By Julia Haimovich, Accredited Practicing Dietitian.
When we think of aggression, we often attribute it to stress, mental health conditions, or personality traits. However, recent research is shedding light on another contributing factor: nutrition. A growing body of evidence shows that what we eat can significantly impact our mood and behaviour. A study published in *Frontiers in Psychiatry* by Olivia Choy (1) in 2023 explores the connection between nutrition and aggression, offering valuable insights into how dietary choices may influence aggressive behaviour.
While aggression is a complex issue influenced by psychological and environmental factors, this research suggests that diet could be playing a bigger role than we’ve previously realised. Explore some key nutritional factors that can exacerbate or help mitigate aggression.
Omega-3 Fatty Acids and Brain Function.
Omega-3 fatty acids are well-known for their benefits to heart and brain health but also profoundly impact behaviour. Choy’s research highlights the strong association between low levels of omega-3 and increased aggression (1). Omega-3s, found in oily fish like salmon, sardines, and mackerel, are crucial for maintaining healthy brain function, particularly in areas related to mood regulation.
Multiple studies support this claim. For instance, a study by Hibbeln et al. (2) demonstrated that low dietary intake of omega-3 fatty acids was linked to higher aggressive and impulsive behaviour rates in adults and children. Omega-3s help maintain the structure of brain cells and facilitate communication between neurons, both essential for controlling emotions and reducing irritability.
Incorporating more fish into your weekly diet or considering algae or fish oil supplements could be a simple yet effective way to improve mood stability and reduce irritability.
Another significant factor highlighted by Choy’s study is the impact of micronutrient deficiencies, specifically in zinc, magnesium, and vitamin D, on aggression. Zinc and magnesium are key in neurotransmitter function, directly affecting mood and impulse control (1). For example, zinc deficiency has been associated with irritability and aggression, as seen in a study conducted by Peet and Stokes (3). Magnesium, which is necessary for nerve function, helps keep the nervous system balanced, and low levels have been linked to increased aggression and hyperactivity (4).
Vitamin D deficiency is another crucial aspect discussed in Choy’s research. Vitamin D is pivotal in serotonin production, a neurotransmitter regulating mood. Choy points out that people with low levels of vitamin D are more likely to experience mood instability, depression, and increased irritability, which can manifest as aggression (1). This link is supported by a study from Zhao et al. (5), which found that individuals with lower levels of vitamin D were more prone to mental health issues, including aggression.
This is a particularly relevant concern in locations where vitamin D deficiency can occur due to limited sunlight exposure during winter months. Increasing vitamin D intake through foods like fortified dairy products, eggs, and fish or spending more time outdoors can help address these deficiencies.
Choy’s study also draws attention to the impact of blood sugar imbalances on aggression. Diets high in refined sugars and simple carbohydrates can cause rapid spikes and drops in blood glucose levels, leading to mood swings and aggressive behaviour (1). When blood sugar levels drop, the brain is deprived of glucose, its primary fuel source, which can trigger irritability and anger.
This is particularly relevant in modern diets, often heavy in processed foods and sugary snacks. Studies have shown that erratic blood sugar levels are linked to aggressive and impulsive behaviour (6). Focusing on balanced meals that include complex carbohydrates, lean proteins, and healthy fats is essential to avoid these mood swings. These foods help maintain a slow and steady release of energy, preventing the highs and lows associated with sugary or processed foods.
Choy also discusses the growing evidence supporting the role of gut health in mood regulation and aggression (1). The gut-brain axis, which connects the digestive system and brain, is crucial to mental health. Imbalances in gut bacteria, often caused by poor dietary choices, have been linked to increased aggression and mood disorders.
Inflammation is another factor in this equation. Diets high in processed foods, artificial additives, and unhealthy fats can lead to chronic inflammation, affecting the gut and the brain. A study from Maes et al. (7) supports this connection, finding that inflammation in the gut can trigger inflammatory responses in the brain, worsening mood disorders and increasing aggression.
On the other hand, a diet rich in anti-inflammatory foods like fruits, vegetables, whole grains, and healthy fats can promote a healthier gut and reduce aggressive tendencies. Incorporating probiotic-rich foods like yoghurt, kefir, and fermented vegetables can further support gut health and help manage mood swings.
The findings of Choy’s 2023 study provide a compelling case for addressing aggression through dietary interventions. Here are a few practical tips based on her research and supporting studies:
1. **Increase Omega-3 Intake**: Incorporate more fatty fish into your diet, or consider taking a fish oil supplement. Omega-3s support brain function and help stabilise mood.
2. **Boost Micronutrient Intake**: Ensure you’re getting enough zinc, magnesium, and vitamin D through food sources like spinach, nuts, seeds, and fortified dairy products. Sun exposure can also help maintain healthy vitamin D levels.
3. **Balance Blood Sugar**: Avoid excessive sugary snacks and processed foods. Focus on complex carbohydrates, lean proteins, and healthy fats to stabilise blood sugar levels and prevent mood swings.
4. **Support Gut Health**: Eat a diet rich in anti-inflammatory foods like fruits, vegetables, whole grains, and probiotic-rich options to promote gut health and reduce inflammation.
Many factors influence aggression, but Choy’s 2023 study highlights nutrition’s significant role in this behaviour. Deficiencies in essential nutrients, blood sugar imbalances, and poor gut health can all increase aggression. Individuals can support better mood regulation and reduce aggressive behaviours by focusing on a balanced, nutrient-dense diet.
