More than 90% of the body’s serotonin is produced in the gut by specific gut microbes. As serotonin is responsible for feelings of happiness and optimism, poor gut function can significantly affect mood and wellbeing.
The remaining 10% of serotonin is produced in our brain. For this to happen, tryptophan has to compete with similar chemicals all trying to cross the blood-brain barrier, which can be one reason for low serotonin production.
Low serotonin levels or imbalances can cause depression, anxiety, insomnia, migraine headaches and cravings. Seasonal affective disorder (SAD) is a type of depression brought on by a seasonally triggered imbalance in serotonin (and other brain chemicals). Reduced daylight in winter can lead some people to experience a reduction in serotonin and an increase in the sleepy hormone melatonin, resulting in feelings of irritability, lethargy, lack of concentration, poor sleep and low mood.
How to increase serotonin through your diet
Since the body can’t make serotonin on its own, one of the most effective ways to increase serotonin is through eating tryptophan-rich foods. Tryptophan is an amino acid, so we get it in most high-protein foods. For example:
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- Poultry – chicken and turkey
- Milk – warm milk has long been used as a relaxing bedtime drink for better sleep. This may be due to its tryptophan content, as serotonin and melatonin are involved in the sleep cycle.
- Nuts – cashew nuts and walnuts are rich in tryptophan, fibre and healthy fats. They also provide magnesium, zinc and vitamin B6 which act as co-factors in converting tryptophan into serotonin.
- Seeds – sunflower, pumpkin, sesame, flax and chia are all great sources of brain-friendly omega 3 and tryptophan.
- Dark chocolate – contains magnesium which can help with stress and stimulates the release of endorphins and serotonin.
- Fish – salmon is a great source of tryptophan, vitamin D and omega-3 fatty acids, which all impact serotonin levels. If fresh salmon isn’t an option, canned salmon is a great alternative. Tuna, snapper and cod are good options, too.
- Eggs – the protein in eggs can significantly boost your blood plasma levels of tryptophan.
- Hard cheese.
Eating carbs along with tryptophan-rich foods can help tryptophan cross the blood-brain barrier. Try eating the foods in the list above with a few oatcakes, or a slice of wholegrain bread.
Other ways to increase serotonin:
Spend time in sunlight
During the darker winter months, a lack of light may affect our serotonin levels. This can be particularly problematic for those suffering from seasonal affective disorder (SAD) and is why it may be beneficial to use a lightbox which mimics natural sunlight. A recent study suggests that exposure to bright light also reduces non-seasonal depression and can be just as effective as anti-depressants, helping to increase the production of serotonin.
Aerobic exercise — walking, running, cycling and swimming — significantly increases serotonin production in the body. Aim for at least 30 minutes of moderate exercise to get the serotonin ‘high’. Other less strenuous exercise like yoga, pilates and weight-lifting increases serotonin, too, just not as much. Exercise can also decrease the number of other competing amino acids therefore creating an ideal environment for more tryptophan to cross the blood-brain barrier.
L-tryptophan and 5-HTP are the two building blocks for serotonin so, in theory, supplements can lead to an increase in serotonin levels. A 2021 review suggests tryptophan supplements can improve mood and decrease anxiety, though more research is needed.
As serotonin production also occurs in the gut, it is important to support gut function. Supplementing with a probiotic can improve the gut microbiome and consequently produce more serotonin.
Ask about medication
Antidepressant drugs called selective serotonin reuptake inhibitors (SSRIs) can increase serotonin levels. These would be prescribed under the guidance of a doctor.
Increasing serotonin levels can be done naturally. The best ways to do this are eating well, getting out in sunlight throughout the year, exercising and, where possible, managing stress.