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The Prediabetes Nutritionist

4 Nutrients You Need to Grow Long, Healthy Hair

High Blood Glucose Affects Your Hair Growth (4 Best Nutrients)

Ignore the noise. Based on science, here are the four nutrients you need to grow long, healthy hair. Spoiler alert: biotin is not one of them. Well, not really!

Type the phrase ‘supplements for hair growth” in Google, and I guarantee that every result will contain biotin.

While some people portray biotin as a hair-growth aid, the TRUTH is that no scientific evidence backs that claim except in certain circumstances.

You can get biotin quickly from food, and your gut bacteria make it.

Biotin is effective for hair growth if you have a diagnosed deficiency. Deficiencies are rare, but they can arise if you have a malabsorption disorder, eat raw eggs or take antibiotics frequently.

If none of those apply, taking biotin supplements for hair growth is likely pointless.

Scientific evidence exists for the role of other nutrients in hair growth. Note, however, that these nutrients promote hair growth only if a deficiency exists.

Before we explore the nutrients that help grow your hair, let’s recap the hair cycle.

The Hair Cycle

Hair primarily comprises keratin protein – the same protein in your skin and nails. Each hair shaft consists of three layers:

  • Cuticle – the protective outer layer
  • Cortex – the middle layer, which contains melanin and determines your hair colour
  • Medulla – the innermost layer which reflects light

Each hair is attached to the scalp via a follicle. On average, healthy humans have 80,000-120,000 follicles on their scalp.

Hair follicles cycle through three phases: anagen, catagen and telogen.

The anagen (growth) phase lasts between two and six years; at any given time, 85-90% of hair follicles are in this phase. Some hairs begin to regress and enter the catagen (transition) phase, lasting between two and four weeks. After the transition phase, hairs enter the telogen (resting) phase, which lasts around three months.

Hair is shed after the telogen phase, new hair grows, and the whole cycle repeats itself.

This cycle of growth, followed by resting and shedding, varies significantly between people. And it depends on various factors, including age, genetics, health status, hormonal imbalances and diet.

Healthy adults shed 70-100 hairs naturally daily. But because new hairs constantly grow and replace them, this natural hair loss isn’t noticeable, and hair volume remains constant.

However, when hair shedding exceeds the usual rate, your hair becomes noticeably thin. If no new hair grows and replaces the hair, that part of the skin becomes bald.

This phenomenon is called alopecia. There are different types of alopecia, but a comprehensive review of alopecia is beyond the scope of this article. However, it is essential to discuss the impact of diabetes on hair growth.

Hair Growth and diabetes

Slow hair growth and hair loss are common issues that can be caused by various factors, including genetics, ageing, stress, and certain medical conditions, including diabetes.

High glucose levels in diabetes can damage the small blood vessels that supply nutrients to the hair follicles, leading to hair thinning or slow growth.

A 2019 study found that type 2 diabetes was associated with a 68% increased risk of severe central scalp hair loss in Black women, especially if they had diabetes for at least 10 years.

Thyroid hormones play a crucial role in regulating hair growth, and disruptions in these hormones can lead to hair loss (Hussein et al., 2023). Diabetes is closely associated with thyroid disorders; it is estimated that 9-48% of people with diabetes have thyroid disorders.

Furthermore, thyroid disorders are more common in women (31.4%) than men (6.9%) with type 2 diabetes (Hussein and AbdElmageed, 2021).

Moreover, high cortisol levels due to high stress levels can affect the hair follicle, leading to growth disorders such as telogen effluvium (Thom, 2016). Telogen effluvium is a temporary hair loss that occurs when many hair follicles enter the resting phase of the growth cycle simultaneously, causing more hair to fall out than usual (Hughes and Saleh, 2023).

Hair loss can be a potential symptom of diabetes, and it is essential to monitor blood glucose levels and seek medical attention if hair loss or thinning occurs. In addition, managing stress levels, maintaining healthy thyroid function, and eating a balanced diet can help support healthy hair growth.

Eat These Four Nutrients for Healthy Hair

1 | Protein
Protein - grow healthy hair

Protein comprises amino acids; you need 20 amino acids to function.

Your body can make eleven of them, and these amino acids are known as non-essential amino acids. The other nine are essential amino acids because your body can only get them from food.

Cysteine, methionine and lysine are the vital amino acids that control hair health and growth.

Cysteine and methionine (essential amino acid) are the main building blocks of keratin protein. Cysteine also maintains hair diameter and growth rate.

Lysine, an essential amino acid, maintains hair volume and shape. Lysine deficiencies can cause brittle, thin and limp hair.

