On average, people have about 5,000,000 hairs. (14) Hair grows on almost the entire surface of the body except for the lips, soles of the feet, and palms of the hands. (18) Hair care is important to many people, and according to a 2021 market survey conducted by Mordor Intelligence, the US salon care market is forecasted to reach 3.2 billion dollars by 2023. (24) Keep reading to learn how to get healthy hair and how certain hair care habits and proper nutrient intake can help maintain healthy hair and hair growth.
How is hair structured?
Human hair is a part of the integumentary system, an organ system that includes hair, skin, and nails. It has a sensory function (nerve fibers are located under the skin) (13) and can help protect the body from cold temperatures and ultraviolet radiation from the sun. (15)
Did you know? The hair shaft has an outer cortex that’s surrounded by cuticle cells and depending on the type of hair, may also have a medulla at its center (common in thick hair). (15)
In the past, some researchers have differentiated hair variability according to a small number of human ethnic groups; however, this approach doesn’t take into account the complexity of human biological diversity. (23)
A 2007 study aimed to assess the worldwide diversity of hair curliness using a new method of assessment. The researchers examined the hair of 2,449 volunteers from 22 regions and five different continents. Four parameters including curve diameter, curl index, highest number of waves, and number of twists were used to carefully assess 6 cm (2.4 inches) of cut hair from each participant. Based on results using these parameters, researchers were able to identify eight hair types. The eight hair types get progressively curlier, can apply to anyone, and are not based on ethnic origin. (23)
While some individuals have a regular hair growth cycle that allows for a fuller head of hair, hair loss can occur for a variety of reasons, such as stress, genetics, life stage (e.g., menopause), or certain health conditions.
How fast does hair grow? Human hair grows at a rate of 0.5 inches (1.27 cm) per month or about six inches (15 cm) per year. (25) The papilla area of the hair follicle supports the hair growth process as well as the size and color of the hair shaft. Essential growth factors such as insulin-like growth factor, keratinocyte growth factor, bone morphogenetic protein, and stem cell factor also play a role in hair growth. The hair follicle grows in a cycle and the hair shaft’s growth varies depending on the phase it’s in. Hair follicle cycle phases include the anagen phase (growth), the catagen phase (transition), and the telogen phase (rest). (15)
Did you know? As part of the normal hair growth cycle, most people shed approximately 100 hairs each day. (25)
Rice water for hair growth
Rice water, the milky water that’s left over after soaking rice in water, has been used traditionally in some areas of the world including certain villages in China, such as Huangluo, a region where women regularly rinse their hair with a rice water mixture to promote hair growth. (6) Although research to support rice water for hair growth is limited, one study did examine the effects of rice bran mineral extract on molecules involved in the active phase of hair growth in human dermal papilla cells (anagen phase). They found that rice bran mineral extract may help prolong the anagen phase and decrease certain inflammatory biomarkers. These findings suggest an association between rice bran mineral extract and hair growth enhancement. (20)
How to get healthy hair: 6 top hair care habits
There are simple habits you can incorporate into your hair routine that will help maintain healthy hair and prevent damage such as breakage.
