Straight or curly. Black, brown, auburn or blonde. Long or short. The hair on our head is a part of who we are. It can help us to express our personality, thoughts, beliefs and how we feel, to the world around us.
It is not surprising therefore that ‘hair’, is also a multimillion industry and research reveals that as consumers, we are beginning to expect far more from our haircare products than we used to. Increasingly we are looking for brands that reflect our own personal values on social, ethical, and environmental issues, not to mention our increasingly sophisticated understanding around the effect’s chemicals used in hair care preparations have on our bodies.
Being able to make active and informed choices to avoid shampoos and conditioners packed with ingredients like sodium laurylsulphate, which may irritate the scalp and strip hair of its natural oils along with silicone and paraben free products to help delicate scalp skin is now possible. More and more we are looking for products that are free from artificial fragrances and additives that will clean and improve how our hair looks and feels from the outside as well as those that nourish and protect our hair and hair growing cells and structures from the inside.
Before delving into such issues, it is worth getting our facts about hair in place. However, our hair helps us to feel and whatever it says about us, physiologically, apart from our palms and the soles of our feet, our entire body has hair, and it is there for reasons that goes beyond aesthetics.
Hairs on our skin for example stand up when it’s cold, keeping warmed air close to our body and helping to regulate our body temperature. The hair on our head offers protection to our scalp from the sun’s damaging ultraviolet rays. Our eyelashes and eyebrows meanwhile, form part of our immune system, working to keep dirt, dust, and sweat from landing in our eyes and the tiny hairs in our nose and ears form a physical barrier to bacteria and viruses.
The hair on our head, as well as eyelashes, eyebrows, chest, and belly hair are known as ‘terminal’ hairs and are longer and thicker than the shorter, thinner ‘vellus’ hairs or peach fuzz, on our body. How much of each type we have, varies depending in part on our age and gender.
How do Hairs Grow?
Regardless of its type and position on our body, each hair has a root in which it starts life. Hair roots are buried within the deeper layers of our skin, and each is surrounded by a hair follicle, which is connected to a gland that produces oil, known as the ‘sebaceous’ gland. The visible part of our hair, that sticks out of our skin, is known as the shaft.
It’s hard to imagine, but every single hair follicle, whether it is a terminal hair on our head or vellus hair on our body, is attached to a tiny muscle, which when it contracts, can make the hair stand up. The follicle is also attached to many nerves, which are so sensitive, they can react to even the slightest draft in the hair.
At the base of each rounded hair root is the ‘papilla’, which supplies blood and therefore oxygen and nutrients needed for hair to grown. Every new hair on our body starts its life growing in the hair bulb at the base of each hair root, and this constant process, happens throughout life, starting in the womb.
As the new hair cells constantly grow in each hair bulb, they begin to stick to each other and gradually become harder. These hardened cells are gradually pushed up the follicle and eventually, pop out of our skin, where we can see them. A single hair on our head grows on average at one centimetre a month, while those on our face, eyelashes, eyebrows, and body, grow at a slower rate.
While straight hair looks round if you look at its cross section under a microscope, the more oval-shaped the cross-section, the curlier the hair will be.
The colour of our hair meanwhile is determined by the amounts of pigments in our hardened hair cells. These vary from person to person, and can change over our lifespan, with the quantity of pigments, reducing over time. As we move through the decades, we have less pigment and more air trapped in each hair, which makes it look white. Depending on our original hair colour and the number of white hair cells that grow, our hair looks grey or white in older age.
The roots of hairs on our head can continue to produce hair cells for several years, which means it can grow around a metre in length over this time, without a cut. Eyelashes and eyebrow hairs on the other hand, tend to just grow for three or four months.
Either way, once the growth cycle of a hair root stops, it takes about two to four weeks for the hair to separate from the blood supply and fall out. We tend to lose around 70 to 100 hairs from our head, each day. The good news is that new hair cells then usually start to multiply again at the base of the “empty” hair follicle to form a new hair.
What Causes Extra Hair Loss?
Usually, we shed between around 50 to 100 hairs each day. When losses go above a hundred, this known as alopecia. There are different types of alopecia that can cause hair loss on the scalp. If the root of the hair is damaged, then growth rates slow down and if this happens to lots of hair roots at the same time, then loss of hair can be noticeable. If no new hair grows to replace old ones, then that part of the skin or scalp, becomes ‘bald’. Sometimes this is a temporary situation caused by a shock, poor long-term nutrition, and low immunity but it can also be permanent and in either case, both can be triggered by stress.
Does What We Eat, Affect Our Hair and Scalp?
