7 Nutrients for Strong, Healthy Nails

1. Biotin

Biotin is a B-complex vitamin also known as vitamin B7, coenzyme R, or vitamin H. It promotes healthy cell growth and aids in the metabolism of protein-building amino acids that are essential for nail growth.

Biotin-rich foods and supplements may help strengthen your brittle fingernails. A few small studies support biotin supplement use to that effect, but it’s important to note that these studies are from the late 1980s to early 1990s.

A 1993 study, for example, examined 35 people with brittle fingernails. Researchers found that 2.5 mg of biotin per day for six weeks to seven months improved symptoms in 63% of participants.

Deficiency in this vitamin is rare. While there is no Recommended Dietary Allowance (RDA) for biotin, the Adequate Intake (AI) recommendation for adults has been set at 30 micrograms (mcg) per day.

Biotin is most concentrated in organ meats such as liver, but it can also be found in:

• egg yolks
• dairy
• yeast
• salmon
• avocado
• sweet potato
• nuts
• seeds
• cauliflower

2. Other B vitamins

Vitamin B12 plays a role in iron absorption and the development of red blood cells. Both iron and B12 are necessary for keeping nails strong and healthy.

A B12 deficiency can result in entirely blue nails, bluish-black pigments with wavy longitudinal dark streaks, and brownish pigmentation.

Likewise, folate, or vitamin B9, is important for nail growth and health by contributing to red blood cell formation and the development of new cells.

A folate deficiency can cause a pigment change in nails, making them rigid and brittle.

To prevent deficiencies, adults require 2.4 mcg of vitamin B12 and 400 mcg of folate per day, though pregnant people have an increased need.

Folate can be found in:

• dark green vegetables
• citrus fruits
• beans
• peas
• nuts
• seeds
• avocado

B12 is primarily found in animal foods, such as meat, poultry, fish, eggs, and dairy, though it can be fortified into other foods and beverages.

3. Iron

Iron composes the center of red blood cells, which carry oxygen to your organs and every cell in your body — including your nails. Without iron, oxygen does not get adequately carried to your cells.

An iron deficiency or anemia can lead to vertical ridges in your nails, or your nails may be concave or “spooned.”

The RDA for iron varies considerably depending on age, sex, and hormonal fluctuations. Most adults need at least 8 milligrams (mg) per day.

Your body absorbs the iron found in animal foods — including beef, chicken, fish, and eggs — better than that in plant foods, such as dark green leafy vegetables, peanuts, seeds, and beans.

Eating something rich in vitamin C alongside a plant-based iron food source can help with this. For example, eating oranges and strawberries alongside a spinach salad with beans and seeds improves your iron absorption.

4. Magnesium

Magnesium is a mineral involved in over 300 reactions in your body, including protein synthesis, which is required for nail growth. Vertical ridges in your nails may be a sign of a magnesium deficiency.

The RDA for magnesium varies considerably depending on age, sex, and hormonal fluctuations. Adults require anywhere from 310 mg to 320 mg per day.

Whole grains, specifically whole wheat, are a rich source of magnesium. Other sources include:

• dark green leafy vegetables
• quinoa
• almonds
• cashews
• peanuts
• edamame
• black beans

5. Protein

Nails are primarily made of a fibrous structural protein called keratin. This is what gives nails their strength and resilience. It also protects your nails from damage or stress.

Interestingly, the keratin you see is actually dead. Nails are formed by dead cells, which your body sheds as new cells push up from underneath.

Eating enough protein is essential for boosting keratin production and thus creating strong nails, whereas low protein intake may cause weaker nails.

The RDA for protein is 0.36 grams per pound (lb), or 0.8 grams per kilogram (kg) of body weight per day. This equals approximately 55 grams of protein per day for a 150-lb (68-kg) person.

However, the Acceptable Macronutrient Distribution Range (AMDR) allows protein to account for 10% to 35% of your total daily calories — significantly more than the RDA.

Protein is found in a variety of animal and plant foods, including:

• meat
• poultry
• fish
• eggs
• dairy
• soy legumes
• beans
• nuts
• seeds
• whole grains

6. Vitamin C

Vitamin C is essential for the production of collagen, a protein that gives shape, strength, and integrity to many tissues and is the building block of fingernails, hair, and teeth.

Deficiency can result in brittle nails, as well as slowed nail growth.

Vitamin C is an essential nutrient that the body cannot produce. The RDA for vitamin C varies depending on age, sex, and hormonal fluctuations. Adults require anywhere from 65 mg to 120 mg per day.

While citrus fruits are thought to be the best sources of vitamin C, bell peppers, green vegetables, and tomatoes are also very high in this nutrient.

7. Zinc

Zinc is required for many reactions in your body, including the growth and division of cells.

Nails are made up of a type of cell that grows and divides rapidly. Because of this fast production, a steady supply of zinc is needed to promote the healthy growth of nails.

Inadequate zinc intake can contribute to degeneration of the nail plate, causing white spots on the nails. The RDA for zinc is 8 mg to 13 mg for adults.

Zinc is found in a variety of animal and plant foods, including:

• beef
• poultry
• fish
• eggs
• soy
• chickpeas
• black beans
• almonds
• cashews
• seeds

The bottom line

While consuming a variety of vitamins, minerals, and nutrients through food contributes to growing and maintaining healthy nails, evidence suggests that supplementing with them may not.

Biotin is the exception, and supplements of this vitamin may help restore brittle nails.

Overall, if you want strong, shiny nails, be sure to include a variety of fruits, vegetables, nuts, and seeds in your diet, as well as adequate protein.