Foods that cause hair loss are a growing concern for many people noticing increased shedding or thinning. Whilst no single food directly triggers hair loss, certain dietary patterns — including high-glycaemic diets, excess selenium intake, and prolonged nutritional deficiencies — can disrupt the hair growth cycle and contribute to conditions such as telogen effluvium. Hair follicles are metabolically demanding structures that rely on a steady supply of protein, vitamins, and minerals. Understanding the relationship between diet and hair health can help you make informed choices and identify when further medical investigation may be warranted.

How Your Diet Can Affect Hair Growth and Loss

Hair follicles require adequate protein, vitamins, and minerals to complete their growth cycle; nutritional imbalance can cause the body to deprioritise hair, triggering increased shedding or slowed regrowth.

Hair is one of the fastest-growing tissues in the human body, and like all living tissue, it depends on a steady supply of nutrients to function properly. The hair follicle is a metabolically active structure that requires adequate protein, vitamins, minerals, and energy to progress through its natural growth cycle — anagen (growth), catagen (transition), and telogen (shedding). When nutritional intake is insufficient or imbalanced, the body prioritises vital organs over non-essential structures such as hair, which can result in increased shedding or slowed regrowth.

Diet is rarely the sole cause of hair loss, but it can be a significant contributing factor, particularly in cases of telogen effluvium — a condition where a large number of hair follicles prematurely enter the resting phase, leading to diffuse shedding. Shedding typically begins two to three months after a triggering event and, once the cause is addressed, recovery usually occurs over six to nine months. This type of hair loss is often triggered by physiological stress, including crash dieting, rapid weight loss, or prolonged nutritional deficiency. Postpartum hair loss is another common, non-dietary trigger of telogen effluvium and is a normal, temporary response to the hormonal changes following childbirth.

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It is important to understand that the relationship between diet and hair loss is complex and bidirectional. Eating a poor diet does not automatically cause hair loss, and not all hair loss is diet-related. Genetic, hormonal, autoimmune, and environmental factors all play a role. However, optimising nutritional intake is a modifiable factor that can support overall hair health and, in some cases, reduce excessive shedding. Understanding which foods and dietary patterns may be problematic is a useful starting point for anyone concerned about hair loss.

Further information is available from the NHS hair loss (alopecia) page and the British Association of Dermatologists (BAD) patient information leaflet on telogen effluvium.

Foods and Nutrients Linked to Increased Hair Shedding

High-glycaemic foods, excess selenium, heavy alcohol use, very high-mercury fish, and large quantities of raw egg whites have all been associated with increased hair shedding through hormonal, toxic, or nutritional mechanisms.

Whilst no single food directly causes hair loss in isolation, certain dietary patterns and specific foods have been associated with increased hair shedding in some individuals. These associations are generally indirect, mediated through hormonal, inflammatory, or nutritional mechanisms rather than a direct toxic effect on the hair follicle.

High-glycaemic index (GI) foods — such as white bread, sugary cereals, fizzy drinks, and processed snacks — have been proposed to contribute to hair loss by promoting insulin resistance and elevating androgen levels. Androgens, particularly dihydrotestosterone (DHT), are well-established drivers of androgenetic alopecia (pattern hair loss). However, it is important to note that the evidence linking high-GI diets directly to increased hair shedding is currently limited and largely observational; this mechanism remains biologically plausible but not firmly established. A diet consistently high in refined carbohydrates and free sugars is nonetheless discouraged on broader health grounds, in line with NHS dietary guidance.

Excess selenium is another dietary concern. Selenium is an essential trace mineral, but in high doses it can be toxic. The NHS advises that men need approximately 75 micrograms of selenium per day and women approximately 60 micrograms per day. Adults should not regularly take more than 350 micrograms of selenium per day from supplements, as exceeding safe upper limits over time may cause selenosis — a condition whose symptoms can include hair loss, brittle nails, and gastrointestinal disturbance. Excessive consumption of Brazil nuts (which are very high in selenium) is a recognised dietary source of excess intake.