The answer is yes, not least because the tiny hair follicles that sit in the lower level of our skin are some of the most metabolically active structures in our body. In other words, they need a constant supply of energy (calories) as well as protein, vitamins, minerals, and antioxidants. When in short supply, hair follicles are not be able to support hair growth. A lack of vital nutrients can also impact the condition of our scalp, with too little of certain ones triggering dry skin and, in some cases contributing to eczema and dermatitis.
Iron and Hair Loss
A lack of iron can lead to hair loss, probably because too little iron reduces oxygen supply to all cells, including our hair bulb. Teenage girls and women are particularly vulnerable to iron intakes dipping below ideal levels.
Restoring levels to normal seems to reverse this effect. It is a good idea to have your iron levels checked if you feel tired and stressed, experience heavy menstrual losses, have been diagnosed with Coeliac Disease or are following a vegetarian or vegan style of eating. Foods good for iron include lean red meat, oily fish, and eggs.
Plant foods that provide iron include pulses, peas, nuts, green leafy vegetables, dried apricots, and figs. It is important to eat vitamin C rich foods like citrus fruits or berries alongside plant-based sources of iron to help our bodies to absorb it while at the same time, having them away from tea, which can hinder iron absorption.
Zinc and Hair Loss
Researchers have also linked lower levels of zinc in our blood with an increased risk of hair loss. As with iron, the good news is that a reversal of hair loss has been observed, once deficiencies of zinc are corrected. Too much zinc can be dangerous and so it is not a good idea to supplement with more than the daily recommended intake of 9.5mg a day for men and 7mg daily for women. Taking blood pressure medication, having inflammatory bowel disease, gastric bypass surgery or following a vegetarian or vegan style of eating may put us at risk of lower zinc levels.
Selenium and Protection of the Hair Follicle
This mineral helps to protect hair follicles from damage because it acts as an antioxidant. It is one of the minerals that we tend to struggle to meet our daily requirements of in the UK. Having just four Brazil nuts a day will keep us topped up, without overdoing intakes. Other foods that provide us with selenium include fish, meat, and eggs. It is important to remember that you can have too much of a good thing. If you chose to supplement, stick with 75 micrograms a day for men and 60 for women because an excess selenium can ironically lead to hair loss.
Vitamin D and Hair Growth
Around a quarter of us in the UK have low levels of vitamin D in our blood. As well as being vital for helping us to absorb bone-building calcium from the foods we eat, vitamin D also seems to play a role in the growing phase of hair production. Taking a 10-microgram daily supplement is advised by the Department of Health during winter months and for some people, the whole year round in the UK for bone health and the good news is this may also benefit hair growth.
Vitamin E and Dry Scalp
Like selenium, vitamin E acts as an antioxidant in our body. A lack of this nutrient can lead to skin dryness, which could affect the health of our scalp. Improving intakes if low, may help with protecting the hair follicle and hair growth. Foods giving us vitamin E include nuts, seeds, and wholegrains like wholemeal bread.
Biotin and Scalp Health
Although deficiency of this B vitamin is usually rare, if you have been taking antibiotics over an extended period, it can become an issue. A lack of biotin can lead to both eczema on the scalp and hair loss. Topping up with extra biotin may be helpful if you stick with intakes of no more than 0.9mg or less per day.
Fatty Acids and Healthy Scalp
Too few essential fatty acids including omega 6 versions in borage and evening primrose oil omega-3 fatty acids from oily fish and plankton, walnuts and flaxseeds can lead to hair loss on our scalp and eyebrows as well as triggering a lightening in colour of our hair. Rubbing oils rich in essential fatty acids onto our scalp as well as having them in our diets or in supplement form, may help to encourage hair growth.
Antioxidants and Hair Follicle Blood Supply
Selenium and vitamin E are both antioxidants, which help to protect the blood supply to our hair follicles. Super nutrients in fruits and vegetables known as ‘polyphenols’ also have antioxidant properties and may also play an important role in keeping hair growing at a healthy and normal speed.
Probiotics, Hair Growth and Stress Busting
Early studies have linked improving the probiotic intake of both women and men in Korea with both improved hair count and hair thickness within four months by helping to stimulate the growth phase of individual hairs. A healthy balance of good gut bacteria has also been linked with improved mood and reduction of stress by helping to rebalance levels of ‘feel-good’ chemicals like dopamine, and serotonin. Stress is a trigger for hair loss, which can be reversed once levels of stress and on-going anxiety are under control.
Registered Nutritionist AFN
PG Dip Dietetics,
Associateship King's College (AKC)