Your hair is essentially dead protein. Each strand is made primarily of keratin, and by the time it emerges from your scalp, it's no longer receiving nutrients. What you eat affects hair growth at the follicle level - the living part beneath the skin where new hair is produced.
This means diet influences hair health, but with a delay. Nutritional changes won't transform existing hair; they affect what grows in the coming months. And while nutrition matters, it's one factor among many - genetics, hormones, age, stress, and health conditions all play significant roles.
Managing Expectations
No food will reverse male pattern baldness or hormonal hair loss. These are largely genetic and hormonal issues that diet can't override. However, ensuring adequate nutrition prevents hair problems caused by deficiency - which is more common than many realise, especially with restrictive dieting.
Key Nutrients for Hair Health
Hair follicles are among the most metabolically active cells in your body. They require a steady supply of nutrients to function optimally:
Protein
Hair is 95% keratin protein. Inadequate protein intake can lead to hair thinning or shedding. This is common in very restrictive diets.
- Eggs
- Fish and poultry
- Legumes
- Greek yoghurt
Iron
Iron deficiency is a leading cause of hair loss, particularly in women. Ferritin (stored iron) levels correlate with hair growth.
- Red meat
- Spinach, lentils
- Fortified cereals
- Pair with vitamin C for absorption
Zinc
Supports hair follicle structure and oil gland function. Deficiency causes hair shedding and slow regrowth.
- Oysters (exceptionally high)
- Beef and lamb
- Pumpkin seeds
- Chickpeas
Biotin (B7)
Often marketed for hair growth, but deficiency is rare. Supplements only help if you're actually deficient.
- Eggs (cooked - raw whites block absorption)
- Nuts and seeds
- Salmon
- Sweet potatoes
Omega-3 Fatty Acids
Support scalp health and hair hydration. May reduce inflammation that affects follicles.
- Oily fish (salmon, mackerel, sardines)
- Walnuts
- Flaxseeds, chia seeds
- Algae supplements
Vitamin D
Plays a role in hair follicle cycling. Deficiency is linked to alopecia areata and general hair thinning.
- Sunlight exposure
- Oily fish
- Egg yolks
- Fortified foods
Best Foods for Hair Health
Rather than chasing individual nutrients, focus on nutrient-dense foods that cover multiple bases:
Top Hair Foods
- Eggs - Protein, biotin, zinc, selenium
- Salmon - Protein, omega-3s, vitamin D
- Spinach - Iron, folate, vitamins A and C
- Sweet potatoes - Beta-carotene (vitamin A precursor)
- Oysters - Zinc (the richest food source)
- Nuts - Vitamin E, zinc, selenium
- Seeds - Zinc, vitamin E, omega-3s
- Greek yoghurt - Protein, B5
Good Additions
- Beans and lentils - Protein, iron, zinc, biotin
- Bell peppers - Vitamin C (aids iron absorption)
- Avocados - Vitamin E, healthy fats
- Berries - Vitamin C, antioxidants
- Lean poultry - Protein, B vitamins
- Whole grains - Iron, zinc, B vitamins
- Bone broth - Collagen, amino acids
What Can Harm Hair Health
Dietary Factors
- Very low calorie diets (causes hair shedding)
- Low protein intake
- Excessive vitamin A (can cause hair loss)
- Crash dieting / rapid weight loss
- Unbalanced diets lacking variety
- Raw egg whites regularly (blocks biotin)
Non-Dietary Factors
- Chronic stress
- Hormonal changes (pregnancy, menopause, thyroid)
- Genetics (male/female pattern hair loss)
- Medications
- Tight hairstyles (traction alopecia)
- Heat and chemical damage
The Supplement Question
Hair supplements are a massive industry with often exaggerated claims. The reality:
- If you're deficient, supplements can help. Iron supplements for deficient women, vitamin D if levels are low.
- If you're not deficient, extra biotin, keratin, or other supplements likely won't improve hair growth.
- High-dose biotin can interfere with lab tests (including thyroid and troponin - important for heart attack diagnosis). Inform your doctor if you're taking it.
- Collagen supplements have limited evidence for hair specifically, though may support skin and nail health.
When to Seek Help
Sudden or patchy hair loss, hair loss with other symptoms (fatigue, weight changes), or significant shedding warrants medical investigation. It could indicate thyroid problems, iron deficiency anaemia, autoimmune conditions, or hormonal issues. Don't just take supplements - get properly tested.
A Practical Approach
- Eat enough calories - Under-eating is a common cause of hair shedding. If dieting, do so moderately.
- Prioritise protein - Include a protein source at each meal. Around 0.8-1g per kg body weight minimum.
- Check iron levels - Especially if you menstruate, are vegetarian, or exercise heavily. Ferritin below 30 μg/L often affects hair even before anaemia develops.
- Include oily fish twice weekly - Or consider omega-3 supplementation if you don't eat fish.
- Don't fear healthy fats - Very low fat diets can affect hair health.
- Eat the rainbow - Variety ensures you cover micronutrient bases.
- Manage stress - Significant stress can trigger telogen effluvium (temporary shedding) months later.
The Bottom Line
Hair health reflects overall nutritional status more than any single "superfood." The key nutrients are protein, iron, zinc, omega-3s, and vitamin D. Most people eating a varied diet with adequate protein and calories get enough for healthy hair. Problems arise with restrictive dieting, nutritional deficiencies, or crash weight loss. If you're experiencing significant hair changes, get tested for underlying issues rather than just supplementing blindly.
References
- Almohanna, H.M., et al. (2019). The Role of Vitamins and Minerals in Hair Loss: A Review. Dermatology and Therapy, 9(1), 51-70. doi:10.1007/s13555-018-0278-6
- Guo, E.L., & Katta, R. (2017). Diet and hair loss: effects of nutrient deficiency and supplement use. Dermatology Practical & Conceptual, 7(1), 1-10. doi:10.5826/dpc.0701a01
- Rushton, D.H. (2002). Nutritional factors and hair loss. Clinical and Experimental Dermatology, 27(5), 396-404. doi:10.1046/j.1365-2230.2002.01076.x
- British Association of Dermatologists. (2024). Hair Loss (Alopecia). bad.org.uk
