Gut microbiota-derived vitamins - underrated powers of a multipotent ally in psychiatric health and disease.

Despite the well-established roles of B-vitamins and their deficiencies in health and disease, there is growing evidence indicating a key role of those nutrients in functions of the central nervous system and in psychopathology. Clinical data indicate the substantial role of B-vitamins in various psychiatric disorders, including major depression, bipolar disorder, schizophrenia, autism, and dementia, including Alzheimer's and Parkinson's diseases. As enzymatic cofactors, B-vitamins are involved in many physiological processes such as the metabolism of glucose, fatty acids and amino acids, metabolism of tryptophan in the kynurenine pathway, homocysteine metabolism, synthesis and metabolism of various neurotransmitters and neurohormones including serotonin, dopamine, adrenaline, acetylcholine, GABA, glutamate, D-serine, glycine, histamine and melatonin. Those vitamins are highly involved in brain energetic metabolism and respiration at the cellular level. They have a broad range of anti-inflammatory, immunomodulatory, antioxidant and neuroprotective properties. Furthermore, some of those vitamins are involved in the regulation of permeability of the intestinal and blood-brain barriers. Despite the fact that a substantial amount of the above vitamins is acquired from various dietary sources, deficiencies are not uncommon, and it is estimated that micronutrient deficiencies affect about two billion people worldwide. The majority of gut-resident microbes and the broad range of bacteria available in fermented food, express genetic machinery enabling the synthesis and metabolism of B-vitamins and, consequently, intestinal microbiota and fermented food rich in probiotic bacteria are essential sources of B-vitamins for humans. All in all, there is growing evidence that intestinal bacteria-derived vitamins play a significant role in physiology and that dysregulation of the "microbiota-vitamins frontier" is related to various disorders. In this review, we will discuss the role of vitamins in mental health and explore the perspectives and potential of how gut microbiota-derived vitamins could contribute to mental health and psychiatric treatment.

Impact of Hyperhomocysteinemia and Different Dietary Interventions on Cognitive Performance in a Knock-in Mouse Model for Alzheimer's Disease.

BACKGROUND: Hyperhomocysteinemia is considered a possible contributor to the complex pathology of Alzheimer's disease (AD). For years, researchers in this field have discussed the apparent detrimental effects of the endogenous amino acid homocysteine in the brain. In this study, the roles of hyperhomocysteinemia driven by vitamin B deficiency, as well as potentially beneficial dietary interventions, were investigated in the novel AppNL-G-F knock-in mouse model for AD, simulating an early stage of the disease. METHODS: Urine and serum samples were analyzed using a validated LC-MS/MS method and the impact of different experimental diets on cognitive performance was studied in a comprehensive behavioral test battery. Finally, we analyzed brain samples immunohistochemically in order to assess amyloid-ß (Aß) plaque deposition. RESULTS: Behavioral testing data indicated subtle cognitive deficits in AppNL-G-F compared to C57BL/6J wild type mice. Elevation of homocysteine and homocysteic acid, as well as counteracting dietary interventions, mostly did not result in significant effects on learning and memory performance, nor in a modified Aß plaque deposition in 35-week-old AppNL-G-F mice. CONCLUSION: Despite prominent Aß plaque deposition, the AppNL-G-F model merely displays a very mild AD-like phenotype at the investigated age. Older AppNL-G-F mice should be tested in order to further investigate potential effects of hyperhomocysteinemia and dietary interventions.

B Vitamins and Ageing.

Vitamin B contributes to the overall health and wellbeing, including that of energy metabolism, methylation, synthesis and DNA repair and proper immune function. Deficiency in B vitamins has been linked to neurocognitive disorders, mitochondrial dysfunction, immune dysfunction and inflammatory conditions. In ageing populations B vitamin deficiency has been linked to cardiovascular disorders, cognitive dysfunction, osteoporosis and methylation disorders and can increase the risk of developing degenerative diseases, particularly cardiovascular disease, cognitive diseases and osteoporosis. Optimization of B vitamin status in the elderly may prove beneficial in the prevention of degenerative diseases. Here we discuss broadly the role of B vitamins in ageing.

Potential Links between Impaired One-Carbon Metabolism Due to Polymorphisms, Inadequate B-Vitamin Status, and the Development of Alzheimer's Disease.

Alzheimer's disease (AD) is the major cause of dementia and no preventive or effective treatment has been established to date. The etiology of AD is poorly understood, but genetic and environmental factors seem to play a role in its onset and progression. In particular, factors affecting the one-carbon metabolism (OCM) are thought to be important and elevated homocysteine (Hcy) levels, indicating impaired OCM, have been associated with AD. We aimed at evaluating the role of polymorphisms of key OCM enzymes in the etiology of AD, particularly when intakes of relevant B-vitamins are inadequate. Our review indicates that a range of compensatory mechanisms exist to maintain a metabolic balance. However, these become overwhelmed if the activity of more than one enzyme is reduced due to genetic factors or insufficient folate, riboflavin, vitamin B6 and/or vitamin B12 levels. Consequences include increased Hcy levels and reduced capacity to synthetize, methylate and repair DNA, and/or modulated neurotransmission. This seems to favor the development of hallmarks of AD particularly when combined with increased oxidative stress e.g., in apolipoprotein E (ApoE) ε4 carriers. However, as these effects can be compensated at least partially by adequate intakes of B-vitamins, achieving optimal B-vitamin status for the general population should be a public health priority.

