Common nutritional deficiencies in psychiatric patients
Mechanisms leading to nutrient deficiencies in patients with mental disorders
Nutrient deficiencies in patients with mental disorders result not only from an improper diet, but also from biological mechanisms that disrupt the absorption and metabolism of nutrients. In this part, we will present a detailed explanation of why people with mental disorders often suffer from vitamin and mineral deficiencies, and the processes behind this (Zielińska et al., 2023; Onaolapo & Onaolapo, 2021; Rao et al., 2008).
1. Disorders of nutrient absorption and metabolism
Nutrient absorption is the process by which the intestines take in vitamins, minerals, and other substances essential for the proper functioning of the body. Once absorbed, these nutrients are transported to various tissues, where they perform key roles—such as supporting brain function, regulating metabolism, and contributing to neurotransmitter production. However, in individuals with mental disorders, this process can be impaired. Malabsorption may mean that a patient consumes an adequate amount of nutrients, but the body is unable to absorb them effectively. As a result, deficiencies may occur, which can exacerbate symptoms of mental illness.
Main causes of impaired absorption and metabolism of nutrients in psychiatric patients:
- Changes in gut microbiome (dysbiosis);
- Intestinal inflammation – Inflammation of the intestines is an overactivation of the immune system, which damages the intestinal lining and impairs its absorption function
- Food intolerances and autoimmune diseases (e.g. coeliac disease);
- Disorders in the transport of nutrients to the brain.
The most common absorption problems include:
A. Gluten intolerance and coeliac disease in patients with schizophrenia (Onaolapo & Onaolapo 2021):
- Coeliac disease is an autoimmune condition in which the consumption of gluten (a protein found in wheat, rye and barley) triggers an immune response that damages the villi in the small intestine. These villi are responsible for nutrient absorption, so their damage leads to deficiencies in iron, zinc, calcium, magnesium, B vitamins and vitamin D.
- Gluten intolerance is a slightly milder condition in which gluten causes inflammatory reactions in the intestines but does not lead to permanent damage of the villi. However, chronic inflammation can still limit the absorption of key vitamins and minerals, increasing the risk of nutritional deficiencies.
Chronic inflammation, especially in the gut, can negatively affect the body’s ability to absorb nutrients. Inflammation causes (Onaolapo & Onaolapo 2021):
- Increased intestinal permeability (so-called „leaky gut”), which means nutrients are not properly absorbed and harmful substances may pass into the bloodstream, triggering further inflammatory responses;
- Impaired production of digestive enzymes, which hampers proper digestion and nutrient absorption.
B. Gut microbiome disturbances (dysbiosis) in patients with depression and schizophrenia The gut microbiome – the collection of bacteria residing in the gastrointestinal tract – plays a key role in mental health and nutrient metabolism. In patients with mental disorders, the following are often observed:
- Reduced levels of beneficial bacteria: gut bacteria support the production of certain vitamins such as vitamin K, biotin, and folic acid (B9). Deficiencies in these nutrients can impair the metabolism of neurotransmitters like serotonin and dopamine, increasing the risk of depression and anxiety disorders.
- Increased levels of pathogenic bacteria: some harmful bacteria can cause chronic inflammation, damage the intestinal lining, and weaken the body’s ability to absorb nutrients, which can exacerbate symptoms of mental illness (Onaolapo & Onaolapo 2021).
C. Elevated homocysteine levels in patients with schizophrenia
- Homocysteine is an amino acid produced during protein metabolism. High levels of homocysteine are associated with an increased risk of heart disease and neurological disorders. Patients with depression and schizophrenia often exhibit elevated homocysteine levels, which suggests a deficiency in vitamins B6, B9, and B12 – all essential for neutralizing homocysteine. Excess homocysteine can damage blood vessels in the brain, increasing the risk of mood disorders, memory problems, and worsening of schizophrenia symptoms (Onaolapo & Onaolapo 2021).
