Nutrition and mental health, state of the art and perspectives

Exploring the crucial link between nutrition e mental health, this review offers unique insights addressing the “triple burden” of malnutrition: malnutrition, overnutrition and micronutrient deficiencies. We delve into the mechanisms of psychobiotics, including specific strains such as Lactobacillus plantarum PS128 e Bifidobacterium longum 1714, and we examine the impact of the psychiatric drugs on intestinal microbiome, a critical factor often overlooked in traditional approaches.

This analysis, based on recent clinical studies (Vicariotto et al. 2023; I have et al. 2021), aims to promote integrated strategies of nutritional psychiatry for the prevention and management of mental disorders. With focus on key nutritional components such as fatty acids Omega-3, antioxidants and Probiotics for a brain health optimal and the psychological well-being. Emerging areas such as microalgae (Chlamydomonas reinhardtii) and theastaxanthin, also addressing the importance of nutritional policies public, including Nutri score e fiscal measures, to shape healthier eating patterns.

1. Nutrition and mental health

Modern society faces a “triple burden” of malnutrition: malnutrition, overnutrition and micronutrient deficiencies, all closely linked to mental health outcomes. A varied and balanced diet is crucial to maintain psychological well-being and prevent psychiatric disorders:

• diets rich in fruits, vegetables, whole grains, lean proteins and healthy fats support brain function and emotional regulation;

• The omega-3 fatty acids, present in fatty fish and dried fruit, help maintain neuronal integrity and reduce inflammation;

• The antioxidants Fruits and vegetables fight oxidative stress, which is linked to neurodegenerative and psychiatric conditions.

Studies such as the SMILES trial by Jacka et al. (2017) demonstrated that improving diet can significantly reduce depressive symptoms, highlighting the therapeutic potential of nutrition in mental health care.

1.1. Obesity, overweight and mental health

Obesity and being overweight are significant risk factors for psychiatric conditions, including depression, anxiety, and eating disorders:

• chronic low-grade inflammation associated with obesity disrupts thegut-brain axis, leading to neuroinflammation and altered neurotransmitter function;

• obesity is often linked to metabolic conditions, such as type 2 diabetes and cardiovascular disease, which increase the mental health risks.

A study by Luppino et al. (2010) found a bidirectional relationship between obesity and trough, with each condition exacerbating the other. The social stigma and discrimination faced by people with obesity contribute to low self-esteem and body dissatisfaction, worsening mental health outcomes and creating a vicious cycle.

1.2. Nutrient and micronutrient imbalances

Deficiencies in essential nutrients, such as B vitamins, zinc, magnesium, and omega-3 fatty acids, can significantly affect the nervous system and contribute to psychiatric disorders. Research suggests that thetargeted food supplementation can help improve mental health, especially in conditions such as depression and anxiety. For example:

• compounds such as S-adenosylmethionine (SAM), N-acetylcysteine, zinc, B vitamins, and omega-3 fatty acids play critical roles in maintaining psychological well-being;

• Imbalances in macronutrient and micronutrient intake, such as deficiencies of vitamin D and omega-3 fatty acids, can exacerbate mental health conditions.

2. Nutritional interventions with preventive potential

Nutritional psychiatry is exploring the preventive role of nutrition in mental health. Diets rich in omega-3 fatty acids, antioxidants, and micronutrients have been consistently linked to a reduced risk of developing mental disorders:

• The omega-3 fatty acids are essential for brain function and have anti-inflammatory properties, which help relieve depression and anxiety;

• The antioxidants, including vitamins C and E, reduce oxidative stress, a major contributor to neurodegenerative and psychiatric conditions;

• i micronutrients as zinc, magnesium and B vitamins support neurotransmitter synthesis and neural function, further supporting mental health.

Emerging evidence suggests that the personalized nutrition, tailored to an individual’s genetic, metabolic and microbiome profile, may offer significant potential to prevent mental health disorders. This approach recognizes the unique relationship between diet, gut microbiota and the gut-brain axis, allowing for more targeted and effective dietary interventions to optimize mental well-being.