Homocysteine and DNA methylation: a review of animal and human literature.

Homocysteine (Hcy) is a sulfur-containing non-protein forming amino acid, which is synthesized from methionine as an important intermediate in the one-carbon pathway. High concentrations of Hcy in a condition called hyperhomocysteinemia (HHcy) are an independent risk factor for several disorders including cardiovascular diseases and osteoporotic fractures. Since Hcy is produced as a byproduct of the methyltransferase reaction, alteration in DNA methylation is studied as one of the underlying mechanisms of HHcy-associated disorders. In animal models, elevated Hcy concentrations are induced either by diet (high methionine, low B-vitamins, or both), gene knockouts (Mthfr, Cbs, Mtrr or Mtr) or combination of both to investigate their effects on DNA methylation or its markers. In humans, most of the literature involves case-control studies concerning patients. The focus of this review is to study existing literature on HHcy and its role in relation to DNA methylation. Apart from this, a few studies investigated the effect of Hcy-lowering trials on restoring DNA methylation patterns, by giving a folic acid or B-vitamin supplemented diet. These studies which were conducted in animal models as well as humans were included in this review.

Peculiarities of one-carbon metabolism in the strict carnivorous cat and the role in feline hepatic lipidosis.

Research in various species has indicated that diets deficient in labile methyl groups (methionine, choline, betaine, folate) produce fatty liver and links to steatosis and metabolic syndrome, but also provides evidence of the importance of labile methyl group balance to maintain normal liver function. Cats, being obligate carnivores, rely on nutrients in animal tissues and have, due to evolutionary pressure, developed several physiological and metabolic adaptations, including a number of peculiarities in protein and fat metabolism. This has led to specific and unique nutritional requirements. Adult cats require more dietary protein than omnivorous species, maintain a consistently high rate of protein oxidation and gluconeogenesis and are unable to adapt to reduced protein intake. Furthermore, cats have a higher requirement for essential amino acids and essential fatty acids. Hastened use coupled with an inability to conserve certain amino acids, including methionine, cysteine, taurine and arginine, necessitates a higher dietary intake for cats compared to most other species. Cats also seemingly require higher amounts of several B-vitamins compared to other species and are predisposed to depletion during prolonged inappetance. This carnivorous uniqueness makes cats more susceptible to hepatic lipidosis.

Adult-onset cerebral folate deficiency.

OBJECTIVE: To report new manifestations of cerebral folate deficiency, a rare metabolic autoimmune syndrome,in an adult. DESIGN: Case report. SETTING: University teaching hospital. PATIENT: A 58-year-old woman with progressive memory loss and myoclonus presented for medical attention. Results of cerebral spinal fluid analysis showed low levels of tetrahydrobiopterin and 5-methyltetrahydrofolate. The patient's serum folate level was normal. Serum contained folate receptor 1 blocking and binding antibodies. RESULTS: The patient was treated successfully with folinic acid supplementation, and after 6 months of treatment,clinical symptoms had resolved. CONCLUSIONS: To our knowledge, we report the first case of adult-onset cerebral folate deficiency. Furthermore, this condition could represent a treatable form of early-onset dementia.

Biotin deficiency in a glycogen storage disease type 1b girl fed only with glycogen storage disease-related formula.

Glycogen storage disease type I is an autosomal recessive disorder caused by the defect in the glucose-6-phosphate enzyme system. Frequent intake of glucose-containing glycogen storage disease formula, uncooked cornstarch, or both, are usually needed to maintain normal blood glucose level. We report a glycogen storage disease type 1b girl with biotin deficiency caused by an exclusive glucose-containing glycogen storage disease formula for years, presenting with the appearance of severe skin lesions, and diagnosed by urinary organic acid analysis by gas chromato-spectrometry, and blood acylcarnitine analysis by tandem mass-spectrometry.

Muscle carnitine deficiency: adult onset lipid storage myopathy with sensory neuropathy.

Muscle carnitine deficiency usually results in a lipid storage myopathy, but more rarely, neuropathy occurs in this condition. We report herein a 29-year-old man with muscle carnitine deficiency who developed not only a lipid storage myopathy, but also a severe sensory neuropathy. Oral therapy with levo-carnitine (3 g per day) for 3 months produced a remarkable improvement of the myopathy and sensory neuropathy. Six months later, he remained in good condition under strict dietary control. This report emphasizes that severe neuropathy may occur in some patients with muscle carnitine deficiency, and highlights the need for the neurologist's familiarity with those afflicted to achieve optimal clinical management.

