by Dr Sarah R Dash
Nutrition research is constantly evolving, and it can be difficult to keep up with the latest advice in order to make informed choices. Based on what we know about the obesity epidemic, it may not be surprising to learn that over half of the total daily caloric intake of Americans now comes from ultra-processed foods – a trend we are seeing worldwide. We are increasingly reliant on convenience foods and less likely to reach for fruits and vegetables. Very few of us are meeting basic dietary recommendations, and our health is suffering for it. We know that nutritious food is essential for our brains as well as our bodies, and here are a few lessons we can take from the literature to the dining table.
It’s no accident that treats (chocolate, chips…) are called ‘comfort foods’; food choice is undoubtedly influenced by how we feel, and studies have shown that feeling low, anxious or stressed can make us more likely to reach for high carbohydrate, sugar or salty foods. While this might make us feel better momentarily, the long-term effects of poor quality foods as part of an everyday diet are less comforting. Research has consistently shown that a ‘junk’ food diet is associated with increased risk of mental disorder. Interestingly, the findings of a recent study in Australia suggest that junk foods may actually ‘shrink’ the hippocampus- part of your brain with a key role in mood regulation. Additionally, poor diet can also contribute to activation of the inflammatory/immune systems, as well as an imbalanced or ‘leaky gut’ – risk factors for a range of mental and physical problems. It’s also important to consider that unhealthy foods displace the good stuff – if meals and snacks are composed of high energy, nutrient poor foods, then there’s less room in your diet (and likely, your belly) for wholesome foods that provide the nutrients that your body – and brain – need.
Thankfully, research also tells us that a diverse, nutrient-rich diet can be protective of your brain and mood. We know that eating well can reduce the risk of some mental disorders, and at the start of this year, the results of the very first diet-depression randomised controlled trial (the SMILES trial) were published. The SMILES trial aimed to answer the question ‘if I improve my diet, will my depression improve?’, and, excitingly, found that those who participated in the dietary intervention had significantly greater improvement in their depression symptoms, compared with those in the social support (control) condition. Further, a publication led by SMILES trial researcher and clinical dietician, 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.
- Incorporate coping strategies that are not related to food: evidence supports exercise and mindfulness
- Include foods that promote gut health: yogurt, garlic, leeks, Jerusalem artichoke, kefir, foods rich in dietary fibre (whole grains, plant foods) 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