Experts link everyday foods to increased hair shedding, recommend tests and dietary swaps

A growing body of research and clinical advice from dermatologists underscores the role of diet in hair loss, with experts warning that common foods such as refined carbohydrates, Brazil nuts and certain tuna may accelerate shedding, while protein-rich foods like eggs can help maintain healthy hair.

A study published last month that linked frequent consumption of fizzy drinks to hair loss highlighted nutrition as a modifiable factor in a condition that affects millions. Consultant dermatologist Dr. Ellie Rashid said diet can amplify or mitigate other causes of hair loss, including genetics, hormonal pattern baldness and autoimmune conditions such as alopecia areata.

"Diet is so important," Dr. Rashid said. "Deficiency of the right nutrients will lead to brittle hair, less hair growing or hair being shed more readily." She recommended blood tests for iron, zinc, vitamin D and folate (vitamin B9) to identify deficiencies that can affect the hair growth cycle. She advised increasing iron through foods such as red meat, lentils and leafy greens including spinach and kale, topping up vitamin D through sunlight and supplements, and boosting zinc with foods or supplements such as pumpkin or sesame seeds.

Dermatologists point to several everyday items that evidence or clinical experience suggests may harm hair when consumed in excess. Refined carbohydrates — including white bread, pasta made from highly processed flours, cakes, sweets and sugar-sweetened drinks — digest quickly and cause spikes in blood sugar and insulin. A 2016 review published in Menopause Review concluded that consumption of highly processed foods rich in simple sugars can be a factor in hair loss. The review described insulin-related effects on blood vessels that can reduce oxygen supply to the scalp and disrupt cellular processes such as keratin formation.

"Refined carbs are a driver of inflammation. They negatively impact cellular processes such as keratin formation — meaning hair doesn’t grow as well as it should," Dr. Rashid said, recommending people switch from white bread and refined pasta to wholemeal alternatives.

Nuts are commonly recommended as part of a balanced diet, but dermatologists caution against overconsumption of Brazil nuts because of their high selenium content. Dr. Paul Farrant, a consultant dermatologist at Experts In Skin And Hair, said selenium is essential for thyroid and immune function but can be harmful in excess.

"The recommended dose of selenium can come from as little as one Brazil nut a day. It’s easy to take too many. Selenium toxicity is linked to brittle hair and disturbs the hair cycle," Dr. Farrant said.

Large predatory fish can also pose a risk through heavy metal exposure. Tuna, particularly larger species such as yellowfin and bluefin, may contain mercury accumulated from contaminated prey. Mercury can damage the nervous system, kidneys and hair follicles, and in rare cases of high exposure can contribute to hair loss.

"It’s not something most of us eat in sufficient quantities to get toxicity, but you can get heavy metal poisoning from tuna. Hair needs good nutrition, and if you add things that are effectively poisons it will affect hair growth and cause hair loss," Dr. Farrant said.

On the positive side, clinicians identify eggs as among the most beneficial everyday foods for hair. Eggs are rich in protein, which is the structural basis of hair keratin, and contain vitamin B12, folate and some vitamin D — nutrients linked to the hair growth cycle.

"If you eat lots of eggs, your hair will benefit. Hair is a protein-rich structure, based on keratin, which means you need plenty of protein in your diet to grow strong hair," Dr. Farrant said. He noted vitamin D deficiency can shift hairs from the growing phase into a shedding phase.

Clinicians advise that while diet is an important and modifiable factor, hair loss is multifactorial. Genetic pattern baldness remains the most common cause, and autoimmune conditions such as alopecia areata involve immune attack on hair follicles. Diet, they say, can "ramp up" or "dial down" the effects of these other drivers.

Practically, dermatologists suggest routine screening for nutrient deficiencies in people experiencing increased hair shedding and recommend dietary swaps such as choosing wholegrain carbohydrates over refined options, moderating intake of high-selenium foods like Brazil nuts, limiting frequent consumption of large tuna species, and including adequate protein sources such as eggs. Clinicians also remind patients that seasonal patterns exist: September is commonly reported as a peak month for hair shedding, which may relate to temperature and seasonal changes.

The advice from clinicians aligns with a broader public health emphasis on balanced diets and targeted testing to identify and correct nutrient deficits that can influence hair health alongside medical evaluation for underlying causes.