1. Cleanse and condition your hair
When washing your hair, massage shampoo into your scalp and, if you have longer hair, avoid rubbing shampoo through the length of your hair, which can cause breakage. Instead, let the shampoo on your scalp flow through your hair as you rinse your scalp. (1)
It’s also helpful to use conditioner on the ends of your hair after every shampoo, as they are the oldest and generally driest parts of the hair. Apply conditioner, let it sit on the hair for a few minutes, then gently rinse it out. (17)
2. Let your hair air-dry
Allow your hair to air-dry instead of rubbing it with a towel to help prevent damage from pulling. Wrapping your hair in a towel is appropriate as long as you avoid rubbing the hair while it’s still wet. (1)
For individuals with certain hair types, hair can be more fragile and susceptible to damage when it’s wet. If you have tight curls or kinky hair, gently combing your hair with a wide toothed comb while it’s still damp is helpful. (1) However, individuals with straight hair types may wish to wait until their hair has dried before combing it through to prevent breakage from pulling. (1) If you do brush your hair when it’s damp, using a conditioner beforehand can help minimize tangles. When brushing, always begin combing your hair at the ends and work your way up to the root in order to prevent excess pulling. (8)
3. Limit heat and product use
Hair products such as hair sprays or curl waxes can help with styling hair, but their ingredients may also be harsh and damage hair over time. Heat can also damage and dry out hair. If you choose to use a curling iron, hot comb, or blow dryer, try using them infrequently and on the lowest heat setting. (1) Using a heat protective product on wet hair before styling with heat may also lessen heat damage. (2) Ensuring that your hair is healthy before applying color, using relaxing products, or perming, is especially important as these treatments can make hair more prone to breakage. Lastly, If you’re considering a change, consult a professional hair stylist about the best hair treatments for you. (8)
4. Manage the amount of pulling
Tight braids, ponytails, cornrows, heavy weaves, or hair extensions may pull at the hair and cause damage or breakage. To help minimize hair damage, it can be helpful to leave weaves or extensions in for no more than two to three months and give your hair a break between styles. Wearing looser extensions or a lighter weave is also helpful. (16)
5. Protect your hair while swimming
Chemicals used in pools and hot tubs such as chlorine can damage your hair. Wearing a swim cap or keeping your head above water while swimming can help prevent damage. Rinsing your hair immediately following swimming is also helpful. (17)
6. Wash your hair
How often should you wash your hair? How often you wash your hair is a personal preference and may depend on your hair type. Washing your hair once per day or once per week is appropriate depending on how oily or dry your hair is. (8) For example, individuals with straight hair types may notice that their hair gets oilier more quickly than individuals with kinky or curly hair types. Regardless of how often you choose to wash your hair with shampoo, it can be helpful to avoid a buildup of dirt and dust on the scalp by rinsing the scalp with water alone every few days. (8)
How to promote hair growth: 6 vitamins and minerals for healthy hair
Vitamins and minerals may play a role in hair follicle development and are necessary for normal cell growth. Hair follicle quality is dependent on the supply of nutrients to the hair root as well as hormone balance and metabolism. (5)
Given that several nutrients are needed to support hair growth, micronutrient deficiencies may contribute to hair loss. Consuming more nutrient-dense foods and incorporating vitamin and mineral supplementation when advised by your integrative healthcare practitioner may improve symptoms of hair loss. (5) The following vitamins and minerals can be obtained from the diet, supplementation, and may play a role in hair follicle development.
1. Vitamin A
Vitamin A is a fat-soluble antioxidant vitamin involved in immune function, growth and tissue healing, as well as hair, skin, and eye health. (9)(12) In most cases, a healthy amount of vitamin A is supplied to the body through a balanced diet; however, too little or too much vitamin A may negatively impact hair growth. Within the hair follicle, different layers of epithelial cells surround the hair fiber, and vitamin A is important for the development of hair epithelial tissue. (9)
Certain factors can affect vitamin A absorption and storage such as alcohol consumption, illness, or high stress levels. Adequate intake of the mineral zinc is also necessary for the body to release stores of vitamin A. Sources of vitamin A include fish, cod liver oil, animal liver, egg yolks, milk products, yellow and orange colored fruits and vegetables, and leafy and green vegetables. (12)
2. Vitamin D
