(Part Two of a Two Part Review)
Oxidative Stress Theory: Hydrogen Peroxide & Gray Hair
(Part Two of a Two Part Review)
By: Frederica Hegney
It's no secret that spotting your initial silver strand could be a stressful situation and news reports and articles or blog posts aren't making it much better. From perpetuating myths on fighting gray hair (Drink carrot juice!; Don't pluck the hair strands!) within the raging debate on whether or not to go faux or permit the silver strands go, graying hair is rife with anxiety, confusion and stress.
Well, stop stressing. Knowing the origins of one's graying hair can assist you to debunk irresponsible gray hair myths and take your anxiety down several notches and did we mention that stress only aggravates your graying hair?
Our bodies are always on the look-out for free radicals, also often known as pro-oxidants. When dangerous free radicals enter our bodies (a result of exposure from pollution, very poor dieting, lack of exercise and smoking), specialized enzymes, proteins and vitamins termed antioxidants seek out these damaging radicals and destroy them. Nonetheless, if the body is exposed to an overwhelming volume of free radicals, the antioxidants are unable to destroy all of the pro-oxidants; thus, oxidative stress occurs.
With this second part we will discuss a distinctive class of oxygen based free radicals referred to as Superoxides and see how they wreak havoc by means of the hydrogen peroxide pathway.
Super Oxides are free radicals that results from metabolic activity inside the body such as our response to stress. The body has evolved an elegant strategy of handling these Super Oxides; 1st the body unleashes a category of enzymes called Superoxide Dismutase (SOD) that helps to convert these Superoxides into h2o and hydrogen peroxide. Now in smaller concentrations hydrogen peroxide is easily broken down into hydrogen and h2o by yet another type of enzymes named Peroxidases. The key peroxidases employed by the body are the enzymes Glutathione Peroxidase and Catalase.
Studies have shown that Iodine in combination with selenium increased the activities of type 1 deiodinase (D1) and glutathione peroxidase(GSHPx). Ed. note: Wish I had known THAT when I was in my twenties and my hair was starting to turn grey!
As discussed in Part 1 Gray Hair Free Radicals free radicals in and of themselves can harm the hair follicle and results in graying. Unfortunately, in circumstances of prolonged stress, the amount of hydrogen peroxide being manufactured overwhelms the body's ability to break it down resulting in oxidative stress along with your gray hair. [Arck PC, Overall R, Spatz K et al (2006). Towards a free radical theory of graying: Melanocyte apoptosis in the aging human hair follicle is an indicator of oxidative stress induced tissue damage. FASED J 20: 1567-1569.] The hydrogen peroxide builds up all through the body, including within papillary cavities underneath the epidermis of the scalp. These cavities are the place hair follicles originate, and also where specialized cells - named melanocyte produces melanin for the hair strand.
The hair development cycle has three major stages, which are called the anagen stage (the growth stage), the telogen stage (where the follicle is at a period of rest) and the catagen stage (the transitional period between the former stages). The anagen stage may be decreased into 6 parts; however, melanocyte plays their most significant function in the third and fourth stages. During anagen stage III, melanocyte start to grow and accumulate in the papillary cavities; when the hair follicle starts to grow towards the epidermis, the melanocyte pigments the hair. [TOBIN DJ, SLOMINSKI A, BOTCHKAREV V et all (1999). The Fate of Hair Follicle Melonocytes During the Hair Growth Cycle. J Investig Dermatol Symp Proc 4.323-332].
Now whilst the hair grows in the anagen phase, the accumulated hydrogen peroxide sits in the papillary cavity where it bleaches the hair as it grow no different than if we bleached your hair yourself with a bottle of bleach. Over time it's also most likely the melanocyte cells will die off because the hydrogen peroxide interact with other crucial enzymes such as MSRA and MSRB and deactivate them preventing the hair follicles from repairing itself leading to other aspects of aging hair which includes thinning and weak/brittle hairs leading to wholesale greying.
THIS IS THE END OF A TWO PART SERIES ON OXIDATIVE STRESS THEORY OF GREYING
Frederica Hegney is Moderator of the Grey Defence weblog.
You can also follow her on twitter @GreyHairDefence