Yellow soybean (or soya bean) has been known its benefits of cholesterol-lowering.
Now, a recent animal study in Korea suggested that intake of black soya beans could
also benefit high cholesterol and may help prevent diabetes. In this animal study, the
group eating black soya prevented weight gain and improved cholesterol levels. This
finding can be beneficial to diabetes. It is because the key problem in Type 2 diabetes
is the impairment of insulin action, mainly as a result of excess abdominal adipose
tissue - so loss of weight is believed to benefit Type 2 diabetes. [14]

In fact, a while ago, Japanese researchers found black soybean had an inhibitory effect
of black soybeans on low density lipoprotein (LDL) oxidation. The extract from black
soybean also had a longer LDL oxidation lag time than that from yellow soybean. [9]

Black soya bean (soybean) is rich in antioxidants.

Black soybean [Glycine max (L.) Merr.] has been used as a health food and herb in
China for hundreds of years. [1] Several studies have demonstrated that the daily
intakes of soy foods were associated with a reduced cardiovascular risk. [9]

Researchers from Japan found black soybean seed coat contained a variety of
procyanidins, And, they showed high radical-scavenging activities of these procyanidins
in test-tube studies. [2] While researchers from Korea considered that the seed coat of
black soybean was a good source of anthocyanin pigments such as
cyanidin-3-glucoside and delphinidin-3-glucoside. [3]

What are other potential benefits of eating black soya bean (soybean)?

Eating black soya bean may reduce the risk of cancer and heart diseases.

Korean researchers showed that anthocyanins isolated from black soybean seed coat
inhibited TNF-alpha-induced vascular cell adhesion molecule-1, intracellular adhesion
molecule-1, and cyclooxygenase-2 levels. Further, anthocyanins protected myocardiac
injury from ischemia-reperfusion in rats. Thus, anthocyanins from black soybean seed
coat benefit conditions like cardiovascular disorders. [11]

Researchers from Taiwan extracted a polysaccharide from the black soybean. They
found that this polysaccharide indirectly inhibited proliferation and induced
differentiation of human leukemic U937 cells via activation of mononuclear cells in the
study. [1]

Researchers found tryptophol from black soybean vinegar could inhibit the proliferation
of human monoblastic leukemia U937 cells by inducing apoptosis via a pathway
involving caspase-8 followed by caspase-3, without affecting normal lymphocytes. [13]

Researchers from Taiwan noticed the promotion of myelopoiesis by an active
polysaccharide of black soybean in a study of murine spleen cells. They also found that
oral administration of that active polysaccharide of black soybean in mice restored the
leukocyte counts reduced by total body-irradiation and 5-fluorouracil (5-FU) treatment. [6]

Eating black soya bean may enhance pregnancy.

Chinese researchers demonstrated the estrogenic activities of an ethanol extract of
black soybean. They found that the ethanol extract of black soybean stimulated the
growth of MCF-7 cells and increased the expression of estrogen receptor-responsive
gene in their study. [12] A clinical study of 36 patients in Japan demonstrated that intake
of black soybean powder for six months improved ovulation and pregnancy. [10]

Black soya bean may have anti-fungi, anti-viral activities.

Hong Kong researchers isolated a monomeric protein, with a molecular mass of 25
kDa and an N-terminal sequence resembling a segment of chitin synthase from the
seeds of the black soybean Glycine soja. This protein, glysojanin, demonstrated potent
antifungal activity against the fungi Fusarium oxysporum and Mycosphaerella
arachidicola. It also inhibited HIV-1 reverse transcriptase in test-tubes. [5]

Japanese researchers found significant antiviral activities of a hot-water black soybean
extract in a test-tube study. This black soybean extract showed significant antiviral
activity against human adenovirus type 1 and coxsackievirus B1 in a dose-dependent
manner, [4]

[1] Liao HF et al, Isolation and characterization of an active compound from black soybean [Glycine max (L.)
Merr.] and its effect on proliferation and differentiation of human leukemic U937 cells. Anticancer Drugs. 2001
Nov;12(10):841-6. [2] Takahata Y, et al, Highly polymerized procyanidins in brown soybean seed coat with a high
radical-scavenging activity. J Agric Food Chem. 2001 Dec;49(12):5843-7. [3] Choung MG, et al,  Isolation and determination of
anthocyanins in seed coats of black soybean (Glycine max (L.) Merr.). J Agric Food Chem. 2001 Dec;49(12):5848-51. [4] Yamai
M, et al, Antiviral activity of a hot water extract of black soybean against a human respiratory illness virus. Biosci Biotechnol
Biochem. 2003 May;67(5):1071-9. [5] Ngai PH, Ng TB. Purification of glysojanin, an antifungal protein, from the black soybean
Glycine soja. Biochem Cell Biol. 2003 Dec;81(6):387-94. [6] Liao HF, et al, A novel polysaccharide of black soybean promotes
myelopoiesis and reconstitutes bone marrow after 5-flurouracil- and irradiation-induced myelosuppression. Life Sci. 2005 Jun
10;77(4):400-13. Epub 2005 Feb 25. [9] Takahashi R, et al, Antioxidant activities of black and yellow soybeans against low
density lipoprotein oxidation. J Agric Food Chem. 2005 Jun 1;53(11):4578-82. [10] Kohama T, et al, The effect of soybeans on
the anovulatory cycle. J Med Food. 2005 Winter;8(4):550-1. [11] Kim HJ, et al, Anthocyanins from soybean seed coat inhibit the
expression of TNF-alpha-induced genes associated with ischemia/reperfusion in endothelial cell by NF-kappaB-dependent
pathway and reduce rat myocardial damages incurred by ischemia and reperfusion in vivo. FEBS Lett. 2006 Feb
20;580(5):1391-7. Epub 2006 Jan 26. [12] Zhao QW, et al, Estrogenic activity and its mechanism of ethanol extract from black
soybean Zhongguo Zhong Yao Za Zhi. 2006 May;31(10):825-8. [13] Inagaki S, et al, Isolation of tryptophol as an
apoptosis-inducing component of vinegar produced from boiled extract of black soybean in human monoblastic leukemia U937
cells. Biosci Biotechnol Biochem. 2007 Feb;71(2):371-9. Epub 2007 Feb 7. [14] Black soya 'cuts diabetes risk' BBC NEWS:  
2007/02/26 10:23:23