2. Increased nutrient requirements
Individuals suffering from mental illnesses often have higher nutritional requirements than healthy individuals. This can result from several factors, such as:
- Elevated levels of stress hormones, such as cortisol.
- Increased brain metabolic rate.
- The impact of psychotropic medications on nutrient balance.
- Chronic fatigue and deficiencies resulting from poor diet.
- Increased inflammatory activity and oxidative stress.
These factors mean that psychiatric patients may need more vitamins, minerals, and omega-3 fatty acids than healthy individuals in order to maintain proper brain and nervous system function (Onaolapo & Onaolapo 2021).
Increased inflammatory activity and oxidative stress
- Coeliac disease is an autoimmune condition in which the consumption of gluten (a protein found in wheat, rye and barley) triggers an immune reOxidative stress is a condition in which there is an excess of free radicals in the body – reactive molecules that can damage cells, including neurons in the brain.
- Research shows that individuals suffering from schizophrenia, depression, and bipolar disorder have higher levels of oxidative stress, which leads to neuronal damage and impaired cognitive function.
- The brain is particularly vulnerable to the effects of free radicals because it consumes large amounts of oxygen and contains high concentrations of polyunsaturated fatty acids, which are prone to oxidation.
Which nutrients help combat oxidative stress?
- Antioxidant vitamins (vitamin C, vitamin E, beta-carotene) – neutralize free radicals and protect neurons from damage.
- Zinc and selenium – support the activity of antioxidant enzymes such as superoxide dismutase, which protects brain cells.
- Omega-3 fatty acids – reduce inflammation in the brain and support neuron regeneration (Onaolapo & Onaolapo, 2021).
Elevated levels of stress hormones such as cortisol
- Cortisol is a stress hormone that is essential for normal body function in appropriate amounts, but chronically elevated cortisol levels can lead to mental health disorders such as depression and anxiety (Zielińska et al., 2023).
- High cortisol levels may lead to:
✔ increase magnesium depletion, which is critical for nervous system function;
✔ lead to a deficiency in B vitamins, which are necessary for the production of neurotransmitters like serotonin;
✔ disrupt calcium-magnesium balance, which can worsen anxiety and irritability symptoms (Zielińska et al., 2023)
- Which nutrients help regulate cortisol levels?
- Magnesium – has a calming effect on the nervous system and reduces the impact of chronic stress.
- B vitamins (B6, B9, B12) – support the functioning of the nervous system and help regulate cortisol levels.
- Omega-3 fatty acids – may lower cortisol levels and improve stress resilience (Zielińska et al., 2023).
Increased brain metabolism and energy demand
- The brain consumes about 20% of the body’s total energy, but in individuals with mental disorders, it may require even more energy and nutrients.
- In depression and schizophrenia, glucose metabolism is often impaired, meaning that brain cells may have difficulty obtaining energy. This can lead to:
✔ impaired cognitive function (memory and concentration problems);
✔ low mood and increased irritability;
✔ disrupted neurotransmitter production (Onaolapo & Onaolapo, 2021).
Which nutrients support brain metabolism?
✔ Omega-3 fatty acids – provide energy and support neuronal cell membranes.
✔ Coenzyme Q10 – supports energy production in mitochondria, the „powerhouses” of brain cells.
✔ B vitamins – help convert glucose into energy (Onaolapo & Onaolapo, 2021).
3. Side effects of psychotropic medications and nutrient deficiencies
Psychotropic drugs used to treat conditions such as schizophrenia, depression, bipolar disorder, and anxiety are essential for therapy, but they can lead to nutrient deficiencies through several mechanisms:
• impaired absorption of vitamins and minerals;
• increased excretion of nutrients;
• metabolic changes leading to insulin resistance and obesity;
• effects on appetite, resulting in improper nutrition.
Each of these mechanisms can cause deficiencies that may weaken the effectiveness of psychiatric treatment and negatively affect the client’s/patient’s quality of life.
