Is Healthy Hair Genetic? Or Does it Boil Down to Diet?

If every day is a bad hair day, it might be time to look to your genes and consider nutritional strategies that can help your hair blossom. Several genetic disorders impact the health of hair, leading to fragile hair that breaks, falls out more easily, that causes split ends, and even tangles. While there’s not much you can do to rewrite your genetic code (at least not yet!), there is some evidence that diet choices can help to improve hair affected by genetic mutations. What kind of hair issues are we talking about? Here are some of the most common hair problems with a genetic cause or where your genes may be a contributing factor:

• Trichoptilosis (split ends)
• Trichorrhexis nodosa (hair with nodules, where breaks occur), related to:
  • pili torti (twisted hair)
  • Trichorrhexis invaginata (bamboo hair)
  • monilethrix.
• Pili annulati (banded colouring)
• Pili trianguli (uncombable, frizzy hair)
• Pseudofolliculitis barbae (a shaving-induced condition)
• Androgenetic alopecia (male pattern baldness or thinning hair in women).

This post will discuss each of these hair health issues, their relation to genetic mutations, and how to take a nutritional approach to improving our overall hair health.

Hair health and genetics

Note that many of the issues in this list, including trichoptilosis and trichorrhexis nodosa, are not genetic disorders in themselves. Instead, they describe certain kinds of hair shaft anomalies with a variety of possible causes, including genetic mutations. We’ll go over below a bit about the genetics at play in several hair conditions, as well as how nutritional factors contribute directly and indirectly to genetic hair problems. If you have any concerns about your hair health, you should always consult with a doctor.

Nutrition recommendations by hair condition

Condition	Symptoms	Genes involved	Nutrients involved
Trichoptilosis	Split ends	Not specified	Deficiencies in iron and Vitamins A, B, C, and E may be involved in the development of split ends
Trichorrhexis nodosa	Hair with nodules, where breaks occur (includes pili torti, Trichorrhexis invaginata, and monilethrex)	Monilethrex cases may be related to mutations of KRT81, KRT83, KRT86, or DSG4 genes; ATP7A gene for pili torti	Deficiencies in iron, cysteine may be present, along with excess of Vitamin A; possible protein deficiencies for monilethrex and vitamin A/D cofactors in keratin production
Pili annulati	Banded coloring, light and dark segments of hair	Not specified	Can be caused by disorder in protein metabolism (keratin formation), may respond well to increased intake of amino acids and nutritional co-factors in keratin formation
Pili trianguli	Lengthwise grooves in the hair shaft, leaving hair uncombable and frizzy; hair may be silvery or white and dry	PADI3, TGM3, TCHH genes	Issues with protein metabolism in hair shaft formation
Pseudofolliculitis barbae (razor bumps)	Shaving-induced, largely affecting black men with curly hair	K6hf gene	Treatment involves adjustments in hair removal process, exfoliation, and prescription antibacterial lotions or over-the-counter steroid creams
Androgenetic alopecia (AGA)	Male-pattern baldness or thinning hair in women	AR gene, though others are expected to have involvement	Hair follicles are more vulnerable to the negative effects of high levels of dihydrotestosterone (DHT); a diet rich in soy (for men) and zinc may decrease risk of AGA

Trichoptilosis, Trichorrhexis invaginata and Trichorrhexia nodosa

Trichoptilosis is characterized by split ends, which can result from over-styling, chemical and heat damage, sea and sun damage (or damage from tanning beds), malnutrition, and other factors. Trichorrhexis invaginata (bamboo hair) is caused by a defect in keratinization of the hair shaft, leading to hair that is brittle and that breaks easily. Trichorrhexia nodosa is characterized by hair that is riddled with small nodes or bumps, which create weak spots where the hair breaks more easily. This condition may be associated with pili torti, trichorrhexis invaginata, and monilethrix, all of which have some connection to genetics. Trichorrhexia nodosa can result from deficiencies of specific nutrients, including iron and the amino acid cysteine, and has been associated with an excess of vitamin A. ^{1 2 3} Trichorrhexia nodosa and hair loss may also be caused by hypothyroidism and may be remedied by correcting related deficiencies in zinc and iodine. ⁴

