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The Food-Brain-Mood Link



You are complex, so are your moods. But nutrition can make a magical difference to your mental wellbeing.

  • Cutting-edge science now reveals eight biological processes are core to how you feel.
  • All these processes lead to the brain. And your diet can have a noticeable impact on them.
  • Which means the right nutritional choices could make a distinct difference to your moods.




Core Biological Mechanisms

Brain Balance

(Good) Mood


How you feel each day - whether you feel a bit down and on edge, or ready to take on the world - has long been a mystery to scientists.

But our understanding of the brain - and more recently the brain-gut axis - has been making major advances. And these advances reveal that there are key biological mechanisms going on in your brain (and body) which can affect your moods - that can all be impacted through nutrition.

This isn’t just theoretical. The nascent field of nutritional psychiatry - which our Harvard scientist Dr Uma Naidoo is one of the global pioneers in - has been running clinical trials showing how a change of diet can seriously improve moods.

The natural power of nutrients is the new frontline for better mental wellbeing.



The food you eat doesn’t simply pass through you - it permeates every cell in your brain and body:

  • Nutrients get absorbed in your gut - your second brain - and feeds the billions of bacteria that produce neurotransmitters like serotonin, the brain chemical associated with happiness
  • Nutrients also directly enter the bloodstream and get circulated to the brain

In fact, the very latest science shows there are 8 evidence-based biological mechanisms that are thought to have an impact on our brains and how we feel - which can be positively affected by what we eat.

When your immune system sends out cells to fight bacteria or heal an injury - but becomes damaging (chronic) when still sending inflammatory cells even when there is no outside danger.

Studies show that people with higher inflammation have greater risk of developing negative thoughts.

Healthy diets have been shown to reduce systemic inflammation.

When the body’s antioxidant levels are low and free radicals are dominant - which can damage cells and tissues.

Ongoing oxidative stress is cited as a pathway affecting psychological function.

Certain nutrients - such as polyphenols - are natural antioxidants.

The gut-brain axis - a two-way highway running through the vagus nerve - is at the forefront of the latest research into mental wellbeing. The gut is increasingly considered a ‘second brain’.

Randomised clinical trials have shown a change in diet - such as adopting the Mediterranean way of eating - can have a profound impact on people’s moods.

The full potential of the microbiota is coming to light. Ongoing animals studies show changing the gut bacteria can transform personality - from being shy to confident!

The hypothalamic-pituitary-adrenal axis is the interaction between the hypothalamus, pituitary gland, and adrenal glands - and plays an important role in how the body responds to stress.

Studies using foods rich in polyphenols reported a reduction in cortisol levels in healthy people.

New neurons being formed in the brain - particularly in the hippocampus, the part of the brain that’s key to learning, memory and psychological function. The plasticity of the hippocampus allows these new cells to grow.

Diet quality appears to influence hippocampal volume - with a better diet leading to a much larger hippocampus.

Tryptophan is an essential amino acid that must be supplied through diet - and helps the production of serotonin and melatonin.

Most tryptophans come from proteins in our diet.

Mitochondria are powerhouses - turning food molecules into energy to fuel cells. When the mitochondria become less efficient this impacts psychological function and maybe even reduce the formation of new neurons.

Evidence suggests that poor diet may contribute to mitochondrial dysfunction.

How our lifestyles and environment affect the way our genes function; genes can impact so many of the processes that underpin the Mood-Brain balance.

Increasing evidence shows that a nutrient-rich diet can help the positive expression of genes.



Breakthrough science is slowly unpeeling the mysteries of the mind. What’s becoming ever more clear is just how strong the mood-food link is. Nutrients really are vital fuel for our moods and energy levels. Your diet really can change how you feel.

Karmacist’s mission is to shout from the rooftops about the natural power of nutrients to boost mental wellbeing. To help guide people to the right dietary choices. And to make each day better, one nutrient at a time.

Scans show a well-functioning, nourished brain is full of activity - with all parts in harmony with each other.

Sources + further reading

Marx, W., Lane, M., Hockey, M. et al. Mol Psychiatry 26, 134–150 (2021).

Firth J, Solmi M, Wootton RE, Vancampfort D, Schuch FB, Hoare E, Gilbody S, Torous J, Teasdale SB, Jackson SE, Smith L, Eaton M, Jacka FN, Veronese N, Marx W, Ashdown-Franks G, Siskind D, Sarris J, Rosenbaum S, Carvalho AF, Stubbs B. World Psychiatry. 2020 Oct;19(3):360-380. doi: 10.1002/wps.20773. PMID: 32931092; PMCID: PMC7491615.

Jacka FN, O'Neil A, Opie R, Itsiopoulos C, Cotton S, Mohebbi M, Castle D, Dash S, Mihalopoulos C, Chatterton ML, Brazionis L, Dean OM, Hodge AM, Berk M. BMC Med. 2017 Jan 30;15(1):23. doi: 10.1186/s12916-017-0791-y. Erratum in: BMC Med. 2018 Dec 28;16(1):236. PMID: 28137247; PMCID: PMC5282719.

Parletta N, Zarnowiecki D, Cho J, Wilson A, Bogomolova S, Villani A, Itsiopoulos C, Niyonsenga T, Blunden S, Meyer B, Segal L, Baune BT, O'Dea K. Nutr Neurosci. 2019 Jul;22(7):474-487. doi: 10.1080/1028415X.2017.1411320. Epub 2017 Dec 7. PMID: 29215971.

Firth J, Marx W, Dash S, Carney R, Teasdale SB, Solmi M, Stubbs B, Schuch FB, Carvalho AF, Jacka F, Sarris J. Psychosom Med. 2019 Apr;81(3):265-280. doi: 10.1097/PSY.0000000000000673. Erratum in: Psychosom Med. 2020 Jun;82(5):536. Erratum in: Psychosom Med. 2021 Feb-Mar 01;83(2):196. PMID: 30720698; PMCID: PMC6455094.

Opie RS, Itsiopoulos C, Parletta N, Sanchez-Villegas A, Akbaraly TN, Ruusunen A, Jacka FN. Nutr Neurosci. 2017 Apr;20(3):161-171. doi: 10.1179/1476830515Y.0000000043. Epub 2016 Mar 2. PMID: 26317148.

Lassale C, Batty GD, Baghdadli A, Jacka F, Sánchez-Villegas A, Kivimäki M, Akbaraly T. Mol Psychiatry. 2019 Jul;24(7):965-986. doi: 10.1038/s41380-018-0237-8. Epub 2018 Sep 26. Erratum in: Mol Psychiatry. 2018 Nov 21;: Erratum in: Mol Psychiatry. 2021 Jul;26(7):3657. PMID: 30254236; PMCID: PMC6755986.

De Filippis F, Pellegrini N, Vannini L, Jeffery IB, La Storia A, Laghi L, Serrazanetti DI, Di Cagno R, Ferrocino I, Lazzi C, Turroni S, Cocolin L, Brigidi P, Neviani E, Gobbetti M, O'Toole PW, Ercolini D. Gut. 2016 Nov;65(11):1812-1821. doi: 10.1136/gutjnl-2015-309957. Epub 2015 Sep 28. PMID: 26416813.

Dinan TG, Stilling RM, Stanton C, Cryan JF. J Psychiatr Res. 2015 Apr;63:1-9. doi: 10.1016/j.jpsychires.2015.02.021. Epub 2015 Mar 3. PMID: 25772005.