Your fingernails can say a lot about your health.
Nail beds constantly give rise to nail tissue, and adequate vitamin, mineral and nutrient intakes help support the growth, formation and strength of new nail cells.
A change in the appearance, texture or shape of your nails could indicate nutrient deficiencies.
Here are the 8 most important vitamins and nutrients to keep your nails healthy.
Biotin is a B-complex vitamin, also known as vitamin B7, coenzyme R and 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 (, , ).
One study in 35 people with brittle fingernails 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, and while there is no Recommended Dietary Allowance (RDA) for biotin, the Adequate Intake (AI) recommendation for adults has been set at 30 mcg per day ().
Summary Biotin deficiency is rare, but consuming biotin through foods or supplements may help strengthen brittle nails and improve their growth.
Other B vitamins are also important for nail health.
Vitamin B12 plays a role in iron absorption, as well as the development of red blood cells. Both iron and B12 are necessary for keeping nails strong and healthy.
A deficiency in vitamin B12 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 deficiency in folate can cause a pigment change in your nails and make them rigid and brittle ().
To prevent deficiencies, adults require 2.4 mcg of vitamin B12 and 400 mcg of folate per day, though pregnant women have an increased need ().
Folate can be found in dark green vegetables, citrus fruits, beans, peas, lentils, nuts, seeds and avocado. On the other hand, 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.
Summary Both vitamin B12 and folate play a role in red blood cell production and oxygen transportation to nail cells. Inadequacies can result in discoloration of your nails.
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.
As oxygen is needed for healthy nails, an iron deficiency or anemia can lead to vertical ridges in your nails or your nails may concave or “spoon” (, ).
RDAs for iron vary considerably depending on age and gender. The recommendation for men is 8 mg per day, while that of women aged 19–50 is 18 mg per day. After women hit age 50 or go through menopause, their iron needs drop to 8 mg daily ().
Your body absorbs the iron found in animal foods, such as beef, chicken, fish and eggs, better than that in plant foods like dark green leafy vegetables, peanuts, seeds, beans and other fortified foods.
However, eating a food rich in vitamin C together with a plant-based iron food source improves absorption. For example, eating oranges and strawberries alongside a spinach salad with beans and seeds improves your iron absorption.
Summary Iron is needed to provide your cells with adequate oxygen, which, in turn, is necessary for healthy nails. If you have an iron deficiency, the shape and appearance of your nails can be affected.
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. Despite worldwide availability of this mineral, the World Health Organization (WHO) reports that less than 60% of the US population consumes the recommended amount ().
The RDA is 400-420 mg and 310–320 mg per day for men and women respectively ().
Whole grains, specifically whole wheat, are a rich source of magnesium. Dark green leafy vegetables, as well as quinoa, almonds, cashews, peanuts, edamame and black beans, are good sources, too.
Summary Adequate magnesium intake is crucial to prevent vertical ridges in your nails. This mineral also helps with protein synthesis and the formation of new nails.
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 (12, ).
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 (12).
Eating enough protein through your diet 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 (0.8 grams per 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 10–35% of your total daily calories — significantly more than the RDA ().
Protein can be found in animal foods like meat, poultry, fish, eggs and dairy, as well as plant foods, such as soy, legumes, beans, lentils, nuts, seeds and whole grains.
Summary Adequate protein intake is needed to produce keratin, which is responsible for keeping your nails strong and resilient.
Omega-3 fatty acids can help lubricate and moisturize your nails, giving them a shiny appearance.
These fatty acids may also reduce inflammation in your nail bed, which nourishes and promotes the health of cells that give rise to your nail plate. A lack of omega-3 fatty acids could contribute to dry and brittle nails ().
There is no RDA for omega-3 fatty acids, but the AI is 1.6 grams and 1.1 grams per day for men and women respectively. The AMDR says that up to 1.6% of total calories can come from omega-3s (, ).
Summary To prevent dry and brittle nails, consume adequate omega-3 fatty acids. They help lubricate your nails, giving them a shiny appearance.
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 ().
A deficiency in vitamin C can result in brittle nails, as well as slowed nail growth ().
Vitamin C is an essential nutrient and cannot be produced by your body. Men require 90 mg and women 75 mg per day ().
While citrus fruits, such as oranges, strawberries and kiwi are thought to be the best sources of vitamin C, bell peppers, green vegetables and tomatoes are very high in this nutrient as well.
In fact, red bell peppers have more than twice the vitamin C of an orange (19).
Summary Vitamin C is essential for collagen production, which helps provide strength and integrity to your nails.
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 a degeneration of your nail plate, causing the appearance of white spots on your nails (, ).
The RDA for zinc is 11 mg and 8 mg per day for men and women respectively ().
Animal proteins like beef, poultry, fish and eggs are rich sources of zinc. However, soy, chickpeas, black beans, nuts (such as almonds and cashews) and seeds also contain it.
Summary Zinc is required for the healthy growth of your nails. Animal proteins are a great way to consume adequate zinc through your diet, though certain plant foods pack this mineral as well.
A nutrient-rich diet is likely the best way to achieve strong, shiny, healthy nails.
While there are many supplements marketed for strengthening nails, scientific evidence is lacking. To date, biotin supplements are the only type shown to have a possible effect (, , ).
However, it’s important to note that deficiencies in certain vitamins, minerals and nutrients may negatively affect your nail health.
Try to get your vitamins and nutrients from food, but when you can’t, taking a supplement can help you meet your needs and likely improve your nail health.
Summary Consuming a variety of vitamins, minerals and nutrients through food is the best way to improve and maintain nail health. Under certain circumstances, taking a supplement may be beneficial, though scientific research is lacking in this regard.
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 and omega-3 fatty acids.