Mental health is an issue faced by more than one in five Australians. This is a number that has grown exponentially over the last decade. Antidepressant use is widespread, but their effectiveness is limited, and they do come with some side-effects so looking for ways to improve mental health either with or without antidepressants is important.
Our brains are at work, even while we sleep. This means your brain requires a constant supply of fuel. That “fuel” comes from the foods you eat — and what’s in that fuel makes all the difference. Put simply, what you eat directly affects the structure and function of your brain and, ultimately, your mood.
Like an expensive car, your brain functions best when it gets only premium fuel. Eating high-quality foods that contain lots of vitamins, minerals, and antioxidants nourishes the brain and protects it from oxidative stress — the “waste” (free radicals) produced when the body uses oxygen, which can damage cells.
Unfortunately, just like an expensive car, your brain can be damaged if you ingest anything other than premium fuel. If substances from “low-premium” fuel (such as what you get from processed or refined foods) get to the brain, it has little ability to get rid of them. Diets high in refined sugars, for example, are harmful to the brain. In addition to worsening your body’s regulation of insulin, they also promote inflammation and oxidative stress.
Multiple studies have found a correlation between a diet high in refined sugars and impaired brain function — and even a worsening of symptoms of mood disorders, such as depression. It makes sense. If your brain is deprived of good-quality nutrition, or if free radicals or damaging inflammatory cells are circulating within the brain’s enclosed space, further contributing to brain tissue injury, consequences are to be expected. What’s interesting is that for many years, the medical field did not fully acknowledge the connection between mood and food.
How the foods you eat affect how you feel
Inflammation is a major driver of mood disorders. We are learning more each day about the connection between the gut, inflammation and brain health. What goes on in the gut, as well as the inflammatory response that might follow, can disrupt the processes in the brain that help regulate our mood. For the health of your belly, body and brain, aim to avoid heavily processed foods, and instead rely on a range of colourful, fibre rich foods in your daily diets. When it comes to inflammation, it’s best to choose foods that come from a farm rather than a package.
Serotonin is a neurotransmitter that helps regulate sleep and appetite, mediate moods, and inhibit pain. Since about 95% of your serotonin is produced in your gastrointestinal tract, and your gastrointestinal tract is lined with a hundred million nerve cells, or neurons, it makes sense that the inner workings of your digestive system don’t just help you digest food, but also guide your emotions. What’s more, the function of these neurons — and the production of neurotransmitters like serotonin — is highly influenced by the billions of “good” bacteria that make up your intestinal microbiome. These bacteria play an essential role in your health. They protect the lining of your intestines and ensure they provide a strong barrier against toxins and “bad” bacteria; they limit inflammation; they improve how well you absorb nutrients from your food; and they activate neural pathways that travel directly between the gut and the brain.
Studies have shown that when people take probiotics, their anxiety levels, perception of stress, and mental outlook improve, compared with people who did not take probiotics. Other studies have compared “traditional” diets, like the Mediterranean diet and the traditional Japanese diet, to a typical “Western” diet and have shown that the risk of depression is 25% to 35% lower in those who eat a traditional diet. Scientists account for this difference because these traditional diets tend to be high in vegetables, fruits, unprocessed grains, and fish and seafood, and to contain only modest amounts of lean meats and dairy. They are also void of processed and refined foods and sugars, which are staples of the “Western” dietary pattern. In addition, many of these unprocessed foods are fermented, and therefore act as natural probiotics. Fermentation uses bacteria and yeast to convert sugar in food to carbon dioxide, alcohol, and lactic acid. It is used to protect food from spoiling and can add a pleasant taste and texture.
This may sound implausible to you, but the notion that good bacteria not only influence what your gut digests and absorbs, but that they also affect the degree of inflammation throughout your body, as well as your mood and energy level, is gaining traction among researchers. The results so far have been quite amazing.
What does this mean for you?
Start paying attention to how eating different foods makes you feel — not just in the moment, but the next day. Try eating a “clean” diet for two to three weeks — that means cutting out all processed foods and sugar. Add fermented foods like kimchi, miso, sauerkraut, pickles, or kombucha if you can tolerate them. You also might want to try going dairy-free — and some people even feel that they feel better when their diets are grain-free. See how you feel. Then slowly introduce foods back into your diet, one by one, and see how you feel.
A publication led by SMILES trial researcher and clinical dietitian, Rachelle Opie has summarised recommendations for the prevention of depression that are applicable to mood more broadly, and to health overall. Opie and colleagues suggest increasing consumption of fruits, vegetables, whole grains and nuts, foods high in omega-3 polyunsaturated fatty acids (like fish), swapping poor quality foods for more nutrient rich options, and limiting intake of fast foods and sweets. An overall healthy diet can keep your gut healthy and reduce inflammation, and making lasting, sustainable improvements to diet (and of course, other lifestyle factors like exercise) is central to promoting mental health.
Parletta et al., (2017) found that following a Mediterranean diet; over 3 months, there were several statistically significant correlations between improved diet and better mental health. Adherence to a Mediterranean diet was associated with lower depression, anxiety, negative affect and better coping and overall quality of life.
• Incorporate coping strategies that are not related to food: evidence supports regular exercise, quality sleep and mindfulness
• Include foods that promote gut health: yogurt, garlic, leeks, Jerusalem artichoke, kefir, foods rich in dietary fibre and colourful fruits and vegetables.
• Implement sustainable changes in your diet, as evidence supports the importance of long-term diet on mental health – swapping an unhealthy afternoon snack for a healthy one, eating vegetables at each meal, etc.
• Moderate red meat consumption (that is 3-4 65-100g portions per week) may be beneficial for depression and anxiety
• Remember there isn’t a one size fits all. We all have genetic predispositions that make different diets more suitable for different people. One of the most researched diets that seems to have a positive impact on many is the Mediterranean Diet…
• We have forgotten how powerful we are in creating our own health outcomes. The brain and the body are intertwined and what we eat, think & do affects both our physical and mental health. Making positive steps can help us to become more resilient and better manage our own health.
Chatterton, M., Mihalopoulos, C., O’Neil, A., Itsiopoulos, C., Opie, R., & Castle, D. et al. (2018). Economic evaluation of a dietary intervention for adults with major depression (the “SMILES” trial). BMC Public Health, 18(1). doi: 10.1186/s12889-018-5504-8
Parletta, N., Zarnowiecki, D., Cho, J., Wilson, A., Bogomolova, S., & Villani, A. et al. (2017). A Mediterranean-style dietary intervention supplemented with fish oil improves diet quality and mental health in people with depression: A randomized controlled trial (HELFIMED). Nutritional Neuroscience, 22(7), 474-487. doi: 10.1080/1028415x.2017.1411320