Tuna and other surprising causes of hair loss

Almost 80% of men and 40% of women will experience hair loss at some point in their lives, and while genetics and ageing are the most common causes of this, there are several other factors that can contribute to thinning hair.

“Hormonal imbalances, such as those related to thyroid disorders, pregnancy, or polycystic ovary syndrome (PCOS), can lead to hair shedding,” says Dr Bessam Farjo, Hair Transplant Surgeon at Farjo Hair Institute. 

He continues: “Certain medications, including chemotherapy drugs, antidepressants and blood thinners, can also cause hair loss as a side effect.”

However, your hair loss may also be triggered by less obvious factors, such as diet and lifestyle. If you're noticing more hair in your brush lately, here are five possible causes of hair loss that might surprise you.

1. Eating fish with high levels of mercury

Tuna lovers, watch out! Too much mercury can lead to hair problems and fish like tuna and swordfish contain the highest amounts.

“High mercury levels (mercury toxicity) can cause numerous health problems, which may include hair loss,” say Anabel Kingsley, Consultant Trichologist at Phillip  Kingsley. 

“Mercury is a heavy metal and can be poisonous. If you eat excessive amounts of high mercury fish, like fresh tuna, yellowfin tuna and swordfish, your mercury levels may become elevated, and this could impact your health and your hair – the two being closely linked.”

While the FSA only has recommendations for how much tuna pregnant women should eat – no more than four cans a week - it's worth noting that the effects on hair health can be relevant for people of all ages.

2. Certain supplements

Ironically, what you think is a healthy vitamin routine could be one of the causes of hair loss, if you're taking the wrong supplements or too many.

“I see this most commonly in people who take multiple supplements and don’t cross-check what’s in them,” says Annabel. “For instance, intaking excessive amounts of Vitamin A can cause hair loss.”

Dr Bessam stresses that a healthy, well-balanced diet will benefit your health and hair more than taking supplements.

“Getting nutrients from a well-rounded diet rather than relying heavily on supplements is the safest approach,” he says. “If hair loss occurs after starting a new supplement regimen, reducing intake and consulting a healthcare professional would be recommended

3. Stress

Your body responds to stress in surprising ways. When you're stressed, your body diverts energy away from hair growth.

“Stress is such a common cause of a type of hair loss called ‘telogen effluvium’ (excessive daily hair shedding)’,” explains Annabel

She continues: “The stress hormone, cortisol, can shorten the anagen (growth phase) of the hair growth cycle and prolong the telogen (resting) stage. This results in more daily hair fall and less density of scalp hair.”

If you’re stressed, you may not be eating properly and so not getting the right nutrients into your body – and hair. 

Stress can also aggravate scalp conditions, causing inflammation, which can lead to hair loss.

“Scalp health is vital to hair growth,” says Annabel. “Inflammation and a flaky scalp can contribute to hair loss.”

She suggests taking care of your scalp like you would your skin. As well as shampooing regularly and thoroughly, she also recommends a regular scalp exfoliation. 

“Exfoliate your scalp once a week with a chemically exfoliating scalp mask,” she says. “Don’t use masks with large, abrasive particles (like salt), and there’s no need to buy a special scalp massage brush. Some of these can damage your hair and scalp, and really – your fingertips are your best tool.”

While stress can be related to situations beyond your control, deep breathing or yoga can help keep it under control, while also helping those hair follicles to stay strong. Alternatively, chat to friends or message a mental health support service like Shout.

4. Weight loss

Rapid weight loss can shock the body, and hair is often one of the first areas to show the effects. 

“When the body undergoes significant stress, such as sudden calorie restriction or intense exercise, it may redirect nutrients away from non-essential functions like hair growth to prioritise vital organs,” says Dr Bessum. 

Thankfully he says that this kind of hair loss is usually temporary, however it can last several months before regrowth begins. His tip? Lose weight gradually and ensure your diet is balanced with the right amount of protein, healthy fats and vitamins. 

5. Low iron and vitamin levels

When it comes to female hair loss, Annabel says one of the common causes she comes across is low levels in certain vitamins and minerals. 

“The most common causes of telogen effluvium that I see in women are low ferritin (stored iron) levels and Vitamin B12 and Vitamin D deficiency,” she says. “Crash dieting, skipping meals and inadequate nutrient/calorie intake are also common triggers.”

She also says that while most hair loss for women is genetic, hormonal changes can worsen it, especially if you are also stressed.

If you're unsure whether your iron or vitamin levels are low, consult your GP, who can order a simple blood test.