Foods with a potentially negative effect on hair health and growth include:

Simple carbohydrates

A 2016 studyTrusted Source suggested that diets rich in simple carbohydrates may contribute to hair loss.

The authors suggest eating simple carbohydrates increases sebum production, an oily substance that the glands attached to hair follicles release. While sebum is beneficial for hair health, excess amounts can lead to inflammation that is harmful to hair health.

Sugary foods also cause the pancreas to increase the production of the hormone insulin, which negatively affects blood vessels in the scalp.

People should avoid eating too many simple carbohydrates, such as candy, cakes, and cookies. These foods also include refined grains, such as white rice, pasta, or bread. Complex carbohydrates are a more nutritious alternative that includes whole grains, beans, and vegetables.

Fish with high mercury content

A 2019 case reportTrusted Source on two women experiencing hair loss found they had high mercury levels in their blood from eating fish. The hair loss improved after they reduced their intake of mercury-rich fish.

The Food and Drug Administration (FDA)Trusted Source still recommends eating 2–3 servings of fish per week due to its high nutritional value. Therefore, sticking to fish low in mercury, such as tuna, salmon, and cod, could be beneficial for people experiencing hair loss.

Fried foods and red meat

An older study from 2010Trusted Source suggested avoiding fried foods and red meat for hair health. The authors stated these foods could negatively affect hair health because they cause the overactivity of sebum and oil glands.

Studies exploring the effect of diet on hair loss are still in the early stages. However, a 2020 reviewTrusted Source suggested a form of hair loss called telogen effluvium may sometimes stem from a diet severely lacking in calories, protein, or certain micronutrients.

A 2016 studyTrusted Source suggests eating a balanced diet, including sufficient amounts of protein, vitamins, and minerals, is necessary for hair health and growth.

The following are some of the dietary recommendations:

• Protein: Proteins contain amino acids necessary for hair growth. Examples of protein sources include:
  • cottage cheese
  • yogurt
  • beans
  • poultry
  • seeds and nuts
  • eggs
  • fish
• Healthy fats: Unsaturated fats hydrate the hair and may prevent hair loss. Some sources include:
  • fatty fish, such as salmon
  • flax seeds
  • walnuts
  • olive oil
• Vitamin C: A vitamin C deficiency may negatively affect the creation of hair shafts. Sources include:
  • green, leafy vegetables
  • strawberries
  • citrus fruits
• Folate: This form of vitamin B stimulates the rebuilding of hair. Examples of folate sources include:
  • peas
  • beets
  • asparagus
• Biotin: Biotin can promote hair growth. Sources include:
  • egg yolk
  • sweet potatoes
  • salmon
  • sunflower seeds
  • almonds
• Niacin: This B vitamin is necessary for hair health. Some sources include:
  • salmon
  • tuna
  • marinara sauce
  • whole grains
  • peanuts
  • seeds
• Iron: Insufficient iron can cause hair loss. Sources include:
  • beef
  • poultry
  • spinach
  • white beans
  • lentils
  • dried apricots

Diet is one factor in preventing hair loss, but other practices that also might help include the below.

Quitting smoking

Research from 2020Trusted Source involving 1,000 healthy men found hair loss was more common in smokers than nonsmokers. The results suggest that nicotine may speed up the progression of hair loss.

Avoiding hair-damaging products

The American Academy of Dermatology Association (AADA) suggests products for coloring, relaxing, or perming the hair can have damaging effects and may cause hair loss.

Avoiding pulling hair

The AADA also states that hairstyles that pull the hair back tightly against the scalp can cause permanent hair loss. Pulling on the hair to relieve stress is also harmful.

Certain diets and specific foods may affect hair loss. For example, eating too many simple carbohydrates or fish high in mercury could increase this risk. Nutritious foods, especially those high in micronutrients, such as vitamins B and C, could prevent hair loss and improve hair health. These foods include leafy green vegetables, fruits, and nuts.

However, research in this area is still in its infancy. Following basic haircare tips, such as avoiding hair-damaging products, will also help reduce the risk of hair loss.