Hair grows from the roots, so the key to healthy hair growth lies in improving the health of the scalp and hair follicles.
This article looks at the best foods and nutrients to promote hair growth.
How does diet impact hair growth?
Hair is continuously growing and being replaced, and the follicles are constantly creating new hairs from nutrients in the body.
The foods people eat affect how their hair grows and its quality. Certain proteins, fats, vitamins, and minerals are especially important for strong, healthy hair.
Eating a varied, nutritious diet can also boost nail and skin health. The changes will be most noticeable in people who previously had vitamin or nutrient deficiencies. Even so, it may take a while to see the positive results, in terms of hair growth.
The American Academy of Dermatology estimate that people lose 50–100 hairs each day. Shortly afterward, new hairs regrow from the same follicles. Head hair usually grows around 6 inches per year.The following sections look at key nutrients for hair growth and which foods contain them.
Eggs are a good source of biotin, a mineral that may help boost hair growth.
Thinning hair and a loss of body hair are two symptoms of a biotin deficiency. Other symptoms include rashes around the face and anus, skin infections, and brittle nails. Biotin deficiencies are rare.
Many dietary supplements for hair growth contain biotin. However, there is little scientific evidence that biotin improves hair, skin, or nail health.
Examples of other foods that contain biotin:
- meat, including fish
- some vegetables, such as sweet potatoes, spinach, and broccoli
Eggs also contain other compounds that can boost hair growth, including L-lysine, vitamin D, and certain minerals. Read on for more information.
2. Brazil nuts
Brazil nuts are an excellent source of selenium, a mineral that may help boost hair growth.
Authors of a scientific review note that selenium is involved in creating hair. They report that newly forming hair takes up selenium after receiving trace elements from the blood.
However, too much selenium can cause brittle hair and hair loss, along with nausea, skin rashes, and nervous system problems.
The recommended upper limit for selenium in adults is 400 micrograms (mcg). Brazil nuts are very rich in selenium — one brazil nut offers 68–91 mcg — so people may wish to limit their intake to around four Brazil nuts per day.
Selenium concentrations in plant-based foods vary with geographic location and soil content.
Other foods that contain selenium include:
- meat, including liver and fish
- milk and other dairy products
- breads and cereals
3. Fatty fish
Healthful fats are an important part of every diet, and omega-3 fatty acids are good for the heart as well as the hair, skin, and eyes.
Fish can be good sources of omega-3s as well as vitamin D, which can boost hair health.
In addition, people who eat fish have a reduced risk of various chronic diseases, and eating fatty fish helps keep the heart healthy, lowering the risk of heart attack and stroke.
In a 2018 animal study, researchers found that fish oil extract containing docosahexaenoic acid, an omega-3 fatty acid, boosted hair growth by increasing the activity of certain proteins in the body.
Also, a small-scale study found that taking omega-3 supplements along with marine proteins could reduce hair loss, though the researchers noted that it did not specifically promote hair growth.
The richest fish sources of omega-3 fatty acids are:
People who follow a vegetarian or vegan diet can get omega-3s from the following plant-based sources:
- seeds, such as flaxseeds and chia seeds
- flaxseed oil, soybean oil, and canola oil
- algae, such as spirulina
- fortified foods
4. Foods fortified with vitamin D
Some research suggests that vitamin D may help improve hair growth
Vitamin D is also important for muscle, nerve, and immune system functions.
In most American diets, fortified foods provide the bulk of the vitamin D. Some foods that tend to be fortified include:
- breakfast cereals
- orange juice
- soy drinks
Other foods that contain vitamin D include:
- fatty fish
- beef liver
5. L-lysine sources
Certain amino acids in protein-rich foods may help promote hair growth, and L-lysine is one example.
L-lysine is also present in the hair's root, and it is responsible for the shape and volume of the hair.
An L-lysine deficiency can cause hair loss, but getting enough of this amino acid can prevent this issue and promote regular hair growth.
People can take L-lysine supplements. It also exists, as dietary protein, in the following foods:
Certain deficiencies can cause hair loss, and restoring levels of these nutrients and minerals may boost hair growth:
- Iron. Even mild cases of iron-deficiency anemia can cause hair loss.
- Zinc. Insufficient zinc can lead to dry hair and, possibly, hair loss.
- Protein. A lack of protein can weaken the hair and make it look dull.
Though the scientific research is limited, some sources suggest that the following nutrients can boost hair growth:
- niacin, to support healthy hair follicles
- folic acid, to promote new hair growth
- vitamin A, to protect hair follicles
- vitamin C, an antioxidant, to prevent hair damage and support collagen levels
Some people use herbal supplements to promote hair growth, though research has not confirmed that these remedies work.
Specifically, some find that saw palmetto supplements help prevent and even partially reverse hair loss.
Others use Ginkgo biloba, an herbal supplement associated with boosting the memory, to encourage hair growth, believing that it improves the delivery of nutrients to the scalp.
What factors affect hair growth?
As people age, they may notice that their hair does not grow as quickly as before and that it is less thick. Some follicles may stop producing new hairs, leading to hair thinning or loss.
This results from a combination of genetics and natural aging processes. Hair shafts also become finer and start to lose their color.
Childbirth, stress, thyroid conditions, and a health issue called alopecia can cause more sudden loss of hair. Eating a healthful diet, even one designed to support hair growth, may not address genetic or systemic problems.
Aside from aging, illness, and genetics, malnutrition is one of the most common causes of hair loss. Following a healthy, well-balanced diet can help people maintain typical levels of hair growth and replacement.
Nutritious eating can also help prevent these signs of unhealthy or damaged hair:
- a brittle texture
- visible dandruff
- a dull appearance
- a tendency to break easily
Heredity and natural aging processes play major roles in hair loss. However, the quality, quantity, and growth of hair are also closely linked to the diet.
Maintaining a nutritious diet is the best way to improve the health and growth of hair.
Doctors recommend that diets are varied. For omnivores, they should include adequate amounts of protein from fish, beans, eggs, and lean meats, as well as lots of fresh fruits, vegetables, and whole grains.