Hormones may be the key to treating anorexia

But anorexia nervosa — like other conditions primarily affecting women — has been poorly understood, under-recognised, under-researched, and underfunded for decades.

Case in point: there are only seven high-quality reviews synthesising decades of research from around the world on anorexia, compared to 226 for generalised anxiety disorder, despite both conditions having a similar prevalence.

Fortunately, the tide is turning.

Medical scientists have made significant strides in understanding how hormonal changes impact women’s mental health over the last two decades. And research by institutions including Monash University’s HER Centre Australia and Monash Alfred Psychiatry Research Centre has shed light on how hormonal changes during various life stages — menstruation, contraception use, pregnancy, postpartum, and menopause — affect mental illnesses.

The oestrogen link

For more than 50 years, theories have suggested a link between anorexia and female hormones.

In animal models, oestrogen has been shown to reduce food intake in the short term. Given that anorexia nervosa often manifests in the years following the onset of menstruation — a time when the female body experiences a surge of oestrogen — some experts think oestrogen may be part of its cause.

But here’s where it gets complicated. Women with eating disorders typically exhibit low oestrogen levels compared to unaffected women. It’s unclear whether it’s the malnutrition from anorexia that causes this low oestrogen or vice versa. This oestrogen-deficient state severely impacts a patient’s bone health, but does not reverse their anorexia.

Scientists have also found that oestrogen receptors throughout the body, including the brain, have varying and sometimes opposing effects. These receptors trigger a cascade of responses, including sensitising the body to other hormones like thyroxine and ghrelin, which themselves influence weight and appetite (while an increase in ghrelin directly increases appetite, thyroxine influences weight in more complex ways).

Is oestrogen replacement therapy the answer?

Given the link between oestrogen and anorexia, researchers — including myself and colleagues at Monash University’s HER Centre, within its Li Transformative Hub for Research into Eating Disorders (Li-THRED) — are hoping to develop new treatments for anorexia, drawing on not only oestrogen’s potential to impact weight and appetite, but also its broader impact on mood and thinking.

There are currently no effective medication treatments for anorexia. The cornerstone of treatment is psychological therapy with support for a patient’s nutritional and medical needs.

But accessing psychological therapies is challenging due to workforce shortages, lack of specialist services (especially in regional and remote areas) and growing out-of-pocket costs for Medicare-funded services.

At times patients are so unwell from malnutrition, they are deemed “too unwell” to participate in psychological therapy. Some patients are also ambivalent about recovery, as the nature of their illness makes them wary of relinquishing control over their diet and working toward weight restoration. Even when patients can access specialist psychological therapies, a significant number still don’t respond to treatment.

This lack of accessible and effective treatments underscores the urgent need for more research into medication treatments for anorexia.

Here’s where new research into oestrogen replacement therapy comes in.

Anorexia is a complex illness that intertwines abnormal eating behaviours with significant disturbances in cognitive function, mood states, and self-perception.

Oestrogen replacement therapy has been successfully used to treat cognitive impairment and mood disorders in premenstrual dysphoric disorder and the perimenopausal period. It is hypothesised that by improving cognitive function and mood disturbances, oestrogen, coupled with psychological therapy, may help reduce the psychological symptoms of anorexia, making it easier for patients to recover.

This could be the case for all women with anorexia — and not just for women in life stages where their oestrogen has recently dropped, such as in the time around menopause.

While research has shown that transdermal oestrogen, oestrogen given by applying a medicated patch to the skin, can benefit bone mineral density for people with anorexia, only one known study has investigated its effects on other aspects of anorexia.

This study, conducted with 37 adolescent women, found that 100 mcg of transdermal oestrogen over 18 months reduced some aspects of anxiety. Another study examined the effects of 12 months of 100 mcg transdermal oestrogen on 73 amenorrheic athletes without anorexia but with anorexia-like mental traits, finding that oestrogen administration reduced eating disorder thoughts and body dissatisfaction.

Research in this space is still in early days, but offers hope.

Research teams like the Li-THRED team at Monash University are conducting clinical trials to investigate new medication and brain stimulation treatments for anorexia, including trans magnetic stimulation, dietary supplements, and female hormones. Li-THRED’s trials are ambitious, aiming to recruit more than 200 participants.

What more is needed

Fortunately, eating disorders have gained more public funding in recent years.

Government spending on eating disorder initiatives has increased sharply from AU$500,000 in 2012-13 to AU$71 million in 2021-22. In 2019, new Medicare items allowed patients with anorexia to access up to 40 psychology and 20 dietetics appointments per year — a significant increase from the previous 10 psychological and five allied health sessions.

But despite these wins, research in Australia remains chronically underfunded and often relies on donations.

The Australian economic and social costs of eating disorders were $20.8 billion in 2023, according to a March 2024 report by peak eating disorders body The Butterfly Foundation. And amid a cost-of-living crisis, “most of the costs associated [with treatment] are financially crippling, particularly for individuals and their families.”

What’s more, many Australian psychiatrists and general doctors still lack the skills or experience to diagnose and treat these conditions effectively. Due to the difficulties accessing effective treatments, many GPs are left managing these complex patients on their own. More training and funding for community based and inpatient eating disorder services could help, as could the discovery of more effective treatments.

While progress has been made in understanding the relationship between women’s hormones and anorexia nervosa, much work remains. Continued research and innovative treatments are essential to improving outcomes for those affected by this complex and life-threatening illness.

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