Monilethrix

Monilethrix is one of the most common genetic hair conditions and is characterized by a beaded appearance to the hair. This condition is caused by genetic mutations that affect the formation of important proteins, namely keratin and desmoglein 4, involved in hair growth. Most cases of monilethrix are due to mutations in KRT81, KRT83, KRT86, or DSG4, which code for these proteins. People with monilethrix also tend to have follicular hyperkeratosis on the scalp, nape of neck, upper arm and thighs. If you have monilethrix, you’re arguably more vulnerable to dietary insufficiencies affecting hair growth, including protein insufficiency and nutritional cofactors in keratin and desmogelin 4 production. Such cofactors include vitamins A and D, which are needed for proper keratin production in the skin, hair, and nails. ⁵

Pili torti, Pili annulati, and Pili trianguli

Just as “thrix” is Greek for hair, pili is Latin for hair (plural), hence its appearance in the names of many hair conditions. Pili torti is characterized by coarse, kinky hair that is flattened and twisted, and which breaks more easily due to a defect in keratin formation. Some cases of pili torti are also linked to malnutrition, anorexia, and deficiencies or excesses of certain nutrients or genetic issues affecting how the body metabolizes nutrients. ⁶ For instance, pili torti is a characteristic symptom of Menke’s syndrome, a sex-linked recessive disorder caused by a defect in the ATP7A gene that affects the metabolism of copper, a mineral needed as a cofactor for the enzymes involved in keratin formation. Pili annulati is a genetic condition where hair is alternatively banded with light and dark segments. This appearance of hair may suggest periods of malnutrition and has been linked to auto immune alopecia areata and thyroid disease. ⁷ It can be caused by a disorder in protein metabolism, specifically keratin formation. ⁸ Because pili annulati can be caused by disordered protein metabolism, related to dysfunction of cytoplasmic ribosomes, it may respond well to enhanced intake of amino acids and nutritional co-factors to keratin formation. ⁸ Pili trianguli is characterized by lengthwise grooves in the hair shaft, creating a triangular appearance and frizzy, uncombable hair. Hair quantity is usually normal, and the hair isn’t typically fragile, but hair may be silvery or white and dry. This condition may be related to genetic defects that also affect the skin, eyes, nails, and other tissues of the body. At least three genes have been identified as being involved in pili trianguli, including PADI3 (peptidylarginine deiminase 3), TGM3 (transglutaminase 3), and TCHH (trichohyalin), all of which play a role in protein metabolism in hair shaft formation. ⁹

Pseudofolliculitis barbae

Pseudofolliculitis barbae is a hair issue that predominantly affects men, especially black men with curly hair. This is because the condition is induced by shaving, and occurs when hairs grow inwards, curling under the skin rather than growing straight. This leads to inflammation, skin bumps, and possible pain and infection. It appears that pseudofolliculitis barbae is related to a polymorphism in the keratin-coding gene K6hf that is expressed in hair follicles. ¹⁰

Androgenetic alopecia

Androgenetic alopecia (AGA) affects people of all genders, including around 50% of women and 80% of men at some point in their lives. ¹¹ This condition results in varying degrees of hair loss and is known to involve nutritional and environmental factors, as well as genetics. Scientists suspect that several genes play a role in androgenetic alopecia, but so far have confirmed the involvement of just one, AR. ¹² The AR gene codes for production of androgen receptors, which control how the body responds to androgen hormones such as testosterone. Variations in the AR gene appear to increase receptivity in hair follicles, which may mean that hair follicles are more vulnerable to the negative effects of high levels of dihydrotestosterone (DHT). This testosterone metabolite, which is created through the activity of the enzyme 5-alpha-reductase, shortens the growth (anagen) stage in hair follicles and shrinks hair follicles, resulting in hair loss and thinning hair. Nutritional factors also play a role in androgenetic alopecia. Diet can have a significant effect on DHT metabolism, for instance, with epidemiologic studies suggesting that men who eat more soy have a lower risk of AGA, possibly because isoflavones like genistein in soy inhibit 5-alpha-reductase activity. ^{13 14} Zinc also inhibits 5-alpha-reductase activity, and zinc is an important nutrient for healing and tissue growth, including hair growth. ¹⁵