3. The microbiome-gut-brain relationship

The idea that gut health is central to overall well-being is not new. As early as the 4th century BC, Hippocrates argued that disease originates in the gut. Modern science has validated this ancient wisdom, revealing the crucial role of the gut microbiota in human health, including its influence on the central nervous system (CNS).

Il intestinal microbiota, composed of trillions of microorganisms, and its collective genome, the microbiome, are key components of the gut-brain axis. This two-way communication pathway links the gut to the cognitive and emotional centers of the brain, highlighting the profound impact of gut health on mental well-being.

THEgut-brain axis is a complex network of nervous, endocrine, immune, and metabolic mechanisms, which highlights the connection between gut health and mental disorders. Dysbiosis, or microbial imbalance, can lead to increased intestinal permeability, inflammation, and oxidative stress, all of which are associated with psychiatric disorders such as depression, anxiety, and schizophrenia.

4. Psychoprotective food ingredients

I Probiotics have emerged as a key area of ​​interest in nutritional psychiatry. These beneficial microorganisms – present in some foods such as dairy products, fermented products and dietary supplements – play a crucial role in maintaining the balance of the gut microbiota (eubiosis) and reducing dysbiosis.

In particular, the psychobiotics (probiotics with proven mental health benefits) exert their effects through mechanisms such as modulation of the hypothalamic-pituitary-adrenal (HPA) axis, regulation of the immune response, and the production of neurohormones and neurotransmitters (Del Toro-Barbosa et al. 2020).

Prebiotics, non-digestible food components such as inulin and fructooligosaccharides, support gut health by promoting the growth of probiotics. symbiotic, which combine both probiotics and prebiotics, offer a synergistic approach to improve the gut microbiota, and their potential should be further explored.

5. The influence of the microbiome on the activity of the nervous system

The gut microbiome influences numerous physiological processes, including immunomodulation, energy balance, and CNS electrophysiological activity. Dysbiosis can lead to increased intestinal permeability, allowing harmful metabolites and bacteria to enter the bloodstream. This condition, known as “leaky gut”, is associated with inflammation and oxidative stress, both of which have been linked to psychiatric disorders such as depression and anxiety.

Recent studies have categorized the effects of microbiome alterations into three main areas:

• psychological effects. Bacterial metabolites, such as short-chain fatty acids (SCFAs), act as epigenetic modulators, influencing cognitive and emotional functions;

• systemic effects. The gut microbiota develops in parallel with the HPA axis, influencing glucocorticoid levels and inflammation. Elevated pro-inflammatory cytokines are strongly associated with psychiatric conditions such as depression;

• neural effects. Intestinal inflammation disrupts tryptophan metabolism, reducing the production of Serotonin. Neurotransmitters such as GABA e glutamate, which regulate neural excitation and inhibition, are also affected. In addition, brain-derived neurotrophic factor (BDNF), crucial for learning and memory, is often reduced in anxiety and depression but can be restored through antidepressant treatment.

6. The influence of psychiatric drugs on the intestinal flora

Conventional psychiatric medications, including antidepressants and antipsychotics, can alter gut flora, potentially worsening dysbiosis and affecting mental health:

• widely used antidepressants such as fluoxetine (Prozac) and escitalopram may alter the gut microbiome;

• mood stabilizers such as valproate e Lithium have been linked to an increase in Clostridium species;

• some antidepressants also inhibit strains of Escherichia coli, further highlighting the complex interplay between psychiatric treatments and gut health.

Further studies are needed to identify the most effective probiotics for individuals undergoing psychiatric medication treatment, as part of a integrated approach to restore gut health and support overall mental well-being.

