Soy (also known as Soya) - In China, the soya bean has been cultivated and used in different ways for thousands of years. In recent times increasing popularity of soy foods is mostly attributed to the large amount of health benefits which are associated with the use of soya beans. The role of soy in the prevention of chronic diseases continues to be a top priority for scientists around the world & the American FDA has confirmed that foods containing soy protein may reduce the risk of coronary heart disease (FDA, 1999). Soy has a high protein content and is rich in fibre, vitamins & minerals (FSANZ, 2010). It is generally very low in or free of fat, cholesterol, and lactose. It is approved for those who are lactose intolerant, and is used as a meat substitute thus soy is very important for vegetarians & vegans.
So what is the best type of soy protein powder? Well just like whey protein, soy also is available in either a "concentrate" or an "isolate". To cut a long story short soy protein concentrate shall always have at least 65% protein with most of the remaining ingredients being carbohydrates. Soy protein isolate on the other hand is the most pure and refined soy protein available. It is made from defatted Soy beans with almost all other products including fats & carbohydrates removed, leaving only protein. Thus a soy protein isolate powder shall have 80% + protein, and is certainly the way to go when choosing your soy supplement. For the purposes of bodybuilding, muscle toning & fat loss, whilst soy protein has a lower biological value than whey protein, it is in general still regarded as an excellent high quality non-meat or vegetarian alternative (Brown et al, 2004).
Soy Protein Supplements are commonly presented & sold as Formulated Supplementary Sports Foods in Australia. Soy protein is not a sole source of nutrition and should be used in conjunction with an appropriate physical training or exercise programme. Not suitable for children under 15 years or pregnant women. Should only be used under medical or dietetic supervision. Always read label prior to use.
Brown et al (2004), Soy versus whey protein bars: Effects on exercise training impact on lean body mass and antioxidant status. Nutrition Journal, 3 (online)
FDA (1999), Federal Register 64 FR 57699 October 26, 1999 - Food Labeling: Health Claims; Soy Protein and Coronary Heart Disease; Final Rule. U.S. Department of Health & Human Services
FSANZ (2010), NUTTAB 2010 Online Searchable Database.