How Shea Butter Works?

Shea butter is an off-white or ivory-coloured fat extracted from the nut of African Shea tree.

Shea nut contains about 60% fat (Shea butter),which is renowned for its use as a component of cosmetic formulations. There are no reports of allergic reaction owing to consumption of Shea butter or its produce. The United States Agency for International Development, Gassel Consulting, and many other companies have suggested a classification system for Shea butter separating it into five grades: A (raw or unrefined, extracted using water), B (refined), C (highly refined and extracted with solvents such as hexane), D (lowest uncontaminated grade), E (with contaminants).

Shea butter is used by local healers as a treatment for rheumatism, inflammation of the nostrils, nasal congestion, leprosy, cough, and minor bone dislocation. It is also used as raw material for the production of margarine, soap, detergent and candle. Shea butter has also been used for soothing and accelerating healing after circumcision, and for preventing stretch marks in African pregnant women and as an insect repellent, providing protection against Simulium infection.

In addition to a stearic and oleic acids rich saponifiable fraction, Shea butter contains an unsaponifiable fraction composed of bioactive substances that are responsible for Shea butter’s medicinal properties. With regional variation in concentrations, the unsaponifiable fraction of Shea butter is composed primarily of triterpene alcohols, with some hydrocarbons, sterols, and other minor components such as vitamin E.

Due to its semi-solid characteristics and buttery consistency, Shea butter is great emollient and moisturizer for the skin, scalp and hair even without further processing. However Shea butter is usually found as active component of processed moisturizers. In addition, fractionated Shea butter especially olein fraction is easily formulated in creams or surfactant based products such as bath products and shampoo to provide the skin, scalp, and hair with well-maintained or increased moisture. Shea butter melts at body temperature, acts as a "refatting" agent, has good water-binding properties and absorbs rapidly into the skin; making it useful for skin care.  For all subjects, a daily application maintains a very good moisturization of the superficial layers of the skin. Shea butter has also been shown to be superior to mineral oil at preventing transepidermal water loss (TEWL). In a test where participants’ arms were washed in ethanol, it was found that Shea butter was able to help the skin totally recover from TEWL within two hours. One study showed that it worked as an emollient for eczema. Using a scale from zero to five — zero denoting clear and five denoting very severe disease — Shea butter took a three down to a one, while Vaseline only took a three down to a two. 

Anti-aging properties: It has been revealed that Shea butter has UV anti-erythemic activity, which helps tissue cell regeneration and softening of the skin. In a clinical study involving 30 volunteers, Renard reported that Shea butter diminished various aging signs. In another clinical study by the same author for studying dry, delicate or aging skin, 49 volunteers applied twice a day either 15% or pure Shea Butter and discovered that Shea butter prevented photo-aging. Also, in a study with rats, Shea butter was shown to boost collagen production. Collagen and elastin are the major structural proteins providing skin with toughness and plumpness and α-amyrin and lupeol, the triterpenes found in the unsaponifiable fraction of Shea butter, were found to contribute to the inactivation of proteases such as metalloprotease (e.g., collagenase) as well as serine protease (e.g., elastase). The anti-aging, potentially collagen-boosting effects were attributed to its unsaponifiable components.

Allergy: Although, Shea nut is distantly related to Brazil nut  which cross-reacts with almond, hazelnut, walnut, and peanut , there are no reports of allergy reaction owing to the topical or oral use of Shea butter. Furthermore, Kanwaljit and co workers reported that Shea butter contains no IgE-binding soluble proteins and reassures that Shea butter is safe for use even for individual with nut allergy. Conversely, Wiedner  found that pharmaceutical composition containing at least 5% of Shea butter’s triterpenes such as butyrospermol, lupeol, parkeol, germanicol, dammaradienol, 24-methylene-dammarenol, and α, and β-amyrins effectively suppresses hypersensitivity reaction such as Immunoglobulin E (IgE)-mediated allergic reactions and autoimmune reactions in mammals. 

In summary, there is enough evidence to substantiate the claims of the health benefits of the topical use of Shea butter. The dietary use of Shea butter, though has the advantage of anti-hypercholesterolemic actions, is suspected to interfere with protein digestion.

Reference:

Malachi Oluwaseyi; Effects of Topical and Dietary Use of Shea Butter on Animals. American Journal of Life Sciences. Vol. 2, No. 5, 2014, pp. 303-307. doi: 10.11648/j.ajls.20140205.18