Which nutrients may be depleted due to the use of psychotropic medications?
✔ Antipsychotic medications (used in schizophrenia and bipolar disorder). Some of them:
Disrupt glucose and insulin metabolism
- Consequences: May lead to insulin resistance, type 2 diabetes, and obesity. Insulin resistance can cause chronic fatigue, concentration problems, and a higher risk of depression.
- Impact on nutrients:
- lower magnesium levels, which is essential for blood glucose regulation and proper nervous system function;
- reduce leptin sensitivity, leading to increased appetite and excessive intake of processed carbohydrates (Onaolapo & Onaolapo, 2021).
- Increase the excretion of vitamins and minerals
- Affect levels of zinc and selenium, which are essential for immune system function and neuroprotective processes. Zinc deficiency may increase susceptibility to depression and worsen memory.
- Vitamin B12 – long-term use of certain antipsychotics may lead to its deficiency, which can cause fatigue, concentration problems, and impaired cognitive function (Rao et al., 2008).
May cause antioxidant deficiencies
- Vitamins C and E – patients taking antipsychotics show increased oxidative stress, which raises the demand for these vitamins. A deficiency may lead to accelerated neuronal damage (Onaolapo & Onaolapo, 2021).
✔ Antidepressants (SSRIs, SNRIs, tricyclic antidepressants). Some of them may:
Affect serotonin metabolism and nutrient balance
- Consequences: Long-term use of antidepressants can affect neurotransmitter balance and increase the demand for nutrients involved in their synthesis.
- Lower zinc and magnesium levels – both elements are essential for mood regulation and reducing anxiety. Their deficiency may cause chronic fatigue and restlessness (Rao et al., 2008).
- Reduce vitamin B6 levels, which is crucial for the synthesis of serotonin (‘the happiness hormone’). A deficiency in this vitamin may reduce the effectiveness of depression treatment.
Disrupt gut microbiome
- Serotonin is produced not only in the brain but also in the gut. SSRI medications can alter the composition of gut microbiota, which may reduce the body’s ability to synthesize neurotransmitters (Onaolapo & Onaolapo, 2021).
✔ Lithium used in bipolar disorder. Lithium may affect:
Electrolyte balance
- Consequences: Lithium affects calcium, magnesium, and sodium levels in the body. It can lead to thyroid and kidney dysfunction, which may worsen the patient’s mental health (Rao et al., 2008).
Nutrient deficiencies.
- It may lower iodine levels, increasing the risk of thyroid problems and slowing metabolism.
- It can reduce vitamin B12 levels, which may lead to fatigue and neuropathies.
4. Poor dietary habits and lifestyle
The Western diet – low in nutrients. A diet rich in fast food, simple sugars, and trans fats can lead to nutrient deficiencies and inflammation, which negatively impact mental health.
Summary :
Nutrient deficiencies in patients with mental disorders result from multiple mechanisms, including impaired absorption, increased nutritional needs, side effects of medications, and poor dietary habits. Professional dietary support and an individualized nutrition plan can complement pharmacological therapy and improve patients’ quality of life.
INTERACTIVE ACTIVITY 28
| Bibliography |
| Zielińska, M., Łuszczki, E., & Dereń, K. (2023). Dietary nutrient deficiencies and risk of depression (Review Article 2018–2023). Nutrients, 15(11), 2433. https://doi.org/10.3390/nu15112433 Onaolapo, O. J., & Onaolapo, A. Y. (2021). Nutrition, nutritional deficiencies, and schizophrenia: An association worthy of constant reassessment. World Journal of Clinical Cases, 9(28), 8295–8311. https://doi.org/10.12998/wjcc.v9.i28.8295 Rao, T. S., Asha, M. R., Ramesh, B. N., & Rao, K. S. (2008). Understanding nutrition, depression and mental illnesses. Indian Journal of Psychiatry, 50(2), 77–82. https://doi.org/10.4103/0019-5545.42391 |