Vitamin D is a fat-soluble sterol (cholesterol-like) vitamin that’s manufactured in human skin following contact with the sun’s ultraviolet B (UVB) rays. (12) Vitamin D helps regulate calcium and phosphorus levels and the normal calcification of bones, and may possess anti-inflammatory and immunoregulatory effects. (5)
Individuals with alopecia areata (AA), an autoimmune condition and common form of hair loss characterized by small round patches of hair falling out, may be deficient in vitamin D, and levels may inversely correlate with the severity of AA. A cross-sectional study that included 86 volunteers with AA, 44 volunteers with vitiligo (a condition that causes a loss of pigment in the skin), and 58 volunteers in good health (control group) determined that vitamin D levels of the AA group were significantly lower than those in the healthy control and vitiligo groups. (3) At this time, there’s insufficient evidence to support vitamin D supplementation as an effective method for treating AA, and more research is needed in this area. (21)(22)
Sources of vitamin D3 include fish liver oil, egg yolks, butter, oily fish, certain fortified cereals, and nutritional supplements. UV-treated mushrooms and dark leafy greens contain plant-derived vitamin D2. (12)
3. Vitamin E
Vitamin E is a fat-soluble vitamin that functions as an antioxidant. Vitamin E helps reduce the oxidation of lipid membranes and reduce inflammation and free radical damage to cells. (12)
A study that examined the effects of supplementing with tocotrienols (antioxidants in the vitamin E family) in individuals with alopecia areata (AA) determined that 100 mg of mixed tocotrienols daily lead to a significant increase in the number of hairs in a predetermined area of hair loss compared to the placebo group. (7) The researchers suggest that the antioxidant activity of tocotrienols may help reduce lipid peroxidation and oxidative stress in the scalp, factors that may be associated with AA. (7)(26)
Vitamin E can be consumed through both animal and plant sources; however, grains, nuts, and seeds are generally the best sources. Egg yolks, milk, and liver also contain vitamin E. (12)
Selenium is a nutrient that functions as a potent antioxidant due to its relationship with an enzyme called glutathione peroxidase. Glutathione peroxidase is an enzyme that helps prevent cellular degeneration and protects cells from lipid peroxidation, a form of oxidative stress that may be associated with AA. (7)(12)(26) Selenium may also play a role in hair follicle morphogenesis (development). (11)
Sources of selenium include brewer’s yeast, wheat germ, brazil nuts, barley, oats, shellfish, certain fish, garlic, onions, swiss chard, and many other foods. Selenium levels in many of these foods are dependent on the amount of selenium present in soil in which they were grown. (12)
Zinc is a mineral that’s essential for growth and development, tissue healing, immune function, sexual function, synthesis of DNA, and many other functions. (12) Zinc is necessary for the activity of over 100 enzymes, some of which are important for protein synthesis and cell division. (11)
A study that examined the zinc and copper status of individuals in four different groups based on type of hair loss including male pattern hair loss, female pattern hair loss, alopecia areata (AA), and telogen effluvium (TE) determined that zinc concentrations were significantly lower in all groups compared to the control group and that copper levels were not significantly different. The researchers hypothesize that zinc metabolism disturbances may play a role in certain types of hair loss. (19)
A study that examined the health of an otherwise healthy four year old girl who had recently begun experiencing hair loss, determined that she had low serum zinc levels. After three weeks of supplementing with 50 mg of zinc per day and modifying her diet, hair loss stopped. At 4 months, there was no evidence of alopecia. The protocol was maintained for a total of six months. (4)
Food sources of zinc include oysters, meats, egg yolks, fish, whole grains, and nuts and seeds such as brazil nuts and pumpkin seeds. (12)
Biotin is one of eight water-soluble B vitamins that function as coenzymes, support different biochemical reactions, and influence the health of hair, skin, and eyes. (12) A deficiency in biotin may cause hair loss, brittle nails, and skin rashes; however, more research is needed to determine if supplementation with biotin reduces hair loss.
Sources of B vitamins include brewer’s yeast, nutritional yeast, beans, peas, nuts, liver, and leafy vegetables. Certain B vitamins can also be produced in the human intestinal bacteria. (12)
The bottom line
Proper nutrient intake, including micronutrients, protein, and fats, and practicing hair care habits such as limiting heat and pulling, letting hair air-dry when possible, massaging shampoo into the scalp, and using a conditioner, can help maintain healthy hair. If you’re experiencing hair loss or simply want to improve the health of your hair, speak with your healthcare practitioner about what would work best for you and your individual needs.
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