The value of genetic testing for hair health

Genetic testing can give you a clearer understanding of the underlying issues contributing to your hair problems. In some cases, your hair issues may provide early warning of an in-born metabolic problem that could lead to more serious health concerns later in life. For example, compared to men without androgenetic alopecia, men with the condition have a much higher chance of developing Metabolic Syndrome (51% vs 28%) and Benign Prostatic Hyperplasia (36% vs 6.8%), suggesting that taking steps to treat AGA, particularly with nutrigenomics, might also help lower the risk of related health issues. By now you should have realized that when it comes to hair and genetics, things get rather complicated rather quickly. There are few cut-and-dried examples where a specific nutrient can correct a genetic hair issue. That said, there’s plenty of evidence for the importance of a wide range of nutrients in fueling healthy hair growth for people with or without the genetic conditions described earlier.

More nutrition tips for hair growth

Healthy hair growth relies on adequate amounts of protein, vitamins, and minerals, as well as other nutrients, including antioxidants, to protect hair follicles against damage. ¹⁶ Without the right building blocks for hair, and nutrients for energy production, hair growth will be slow and may result in weak hair that is more vulnerable to trauma. In-born metabolic defects affecting how your body uses these nutrients can, therefore, also affect your hair, as can defects in protein metabolism, general digestion function, and nutrient absorption. Hair that results from these metabolic and genetic defects is also more likely to develop the nodes of Trichorrhexis nodosa and split ends. Nutritional interventions may also help support hair growth in people undergoing more conventional treatments for genetic hair conditions. Researchers have reported success, for example, in treating monilethrix with minoxidil treatment and a nutrition protocol. The treatment involved a three-day cycle of nutritional supplements, combining antioxidants, calcium, vitamin D3, zinc, magnesium, iron, folic acid, vitamin C, omega-3 fatty acids, B-complex, biotin, and amino acids. In an initial case study involving a 22-year-old woman, clear improvement in hair growth was seen after two months, with less breakage, and hair that went from being dull, dry, and lifeless to healthy, shiny, and bouncy. By four months, the woman’s hair density had improved by 23%, with a 35% reduction in vellus-type hairs, i.e. the light, thin hair that covers most of the body. In a larger study involving several hundred people, consistent improvements were seen in men and women compared to the control groups, including reduced hair loss, a minimum 18% increase in hair density within 2 months, and up to a 156% increase in hair density over 1 year. ¹⁷

Supplements for healthy hair

Given what we now know about the importance of certain nutrients for keratin formation and the health of hair follicles, it’s not all that surprising that these volunteers saw an improvement in hair growth with the supplement regimen. It’s also likely that most of us could see some improvement in hair growth and hair quality by ensuring a good daily intake of protein and essential nutrients such as biotin, preferably in bioactive, coenzyme forms that we can all absorb and use. Biotin is one of the most important nutrients for hair growth, with biotin deficiency causing hair loss and a loss of hair color, as well as brittle nails and dry skin problems. ¹⁸ A deficiency in biotinidase, the enzyme needed to break biotin free from protein, has been linked to trichorrhexia nodosa. ¹⁹ Biotinidase deficiency is relatively common, occurring in 1 in 60,000 newborns. ²⁰ It is easily corrected, however, through the daily use of coenzymated biotin supplements. As we’ve already seen, zinc, iron, vitamin A, vitamin D, and copper are also essential for healthy hair growth, as are silica, iodine, and antioxidant nutrients, and specific amino acids (such as methionine) as part of a good overall protein intake. ²¹ Several genetic conditions, including celiac and Crohn’s disease, can affect how you absorb these nutrients, meaning that poor hair growth may be linked indirectly to genetic variations. So, while there’s no “cure” for genetic hair disorders, nutrigenomics and some lifestyle modifications may help to compensate for poor hair shaft formation and other issues affecting hair health.