Aoife Hearne: What can my teen do to strengthen her brittle nails?

Nails that split, peel, or break easily are common complaints that can often reflect dietary inadequacies

Tue, 01 Apr, 2025 - 02:00

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Dietitian

My 13-year-old’s nails keep breaking, and have recently developed ridges. She’s always been a picky eater, and it looks like it’s catching up with her. What foods should she eat, and would it help if she took a supplement?

Nails that split, peel, or break easily are common complaints that can often reflect dietary inadequacies. Nail beds continually produce nail tissue, and like all tissue in our body, adequate vitamin, mineral, and nutrient intakes are essential for the growth, formation, and strength of new nail cells. Nails are made primarily of keratin, a protein found in hair and skin.

The body needs a mix of vitamins and minerals, as well as adequate protein, to grow strong and healthy nails. This is especially important for teenagers, who are experiencing rapid growth and development.

Protein is a macronutrient responsible for growth and repair in the body. We find protein in meat, fish, poultry, eggs, nuts, cheese, milk, tofu and legumes. The total daily recommended protein for teenagers is at least 0.8g/kg body weight (more if they are involved in sport).

The key to protein intake is little and often, aim to have a protein-rich food at all meals and snacks. It is recommended to have around 20-25g of protein per meal and snack to maximise absorption.

Some of the most critical nutrients for nail health are biotin, B12, iron, omega-3 fats, calcium, and vitamin D.

While biotin deficiency is uncommon, if your daughter is a picky eater, it is possible that she is not consuming enough of the vitamin from her diet. Good sources of biotin are eggs, salmon, almonds, sweet potato, and spinach.

Salmon is also a great source of omega-3 fatty acids, which support lubrication and moisturising nails and prevent them from breaking.

One of the most common causes of brittle nails is iron deficiency. According to the 2020 National Teens’ Food Consumption Survey, most teenagers consume adequate iron. Also, adolescent girls are at increased risk of iron deficiency, especially after they begin menstruating.

Iron-rich foods such as red meat, chicken, lentils, and fortified cereals are great choices and should be consumed regularly. Pairing these foods with vitamin C (like orange juice or a tomato-based sauce) will also help to increase absorption.

Although calcium and vitamin D are often associated with healthy bones, these nutrients also play an essential role in nail strength. Dairy foods such as milk, cheese, and yoghurts are excellent choices to include two to three times a day. Other calcium sources, such as fortified plant milk and leafy greens, can also contribute to daily calcium intake.

Vitamin D is more difficult to get from food alone, and an under-tongue spray can be a helpful addition in the months when sunlight exposure is inadequate.

I would encourage you to take a food-first approach. In terms of supplementation, biotin can be useful in restoring brittle nails.

Before, during, and after supplementation, encourage your daughter to eat a variety of brightly coloured vegetables and fruits along with whole grains, lean protein, and the all-important omega-3 fatty acids on a daily basis.