Irish researchers are investigating the possibility of developing "functional foods" to augment or replace current treatments for depression and other health conditions.
Professor of psychiatry at University College Cork, Ted Dinan, said there were very effective antidepressant medications and psychological therapies for depression, but it would be great if there was a natural alternative.
"It may be possible to provide functional foods which augment current therapies or provide an alternative and a more acceptable treatment approach to people with depression," he said.
Speaking on the topic of Food and Mood at a Food for Life forum organised by the Alimentary Pharmabiotic Centre (APC) at UCC, Prof Dinan explained that a person's risk of heart attack increased significantly in the 10 years following a single depressive episode.
Similar episodes in women could also age a woman's bones by 15 years leading to an increased risk of osteoporosis.
"Serotonin - which plays a pivotal role in mood and appetite regulation - is synthesised from an amino acid called tryptophan," he said.
"But the brain has very little capacity to store this, so humans need to make sure they have a constant intake of tryptophan in the diet to maintain normal serotonin levels."
Food such as chicken and red meat, oats, bananas, milk and yoghurt are rich in trytophan.
The amino acid is sometimes used in cases of severe or intractable depression along with anti-depressants.
Another element of study showed that cortisol levels increase during episodes of depression.
Prof Dinan and his team have found that one form of probiotic called bifidobacterium dramatically reduces cortisol levels.
This suggests that bifidobacterium may have antidepressant properties.
He also pointed out that the Omega 3 fatty acid - which is present in oily fish - also appears to have antidepressant properties although the results of a very large-scale study are awaited.
"Omega 3 is present in oily fish like mackerel," said Prof Dinan.
"But to see its effects it would probably have to be given in capsule form for the treatment of depression as it would be required in large quantities," he said.
Dr Linda Giblin, of Teagasc at Moorepark Food Research Centre, told the forum about her search for a food component or bioactive that could be added to food to help to control weight.
Dr Sinead Corr of APC told the forum there was good evidence to support the use of probiotics in the prevention of gastrointestinal infections but further research was needed in the area.
In her PhD research, she discovered that the lactobacillus salivarius probiotic was able to reduce listeria infection in the gut in animal models by 99.9 per cent.
Her study is the first time a probiotic had been shown to be effective against listeria in a living model.
Head of the biotechnology centre at Moorepark and principal investigator with the APC, Prof Paul Ross spoke about some of the groundbreaking research taking place at the centre into the development of functional foods such as cheese and yoghurts from milk.
They have already found two peptides that can kill many pathogenic bacteria, including the MRSA hospital bug, and are hoping to develop a yoghurt drink which will protect children's teeth.
The APC is a UCC/Teagasc research centre which is focusing on gastrointestinal health and development of therapies for debilitating disorders such as Crohn's disease, colitis, irritable bowel syndrome (IBS) and food poisoning.
