It seems we are just waking up to the idea that what we eat may affect our mood, our risk of depression or even our risk of developing dementia in old age. New research indicates that our health in mid-life may affect our mental health both now and later in life. This emerging area of science was one focus of the recent Food Industry Forum for Nutrition Research in Sydney.
Mood and anxiety disorders affect a large number of people and affect people from a very young age. One Australian study found that 35% of women reported having had a mood or anxiety disorder at some stage during their lives.1 The average age of onset of anxiety disorders is 6 years old and depression is 13 years old. Given these figures it is not surprising depression is anticipated to be the second highest cause of disability in the world by 2020. What may be surprising though is that these mental disorders appear to be linked to the choices we make in the food we eat.
At the Food Industry Forum in September, Associate Professor Felice Jacka gave a presentation of the latest research in this area including a number of studies conducted in Australia. In an Australian study of 1,000 women a ‘traditional diet’ consisting mainly of vegetables, fruit, beef, lamb, whole grains and fish was linked to lower risk of both anxiety and depression. A ‘Western diet’ characterized by high intakes of fast food and junk food increased risk of these conditions.2 A/Professor Jacka explained there are now a large number of population studies that indicate a less healthy diet is linked to higher risk of mental disorders, even when taking into account other factors such as social situation, income, age or family history.
Interestingly studies in teenagers show similar results. In one example an Australian prospective cohort study of adolescents found that teens whose diet became less healthy were more likely to have deteriorating mental health. Given the young age of onset of mental health disorders, the authors suggest it is possible a healthier diet could help prevent common mental health disorders in adulthood.
Our physical health in our early years may also affect our mental health later in life. At the Forum, Professor Kaarin Anstey from the Australian National University presented the findings of a systematic review of the link between mid-life obesity and increased risk of late-life dementia. The review found that people who are overweight or obese in mid-life are more likely to suffer Alzheimer’s disease and dementia later in life. It appears that abdominal adiposity (carrying more weight around the belly) in particular increases risk.
Professor Dye from Leeds University in the UK explained that changes in cognition may be due to foods having direct effect on the brain. Alternatively, changes in the food we eat may also lead to better health by lowering blood pressure, losing weight, improving blood sugar control or blood flow. Better health may help to improve brain function as trials have shown that people who are obese, have type 2 diabetes or impaired glucose tolerance do not do as well in tests of memory and concentration.
So, a healthy diet now is not just important for your physical wellbeing, it may also help keep your mind healthy well into old age. To reduce your risk of declining mental health due to gaining weight, or developing chronic disease such as diabetes and heart disease enjoy a variety of vegetables, fruit, whole grains and legumes every day.
Presentations from the Food Industry Forum for Nutrition Research
- Associate Professor Felice Jacka, Deakin University: Diet as a modifiable risk factor for depression
- Professor Kaarin Anstey from the Australian National University: The association between obesity, cognitive decline and dementia from middle age to late life
- Louise Dye, University of Leeds: Foods for cognitive performance
1. Williams L, et al. The prevalence of mood and anxiety disorders in Australian women. Australas Psychiatry. 2010 Jun;18(3):250-5.
2. Jacka F, et al. Association of Western and traditional diets with depression and anxiety in women. Am J Psychiatry. 2010 Mar;167(3):305-11.
3. Jacka F, et al. A Prospective Study of Diet Quality and Mental Health in Adolescents. PLoS One. 2011;6(9):e24805