Since ancient times people have tried to solve the puzzle of hair turning grey as one gets older. Clay tablets from the ancient Assyrian Empire from 7th century B.C. have included medical texts, written in cuneiform, which describes how to darken prematurely grey hair by applying various mixtures of ingredients that included leek seeds, poppyseeds, cypress oil, pine gum, and the head of a black raven or gall from a black ox. This had to be applied for days at a time.
Scientists still continue to look for ways to reverse the graying process, but with little success so far. Hair greying is a visible sign of aging and popular belief has it that stress would hasten this process, but without any scientific evidence. However, a recent study, which profiled hair pigmentation patterns along individual human hair shafts, has produced quantifiable physical timescales when rapid greying occurred.
This new method of measuring small changes in hair coloring indicates the possibility of using hair pigmentation patterns as tell-tale signs of events that influenced hair color, much like tree rings hold information about past decades.
How does hair grow?
Each hair on our heads is made up of two parts, namely the colored part we see growing out of our heads called the shaft, and the bottom which anchors the hair under the scalp, called the root. The root is surrounded by a tube-like structure under the skin called the hair follicle.
Hair strands grow from the root of the hair follicle and are formed by cells multiplying and fed by nutrients supplied by blood vessels in the scalp. Once the hair reaches the top of the shaft, it emerges from the skin.
Where does hair color come from?
Within each hair follicle are cells called melanocytes that produce one of two basic pigments, namely eumelanin or pheomelanin, depending on your DNA. When eumelanin is present, lots of it result in black hair, moderate amounts result in brown hair, and very little results in blond hair. When eumelanin is barely present, pheomelanin would dominate and result in red hair.
As we age, melanocytes would decrease in number, leading to less melanin being produced and less pigment in the hair, resulting in hair with a silver-gray color.
The age at which we do get grey hair is determined by our genes, meaning most of us will start having grey hair around the same age that our parents or grandparents first did.
Some people think that a big shock or drama can turn a person’s hair grey overnight, but scientists don’t really believe this happens. From the time a person first notices a few grey hairs, it may take on average more than 10 years for all of the hair to turn grey, once again depending on genetic factors.
Does stress influence hair turning grey?
A 2020 study by Harvard Medical School on mice has demonstrated how their fur may turn grey under stress, but it is not clear whether this applies to humans.
The recent study that compared hair pigmentation patterns to tree rings may shed some light on whether stress may affect the greying of hair:
- Haie growth is quite an active process inside the hair follicles, which demand energy supplied by the mitochondria, the components inside cells that transform chemical energy from nutrients circulating in the bloodstream into electrical energy to provide energy for processes taking place inside cells.
- While hairs are growing, cells receive signals from elsewhere in the body, such as stress hormones. Researchers think it is possible that these exposures can change proteins and other molecules that are laid down in the growing hair shaft.
- The hair hardens as it grows out of the scalp, which preserves these molecules, and it is visible as patterns of pigmentation.
- Examining single hairs and matching patterns of pigmentation to life events could allow researchers to look back in time through a person’s biological history, which revealed that some white hairs naturally regained their color.
- This suggests that a stressful event might trigger hair into temporary graying, but if a hair is just above the threshold when the stressful event ends, it could revert back to its normal color.
- This new method for measuring small changes in hair color offers the possibility of using hair pigmentation patterns, like with tree rings, to potentially track the effect of past life events on human biology.
- This offers the possibility of monitoring hair pigmentation patterns to trace, for example, the effectiveness of stress reducing treatments, or treatments for slowing down the aging process.
Some illnesses can cause grey hair:
Most people with grey hair experienced age-related graying of the hair. Sometimes graying hair is caused by an illness, especially if it occurs at a relatively young age, such as the following conditions:
- Vitamin B12 deficiency.
- Thyroid disease.
- Neurofibromatosis, which refers to a group of inherited diseases that cause tumors to grow along nerves, and abnormal development of bones and skin.
- Vitiligo is a condition that causes the cells at the base of hair follicles that produce color (melanocytes) to die or stop functioning.
- Alopecia areata is a disorder in which patches of hair may be suddenly lost, especially the non-gray hairs. This may have led to the common belief of someone turning gray “overnight”, as the colored hair are suddenly lost and the existing grey hairs then become more noticeable.
Conclusion:
Grey hair is one of the universal signs of advanced age. Some individuals would contain hair color well into their older age, but most do not. Understanding how and why hair will start to go grey could help to accept this natural aging process.
The good news is that it is not going to kill you, as researchers in a 23-year study in Denmark found no correlation between mortality and the extent of the graying of the hair.
Going gray as you grow older is inevitable, but the way you think about it is within your control, so embrace the change and your silver, “salt and pepper” hair!
References:
Quantitative mapping of human hair graying and reversal in relation to life stress. Published 22 June 2021 in eLife. PubMed Central. National Centre for Biotechnology Information. US National Library for Medicine. National Institutes of Health. USA. (www.ncbi.nlm.nih.gov)
Why does hair turn grey? Published 24 March 2022. Harvard Health Publishing. Harvard Medical School. (www.health.harvard.edu)
Why does hair turn grey? Published online. Nemours Kids Health. The Nemours Foundation. (www.kidshealth.org)
The science of grey hair. Published 30 March 2022. Columbine Health Systems. Center for Healthy Aging. Colorado State University. (www.research.colostate.edu)
What are the causes of grey hair as you age? Published online and updated 24 April 2023. AARP. (A non-profit, nonpartisan organization.) (www.aarp.org)
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