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Vitamin D and probiotics improve the metal health of schizophrenic people

Vitamin D and probiotics improve the metal health of schizophrenic peopleSchizophrenia is known to impair quality of life and reduce life expectancy. Diet, lack of nutrients, and digestion are all important for the progression of the disease, according to an Iranian study of schizophrenics who were given supplements of vitamin D plus lactic acid bacteria and bifidobacteria. The study is published in Neuropsychopharmacology Reports and reveals that these supplements were able to significantly improve the cognitive skills of the patients. The researchers also mention that these supplements have a role in regulating the body’s production of dopamine, controlling inflammatory processes, and controlling the gut-brain-axis that is important for the communication between the gut and the brain.

Millions of people globally suffer from schizophrenia and have symptoms such as delusions, hallucinations, and cognitive difficulty. Science does not know all that much about the underlying mechanisms, but it appears that local brain inflammation plays a key role. Also, there is an imbalance in the brain’s dopamine levels. Dopamine is a neurotransmitter that fuels our actions and is also a so-called reward molecule. Drugs that block the dopamine synthesis effectively treat delusions and hallucinations, but they are less effective when it comes to cognitive disturbances.
Moreover, antipsychotics used to treat schizophrenia are associated with adverse effects such as constipation and weight gain. Imbalances in the intestinal microflora can affect the disease progression, and antipsychotics can throw the intestinal microflora off balance.
Also, widespread vitamin D deficiency problems may be involved in the progression of the disease and the condition of the gut flora.
The new study looked closer at how regulation of the intestinal microflora combined with vitamin D supplementation could improve symptoms and cognitive skills in patients suffering from schizophrenia.

The positive synergy between vitamin D and probiotics

The study included 70 schizophrenia patients aged 18-65 years (one dropped out of the study). The participants were split into two groups. One group got a combined capsule with vitamin D (10 micrograms) and different kinds of lactic acid bacteria and bifidobacteria (Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus reuteri, Lactobacillus paracasei, Bifidobacterium longum, Bacillus coagulans). The other group got matching placebo. Neither the participants nor the researchers knew who got what. This was not disclosed until the study had been completed after 12 weeks. Prior to study start, the scientists assessed the severity of the patients’ condition and evaluated their cognitive skills using a scale called PANSS (Positive and Negative Syndrome Scale) and a test called MoCA (Montreal Cognitive Assessment). In addition, they measured and registered the patients’ lipid profile, BMI (Body Mass Index), and any gastrointestinal problems. They also measured blood levels of CRP (C-reactive protein) and ESR (erythrocyte sedimentation rate), both of which are inflammation markers.
The study showed a significantly increased MoCA score in the group that was supplemented with vitamin D and probiotics. Also, levels of CRP were significantly reduced, and there was a substantial improvement of the digestion compared with the patients in the placebo group. The researchers concluded that supplementation with vitamin D and probiotics has a positive effect on patients suffering from schizophrenia. They also write that this is the first study to show that the combination of vitamin D and probiotics has a synergistic effect.

Vitamin D’s importance for the brain

Nearly all cells in the body have vitamin D receptors (VDR) that control a variety of different genes and metabolic processes. There are vitamin D receptors in several parts of the brain where vitamin D helps regulate neurotransmitters like dopamine. Also, vitamin D counteracts oxidative stress and inflammation, which are associated with damaged nerve cells and various neurological disturbances. It has even been seen that maternal lack of vitamin D during pregnancy increases the child’s risk of developing schizophrenia later in life.
In the current study, the participants were given low doses of vitamin D (10 micrograms/day), and the researchers did not measure if this effectively optimized blood levels of the nutrient. In their article, they refer to a previous study where schizophrenic patients were given 1,250 micrograms (50,000 IU) weekly for two months to correct acute deficiency. This dose translates into a daily dose of 179 micrograms daily. The treatment had a positive effect on their antipsychotic medical treatment.
Although one can administer large doses of vitamin D for short periods of time to correct deficiencies, the European Food Safety Authority (EFSA) has established a safe upper intake level for vitamin D of 100 micrograms daily

The gut flora and its importance for the brain

Our gut flora consists of billions of bacteria and other microorganisms that are important for nutrient uptake, synthesis of vitamins and neurotransmitters, maintenance of normal pH values, and our metabolism of indigestible carbohydrates (dietary fiber). The many different microorganisms in our gut flora share a delicate balance that is called symbiosis. If our symbiotic equilibrium is disrupted for any reason, we risk something called dysbiosis, where some species are suppressed, and others dominate and become harmful. Our gut flora and digestion affect our mood and mental health, which is why the gut is referred to as the “second brain”. Apparently, different neurological disorders are associated with intestinal dysbiosis. In their study, the researchers describe how probiotics can regulate the production of neurotransmitters such as serotonin and GABA (gamma-aminobutyric acid) via the gut-brain-axis. Probiotics also help regulate inflammation, the cholesterol balance, and blood sugar levels, and they can even improve the cellular vitamin D receptors, which contributes to the synergistic effect.


Aida Mohammadi et al. Co-administration of probiotic and vitamin D significantly improves cognitive function in schizophrenic patients: A double-blinded randomized controlled trial. Neuropsychopharmacology Reports 2024

Renata Aparecida et al. Vitamin D: A potent regulator of dopaminergic neuron differentiation and function. Journal of Neurochemistry, 2023

Shreeya S Navale et al. Vitamin D and brain health: an observational and Mendelian randomization study. The American Journal of Clinical Nutrition, 2022

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