It’s midweek, mid-afternoon and you’ve hit a slump. How many of us have googled, ‘food to boost your mood’, before reaching for the sugar-rush anyway?
Nutritional therapists and dietitians have long been advocating the link between mental health and diet, and there’s an ever-increasing amount of research in the area. So, grab a snack, as we recap everything you need to know about how food really can improve your mood.
What’s the link between food and mental health?
The World Health Organisation reported that over 300 million people around the world battle with some form of depression. And, “studies show that there are clear links between your diet and mood,” says health behaviour change specialist Dr Heather McKee.
This year, researchers at the University of Siena, Italy retrospectively reviewed data from psychiatric patients treated in 2017, looking specifically at their levels of vitamin D. The results confirmed that 94 per cent of those in the study showed vitamin D levels below the normal range, and suggested that “in addition to other benefits, vitamin D supplementation may improve the outcomes of illnesses like depression”.
Meanwhile, a 2019 study by the University of Manchester compared data from over 46,000 people and found that improving diet had a positive effect on mental health, with weight-loss, fat reducing and nutrient-rich diets all having similar benefits for depressive symptoms. “This is actually good news,” says Dr Joseph Firth, honorary research fellow at The University of Manchester, explaining that the findings suggest that “highly-specific or specialised diets are unnecessary for the average individual.” Instead, Firth advocates simple changes: “Eating more nutrient-dense meals, which are high in fibre and vegetables, while cutting back on fast-foods and refined sugars, appears to be sufficient for avoiding the potentially negative psychological effects of a ‘junk food’ diet.”
How does gut health link to your mood?
The gut is often referred to as our second brain. “Looking into the connection between the brain and the gut, it’s important to take into consideration that an estimated 90 per cent of serotonin receptors are located in the gut,” says McKee. Although, she continues: “Researchers recommend ‘fixing the food first’, ie. looking at what we eat, before trying gut modifying-therapies, such as probiotics and prebiotics, to improve how we feel.”
That said, the research is there, and ever increasing. A study on mice by the University of Virginia in 2017 found that eating live-yoghurt containing the probiotic strain, Lactobacillus, reduces the amount of a metabolite in the blood called kynurenic, which helps to reduce inflammation and improve mood. While the researchers recognised that mice have no way to communicate feelings, they studied “depressive-like behaviour” and “despair behaviour”, thought to be the best model for looking at depression in animals. Following these results, lead researcher Alban Gaultier, PhD, is now testing these theories on people. “It would be magical just to change your diet, to change the bacteria you take, and fix your health—and your mood,” says Gaultier.
Elsewhere, Northeastern University in Boston are currently exploring a bacteria in our gut that produces an inhibitory neurotransmitter called gamma-aminobutyric acid (GABA). GABA interferes with signals sent between nerves, which keeps your brain from being overstimulated and provides a sense of calm. If this system isn’t working properly, it can lead to insomnia, anxiety and depression. While there has been significant research in the last 10 years linking the gut microbiome to various aspects of our health, microbiologist on the study Philip Strandwitz PhD, notes that “the general concept of delivering bacteria or manipulating gut bacteria to improve brain health is still new”.
Strandwitz continues: “To be perfectly honest, this is a wild, wild frontier right now. We’re learning so much about ourselves and the brain is no longer this magical organ in isolation. Instead, it’s obviously connected to all facets of our being, and it turns out microbes are part of that.”
What foods can help boost your mood?
Probiotics and prebiotics: Once you’ve assessed your daily diet, it may be worth adding a probiotic and prebiotic into the mix. Fermented foods such as miso, kimchi and sauerkraut are rich in Lactobacillus and probiotic powerhouses. Registered dietitian Alexia Dempsey also recommends upping your in-take of inulin, a prebiotic that helps feed the bacteria, found in Jerusalem artichoke, chicory, lentils, broccoli and garlic.
Tryptophan: Foods rich in tryptophan help to bolster your serotonin levels (the happy hormone), so up your intake of salmon, spinach, seeds and chicken to lift a low mood.
Selenium: Selenium is a powerful antioxidant that helps to protect against oxidative damage and supports your immune and nervous systems. “If you are deficient in selenium it may increase the incidence of feeling depressed and other negative mood states, but eating as much as three brazil nuts a day can help lift your levels,” recommends Dempsey.
B vitamins: “Thiamin B1, Niacin B3 or Cobalamin B12 play a role in energy metabolism, so a lack of them can make you feel tired, irritable and depressed,” explains Dempsey. While these are predominantly found in animal by-products, Marmite and dark leafy vegetables are vegan-friendly options.
Vitamin D: Oily fish, fish liver oils and fortified foods contain the highest levels of vitamin D, although supplements are the easiest way to up your intake.
Fats: “Fast foods and plant oils (omega 6 oils), including rapeseed and canola oils, can have a pro-inflammatory effect in our bodies,” explains nutritional therapist and author of The Human Being Diet, Petronella Ravenshear. “These foods induce inflammation, which directly increases the risk for depression.” That’s not to say all fat is bad. “There are anti-inflammatory fats which come from olive oil, avocados and oily fish that are worth stocking up on, as they reduce inflammation and help improve your mood,” says Ravenshear.
Sugar: Unsurprisingly, Ravenshear is also an advocate of cutting back on sugar to avoid the highs and lows of unbalanced blood sugar levels. “We need whole unprocessed foods, such as fish and shellfish, vegetables including seaweed, fruit and nuts and seeds to stay healthy in mind and body,” she advises.
Water: If you tweak just one thing though, stay hydrated. “As little as 5 per cent dehydration can have effects on your concentration, mood and energy levels, so staying well hydrated might support a positive mood,” says Dempsey.
Dempsey stresses that it’s important to “remember that depression and anxiety are multifactorial in their etiology and no one change is the answer. Seek professional help if you are worried about your mood.”