Words by Molly
6 mins
Intuitively, food makes us feel good. The Sunday roast with family gathered around, siblings squabbling and a large glass of enticing red wine. The cobbled together carb fest, post-rain drenched commute, with cheese (lots of cheese). The well-intentioned “forgive me” dinner that ends in what can only be described as kitchen chaos, but forgiveness, nevertheless. The over-loaded sandwich from the farmer’s market, impossible to eat gracefully, sauce oozing from every angle and sourdough bread chewy enough to give your teeth a run for their money, perusing stalls, sun shining, the faint smell of freshly brewed coffee wafting through the air (well, we can dream).
But why does food make us feel this way? Is it purely learnt from experience and memories, or is there some basic, biochemical process that triggers an emotional response in us. In our latest blog, we’re taking a look at the science behind feel-good food, digging deeper into food, feelings, and how we can eat ourselves happy.
Why no carbs before marbs is (probably) going to make you miserable
For many of us, starchy carbohydrates are the food group we reach for on days when a salad just won’t cut it. There is little more comforting than a bowl of piping hot pasta, doused in sauce and a liberal grating of cheese. Equally, the same could be said for a slice of hot buttered toast, thickly-cut, golden brown and melted butter pooling on the plate – not many smells will draw a crowd quicker.
The biochemical reason behind our love for carbs is, relatively, simple. When we eat carbohydrate rich foods our body releases insulin. Insulin enables sugars within the carbohydrate to enter our cells, and this sugar is used to produce energy. Critically, at the same time as this insulin response, carbohydrate intake triggers entry of tryptophan into our brain.
This is where the food-mood connection comes into play. Tryptophan is an amino acid (the building blocks of protein) and the precursor to the neurotransmitter, serotonin. Low levels of serotonin have been associated with depression, which means that lower carbohydrate intake = less tryptophan into the brain = less serotonin and (possibly) lower mood.
Before we all reach for the white bread and pasta by the bowlful, research has indicated that lower glycaemic index carbohydrates (like wholemeal bread) have longer lasting impacts on brain chemistry and mood. Higher glycaemic foods on the other hand (like white bread) seem to give us a more immediate, but short-lasting buzz.
Tryptophan-rich foods – do they impact our mood?
Being an amino acid, protein-rich foods tend to be a good source of tryptophan. Particularly rich sources include salmon, chicken, turkey, eggs, spinach, pumpkin seeds and soya products. Theoretically, eating these foods could boost your levels of tryptophan and impact your mood, but whether or not this is actually the case (the body can be a weird and wonderful thing at times), including a quality source of protein with every meal is a good idea in the context of a balanced diet.
Gut bacteria, our brain and mood
The latest buzz-word in the world of wellness, gut health definitely doesn’t escape the feel-good food discussion. Around 90% of all serotonin production takes place in the gut, so it makes logical sense to look after your gut if you want to improve your mood. Cutting-edge research has begun to show us a link between the diversity of gut bacteria and mood disorders, and we know there’s a two-way communication system between our gut and our brain.
Targeting gut health to treat depression is a novel therapy that is very much in preliminary stages, but it’s one we might hope to see develop in years to come. In the meantime, what steps can we take to look after our gut (and hopefully our mood)?
1. Enjoy fermented foods: Certain fermented foods, like kimchi, kefir, sauerkraut and kombucha, contain millions of friendly bacteria, the type that we want inside our gut. Including these foods in your diet could increase your ratio of “good” to “bad” bacteria and impact positively on your mood.
2. Aim for 30g of fibre per day, including prebiotic fibre: Fibrous foods encourage good bacteria to thrive. Prebiotic fibre, in particular, is what you might consider the ultimate fuel for our gut bacteria (encouraging them to grow and multiply). Foods rich in this special type of fibre include garlic, onion, leeks, underripe banana and Jerusalem artichokes, to name a few.
3. Get your 5 (or 10) a day for a diet rich in plant phytochemicals: Plant phytochemicals are chemicals produced by plants, generally for the purpose of survival. For years we assumed the benefits of eating fruit and veg came from the micronutrients they contain, but we’re starting to learn that the many thousands of different phytochemicals may also benefit our health (as well as the micronutrients, vitamin C is definitely still important).