Other foods and dietary habits worth noting include:

• Excessive alcohol consumption, which can impair nutrient absorption and disrupt zinc and folate levels. The UK Chief Medical Officers advise that, to keep health risks low, adults should drink no more than 14 units of alcohol per week, spread across three or more days.

• Very high-mercury fish — the NHS advises avoiding shark, swordfish, and marlin due to high mercury content, and recommends limiting tuna intake (no more than four medium-sized tins or two fresh tuna steaks per week for most adults; lower limits apply during pregnancy). Mercury toxicity has been associated with hair loss, though this is uncommon in the general UK population following standard dietary guidance. Note that mackerel (a different species) is generally encouraged as a healthy oily fish.

• Raw egg whites, which contain avidin, a protein that binds biotin and may impair its absorption. This is only clinically relevant with very high, sustained intake of raw egg whites — a pattern atypical of most UK diets.

These associations do not mean these foods must be avoided entirely, but moderation and dietary balance remain key principles. See NHS guidance on selenium, fish and shellfish, and the UK Chief Medical Officers' Low Risk Drinking Guidelines for further detail.

Nutritional Deficiencies That May Contribute to Hair Loss

Iron and vitamin D deficiencies are the most clinically supported nutritional contributors to hair loss; zinc, biotin, protein, and vitamin B12 deficiencies may also play a role and should be confirmed by blood testing before supplementation.

Several well-documented nutritional deficiencies are associated with hair loss, and addressing these through diet or supplementation — under medical guidance — may help reduce shedding and support regrowth.

Iron deficiency is one of the most common nutritional causes of hair loss, particularly in women of reproductive age. Iron is essential for the production of haemoglobin, which carries oxygen to hair follicle cells. Low ferritin (stored iron) levels, even in the absence of frank anaemia, have been associated with telogen effluvium, though the precise ferritin threshold at which hair loss occurs is debated and management should be individualised. The NHS recommends a daily iron intake of 14.8 mg for women aged 19–50 and 8.7 mg for men and post-menopausal women; good dietary sources include red meat, lentils, spinach, and fortified cereals. Iron supplementation should not be started without a confirmed deficiency on blood testing, as excess iron can be harmful. Where iron deficiency is identified, clinicians may also consider screening for underlying causes such as coeliac disease. See NICE CKS: Anaemia – iron deficiency and the BSH guideline on management of iron deficiency anaemia in adults.

Vitamin D deficiency is increasingly recognised as a potential contributor to hair loss. Vitamin D receptors are present in hair follicles, and research suggests that low levels may disrupt the hair growth cycle. Given that vitamin D deficiency is widespread in the UK — particularly during autumn and winter — the NHS recommends that most adults consider a daily supplement of 10 micrograms (400 IU) from October to March. Those at higher risk of deficiency (including people with darker skin, those who are housebound, or those who cover most of their skin) are advised to supplement year-round. Adults should not regularly take more than 100 micrograms (4,000 IU) per day unless advised by a clinician. See NHS: Vitamins and minerals – Vitamin D.

Other key deficiencies linked to hair loss include:

• Zinc: supports hair follicle repair and protein synthesis; found in meat, shellfish, legumes, and seeds. Adults should not regularly take more than 25 mg of zinc per day from supplements, as excess zinc can cause copper deficiency, which may itself contribute to hair problems. See NHS: Vitamins and minerals – Zinc.

• Biotin (Vitamin B7): true deficiency is rare in the UK but can cause hair thinning; found in eggs, nuts, and wholegrains. Importantly, high-dose biotin supplements can interfere with a range of laboratory immunoassays — including thyroid function tests and troponin measurements — potentially causing misleading results. The MHRA has issued a Drug Safety Update on this risk; patients taking biotin supplements should inform their GP or any clinician requesting blood tests before the sample is taken. See MHRA Drug Safety Update: Biotin (vitamin B7) interference with laboratory tests.

• Protein: inadequate dietary protein can trigger telogen effluvium, as hair is primarily composed of keratin, a structural protein. UK reference intakes suggest approximately 0.75 g of protein per kilogram of body weight per day for adults.

