Does a link exist between dietary habits and depression?

Depression is increasingly becoming a widespread ailment, especially among adults. The occurrence of this condition in various age groups ranges from 5 up to 11%. The initial indications are typically noticed between puberty and the age of 30, although they may also manifest earlier or later. The majority of cases are primarily reported among inhabitants of highly developed nations. In as many as 15% of cases of chronic depression, it culminates in suicide. Half of the individuals who have ever exhibited symptoms may experience a recurrence in the future (A. Ruusunen, 2013).

The fundamental symptoms of depression are: – deterioration of mood, – loss of interest in enjoyable pursuits, – impairment of concentration, – exacerbated feelings of sadness and anxiety, – excessive sleepiness or insomnia, – diminished self-worth, – exhaustion and fatigue, – frequent feelings of shame and guilt, – decreased or increased appetite, – emergence of suicidal thoughts. If at least four of the aforementioned symptoms appear, it is typically diagnosed as clinical depression. 4 symptoms suggest a mild form of the condition, 5-6 indicate a moderate stage, and more than 7 symptoms indicate a severe course.

Currently, the causes of depression are not yet fully understood. There are many theories, but none of them have been fully confirmed. According to various sources, the factors that may contribute to the development of this disease are: the diagnosis of depression in other family members, social and environmental factors, as well as increased BMI indicating obesity (P. Majkutewicz et al. 2014). Genetic influence is most evident in cases of severe depression and in cases of early onset illness. Although this is not a rule, the first depressive episode is usually associated with a negative life experience. There are also other, more alternative theories that are still awaiting confirmation in studies, such as the effects of disturbances in serotonin and noradrenaline metabolism, as well as of excessive stress or inflammation in the body (W. Marx et al. 2020).

Depression is a disorder that necessitates the intervention of a psychiatric specialist. It is typically treated through the employment of pharmacotherapy, which is frequently complemented by appropriate psychotherapy. The most commonly used medications for treating depression are selective serotonin reuptake inhibitors (SSRIs) or tricyclic antidepressants (TCAs). Unfortunately, due to the marginalization of the issue, as well as the shame or fear of visiting a psychiatrist, some individuals seek alternative treatment methods. Furthermore, even with the application of complete treatment, the disorder may recur, which is extremely challenging for patients.

There is evidence of the impact of diet on depression. The mere existence of a correlation between a high BMI and an increased risk of developing depression indicates this possibility. Obesity is a diet-dependent condition. The contemporary diet is laden with fats, sugar, and energy, but deficient in vitamins and minerals, which influence not only the nervous system but also the overall functioning of the body. It has been discovered that a low-calorie diet, which enables weight loss, can have a favorable effect on reducing the symptoms of depression (G. E. Simon et al. 2010).

Saturated omega-3 fatty acids are of paramount importance for the proper functioning of the nervous system, acting as a precursor to numerous compounds essential for proper brain function, such as prostaglandins. Additionally, the beneficial effects of saturated omega-3s are associated with their role in the formation of myelin sheaths surrounding neurons and the regulation of nerve impulse flow. Some scientists suggest that a decrease in fish consumption, which is one of the best sources of these fats, may increase the risk of depression. Moreover, supplementation may offer advantages in combating the oxidation process linked with this disorder (Majkutewicz et al. 2014).

There is some evidence to suggest that a deficiency of zinc in the body may be associated with an increased risk of depression (L. Harbottle et al. 2008). However, potential benefits of zinc supplementation were only apparent when combined with pharmacotherapy (A. M. DiGirolamo et al., 2009). Zinc is an essential nutrient for the proper functioning of the body, including the nervous system, particularly the brain. However, its influence on the treatment of depression is not clear and further research is needed to clarify any doubts.

B vitamins are indispensable for the proper functioning of the nervous system. They play a crucial role in the biochemical pathways of neurotransmitters such as serotonin and dopamine. In depressive disorders, two vitamins from this group, B12 and folic acid, are particularly significant. Low concentrations of these vitamins in the blood serum are often observed during the progression of the disorder. Both compounds are also responsible for the occurrence of treatment-resistant depression. Research suggests that high doses of cobalamin in combination with folic acid may improve the sensitivity of patients with depression to medication, leading to more effective and shorter treatment, even in cases of no initial response to selected pharmacotherapy (N. Kate et al., 2010). A deficiency in B vitamins can be caused by diseases of the digestive system or nutritional errors, such as a lack of whole grain products, fruits and vegetables, as well as an excess of processed foods. A specific group at risk for vitamin B12 deficiency are vegans, as this vitamin is only found in animal products, necessitating appropriate supplementation.

There is no doubt that healthy eating also has a positive impact on many aspects of daily life, including maintaining good health.. Scientific research suggests that there may also be a link between diet and mental illness.. Researchers noted that in countries where the intake of processed foods is significantly higher and the proportion of fish, fruits, vegetables, and whole grain products in the daily diet is lower, the risk of depression is higher (H.. Karakuła and Co. 2009). In countries where the intake of healthy foods is significantly higher, the prevalence of this disease is very low and is about.. 5%. In the prevention of this disease, a balanced diet that provides the necessary nutrients plays a significant role (M.. Molendijk and Co. 2018). It is worth paying attention to foods that contain vitamins of the B group, in particular B6, B12 and folic acid.. These nutrients are mainly found in cereal products, nuts, meat, dairy products, eggs or legumes.. In addition to vitamins, it is also important to pay attention to an adequate amount of omega-3 fatty acids, which have an anti-inflammatory effect and protect the cells of the nervous system.. The richest in these substances are fish, especially those rich in fat, such as salmon, trout, mackerel and sardines.. Besides fish, omega-3 fatty acids can also be found in flax seeds and flaxseed oil, walnuts, chia seeds, rapeseed and soybean oil, and depending on the breeding, also in eggs and meat.. The most desirable fractions of these fatty acids are DHA and EPA, which are supplied from animal products and algae.. It is difficult to imagine a healthy and balanced diet without fruits and vegetables.. It is important to choose colorful vegetables and fruits, at least 450 g per day.. Berries, dark green leafy vegetables or those with a purple color are excellent.. They are an excellent source of antioxidants that fight oxidative stress and protect the body from the negative effects of harmful external factors.. Although there is no diet adapted to this specific disease, researchers see a great potential in the application of the principles of the Mediterranean diet in everyday life (A.. Sánchez-Villegas and Co. 2006). It is a diet rich in polyphenols, vitamins of the B group and EPA and DHA fatty acids.. All these nutrients have a potentially significant impact on the course of depression.. This dietary pattern is based mainly on fruits, vegetables, cereal products, olive oil and fish, especially local and seasonal products.. It has a positive impact on the health not only of the nervous system, but also of the entire body.

Depression is a disease that is projected to be one of the most common diseases in the coming years. The negative effects of this disease and the alarming statistics regarding its prevalence highlight the need for preventive measures. Consumption of a monotonous and poor diet appears to have a potentially negative impact on the frequency of depression. Therefore, it is recommended to follow a diverse diet, rich in nutritious products. It is also important to avoid processed foods and base your diet on fresh fruits and vegetables, as well as whole grain products. Some studies suggest that a diet rich in omega-3 fatty acids may not only have a protective effect, but also reduce symptoms in people suffering from depression. More research is however needed to prove the impact of this nutritional intervention on the prevention of depression.