Soy may well be the oldest plant people managed to cultivate in the prehistoric times. Radiocarbon analysis of archaeological findings in Japan, China and Korea shows that soy was grown as early as 10,000 BC. Legend has it that Chinese emperors would plant the first seed with their own hands to start off the new season. There are written accounts of the mythical ruler Shennong declaring 5 plant species sacred. Soy was the first on his list, followed by rice, wheat, oat and millet. Soy was nicknamed ‘the saviour of the people’ because it eased their hunger, diseases and poverty. Li Shizhen recommends soy to the patients with kidney diseases, oedemas and intoxication in his work The Compendium of Materia Medica.
Soy was delivered to Europe by a German naturalist Engelbert Kaempfer who spent some years in the East and wrote a book about local plants. Europeans, however, didn’t begin to cultivate soy until late XIX century. The biggest champion of soy was professor Friedrich J. Haberlandt: he cultivated soy seeds in Vienna, and soon began to distribute them throughout Central and Western Europe. Most of the farmers who received seeds from him grew soy them, then reported their results back to him. They even used to call soy Haberlandt’s beans.
Soy was found in Russia along the shores of the Amur as early as XVII century, most likely it got there from China.
Soy beans were one of the first real examples of biotechnological food. Molecular genetics was applied to change the characteristics of soy beans so that less pesticides were required to grow it. This modification certainly improved the work safety of the people who sow and gather soy. Genetically modified soy has a longer shelf life and requires less preservatives to be stored. In 2010 over 90% of all soy grown in the USA belonged to the genetically modified species. This achievement of modern science gave hope to many people around the world that world hunger can be stopped.
Naturally, most of cultivated soy is used to produce foods of all kind: soy butter, soy flour, soy milk, baby formula, tofu, soy sauce, etc. A complete list of soy products would occupy many pages. Today, however, soy is more and more widely used in cosmetics. It is a source of soy bean extract and is included in the composition of many complex anti-age compounds created with the use of biotechnology. Soy proteins have a pronounced anti-age effect and they are very compatible with many active molecules derived by biotechnological or chemical synthesis.
Soy beans have a high contents of protein. Almost 40% of a bean’s mass is made up by protein complex with very high nutrition value. Soy contains next to no starch, and only a few carbohydrates, mostly arabinoxylan and galactan. Soy contains some common sugars, predominantly raffinose, stachyose and saccharose, all of them have a moisturising and nourishing effect on the skin. Soy contains vitamin E, the so called ‘vitamin of youth’ with antioxidant and restorative properties, vitamin C and B group. Among the latter there is plenty of vitamin B3 or niacinamide with its potent beneficial effect on microcirculation. Vitamin B3 activates the syntheses of various proteins and restores the skin after damage and stress. Soy is rich in minerals: sodium, potassium, calcium, phosphorus; it contains plenty of magnesium, zinc and iron providing soothing and healing for the skin.
The most interesting compounds in soy beans are isoflavones with hormone-like activity, among them primarily genistein, daidzein, biochanin, formononetin and glycitein. These compounds are similar to female hormones oestrogens and have in many ways similar effect on the skin and body as a whole. Isoflavones are also found in hop clover, but their contents in soy beans is much higher: up to 3 mg isoflavones per 1 g soy.
Isoflavones have a phytoestrogen activity and a complex effect on the skin. First, they suppress glycation, a process of the skin collagen’s destruction and transformation, which accelerates with age, resulting in the loss of skin’s elasticity. According to research, soy isoflavones can suppress glycation by almost 25%, at the same time decreasing the activity of collagen-destroying enzymes. Skin collagen ‘grows younger’ and gradually its amount increases, restoring the skin’s youthful elasticity and reducing wrinkles. Isoflavones are recognised by the skin’s hormonal receptors and can activate the same processes as female hormones: the syntheses of new collagen and hyaluronic acid, regeneration and healing, acceleration of cell renewal. Isoflavones have an anti-sun effect as well; they speed up and enhance the skin’s recovery after ultraviolet exposure. Isoflavones have a mild brightening effect because soy extract’s active ingredients can partially block the transfer of melanin pigment from the cells to the upper skin layers.
Just as hop clover extract, soy bean extract has antiandrogenic action: it fights the ferment alpha-reductase which is to blame for acne and hair loss. Soy bean extract is used for oily and problem skin care, acne and seborrhea treatments and medicinal hair care.
Soy isoflavones affect fatty tissue as well suppressing the development of fat cells and the synthesis of fat. This is why recently soybean extract has become a source of new active ingredients in anti-cellulite skincare.
Recently it has been discovered that soy glycoproteins can help regulate circadian processes in the skin boosting nighttime regeneration and increasing the synthesis of collagen type I.