Friday, November 4, 2016

Your skin isn't dead leather & your sebum isn't dead grease. They are ecosystems for enzymes and other substances that play vital roles in skin function. Your sebum contains living cells that produce these substances. Substances that protect and exfoliate. That inhibit DHT production which is a major factor in oily skin, acne and male pattern baldness. Substances that inhibit melanin, reducing hyperpigmentation, Substances that produce retinoids & ceramides.
All those things you pay big money for in moisturizers & creams are made by your skin!  Or would be if you would stop impairing its ability to function. Those ceramides & other lipids are also stripped away by cleansers. Emulsifying agents are even in lotions & creams you think are helping your skin. They are what keep the watery & oily ingredients mixed together so you don't have to shake the bottle before using, because that would be too much to ask. 
Stripping your skin of all these things makes it hard for skin to function and causes the problems we then try to solve with more products. Soaps, cleansers and topicals prevent your skin from functioning.

 Acid Mantle - a layer of sebum and sweat that, among other things, makes the surface of your skin slightly acidic which inhibits the overgrowth of harmful microbes. In addition, the various enzymes involved in normal cell desquammation (exfoliation) need an acidic environment to function. Even store bought BHA and AHA topicals need to be the correct PH to function.
Soaps are alkaline and strip it away. It can take hours to recover during which time your skin is vulnerable to microbes and cells don't exfoliate freely without clogging pores. Tap water in most areas is also slightly alkaline, but your skin should recover from the tap water fairly quickly.

Sebum/lipid permeability barrier
- Normal sebum contains enzymes that inhibit the formation of DHT, the form of testosterone that aggravates acne. It also contains enzymes that dissolve the desmosomes that bind your skin cells together so they can exfoliate normally.

Linoleic acid is a major component of normal sebum. A deficiency in linoleic acid has been found to be involved in many skin issues including acne, excema, atopic dermatis, just plain sensitive easily irritated skin, etc. This applies to all mammals. Where linoleic acid is deficient, oleic acid is used. This produces sebum that is greasy looking and sticky which causes skin cells to be clump together and clog pores.

Sphingolipids, ceramides TBC
P. Acnes TBC
Washing away your sebum stimulates more production of sebum.
Or at least, the abstract of this peer reviewed paper says so. the full text is available here: 
" The epidermis is a very active site of lipid synthesis and when the permeability barrier is disrupted by topical solvents or detergents a marked stimulation of sterol, fatty acid, and sphingolipid synthesis occurs. "

-Acne prone skin (as well as other problem prone skin) is deficient in linoleic acid. And this makes the differenct between sebum that protects and makes your skin glow versus sebum that looks greasy and is sticky and clogs pores. As it's unlikely most people don't get enough in their diets (usually too much) there must be something that either impairs getting it into skin/sebum or we metabolize it too fast for it to be used. Or the quality of the high omega 6 PUFA oil is poor and rancid.
Topical application has been shown to be helpful. Grape seed and safflower oils are both over 70% linoleic acid. See this lengthy thread all about the subject in which I try to figure out why our skin/sebum is deficient and find evidence that topical application is helpful: Another thread with studies such as one where low levels of linoleic acid coincide with acne vulgaris:

-Blood Sugar Stabilizing Diet habits - Excess insulin stimulates the hormones that cause oily skin. And a low GI diet improves the fatty acid composition of sebum according to a recent study.
-Consuming nutrients that inhibit DHT
-Avoiding dairy which contains a precursor to DHT
-Topical application of things that inhibit DHT - Green Tea, mint tea, licorice extract, linoleic acid, zinc (try mineral makeup & sunscreens) ...

Good fats needed for Sebum Quality:
-Consume more Omega 3 EFA sources (like fish, Omega 3 rich vegetables) and less Omega 6 EFA sources (grains and grain-fed animal products). Also avoid bad fats from fried foods, hydrogenated fats like margarine and crisco.
-Linoleic acid a good Omega 6 that your body uses to make Gamma Linoleic acid and an important component in healthy sebum. Diets high in sugar, alcohol, or trans fats from processed foods, as well as smoking, pollution, stress, aging, viral infections, and other illnesses such as diabetes inhibit the body's ability to make GLA. There are GLA supplements. (but linoleic acid may suppress thyroid hormone function, so don't go overboard)
-Mono-unsaturated fats - Olive oil, avocados...

-Blood sugar stabilizing diet habits- Moderate to low GL meals, no binge eating, etc. Affects body's ability to make GLA (among many other things like hormone balance, inflammation, etc.)

Don't strip away skin oils with harsh cleansers. Chemicals and enzymes in sebum play a role in normal desquamation (exfoliation) of skin cells. It can't do that if you wash it all away. Also, your skin needs to be slightly acidic for these enzymes to function. Most cleansers are alkaline.

Quite a bit of info on nutrients involved in quality sebum and many other factors to do with acne formation in this article:

Vitamin D
It had previously been shown that defects in the immune system interfere with the skin's ability to produce a peptide called cathelicidin, which is protective against microbial invasion. In many skin diseases, including eczema, a deficiency of cathelicidin correlates with increased infection.

Study participants (14 with atopic dermatitis and 14 without) were all given 4000 IUs of oral Vitamin D3 (cholecalciferol) per day for 21 days. Skin lesions were biopsied before and after the 21-day period. The researchers found that oral vitamin D use by the patients appeared to correct the skin's defect in cathelicidin.

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