7. Psychobiotics: Potential Contributions to Mental Well-Being

– psychobiotics, defined as probiotics or prebiotics with mental health benefits, are showing a promising role in contributing to mental well-being. These beneficial bacteria, mainly from the Bifidobacterium e Lactobacillus, they exercise anxiolytic and antidepressant effects through mechanisms involving the enteric nervous system and the immune system. Unlike pro-inflammatory bacteria, psychobiotics do not trigger significant immunological reactions, making them safe for long-term use.

7.1. Lactic acid bacteria and depression

A randomized, double-blind, placebo-controlled study of Ho et al. (2021) investigated the effects of Lactobacillus plantarum PS128 (LP128) on mental health and sleep quality in 40 adults with self-reported insomnia. Participants took LP128 or a placebo for 30 days, with assessments at baseline, day 15, and day 30.

While overall results were comparable between groups, the LP128 group showed significant reductions in depressive symptoms (Beck Depression Inventory-II scores), fatigue levels, brain wave activity, and awakenings during deep sleep. These findings suggest that LP128 may help alleviate depression and improve sleep quality, warranting further research.

7.2. Bifidobacterium and stress reduction

Integration with Bifidobacterium has been shown to restore the integrity of the intestinal barrier, reduce stress-induced inflammation, and improve cognitive function. In particular, Bifidobacterium longum 1714 has been shown to significantly reduce stress levels and improve memory in healthy volunteers, suggesting its potential to support mental health.

7.3. Maternal stress and infant microbiota

A randomized, double-blind, placebo-controlled study by Slykerman et al. (2017) evaluated the effect of Lactobacillus rhamnosus HN001 on postpartum depression and anxiety. The study found that those who received HN001 had significantly lower depression and anxiety scores compared to the placebo group, suggesting its potential in alleviating postpartum mental health problems.

8. The gut microbiome in severe psychiatric disorders

The gut microbiome plays a critical role in severe psychiatric disorders such as bipolar disorder , schizophrenia. Dysbiosis has been linked to the severity, symptoms, and treatment responses of these conditions. This growing understanding highlights the potential for microbiota-focused therapies, including dietary and psychobiotic changes, to complement traditional treatments.

8.1. Bipolar disorder

Research has revealed distinct gut microbiota profiles in patients with bipolar disorder (BD), characterized by higher concentrations of actinobacteria and lower than Faecalibacterium e Ruminococcaceae. These microbial alterations are thought to contribute to the pathophysiology of the disorder, potentially through mechanisms involving inflammation, oxidative stress, and impaired gut-brain axis communication.

8.2. Schizophrenia

In schizophrenia, gut microbiota dysbiosis is increasingly recognized as a contributing factor to the onset and progression of the disorder. Studies have shown that patients with first-episode schizophrenic psychosis have significantly lower levels of Bifidobacterium e Lactobacillus, two genera known for their beneficial effects on intestinal and mental health.

9. Provisional conclusions

Addressing the “triple burden” of malnutrition – malnutrition, overnutrition and micronutrient deficiencies – requires robust nutritional policies public. The implementation of front-end nutritional labelling (FOPNL) as the Nutri score e fiscal measures strategic are crucial to mitigate the impact of obesogenic diets and poor nutrition on both physical health and mental.

At the individual level, integrated strategies of nutritional psychiatry, focused on psychobiotics, fatty acids Omega-3 e antioxidants, including theastaxanthin, offer significant potential. In particular, exploring the mechanisms of strains such as Lactobacillus plantarum PS128 e Bifidobacterium longum 1714, and understand the impact of psychiatric medications on intestinal microbiome, is essential for personalized interventions.

Further research should prioritize the effectiveness of microalgae including Chlamydomonas reinhardtii and detailed understanding of thegut-brain axis. Public support is vital to promote these integrated approaches, going beyond traditional treatments to fully exploit the potential of interventions nutritional in the prevention and management of mental disorders. This includes addressing the complex interactions between nutrition, gut health and mental health to optimize the psychological well-being in all populations.

Dario Dongo

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Dario Dongo, lawyer and journalist, PhD in international food law, founder of WIISE (FARE – GIFT – Food Times) and Égalité.