What are Black Soybeans?
Not just for vegetarians, the benefits of the humble soybean have been known to most nutrition-conscious people for a long time now. Black soybeans have recently been ordained into the ranks of the superfood. They are almost identical to the better known green soybean, but the black skinned variety is thought to have even more benefits for the health conscious.
Where do Black Soybeans come from?
Black soybeans are a different subtype of the same plant, Glycine max, that is cultivated to produce green soybeans. This plant is grown worldwide, but the black variety is specifically grown in many Asian countries, particularly China and Korea, where the beans are used to produce popular sauces and condiments. Black soybeans are also grown in the United States. Black soybeans can be bought dried or tinned at many health food stores and some supermarkets. Make sure not to confuse black soybeans with black turtle beans as they are very similar in name and appearance. While the latter, like all legumes, is still a great source of nutrition, they do not have the same benefits as black soybeans.
Black Soybean Benefits
The most obvious difference between black soybeans and green soybeans is the colour. The black colour is due to pigments called Anthocyanins. Anthrocyanins are powerful antioxidants which have been very well studied and are present in high amounts in red and purple fruits and vegetables, like tomato, raspberry, acai berry and purple corn. Black soybeans have the highest measured level of anthrocyanins of any plant source, at 2% (1). Anthrocyanins are also thought to benefit heart health
Black soybeans are also thought to be higher in protein than their lighter cousins. Soy is a complete source of protein, meaning it contains all the necessary amino acids. According to the Protein Digestability Corrected Amino Acid Score, which is used to assess the quality of proteins, soy is just as beneficial as protein from meat, egg and casein, and consuming whole soybeans rather than an extract improves bioavailability. They are also extremely low in carbs, coming in at just over 6%. This is less than most legumes, and most of these carbs are present as fibre.
Soybeans are very high in nutrients. They are one of the richest vegetable-based sources of omega-3 fatty acids, and they're packed with vitamins and minerals including Vitamin A, Iron, Magnesium and Zinc. There is a lot of research into black soybeans at the moment, particularly the isoflavones in the seed coat, which have been tested for a huge variety of benefits, including cancer treatment, metabolism of fat and weight loss, anti-inflammatory effects, antimicrobial ability, and blood clotting.
Black Soybean Benefits for bodybuilding
Bodybuilders have to eat, and a protein-dense, nutrient-rich low-carb food that is tasty and versatile is always going to be a good option when it comes to supporting the gain of lean mass. It is long established that a meal high in protein keeps you feeling fuller for longer, but some research has recently come out looking at a peptide in black soybeans and its role in weight loss. After 12 weeks, overweight and obese subjects who ate the soy peptide lost significant amounts of fat, had lower fasting insulin levels and lower levels of leptin, a hormone involved in regulating appetite (2). The anti-inflammatory effects of black soybean may also help recovery and minimise damage after training. Although quite a few studies demonstrate these properties, a specific effect on exercise has not yet been looked into (3).
Black Soybeans Side Effects, Safety & Negatives
While there are no effects specific to black soybeans, many men are turned off soy in general by the idea that soy phytoestrogens can lower testosterone levels. This has an area that has been thoroughly researched, and an analysis of studies performed concluded that regular consumption of soybeans and their derivatives has no effect on male hormone levels (4).
Black Soybeans - How much Should I Eat?
Black soybeans can easily replace other legumes or even meat in a normal, healthy diet. They have a mild, nutty flavour which goes well in many styles of cooking. You can eat black soybeans to your heart's content, but keep in mind that whilst playground wisdom has identified beans as having noted cardiovascular benefits, it also proffers the existence of a direct dosage effect between consumption and gas production in the lower bowel.
Black Soybean Supplements
It is only a matter of time before the anthrocyanins and active peptides in black soybean are extracted and available as a supplement, but it would be a shame to miss out on the wealth of nutrients and protein obtainable by eating the whole bean.
Stacking Black Soybean
This author recommends stacking black soybeans with ingredients such as tortilla bread, salad, and plenty of hot sauce.(1) Choung MG et al. (December 2001). "Isolation and determination of anthocyanins in seed coats of black soybean (Glycine max (L.) Merr.)". J. Agric. Food Chem.49 (12): 5848–51.
(2) Kwak JH, Ahn CW, Park SH, Jung SU, Min BJ, Kim OY, Jee JH. Weight reduction effects of a black soy peptide supplement in overweight and obese subjects: double blind, randomized, controlled study. Food Funct. 2012 Oct;3(10):1019-24.
(3) Nizamutdinova IT, Kim YM, Chung JI, Shin SC, Jeong YK, Seo HG, Lee JH, Chang KC, Kim HJ. Anthocyanins from black soybean seed coats stimulate wound healing in fibroblasts and keratinocytes and prevent inflammation in endothelial cells. Food Chem Toxicol. 2009 Nov;47(11):2806-12.
(4) Hamilton-Reeves et al (2010), Clinical studies show no effects of soy protein or isoflavones on reproductive hormones in men: results of a meta-analysis. Fertility and Sterility, 94: 997-1007
(5) Scientific Opinion on the substantiation of health claims related to various food(s)/food constituent(s) and protection of cells from premature aging, antioxidant activity, antioxidant content and antioxidant properties, and protection of DNA, proteins and lipids from oxidative damage pursuant to Article 13(1) of Regulation (EC) No 1924/20061, EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA)2, 3 European Food Safety Authority (EFSA), Parma, Italy, EFSA Journal 2010; 8(2):1489