• Vitamin B12: deficiency — common in those following vegan or some vegetarian diets, and in those with malabsorption conditions — may impair red blood cell production and reduce oxygen delivery to follicles. Vegans and others at risk should ensure adequate intake through fortified foods or supplements. See NHS: Vitamins and minerals – Vitamin B12.

Identifying and correcting specific deficiencies through blood tests and targeted dietary changes is more effective — and safer — than taking broad-spectrum supplements without clinical guidance.

What the Evidence Says: Diet and Hair Loss Research

Current evidence is largely observational; a Mediterranean-style diet is associated with reduced androgenetic alopecia risk, and iron and vitamin D supplementation in deficient individuals is reasonably well-supported, but biotin supplements show no proven benefit in non-deficient people.

The scientific evidence linking specific foods to hair loss is growing, though it remains an evolving field with important limitations. Much of the existing research is observational, meaning it identifies associations rather than proving direct causation. Randomised controlled trials in this area are relatively scarce, and many studies involve small sample sizes or short follow-up periods.

A case-control study published in the Journal of the American Academy of Dermatology (2020) found that a Mediterranean-style diet — rich in raw vegetables, fresh herbs, and olive oil — was associated with a reduced risk of androgenetic alopecia or delayed onset. It is important to note that, as an observational study, this finding demonstrates an association only and does not establish causation. The proposed mechanisms — including reduced oxidative stress and modulation of inflammatory pathways — are biologically plausible hypotheses that require further investigation through interventional research before firm clinical recommendations can be made.

Research into the role of the gut microbiome and hair health is also emerging. Some studies suggest that gut dysbiosis — an imbalance in intestinal bacteria, often influenced by diet — may affect nutrient absorption and systemic inflammation, both of which can indirectly impact hair growth. However, this area is at an early stage and does not yet support specific dietary recommendations.

With regard to specific nutrients, the evidence for iron and vitamin D supplementation in deficient individuals is reasonably well-supported. In contrast, the evidence for biotin supplementation in people without a confirmed deficiency is weak; despite its widespread marketing for hair health, clinical trials have not demonstrated significant benefit in non-deficient individuals. Furthermore, as noted above, high-dose biotin supplements can interfere with laboratory immunoassays, a risk highlighted in an MHRA Drug Safety Update. The MHRA and NHS both caution against self-prescribing high-dose supplements without medical advice, as excess intake of certain nutrients can itself cause harm.

Overall, the evidence supports a balanced, varied diet — broadly aligned with the NHS Eatwell Guide — as the most reliable dietary strategy for maintaining hair health.

Dietary Changes That May Support Healthier Hair

Prioritising adequate protein, eating a wide variety of colourful vegetables and fruits, including healthy fats, and avoiding crash dieting are the most evidence-aligned dietary strategies for supporting hair health.

Rather than focusing on eliminating specific foods, a more evidence-informed approach is to adopt a balanced, nutrient-dense diet that supports the hair growth cycle from within. The following dietary principles are broadly aligned with the NHS Eatwell Guide and NICE nutritional guidance and may help reduce diet-related hair shedding.

Prioritise protein at every meal. Since hair is made primarily of keratin, adequate protein intake is fundamental. UK reference intakes suggest approximately 0.75 g of protein per kilogram of body weight per day for adults. Aim to include high-quality protein sources such as:

• Lean meat, poultry, and fish

• Eggs and dairy products

• Legumes, tofu, and tempeh for plant-based options

Eat a wide variety of colourful vegetables and fruits. These provide antioxidants — including vitamins A, C, and E — that help protect hair follicles from oxidative damage. Dark leafy greens such as spinach and kale are particularly valuable, offering iron, folate, and vitamin C simultaneously.

Include healthy fats. Omega-3 fatty acids, found in oily fish (salmon, mackerel, sardines), walnuts, and flaxseeds, support general scalp and skin health. Direct evidence for omega-3 supplementation improving hair growth is limited, but these foods are beneficial for overall health and are consistent with NHS dietary guidance. The NHS recommends eating at least two portions of fish per week, one of which should be oily. Pregnant women and those planning pregnancy should follow NHS guidance on fish portions and species to avoid.

