Experts link refined carbs, some nuts and tuna to hair loss; eggs recommended for healthy locks

Dermatologists and hair specialists are warning that everyday foods may accelerate hair thinning and shedding, with refined carbohydrates, certain nuts and large predatory fish singled out as potential contributors while eggs are highlighted as especially beneficial.

The warnings follow research last month that associated high consumption of fizzy drinks with hair loss and underline the role diet can play alongside genetics and illness. Consultant dermatologist Dr. Ellie Rashid said diet can "ramp up the effects of these other factors or dial them down," and urged patients to check levels of iron, zinc, vitamin D and folate by blood tests and to adopt a balanced diet.

Experts pointed to refined carbohydrates — white bread, pasta made from refined flour, cakes, sweets and other foods high in processed sugar — as a likely driver of increased hair shedding. Refined carbs are digested quickly and cause rapid spikes in blood sugar and insulin. A 2016 review in the journal Menopause Review concluded that consumption of highly processed foods rich in simple sugars is one factor contributing to excess hair loss, and researchers said insulin spikes can disrupt blood vessels and reduce oxygen supply to the scalp.

"Refined carbs are a driver of inflammation," Dr. Rashid said. "They negatively impact cellular processes such as keratin formation — meaning hair doesn’t grow as well as it should." She advised switching from white bread and pasta to wholemeal alternatives to slow glucose absorption and reduce inflammatory effects.

Two other dietary concerns cited by clinicians are selenium toxicity from excess Brazil nuts and mercury exposure from large species of tuna. Brazil nuts are an unusually rich source of selenium, a mineral important for thyroid and immune function, but too much can cause brittle hair and disturb the hair growth cycle, said Dr. Paul Farrant, consultant dermatologist at Experts In Skin And Hair. He noted that the recommended selenium intake can be reached with as little as one Brazil nut a day, making overconsumption easy.

Concerns about tuna focus on heavy metal contamination in larger species such as yellowfin and bluefin. Mercury exposure damages the nervous system and kidneys and can affect hair follicles. "It’s not something most of us eat in sufficient quantities to get toxicity, but you can get heavy metal poisoning from tuna," Dr. Farrant said.

By contrast, clinicians pointed to eggs as one of the most beneficial foods for hair health. Eggs are rich in protein, which is the structural basis of hair (keratin), and contain vitamin B12, folate and vitamin D — nutrients linked to stronger hair and a healthier hair growth cycle.

"If you eat lots of eggs, your hair will benefit," Dr. Farrant said. He added that vitamin D deficiency is associated with more hairs exiting the growing phase and entering the shedding phase, and that adequate protein supports the production of keratin regardless of how eggs are cooked.

Clinicians recommended dietary sources for nutrients that support hair growth. Iron can be increased through red meat, lentils and leafy greens such as spinach and kale. Vitamin D can be obtained from sunlight and supplements, and zinc is available from foods such as pumpkin and sesame seeds or from supplements when indicated. Specialists stressed that deficiencies — not single foods alone — are often the proximate cause of hair problems and that diet can modify the expression of genetic or autoimmune hair disorders.

Pattern baldness, primarily driven by genetics and hormones, remains the most common cause of hair loss. Alopecia areata, an autoimmune condition in which the immune system attacks hair follicles, is another important cause. Both conditions can interact with nutritional status, clinicians said.

Practitioners advised patients concerned about hair thinning to seek medical assessment, including blood tests for iron, zinc, vitamin D and folate, before making major dietary changes or starting supplements. They cautioned that excessive intake of any single nutrient can be harmful and that balanced dietary adjustments are generally safer than high-dose supplements taken without medical supervision.

Clinicians also noted seasonal patterns in shedding: September is commonly reported as a month with increased hair loss, a trend that has been linked by some researchers to changes in temperature and seasonal hair growth cycles.

The message from specialists was pragmatic: improving overall nutrition and addressing specific deficiencies can help support hair health, while moderating intake of certain processed carbohydrates, limiting very selenium-rich nuts to small amounts and being cautious about consuming large predatory fish may reduce risks associated with diet-related hair damage.