How does your diet affect hair loss?

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A deficiency in nutrition can have a significant impact on the roots of your hair, causing them to weaken. This, in turn, visibly affects the structure and growth of your hair, contributing to the problem of excessive hair loss. These effects on hair growth can include acute telogen effluvium, a well-known consequence of sudden weight loss or low protein intake, in addition to a condition called alopecia areata, which is caused by a deficiency in niacin. Studies have also suggested potential links between nutritional deficiencies and androgenetic alopecia, female pattern hair loss, and patchy hair loss.

The hair follicle cells are among the fastest-dividing cells in the body, so it's not surprising that nutrient deficiencies can negatively impact hair growth. Hair growth can be affected by poor nutrition in terms of calorie intake, protein, and the absence of key micronutrients. Often, individuals experiencing significant hair loss may wonder whether taking dietary supplements can help them regain the strength and health of their hair or prevent further hair loss. While it's true that dietary supplements can aid in hair regrowth or preventing further loss, it's crucial to exercise caution and consult a doctor before doing so.

Micronutrient deficiencies and hair loss

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Hair consists of two main components: the visible hair shaft and the hair follicles hidden beneath the skin from which hair grows.

Hair typically grows at a rate of about 0.35 mm per day. It's normal to shed around 100 scalp hairs daily, and this number may increase with hair care practices like washing and brushing.

Here are some nutrients whose deficiency can lead to excessive hair loss:

1. Iron Deficiency: 

Iron deficiency is one of the most common nutritional deficiencies globally and can lead to hair loss. This condition is associated with a type of hair loss known as telogen effluvium, characterized by a disruption in the natural hair growth cycle, leading to excessive hair shedding.

Researchers are still studying how iron deficiency causes substantial hair loss, but it appears to hinder hair growth by redirecting iron stores in hair follicles to other areas of the body. Some studies have shown that people experiencing hair loss tend to have lower levels of iron in both their blood and hair compared to those not experiencing hair loss.

2- Vitamin D Deficiency: 

Vitamin D plays a crucial role in hair growth and the health of hair follicles. Research has shown that individuals with hair loss conditions, including female pattern hair loss and a skin condition called alopecia areata, tend to have lower levels of vitamin D. Studies also suggest that taking vitamin D supplements can promote hair regrowth in some individuals with hair loss related to a vitamin D deficiency.

In fact, a 2020 study involving 109 individuals found that those experiencing hair loss had significantly lower levels of vitamin D in their blood compared to those without hair loss. Nearly 80% of people with hair loss had low vitamin D levels. Additionally, iron deficiency was also common among those with the same issue in the same study.

These findings have led researchers to recommend testing all individuals with diffuse hair loss to check for low levels of vitamin D and iron.

3- Zinc Deficiency:

Zinc is a vital mineral that plays important roles in immune function, protein synthesis, cellular division, and more. It is essential for the function of hair follicles and helps protect against the shrinking of hair roots and slowing hair growth. It also aids in promoting hair follicle recovery.

Zinc deficiency can lead to excessive hair loss. Studies indicate that people with certain hair loss conditions tend to have lower zinc levels compared to healthy individuals who don't experience this problem. These conditions include:

  • Alopecia areata
  • Male pattern hair loss
  • Female pattern hair loss
  • Telogen effluvium

4- Other Nutritional Deficiencies

 In addition to the mentioned vitamins and minerals, research has found that deficiencies in the following nutrients are closely linked to hair loss:

  • Copper
  • Biotin
  • Vitamin B12
  • Folic acid
  • Riboflavin

It's important to note that several factors can contribute to excessive hair loss, often involving more than one nutrient deficiency. If you suspect your hair loss is due to nutritional deficiencies, consult with a healthcare professional. They may recommend blood tests to assess micronutrient levels and rule out deficiencies. You may want to consider tests for iron, vitamin D, zinc, vitamin B, and copper.

5- Calorie and Protein Restriction:

The cells that make up your hair follicles have a high rate of turnover, meaning new cells grow and replace old ones rapidly. For this reason, hair is highly sensitive to calorie and protein deficiencies, which are essential for your follicles to have a constant supply of energy to grow and function properly. Calorie restriction can impact the energy supply to your hair follicles, leading to hair loss.

Studies have shown that very low-calorie diets can result in hair loss in some individuals, and protein restriction in certain low-calorie diets can cause thinning and hair loss. Your hair needs amino acids, which are the building blocks of protein, to grow properly. So, following a diet with insufficient protein may lead to hair growth issues, such as hair loss, thinning, and brittleness. Severely low calorie intake and protein restriction can also negatively affect your overall health in various ways. Therefore, it's crucial to provide your body with sufficient calories and include protein-rich foods in your diet to ensure it receives the necessary nutrients.

6- Using Dietary Supplements

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Using dietary supplements can help you obtain essential nutrients more conveniently, aiding in the maintenance of healthy hair and optimal growth. However, taking certain types of dietary supplements can have the opposite effect. In fact, some dietary supplements are linked to hair loss.

If you don't have nutrient deficiencies, taking high doses of certain dietary supplements can be harmful to your hair. These supplements include:

  • Selenium
  • Vitamin E
  • Vitamin A

For instance, excessive intake of vitamin A through supplements can lead to liver damage. When there's an excess of vitamin A in the liver, the excess vitamin A enters the bloodstream, which can result in elevated levels of it in the blood.

Maintaining optimal levels of vitamin A in the blood is crucial for hair follicle function, and excess amounts of these nutrients in the body can cause excessive hair loss.

A case report featured a woman who consumed 10-15 Brazil nuts, which contain very high levels of selenium, daily for 20 days. She experienced severe health issues and lost all the hair on her head. Healthcare professionals found that her selenium levels were five times higher than the normal range in her blood. Doctors concluded that this was the cause of her hair loss.

What's concerning is that many dietary supplements claiming to enhance hair growth contain high amounts of nutrients that may lead to hair loss when consumed excessively. That's why it's essential to consult a trusted healthcare provider before starting to take dietary supplements.


Many factors can contribute to hair loss, including medical conditions, hormone imbalances, and infections. Other factors that can lead to hair loss include micronutrient deficiencies, inadequate calorie or protein intake, excessive consumption of certain dietary supplements, smoking, alcohol consumption, stress, and lack of sleep.

If you're experiencing significant hair loss, it's important to visit a healthcare professional to identify the cause or causes of your hair loss so that you can get the treatment you need.

In the meantime, you can visit Zen Hair's blog anytime to read more about hair problems and their treatment.