Avoid crash dieting and very low-calorie diets. Rapid caloric restriction is a well-recognised trigger for telogen effluvium. If weight loss is a goal, a gradual, nutritionally complete approach is strongly preferable.

Limit foods high in free sugars, saturated fat, and salt. In line with NHS Eatwell Guide principles, reducing intake of these — commonly found in highly processed foods, confectionery, and sugary drinks — supports metabolic health and helps avoid the insulin spikes and systemic inflammation that may negatively influence hair follicle cycling.

If dietary changes alone do not resolve hair shedding within three to six months, or if deficiencies are suspected, a GP can arrange blood tests to identify underlying causes and advise on appropriate supplementation. Self-prescribing high-dose supplements without a confirmed deficiency is not recommended. See the NHS Eatwell Guide for further dietary guidance.

When to Seek Medical Advice About Hair Loss

Consult your GP if hair loss is sudden, patchy, accompanied by systemic symptoms, or fails to improve with dietary changes, as many underlying medical causes — including thyroid dysfunction and iron deficiency — are treatable once correctly diagnosed.

Hair loss can be distressing, and whilst dietary factors may play a role, it is essential not to overlook other underlying medical causes. Many conditions that cause hair loss are treatable once correctly diagnosed, so timely medical assessment is important.

You should contact your GP if you notice:

• Sudden or rapid hair loss over a short period

• Patchy hair loss or bald spots (which may suggest alopecia areata, an autoimmune condition)

• Hair loss accompanied by fatigue, unexplained weight changes, or feeling cold — potential signs of thyroid dysfunction

• Scalp redness, scaling, itching, or pain, which may indicate a dermatological condition such as scalp psoriasis or tinea capitis (ringworm)

• Signs of scarring on the scalp (such as loss of follicular openings, persistent redness, or burning sensation), which may suggest a scarring alopecia requiring prompt specialist assessment

• Hair loss following a significant illness, surgery, or period of extreme stress

• Postpartum hair loss that is severe, prolonged beyond 12 months, or accompanied by other symptoms

• Features that may suggest hyperandrogenism — such as acne, increased facial or body hair, or irregular periods — which may warrant assessment for conditions such as polycystic ovary syndrome (PCOS)

• Hair thinning that is progressive and does not improve with dietary changes

Your GP may arrange blood tests to check for relevant underlying causes. Tests commonly requested include full blood count (FBC), ferritin, thyroid-stimulating hormone (TSH), vitamin D, vitamin B12, and folate; additional tests may be ordered based on your history and examination findings. If you are taking biotin supplements, inform your GP and the laboratory before blood samples are taken, as biotin can interfere with certain immunoassay results.

Depending on findings, your GP may refer you to a dermatologist for specialist assessment. It is worth noting that whilst some practitioners use the title 'trichologist', this is not a medically regulated profession in the UK, and dermatology referral is the standard NHS pathway for complex or persistent hair loss.

For androgenetic alopecia and alopecia areata, NICE Clinical Knowledge Summaries (CKS) and British Association of Dermatologists (BAD) guidance outline a range of management options. Topical minoxidil is available over the counter in the UK for androgenetic alopecia; patients should read the product's Summary of Product Characteristics (SmPC) carefully, as it should be avoided during pregnancy and breastfeeding and may cause local scalp irritation. If you experience a suspected side effect from any medicine, including topical minoxidil, you can report it to the MHRA via the Yellow Card scheme at yellowcard.mhra.gov.uk.

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The NHS also provides psychological support — including through NHS Talking Therapies — for those significantly affected by hair loss, recognising the impact it can have on mental wellbeing and self-esteem.

In summary, whilst diet is a meaningful and modifiable factor in hair health, it is one piece of a larger clinical picture. A balanced diet, combined with appropriate medical investigation where needed, offers the most rational and evidence-based approach to managing hair loss. See NICE CKS: Alopecia areata, BAD patient information, and the NHS hair loss (alopecia) page for further guidance.

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