein is the nutritional equivalent of meat, eggs, and casein for human growth and health [5].…”

Review of Soybean Phytochemicals and Their Bioactive Properties Relevant for Skin Health

“…Soybeans are exceptional sources of plant proteins and an important staple food source for many communities [23,24]. Lunasin is a 43 amino acid-long peptide present in soybean, and consists of several arginine-glycine-aspartic acid (RGD) residues and a carboxylic acid tail of nine aspartic acid residues [25].…”