Author: Rositsa Tashkova, Master of Molecular Biology and Microbiology
Graying of hair can begin at any age. Even some teenagers and young people in their early 20s have some grey hairs already. This process depends on many factors, among which genetics, certainly, but also stress, smoking and even hair dyeing are a major factor. In this article, we will look in more detail at these factors, as well as some curious questions such as whether hair can turn gray overnight.
What is hair made of
Each hair is made up of a resistant protein called keratin. Hairs are attached to the skin by hair follicles in which the bulbs are located. In the hair bulb, living cells divide and grow to build the hair itself - as we see it.
Cells in the hair bulb are nourished by blood vessels that also deliver hormones that alter the growth and structure of hair at different periods of life. For example, during pregnancy hair looks shinier and denser, since hormones stop the natural process of hair falling [ref. 1].
The color of the hair is created by pigment cells that produce melanin in the hair follicle.
The rate of hair growth is different for each person, but on average it increases by about 1 centimeter per month. Hair growth is divided in cycles consisting of three phases [ref. 2]:
- Anagen (growth phase): each hair spends several years in this phase.
- Catagenic (transitional phase): for a few weeks, hair growth slows down and the hair follicle shrinks.
- Telogen (resting phase): for several months, hair growth stops and soon the hair gets separated from the hair follicle. New hair begins its growth phase, which leads to the falling out of the old one.
Cuases of premature graying of hair
In addition to heredity, a number of other factors may accelerate the process of hair graying.
Low levels of the vitamins biotin, B12, B6, D, E, and the microelement copper can lead to premature graying of the hair, and their return to normal levels in the body - to make the process reversible. Of course, this applies to cases where this deficiency is the only cause of premature graying. [ref. 3]
It has long been known that cigarettes lead to premature graying of hair, except for all other negative effects on human health.
Smokers were found to be at a 2.5 times greater risk of premature loss of natural hair color before they turned 30, compared to non-smokers [ref. 4].
When antioxidants in the body are not enough to neutralize free radicals, oxidative stress occurs. Free radicals have a damaging effect on the molecules in the cell, and this can lead to the development of disease.
An example of their negative effect is the disease condition vitiligo, which can be caused by too strong oxidative stress. Vitiligo affects pigment cells in the skin and leads to their"discoloration". [ref. 5]
Until recently, there was no unanimity on the question of how much daily stress leads to graying hair.
The general opinion is that stress and tension only complement the palette of factors that lead to preamture ageing.
But this year, a team of scientists from the University of São Paulo and Harvard found that stress directly affects stem cells - from which melanocytes are formed - the cells that produce melanin, that is, hair color. [ref. 6]
Well, at least this is the case in laboratory mice. Scientists found that severe pain triggers the release of adrenaline and cortisol, causing the hearts of mice to beat faster and blood pressure to rise, which affects the nervous system and causes acute stress.
This accelerates the depletion of stem cells that produce melanin in the hair follicles, and the fur of mice becomes irreversible.
Some autoimmune diseases, such as alopecia areata, also lead to premature graying of the hair.
A link has also been established between damaged thyroid function and hair condition, according to a 2008 study. [ref. 7], thyroid hormones have a direct influence on hair follicles, and T3 and/or T4 modulate numerous biological parameters of hair, ranging from its life cycle to its pigmentation (staining).
Many of the cosmetic, beauty and hygene products we apply to our hair can damage it. Even some shampoos have a negative effect on its color, destroying melanin.
Hydrogen peroxide, which is contained in many hair dyes, after long use can lead to permanent graying.
Hairs by their very nature do not consist of living cells (except in their bulb), that is, it's safe to say that the visible part of our hair is not alive. As we said, it is a structure consisting of the protein keratin, and its color is given by the melanocyte cells that are at the base of each hair and form the pigment melanin (or pheomelanin in redheads).
When these cells stop producing melanin, the hair grows white.
So how can someone's hair turn gray overnight? Here's what Dr. Alexander Navarini wrote in his article "Marie Antoinette Syndrome", published in 2009 in the journal JAMA Dermatology [ref. 8]:
"Marie Antoinette syndrome denotes a condition in which the scalp hair suddenly grays. The name comes from the story of the unhappy Queen Marie Antoinette of France (1755-1793), whose hair is supposed to have turned white the night before her last trip to the guillotine during the French Revolution. She was 38 years old when she was executed.
Although rare, this stigmatizing phenomenon, which has captured the imagination of storytellers like few other sufferings, appears as a manifestation of severe sorrow in religious texts already in the Talmud.
The story also states that the hair of the English martyr Sir Thomas More (1478-1535) grayed overnight in the Tower of London before his execution. In 1957, an American dermatologist witnessed a 63-year-old man's hair whitening just a few weeks after the man fell down the stairs.
The term canities subita is also used for this disorder. Today, Marie Antoinette syndrome is interpreted as an acute episode of diffuse alopecia areata, in which graying occurs suddenly, "overnight", and is caused by the preferential loss of pigmented hair in this probably immuno-mediated disorder (for a short time only dark hairs fall, and whites remain).
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Regardless of the reasons, whitening hair can also be very stylish - especially in people where this happens on individual strands. To slow down the process, we can try to apply the general recommendations for slowing down aging [ref. 9], reduce the number of bad habits and chemical agents we use on our hair. But first we must learn to accept ourselves as we are and turn apparent cosmetic flaws into advantages. :)
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