‘Nutritional psychiatry’ is an emerging discipline shedding light on the fact that nutritional factors are intertwined with human emotions, cognition and behaviour, and highlights the use of food and supplements to provide these essential nutrients in the prevention of mental health problems and in the management and recovery from these when and if they do occur.⁵

Mental health conditions such as anxiety and depression, can arise at any age or life stage. According to the latest estimates from the World Health Organisation (WHO), approximately 1.3 million Australians are currently experiencing a depressive disorder and 1.6 million are experiencing an anxiety disorder.¹

Studies show that typical Western diets which are high in excess salt, sugar and fat, and deficient in fruits, vegetables and whole grains, are more likely to lead to symptoms of depression and anxiety.²

An increasing amount of research demonstrates that increased consumption of fruits and vegetables is positively associated with mental and subjective well-being,3 yet only around 5% of Australian adults have a sufficient daily intake of both fruit and vegetables.⁴

A 2018 systematic review highlighted twelve key nutrients related to the prevention and treatment of depressive disorders:

1. Folate
2. Iron
3. Long-chain omega-3 fatty acids (EPA and DHA)
4. Magnesium
5. Potassium
6. Selenium
7. Thiamine
8. Vitamin A
9. Vitamin B6
10. Vitamin B12
11. Vitamin C
12. Zinc. 

An Antidepressant Food Score was then used to determine the most nutrient-dense individual foods that prevent and promote recovery from depressive disorders and symptoms. The highest scoring animal foods and plant foods were:

• Oysters and mussels
• Various sea-foods and organ meats
• Leafy greens
• Lettuces
• Peppers, and
• Cruciferous vegetables.⁵

To further ascertain the relationship between well-being and the consumption of fruits and vegetables, researchers drew upon data from the UK Household Longitudinal Study, which contains lifestyle information relating to approximately 50,000 individuals from between 2009 to 2017. Using the General Health Questionnaire and self-reported life satisfaction as indicators, the researchers found that well-being rises in an approximately dose response way with both the number of portions of fruits and vegetables consumed, and the number of days in a given week an individual consumes either fruits or vegetables.³

These findings provide evidence that encouraging our patients to consume more fruits and vegetables may not only benefit their physical health, but also their mental well-being. Practitioners should continue to:

• Encourage frequent consumption of fruits and vegetables, and should always form the basis of a patient’s nutritional foundation
• Educate patients on how to incorporate a range of vegetables and fruit into every meal and offer recipes ideas 
• Understand barriers around why patients may not be consuming vegetables and fruits and work to address these (i.e taste, texture, availability)
• In patients with dietary shortfalls, selective supplementation with a comprehensive multivitamin and omega-3 fatty acids may be beneficial.

References

1. World Health Organisation, Depression and other common mental disorders: Global health estimates. 2017, World Health Organisation: Geneva.
2. Opie, R.S., et al., Dietary recommendations for the prevention of depression. Nutr Neurosci, 2017. 20(3): p. 161-171.
3. Ocean, N., P. Howley, and J. Ensor, Lettuce be happy: A longitudinal UK study on the relationship between fruit and vegetable consumption and well-being. Soc Sci Med, 2018.
4. Australian Bureau of Statistics. National Health Survey Australia 2014-15, 2015.
5. LaChance, L.R. and D. Ramsey, Antidepressant foods: An evidence-based nutrient profiling system for depression. World J Psychiatry, 2018. 8(3): p. 97-104.