How what we eat affects our mental health

Following a healthy diet is a key component of living well, as it provides your body with the vital nutrients it needs to fuel your body and maintain a healthy weight.

But food you eat can have a huge influence on factors that affect your mental wellbeing, such as mood, how well you sleep, how energetic you feel, and how well you’re able to concentrate.

So just how are nutrition and mental health linked? Firstly, your gut and brain talk to one another.

The gut-brain axis essentially describes the communication network that connects your gut and your brain. So, essentially your gut (and the foods you choose to eat) has a direct influence on your mood and your mental health.

Opting for foods based on the Mediterranean diet can have a protective effect on your mental health, according to research such as this 2019 analysis study.

It’s often described as a heart-healthy diet, as it advocates eating plenty of vegetables, fruit, legumes, beans, cereals, wholegrains, fish, and unsaturated fats such as olive oil.

Studies have linked the Mediterranean diet with helping to reduce your risk of depression.

Food and mood – what’s the link?

“Multiple studies have shown a strong link between nutrition and mood regulation,” says Alexa Mullane, a qualified nutritional therapist and adviser to Wiley’s Finest supplements.

“For example, omega-3 fatty acids that are found in fish and flaxseed have been linked with improved mood and reducing the symptoms of depression. Research has also found having low omega-3 levels can affect your stress response and make you more prone to experiencing higher levels of stress.

“Additionally, eating more foods that are rich in antioxidants, such as fruits and vegetables, has also been found to play an important role in the prevention and treatment of depression,” says Mullane.

Making poor nutrition choices, such as opting for ultra-processed and high-fat convenience foods a little too regularly can negatively affect your mental health. Research has found this can actually increase your risk of developing mental health conditions such as depression.

Key nutrients for your mental health

To ensure a good link between your nutrition and mental health, there are certain nutrients you should look to include in your diet.

“If you don’t eat enough food that is rich in vitamins and minerals, this can affect your mood, energy and how your brain functions,” says Clare Thornton-Wood, a registered dietitian and spokesperson for the British Dietetic Association.

Carbohydrates

“Eating enough carbohydrates daily is important as your brain requires energy from the foods you eat in order to work optimally,” Thornton-Wood explains. 

“If you don’t have a regular supply of carbohydrate, you won’t have enough glucose in your blood and this could leave you feeling weak, tired and brain foggy.”

There are many good sources of carbohydrate, including potatoes and wholegrain bread, rice and pasta.

Thornton-Wood adds that wholegrain is best because it contains more vitamins, minerals and fibre. Wholegrain carbohydrates also take longer to digest, so this slow-release effect in the bloodstream helps to balance your energy levels.

“Another dietary aspect that can affect your mood is serotonin, something that’s known as the happy hormone,” she says. “In order to make serotonin, you actually need to have a good supply of carbohydrates throughout the day.”

Fruit and vegetables

Trying to hit the five-a-day target as regularly as possible is also good for your physical health as well as your mental health.

The British Dietetic Association has some great tips to help you reach your daily fruit and vegetables goal.

“Your five portions should ideally be geared a little more towards vegetables (such as a 3:2 ratio) and try to opt for different colours and different types of vegetables and fruit as this will provide a broader range of nutrients,” says Thornton-Wood.

“For example, getting your five-a-day by eating some broccoli, carrots, spinach, and an apple and a banana.”

Omega-3

It’s recommended that we eat two portions of oily fish a week as part of a healthy, balanced diet. 

As we looked at earlier, omega-3 is also beneficial for your mental health. Good sources include mackerel, salmon and pilchards. But if you don't eat fish there are other omega-3 alternatives, incluidng walnuts, pumpkin and chia seeds. Soya bean products such as beans, milk and tofu are also good options.

However, note that tinned tuna doesn’t count due to the way it’s processed.

“Many people mistakenly think it does”, says Thornton-Wood.

Iron

Low levels of iron can lead to anaemia, and this can impact your mood as it can leave you feeling weak and tired. Good dietary sources of iron include lean red meat, eggs, beans and pulses, and fortified breakfast cereals.

Another source that can be something of an acquired taste is molasses.

“You can add molasses to smoothies (so you can’t taste them) or you can eat them off a spoon, but it’s not that nice,” Thornton-Wood says.

B vitamins

“If you’re lacking in B vitamins, this can affect your brain function and leave you feeling low and quite depressed,” Thornton-Wood explains.

“Your body needs to replace these every day as they’re water-soluble vitamins so they aren’t stored.”

Good food sources include leafy green vegetables, oranges, bananas, milk, some fortified breakfast cereals and yeast extract (such as Marmite).

Selenium

Good dietary sources of the mineral selenium include Brazil nuts, wholemeal bread, eggs, whole oats, oily fish, lean red meat and sunflower seeds.