The Impact of Diet Quality on Mental Health – Prof Felice Jacka

Posted on: December 31, 2016
Last Updated: September 27, 2020

Professor Jacka is a psychiatric epidemiologist, Director of the Food and Mood Centre and founder and president of the International Society for Nutritional Psychiatry Research (ISNPR). She is an NHMRC Career Development Fellow at Deakin University in Australia, within the IMPACT SRC at the School of Medicine. She also holds Honorary Principal Research Fellow appointments at the Centre for Adolescent Health, Murdoch Children’s Research Centre; The University of Melbourne; and the Black Dog Institute in NSW. 

Author Quotes  

If we want to think about prevention, we need to be really thinking about these early time periods.

Between 25-30% of young people in Australia are overweight or obese and 65% of the adult population. One of the primary drivers of systemic inflammation is adipose tissue, particularly around the gut.

The higher the level of adherence to a Mediterranean style diet, the lower the risk for new depression over that time frame.

Summary and slides 

A/Prof Felice Jacka begins this section of her talk with a discussion about common mental health disorders – anxiety and depression. The average age of onset for anxiety is six years old; whereas, the average age of onset for depression is 13 years old.

There is good evidence now that suggests that the prevalence of psychological distress, particularly in young people, is actually increasing. In addition, over a similar time period, there has been a significant increase in obesity rates. The apparent increase in the prevalence of psychiatric distress in young people has tracked with the increase in obesity as well.

Two important studies (1 &2) led by A/Prof Jacka found that for each standard deviation increase in the unhealthy ‘Western’ dietary pattern, there was an increase in the odds ratio for the mood disorders – major depression, dysthymia, and bipolar disorder; however, not with anxiety in this particular case (the results were adjusted for age, education, SEIFA (Socioeconomic indexes), PA (Physical activity), smoking, alcohol, energy intake, and BMI).

The SUN cohort study (4) looked at the participants’ level of adherence to a Mediterranean-style dietary pattern (which is a very healthy way of eating), and they tracked them for about 4 ½ years, looking for the incidence of depression.

The Whitehall II cohort study (5) found that higher scores on the Western-type dietary pattern predicted de-novo depression over the 5-year follow-up period and those on the whole food dietary pattern had a reduced risk; not explained by reverse causality.

The SUN Project (6) which studied the role of dietary fat intake and the risk of depression reached the following conclusion-
A detrimental relationship was found between TFA (trans unsaturated fatty acids) intake and depression risk, whereas weak inverse associations were found for MUFA, PUFA and olive oil. These findings suggest that cardiovascular disease and depression may share some common nutritional determinants related to subtypes of fat intake.
Another study (7) investigating the relationship between fast food and commercial baked goods consumption showed an almost 40% increase in new depression over time.

Take-Home Points 

  • The apparent increase in psychiatric distress in young people can be tracked with increases in obesity  
  • Since 2009 there has been a rapid increase in high quality large-scale epidemiological published studies in this field 
  • A primary driver of systemic inflammation is excess adipose tissue 
Quiz


References:

  1. Jacka, F. N., Mykletun, A., Berk, M., Bjelland, I., & Tell, G. S. (2011). The association between habitual diet quality and the common mental disorders in community-dwelling adults: the Hordaland Health study. Psychosomatic medicine, 73(6), 483-490.