4. Include a portion of oily fish in your weekly diet: Oily fish, like salmon and trout, is brimming with two types of beneficial omega-3 fatty acids: EPA and DHA. Intake of oily fish (and therefore of these beneficial nutrients) has been correlated with diverse gut bacteria and overall gut health.
Let’s talk red meat and mood
Red meat hasn’t had a look in yet, but that’s not to say it isn’t important. Red meat is one of the best dietary sources of zinc (sitting just next to oysters) – which happens to be a micronutrient that’s been well-studied in relation to depression and low mood. Depression has been associated with low levels of zinc, and treatment with this nutrient (admittedly with some mixed results and reliance on animal studies) has shown mental health benefits.
Vitamin B12, exclusively found in animal products and rich in red meat, is another vitamin to consider in terms of mood. Being diagnosed with depression whilst also being deficient in B12 is not an uncommon phenomenon, so it’s important to be hitting daily requirements.
… and B6 too
B12 isn’t the only B vitamin that’s important in terms of mood. B6 is crucial for producing neurotransmitters, including both serotonin and dopamine, which are famously associated with mood. Signs of B6 deficiency clearly indicate its role in mood and can include depression, cognitive decline and confusion. The good news? Rich sources of this nutrient include liver, beef, salmon, chicken and turkey (as well as veggie sources like spinach and sweet potato).
Get the green tea in stock
Green tea contains an amino acid called L-theanine. Human studies measuring the impact of this amino acid on the brain have shown that it significantly increases alpha brain waves – the type that are in full swing when you’re relaxed, not thinking too hard, but not asleep. A bit like when you’re on the sofa on a Sunday, watching the cricket with a beer.
Essentially, green tea might help to relax your mind without making you sleepy (thanks to the caffeine content). All of this means that you get a bit of a mood-boosting buzz, without the jitters that usually come with coffee. NB: the levels of L-theanine used in these studies is much higher than you’d get from a single cup of green tea, but we challenge you to try it, you might just see the benefits.
Can you really eat yourself happy?
Food is part of the picture, and likely a bigger part than we’ve previously given credit, but it’s not the whole story. Aside from anything, there are lifestyle factors like exercise and social support, and innate factors like genetics. But seeing as this is a food-based blog, here’s our top 5 take homes from the food side of things:
• Don’t demonise carbs
• Make sure you have a quality source of protein with every meal
• Fill your diet with colourful fruit and vegetables
• Consider trying out fermented foods
• Swap your coffee (once in a while) for green tea
Molly is a Registered Nutritional Therapist.
The nerdy bit:
1. Huang, T.T., Lai, J., Du, Y., et al. (2019). ‘Current Understanding of Gut Microbiota in Mood Disorders: An Update of Human Studies’, Frontiers in Genetics.
2. Jenkins, T.A., Nguyen, J.C.D., Polglaze, K.E. et al. (2016). ‘Influence of Tryptophan and Serotonin on Mood and Cognition with a Possible Role of the Gut-Brain Axis’, Nutrients, 8(1).
3. Kennedy, D.O. (2016). ‘B Vitamins and the Brain: Mechanisms, Dose and Efficacy – A Review’, Nutrients, 8(2).
4. Larrieu, T., & Layé, S. (2018). ‘Food for Mood: Relevance of Nutritional Omega-3 Fatty Acids for Depression and Anxiety’.
5. Nobre, A.C., Rao, A., & Owen, G.N. (2008). ‘L-theanine, a natural constituent in tea, and its effect on mental state’, Asia Pacific Journal of Clinical Nutrition.
6. Sathyanarayana Rao, T.S., Asha, M.R., Ramesh, B.N. et al. (2008). ‘Understanding nutrition, depression and mental illnesses’, Indian Journal of Psychiatry, 50(20).
7.Syed, E.U., Wasay, M., & Awan, S. (2013). ‘Vitamin B12 Supplementation in Treating Major Depressive Disorder: A Randomized Controlled Trial’, The Open Neurology Journal.
8. Wang, J., Um, P., Dickerman, B.A., et al. (2018). ‘Zinc, Magnesium, Selenium and Depression: A Review of the Evidence, Potential Mechanisms and Implications’, Nutrients, 10(5).
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