Nails
How Nutrition Affects Nail Strength: Foods Worth Adding to Your Diet
Nails are made of keratin, and keratin is made from what you eat. Here is which nutrients matter most and the foods that deliver them reliably.
The connection between diet and nail health is real, but it is also frequently overstated. Supplements are marketed for nails with a confidence the evidence rarely warrants. The honest picture is more nuanced: specific nutrient deficiencies do have measurable effects on the nail plate, and correcting them produces genuine improvement. But nails in a well-nourished person are unlikely to transform with additional supplementation.
What follows is a guide to the nutrients that genuinely matter, the food sources that deliver them, and an honest appraisal of what dietary change can and cannot achieve.
Protein
Nails are composed of approximately 90% keratin — a structural protein. This makes total dietary protein the most foundational nutritional factor for nail health, yet it is the one most rarely discussed in nail care marketing.
When protein intake is chronically inadequate, the body prioritises essential functions. Non-critical protein synthesis — including keratin production — slows. The result is slower nail growth, reduced plate density, and greater fragility. Most people eating a varied diet consume sufficient protein, but those following very restrictive diets, athletes in caloric deficit, or older adults may fall short.
Good sources include:
- —Eggs, poultry, fish, and red meat
- —Dairy: Greek yoghurt, cottage cheese, milk
- —Legumes: lentils, chickpeas, black beans
- —Tofu and tempeh
- —Wholegrains paired with legumes (for complete amino acid profiles in plant-based diets)
Biotin (Vitamin B7)
Biotin is involved in fatty acid synthesis and amino acid metabolism — both processes required for keratin production. Several small clinical trials have found that biotin supplementation reduces nail fragility and increases plate thickness in people with brittle nails. The evidence is moderate quality but consistently positive for this specific presentation. Our dedicated article on biotin and nail growth examines the research in detail and clarifies who is most likely to benefit.
Food sources are more reliable than often assumed:
- —Eggs, particularly the yolk
- —Liver and kidney
- —Almonds and other nuts
- —Sweet potato
- —Salmon and other oily fish
- —Avocado
Biotin is water-soluble, which means the body does not store it in large quantities. Consistent daily intake through food is sufficient for most people.
Iron
Iron deficiency produces some of the most recognisable nail changes: brittle nails that break easily, vertical ridging, and — in more severe deficiency — koilonychia, where the nail plate curves upwards into a spoon-like shape. These changes are well documented and clinically significant. The full pattern of what nail changes signal is covered in our article on signs nails reveal about health.
The nails reflect iron status because the matrix cells that produce keratin require oxygen delivered by iron-rich red blood cells. When iron is low, nail growth slows and plate quality declines.
- —Red meat and offal are the most bioavailable sources (haem iron)
- —Plant-based sources: spinach, lentils, tofu, fortified cereals, pumpkin seeds
- —Pairing non-haem iron foods with vitamin C significantly improves absorption — a squeeze of lemon over lentils, or a glass of orange juice alongside a plant-based meal
"Iron is one of the few nutritional causes of nail change where the connection is both clinically documented and visually distinctive — the spoon-shaped nail is a genuine diagnostic marker."
Zinc
Zinc is directly involved in cell division and keratin synthesis. Deficiency contributes to white spots on the nail, slower growth, and — in more severe cases — Beau's lines: horizontal depressions running across the nail plate caused by a temporary slowdown in matrix activity.
Reliable food sources:
- —Pumpkin seeds and sunflower seeds
- —Chickpeas and lentils
- —Cashews and almonds
- —Red meat and shellfish (oysters are the most concentrated source)
- —Wholegrains
Omega-3 Fatty Acids
Omega-3 fatty acids do not form part of the nail plate itself, but they support the nail bed and the skin surrounding the nail. They reduce inflammatory signalling that can affect skin barrier function and contribute to dryness around the cuticle. Well-hydrated, supple skin around the nail supports nail plate flexibility and overall appearance.
Good sources include:
- —Oily fish: mackerel, salmon, sardines, herring
- —Walnuts
- —Flaxseed and flaxseed oil
- —Chia seeds
- —Hemp seeds
Silica
Silica is a trace mineral that supports the cross-linking of collagen and keratin structures. It is not discussed as often as the nutrients above, but some research points to its role in nail plate integrity.
Food sources:
- —Oats
- —Bananas
- —Raisins and dried fruit
- —Wholegrains — particularly barley and rice
A Note on Supplements
For most people eating a varied diet, food-first is the appropriate approach. The body absorbs nutrients from food more efficiently than from isolated supplements, and excess of some nutrients — iron in particular — can cause harm.
Where supplementation may be warranted:
- —Vegetarian or vegan diets where iron, zinc, or omega-3 intake is limited
- —Diagnosed deficiencies confirmed by blood testing
- —Periods of restricted eating
If you suspect a specific deficiency, a blood test is a far more useful starting point than purchasing a general "hair, skin, and nails" supplement.
Managing Expectations
The nail plate grows at approximately 3mm per month. Changes to diet will not become visible in the nail for three to four months — the time required for new, nutritionally-supported cells to grow out sufficiently to assess. This is not a reason to dismiss dietary change; it is simply a reason to be patient and consistent.
At Maison Lumia, we take a long view of nail health. A conversation about diet during an appointment is never out of place — it is part of the same picture we look at with every client, every session.