Shea Butter

A thorough study has been published in a French Ph. D. thesis in pharmacy by F Renard: Thése de doctorat en Pharmacie – Bordeaux 1990 . In it, 2 clinical studies are described on mechanically crushed shea butter:

Skin aging treatment

A clinical study (Chart 1) has been performed on 30 volunteers aged 29 to 82. Shea butter was applied by a daily massage as a balm for 4 to 8 months.

• epidermis aspect: in a few weeks, the rough aspect of a dull - grayish complexion was eliminated, giving way to a smoother, clearer skin.

• combating skin “thinning” for better skin texture: a regenerating effect is observed probably related to the action of the unsaponifiables that are known to reactivate collagen synthesis.

• wrinkles from photoaging due to prolonged sun exposure are visibly diminished in half of the volunteers.

Shea butter proves to be a valuable active for diminishing various aging signs.

Protecting and regenerating treatment

Another clinical study was performed for studying dry, delicate or aging skin. 49 volunteers applied twice a day either 15% or pure shea butter. Both products lead to similar results:

• A reduction in wrinkles and an improvement of skin suppleness was obtained for 75% of the volunteers.

Shea butter demonstrates regenerating properties that target it towards photoaging prevention.

Anti-aging effect

Morganti & al (J appl cosm 1985 3 211-222) showed (Chart 3) that EFA application improves skin's hydration capacity and protects aged skin against environmental insults. A cream containing 3% EFA prevents much better skin atrophy induced by a cortisone like compound which accelerates skin aging process.

Moisturizing properties
A cream containing 5% shea butter and a placebo cream are applied at the beginning of the experiment (Poelman & al.: Les Nouvelles Dermatologiques 1988 7 (1) 78-79) (Chart 4) and reapplied on a daily basis on the volar forearm of 10 volunteers.

The results are the average of 10 measures of skin conductimetry differences between treated and untreated skin.

Short-term moisturization is observed, it peaks after 1 hour and persists for 8 hours. For all subjects, a daily application maintains a very good moisturization of the superficial layers of the skin.

Nutgeren & al (Biochim Biophis Acta 1985 834 429-436) proved that EFAs are absolutely necessary for maintaining the proper condition of water barrier in the skin. Direct topical application of LA to the skin restores the barrier in EFAD animals. It has been shown that radiolabeled LA is incorporated mostly in an acyl ceramide (ceramide 1) in which LA was esterified to the end position of a very long chain unsaturated omega fatty acid. In EFAD, LA is replaced by oleic acid in the ceramide that is unable to form a normal water barrier.

Topical application studies proved that PUFA or preferably PUFA (released by the skin esterase) rich vegetable oils are beneficial for the skin. Prottey et al (J. Invest Dermatol 1975 64 228-234) demonstrated (Chart 5) that after cutaneous application of sunflower seed oil, which is rich in LA, to the right forearm of EFAD volunteers for two weeks, the level of LA in their epidermal lipids was markedly increased, the rate of TEWL was significantly lowered and the scaly lesions have disappeared. No such changes were seen in the left forearms after cutaneous application of olive oil (containing almost no LA).

Anti-inflammation properties
Shea butter is traditionally used for alleviating rheumatism, which suggest an anti-inflammatory activity. This has been substantiated (A.Tella: Br. J. Clin. Pharmac. 1979 7 , 495- 497) in a study of severe nasal congestion. Shea butter is tested on 33 volunteers against conventional nasal drops containing xylomethazoline (as recommended in the British Pharmacopoeia), a placebo and a control. Nasal congestion is created by an edema that can be relieved by two mechanisms: a vasoconstrictor or an anti-inflammatory. Only the second mechanism applies for Shea butter that has never demonstrated any vasoconstricting activity.

PUFA supplementation influences the rate of biosynthesis of EFA derivatives as it seems to depend on the size of the precursor pool. Supplementing GLA results in an increase of the less inflammatory PGE1 instead of the pro-inflammatory PGE2.

Also, DGLA is converted in the skin to PGE1 that is known to raise the levels of cAMP which in turn inhibits PLA2 and so exerts anti-inflammatory effects by keeping AA locked into the phospholipidic membrane. Thus access of free AA to cyclo-oxygenase is denied and pro-inflammatory PG2 level is reduced.

This implies the necessity of a well-balanced mix of PUFA in the diet and in topical application.

Larregue (Prostaglandines et thromboxanes Masson 1997) reviews the importance of prostaglandins (PG) in skin (Chart 7). PGs are not stored but they are synthesized on request after being stimulated. PG2 are synthesized from AA present in cell membranes. PG2 is a powerful vasodilator and contributes to the characteristic edema related to inflammation. It has to be noted that PG1 is less pro-inflammatory. PGs are also immune modulators: PGE2 is a powerful inhibitor of cytotoxic T cells activity. In situ PG production happens simultaneously with UV erythema. Therefore, omega 3 and 6 PUFA by helping in preventing PG2 have a photo-protective effect on skin.

Supplementing GLA results in an increase of the less inflammatory PGE1 instead of the pro-inflammatory PGE2. Also, DGLA is converted in the skin to PGE1 that is known to raise the levels of cAMP which in turn inhibits PLA2 and so exerts anti-inflammatory effects by keeping AA locked into the phospholipidic membrane. Thus access of free AA to cyclo-oxygenase is denied and pro-inflammatory PG2 level is reduced.

Crushed shea butter: the African wonder

It is a slightly ivory granulated butter consisting mostly of triglycerides (which include a fair amount of linoleic acid) and unsaponifiables: mostly: Karisterols ( a spinasterol – D 7 stigmastenol) –

Parkeol – Lupeol – Butyrospermol- Karitene and cinnamic esters.

Shea butter has always served as a staple of African pharmacology. It acts as an effective decongestant, for example. Used for its draining and anti-inflammatory properties, it is soothing in sprains and strains, and is a widely used anti-arthritic treatment. This wonderful healing agent is also used for accelerating the cicatrization of the umbilical cord and after a circumcision.

It is, however, mostly for skin care that Shea butter is hailed for its protecting and emollient properties. Many local soap manufacturers use Shea butter as a raw material. Protecting the skin and the hair from the harsh African climate is vital, and this natural product does so beautifully. Newborn babies are welcomed by a vigorous massage with Shea butter to protect them from the extreme weather. As early as 1940, many scientific observations verified that, among the populations using Shea butter, the occurrence of skin diseases was scarce and the population's skin was exceptionally supple and smooth.

A hardy tree not unlike the oak, the Shea tree ( Butyrospermum parkii Kotsch.) grows up to 15 to 20 meters high. It usually lives for a couple of centuries, covering vast areas. Shea tree is the only Sapotacea on the dry soils of the African Savannah. Odoriferous brownish flowers bloom from December to March. Shea fruit resembles a small avocado with flavorful pulp. The central kernel yields the butter, which represents half of its content. Each mature tree bears 15 to 20 kilos of fruit.

Shea tree has many names in Africa: it is called karité in Wolof and sé in Bambara, which gives "shea" in English.