The feel-good chemical, serotonin, cannot be produced by the body without tryptophan. Without serotonin, people feel low. Ten foods are natural sources of tryptophan.
Low serotonin levels are associated with mood disorders, anxiety, cravings and irritable bowel syndrome (IBS).
In her e-book The Serotonin Secret, Dr Caroline Longmore says the best way to get optimum tryptophan levels is through a carefully devised eating plan. She rates dozens of foods for their levels of tryptophan.
She has long been interested in nutrition and complementary medicine, and operates a naturopathic and nutrition clinic in Britain.
Food to Improve your MoodHave a turkey sandwich. Or a handful of sunflower seeds.
These are among the ten best foods for tryptophan listed in The Serotonin Secret.
Written with Australian-trained medical scientist and naturopath Katrin Hempel, the book has 50 recipes designed to solve serotonin imbalance without drugs.
Dr Longmore says the concept works on the same principle as selective serotonin re-uptake inhibitors (SSRIs), such as popular antidepressant Prozac.
Her top ten good mood foods are mung beans, lobster, turkey, asparagus, sunflower seeds, cottage cheese, pineapple, tofu, spinach and bananas - the foods containing the highest levels of tryptophan.
Britain's Food and Mood Project also recommends eating chicken, sardines, turkey, salmon, fresh tuna, oats, nuts and seeds to boost serotonin levels.
Carbohydrates Help Absorb TryptohanThe Food and Mood project website explains that including carbohydrates in the diet is important to help absorb tryptophan.
“The absorption of tryptophan into the brain is thought to be greatly enhanced by eating carbohydrate-containing foods and carbohydrate cravings have been explained as a subconscious drive to increase serotonin levels,” it says.
“Carbohydrates that are slow releasing can help the absorption of the tryptophan across the blood-brain barrier without creating a rebound hypoglycaemic dip. Oats are particularly important because they have a low Glycaemic Index.”
Avoid Tryptophan SupplementsAustralian mental health experts say the use of tryptophan supplements in Australia has had a chequered history, and should be avoided.
They say that while the theory behind tryptophans for improving mood is solid, its use by depressed patients has not always been successful, and contaminated batches of tryptophan supplements had caused serious side-effects in many patients.
Professor Gordon Parker, of the Black Dog Institute said while some patients strongly believed such supplements were beneficial, scientific evidence was lacking.
"I would say it's something that can be useful for some people but the quality control varies enormously," he said.
Top Ten Good Mood Foods• mung beans
• sunflower seeds
• cottage cheese
Other Mood Foods• chicken