Lysine is also vital for zinc and iron absorption, critical in hair health.

If your diet lacks sufficient quality proteins, your hair can become fragile, brittle and weak and may eventually fall out.  Your hair may also appear lighter or exhibit a banded pattern, known as the flag sign. The darker areas represent those with higher melanin content from improved nutrition.

Good sources of the amino acids you need for healthy hair include fish, poultry, legumes, seeds, nuts, grains and eggs.

2 | Essential Fats
essential fats - grow healthy hair

Your body needs fat to make steroid hormones, sebum and other fat-containing molecules like ceramides, sterols, cholesterol and phospholipids.

Without sufficient fat in your diet, especially essential fats, your hydration levels decrease, compromising the health of your scalp and hair bulbs. You may lose hair on your scalp and eyebrows, and your remaining hair will appear lighter.

Good sources of essential omega-3 fats include fatty fish, flaxseeds, walnuts and chia seeds. Vegetable oils and nuts are good sources of omega-6 fats, which are also necessary to maintain healthy hair.

Our diets are often heavy in omega-6 fats from vegetable oils, so focusing on getting more omega-3s in your diet is essential.

3 | Zinc
Zinc rich foods - grow healthy hair

Over 300 enzymes in your body require zinc to function correctly. Zinc is essential for growth, development, wound healing, collagen synthesis and immunity.

Your body can’t produce zinc. You can only get it through diet, making it an essential mineral. If your intake of animal proteins, such as poultry, meats and fish, is low, your risk of zinc deficiency increases, especially if you eat plenty of phytate-rich cereal grains.

Phytates bind to zinc and prevent zinc absorption.

People with bowel disease and cystic fibrosis may also be at risk of zinc deficiency due to poor absorption.

People with conditions such as renal disease, sickle cell disease, anorexia, and alcoholism who excrete zinc rapidly also have a higher risk of zinc deficiency.

Finally, medications like diuretics, penicillamine and valproic acid lower zinc levels.

Hair dryness, brittleness and alopecia are common and well-established symptoms of zinc deficiency. Studies show hair regrowth with zinc supplementation when deficiencies are present.

It is worth noting that blood serum zinc levels are not a good indicator of the body’s zinc stores. However, if you need to supplement with zinc, a professional must monitor your zinc levels because an overdose can lead to copper or calcium deficiencies, drowsiness, and headaches.

4 | Iron
Iron - grow healthy hair

According to the World Health Organisation, iron deficiency is widespread and affects up to 80% of people worldwide.

Iron has many functions. It

  • transports oxygen around the body,
  • acts as a co-factor for an enzyme vital for DNA synthesis,
  • supports a healthy immune system
  • promotes collagen synthesis
  • acts as a catalyst for many reactions in the body.

Premenopausal women (due to menstrual blood loss), vegans, vegetarians, people with malabsorption disorders (such as celiac disease), and those who use H2 blockers have a higher risk of iron deficiency.

Vegans and vegetarians have a higher risk of iron deficiency because plant foods contain non-heme iron, which humans don’t absorb as efficiently as the heme iron found in animal foods. As a result, vegans and vegetarians may have iron requirements that are 1.8 times higher than meat-eaters.

Vegans and vegetarians can improve iron absorption by eating foods rich in vitamin C alongside plant-based iron-rich foods and avoiding excessive tea and coffee consumption.

If you need iron supplements, your doctor must monitor your iron levels because iron overload can cause toxicity. Toxicity can occur even at low levels if you take supplements for prolonged periods.

In summary

Much of our knowledge about how micronutrients impact hair growth comes from studies conducted on people with deficiencies or diseases. Therefore, taking supplements without a diagnosed deficiency is unlikely to significantly affect your hair’s health and growth.

Hair health and growth can be affected by several factors, including stress, hormonal imbalances, and medical conditions such as diabetes. If you notice significant changes in your hair, it is essential to seek medical attention. Additionally, lifestyle changes and a balanced diet can significantly contribute to hair health.

It’s worth remembering that food is the best source of nutrients for your hair and overall health. Now that you know which foods contain the four essential nutrients needed for healthy hair growth, you can make informed dietary choices and encourage healthy hair growth.

So, what foods will you consume more of to promote healthy hair?


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DISCLAIMER: Not a substitute for medical advice – All content is for informational purposes only and is not intended to provide medical or nutrition advice or to take the place of medical/nutrition advice or treatment from your doctor or health professional. Since each person’s health conditions are very specific, viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. All content, including text, graphics, images, and information in this post/video, is for general information only and does not replace a consultation with your doctor/health professional.

  • First published: 01 May 2021
  • Updated: 09 January 2024

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