Sebum's real role.....The NEW science

[michael barry]

Hautarzt. 2006 Apr;57(4):291-296
Sebaceous glands as transporters of vitamin E

Ekanayake-Mudiyanselage S, Thiele JJ.

Northwestern University, Chicago.

Human sebum is produced by sebaceous glands and reaches the skin surface via secretion through the hair shaft. There is experimental evidence that the sebaceous glands and sebum serve as a transport mechanism taking the lipophilic antioxidant vitamin E from the blood to the skin surface. The highest levels of vitamin E are found in the sebum and in the skin lipid film in sebum-rich areas such as facial skin. Recent studies indicate that daily oral supplementation of moderate doses of alpha-tocopherol for at least 3 weeks leads to significant increases of vitamin E levels in human skin sites with a high density of sebaceous glands, such as the face. Thus, the potential photoprotective and antioxidants effects of oral vitamin E, as well as possibly other antioxidants, are site-dependent. These findings should be considered when designing clinical studies to assess the efficacy of oral antioxidants against oxidative stress in the skin.

PMID: 16477469 [PubMed - as supplied by publisher]




If you want a "little more" here it is:
J Investig Dermatol Symp Proc. 2005 Dec;10(3):194-7.)
The role of sebaceous gland activity and scalp microfloral metabolism in the etiology of seborrheic dermatitis and dandruff.

Ro BI, Dawson TL.

Department of Dermatology, College of Medicine, Chung Ang University, Seoul, Korea.
Beauty Care Technology Division, The Procter & Gamble Company, Cincinnati, Ohio, USA


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quote:
The primary functions of sebum have historically been controversial, but are recently being elucidated. Sebum is involved in development of epidermal structure and maintenance of the epidermal permeability barrier (Pilgram et al, 2001), carrying anti-oxidants to the skin surface (Theile et al, 1999), protection from microbial colonization, generation of body odor, and pheromone generation (Kligman, 1963). It has also recently come to light that sebum is directly involved in skin-specific hormonal signaling, epidermal differentiation, and protection of the skin from ultraviolet irradiation (Thiboutot et al, 2003; Zouboulis, 2003).

 

[chewbaca]

So how does this casue male pattern baldness?

 

[Bryan]

quote:
The primary functions of sebum have historically been controversial, but are recently being elucidated. Sebum is involved in development of epidermal structure and maintenance of the epidermal permeability barrier (Pilgram et al, 2001), carrying anti-oxidants to the skin surface (Theile et al, 1999), protection from microbial colonization, generation of body odor, and pheromone generation (Kligman, 1963).

It's curious to me that they attribute an alleged anti-microbial effect of sebum to Kligman from 1963, whereas the quote below (referencing Kligman from 1963) completely CONTRADICTS that assertion:

"Sebum Secretion and Sebaceous Lipids", Stewart et al, Dermatologic Clinics -- Vol. 1, No. 3, July 1983 (BTW, the "Kligman" being referred to here is Dr. Albert M. Kligman, MD, PhD, one of the most famous names in the history of dermatology):

"Sebum is an oily substance that is secreted onto the skin surface from glands located in the dermis. Although a number of useful functions have been proposed for sebum, proof that sebum performs any of them is lacking. In furred mammals an essential function of sebum is to supply 7-dehydrocholesterol, which is converted to vitamin D by the action of sunlight and then ingested by the animal as it grooms itself. In man, however, the location of 7-dehydrocholesterol has been shown to be the epidermis rather than sebum. Sebum may act as a waterproofing agent for fur, but humans obviously have little need for this function. Kligman has specifically disproved the notions that sebum improves the barrier function of skin, that sebum helps to regulate the water content of the horny layer by forming emulsions with sweat, or that sebum on the skin surface is fungistatic or antibacterial.(21) Kligman regards the human sebaceous glands as 'living fossils' that lost their usefulness to our species as we lost our fur.(21)"

(21) Kligman, A. M.: The uses of sebum? In Montagna, W., Ellis, R. A., and Silver, A. F. (eds.): Advances in the Biology of Skin. Volume 4. Oxford, Pergamon Press, 1963.

 

[michael barry]

Bryan,

THIS Human sebum is produced by sebaceous glands and reaches the skin surface via secretion through the hair shaft. There is experimental evidence that the sebaceous glands and sebum serve as a transport mechanism taking the lipophilic antioxidant vitamin E from the blood to the skin surface. The highest levels of vitamin E are found in the sebum and in the skin lipid film in sebum-rich areas such as facial skin. Recent studies indicate that daily oral supplementation of moderate doses of alpha-tocopherol for at least 3 weeks leads to significant increases of vitamin E levels in human skin sites with a high density of sebaceous glands, such as the face. Thus, the potential photoprotective and antioxidants effects of oral vitamin E, as well as possibly other antioxidants, are site-dependent. These findings should be considered when designing clinical studies to assess the efficacy of oral antioxidants against oxidative stress in the skin.

was the point........................................

Perhaps sebum is a way of getting extra vitamin E to the skin's surface which may act as a bit of a natural sunscreen (God knows balding men need it). Ive wondered about something in sebum also. There is oleic acid present in it (DHT inhibitor). You know, even if some DHT in it is reabsorbed, the oleic acid might be reabsorbed to.........making the hairloss effect of a greasy scalp "sorta" even out. Its a natural substance that our bodies make. Maybe it isnt all that bad. Oleic acid and vitamin E. We could do worse.

 

[Bryan]

Ive wondered about something in sebum also. There is oleic acid present in it (DHT inhibitor). You know, even if some DHT in it is reabsorbed, the oleic acid might be reabsorbed to.........making the hairloss effect of a greasy scalp "sorta" even out. Its a natural substance that our bodies make. Maybe it isnt all that bad. Oleic acid and vitamin E. We could do worse.

Just a few random comments on all that: sebum contains a mixture of triglycerides, free fatty acids, and other fat-related substances. It probably starts out as triglyceride when fat-bloated sebocytes burst and release their contents into the sebaceous canal, but enzymic degradation of some of those triglycerides from bacteria like P acnes are thought to be the reason for the existence of the free fatty acids. Keep in mind that triglycerides have no effect at inhibiting 5a-reductase. Only free fatty acids do that to any significant extent.

Acne patients generally have a relative lack of linoleic acid in their sebum, which tends to get replaced by oleic acid. That specific dysfunction is now being thought to have important connections to the hyper-keratinization which is generally seen in acne.

I strongly doubt that sebum or any of its contents get reabsorbed to any significant extent at all.

Bryan

 

[blaze]

Acne patients generally have a relative lack of linoleic acid in their sebum, which tends to get replaced by oleic acid.

What would help to regulate that bryan?