Hair loss is a common condition known as alopecia in the medical field.
It has many known causes, including (1Trusted Source, 2Trusted Source):
- genetics
- hormonal dysregulation
- hypothyroidism
- tension on the hair
- trauma
- infection
- chemotherapy
Hair loss can also be caused by diet-related factors, such as nutrient deficiencies and supplement use (3Trusted Source).
This article explains how diet can affect hair loss.
Hair is made up of two main structures — the hair shaft, which is what you see, and the hair follicle, which is hidden underneath the skin. Hair grows from the hair follicle (4Trusted Source).
Hair typically grows at a rate of 0.35 mm per day. The scalp sheds about 100 hairs per day, which can increase with hair care practices like washing and brushing (5Trusted Source).
Hair follicles are highly active and sensitive. In fact, hair follicle cells are among the most rapidly dividing cells in your body, so it’s no surprise that nutrient deficiencies can negatively affect hair growth (3Trusted Source).
Iron
Iron deficiency is the most common nutrient deficiency in the world and can cause hair loss (3Trusted Source).
This condition is related to a type of hair loss known as telogen effluvium (TE), a type of hair loss characterized by a disruption in the normal hair growth cycle. This leads to excessive hair shedding and hair loss (5Trusted Source).
Researchers are still studying how iron deficiency causes hair loss, but it appears to disrupt hair growth by diverting iron stores in the hair follicle to other areas of the body (6Trusted Source).
Some studies have shown that people with hair loss tend to have lower iron levels in their blood and hair compared with people who don’t have hair loss (7Trusted Source, 8Trusted Source).
Vitamin D
Vitamin D plays an important role in hair growth and the health of your hair follicles (6Trusted Source).
Research has shown that vitamin D levels are lower in people with hair loss conditions, including female pattern hair loss and an autoimmune skin disease called alopecia areata (9Trusted Source, 10Trusted Source, 11Trusted Source, 12Trusted Source).
Research has shown that taking vitamin D supplements promoted hair regrowth in some people with hair loss related to vitamin D deficiency (13Trusted Source).
A 2020 study that included 109 people found that those with hair loss had significantly lower blood levels of vitamin D than people without hair loss. In fact, nearly 80% of the people with hair loss had low vitamin D levels (14Trusted Source).
Iron deficiency was common among those with hair loss as well (14Trusted Source).
These findings led the researchers to recommend that all people with diffuse hair loss be tested for low vitamin D and iron levels (14Trusted Source).
Zinc
Zinc is a mineral that plays important roles in immune function, protein synthesis, cellular division, and more.
It’s necessary for hair follicle function and helps protect against hair follicle shrinkage and slowed growth. It also helps promote hair follicle recovery (15Trusted Source).
Zinc deficiency can cause hair loss, and studies show that people with certain hair loss conditions tend to have lower zinc levels than people without hair loss. Those conditions include (6Trusted Source, 15Trusted Source):
- alopecia areata
- male pattern hair loss
- female pattern hair loss
- telogen effluvium (TE)
Other nutrients that may affect hair loss
In addition to the vitamins and minerals listed above, research has found that deficiencies in the following nutrients are associated with hair loss (6Trusted Source, 16Trusted Source, 17Trusted Source, 18Trusted Source):
- copper
- biotin
- vitamin B12
- folate
- riboflavin
Keep in mind that a number of factors may cause hair loss, including one or more nutrient deficiencies (18Trusted Source).