Gestational vitamin B deficiency leads to homocysteine-associated brain apoptosis and alters neurobehavioral development in rats.

Hyperhomocysteinemia has been identified as a risk factor for neurological disorders. To study the influence of early deficiency in nutritional determinants of hyperhomocysteinemia on the developing rat brain, dams were fed a standard diet or a diet lacking methyl groups during gestation and lactation. Homocysteinemia progressively increased in the offspring of the deficient group and at 21 days reached 13.3+/-3.7 micromol/L versus 6.8+/-0.3 micromol/L in controls. Homocysteine accumulated in both neurons and astrocytes of selective brain structures including the hippocampus, the cerebellum, the striatum, and the neurogenic subventricular zone. Most homocysteine-positive cells expressed p53 and displayed fragmented DNA indicative of apoptosis. Righting reflex and negative geotaxis revealed a delay in the onset of integration capacities in the deficient group. Between 19 and 21 days, a poorer success score was recorded in deficient animals in a locomotor coordination test. A switch to normal food after weaning allowed restoration of normal homocysteinemia. Nevertheless, at 80 days of age, the exploratory behavior in the elevated-plus maze and the learning and memory behavior in the eight-arm maze revealed that early vitamin B deprivation is associated with persistent functional disabilities, possibly resulting from the ensuing neurotoxic effects of homocysteine.

Safety, tolerability and symptom outcomes associated with L-carnitine supplementation in patients with cancer, fatigue, and carnitine deficiency: a phase I/II study.

Carnitine deficiency is among the many metabolic disturbances that may contribute to fatigue in patients with cancer. Administration of exogenous L-carnitine may hold promise as a treatment for this common symptom. Little is known about L-carnitine safety, tolerability, and dose-response in patients with cancer. We conducted a Phase I/II open-label trial to assess the safety and tolerability of exogenous L-carnitine and clarify the safe dose range associated with symptom effects for future controlled trials. Adult patients with advanced cancer, carnitine deficiency (free carnitine <35 for males or <25 microM/L for females, or acyl/free carnitine ratio >0.4), moderate to severe fatigue, and a Karnofsky Performance Status (KPS) score > or =50 were entered by groups of at least three into a standard maximum tolerated dose design. Each successive group received a higher dose of L-carnitine (250, 750, 1250, 1750, 2250, 2750, 3000 mg/day, respectively), administered in two daily doses for 7 days. To compare symptom outcomes before and after supplementation, patients completed validated measures of fatigue (Brief Fatigue Inventory [BFI]), depressed mood (Center for Epidemiologic Studies Depression Scale [CES-D]), quality of sleep (Epworth Sleeplessness Scale [ESS]), and KPS at baseline and 1 week later. Of the 38 patients screened for carnitine levels, 29 were deficient (76%). Twenty-seven patients participated ("intention to treat, ITT") (17 males, 10 females), and 21 completed the study ("completers"); 17 of these patients ("responders," mean+/-[SD] age=57.9+/-15) had increased carnitine levels at the end of the supplementation period. The highest dose achieved was 3000 mg/day. No patient experienced significant side effects and no toxicities were noted. Analysis of all the patients accrued (ITT, n=27) showed a total carnitine increase from 32.8+/-10 to 54.3+/-23 microM/L (P<0.001) and free carnitine increase from 26.8+/-8 to 44.1+/-17 microM/L (P<0.001). BFI decreased significantly, from 66+/-12 to 39.7+/-26 (P<0.001); ESS decreased from 12.9+/-12 to 9+/-6 (P=0.001); and CES-D decreased from 29.2+/-12 to 19+/-12 (P<0.001). A separate analysis of the 17 "responders" showed a dose-response relationship for total- (r=0.54, P=0.03), free-carnitine (r=0.56, P=0.02) levels, and fatigue (BFI) scores (r=-0.61, P=0.01). These findings suggest that l-carnitine may be safely administered at doses up to 3000 mg/day and that positive effects may be more likely at relatively higher doses in this range. This study provides the basis for the design of future placebo-controlled studies of l-carnitine supplementation for cancer-related fatigue.

Low essential fatty acid and B-vitamin status in a subgroup of patients with schizophrenia and its response to dietary supplementation.

We assessed essential fatty acid (EFA) and B-vitamin status, together with their determinants, in 61 patients with schizophrenia and established whether those with poor status responded biochemically to the appropriate dietary supplements. As a group, the patients had high erythrocyte saturated fatty acids (FAs), monounsaturated FA and low polyunsaturated FA of the omega3 and omega6 series. Patients reporting not to take vitamin supplements had low vitamin B12 and high homocysteine. Homocysteine variance proved best explained by folate in both the total group and male patients, and by vitamins B12 and B6 in females. Alcohol consumption and duration of illness are risk factors for low polyunsaturated FA status (< P2.5 of reference range), while male gender and absence of fish consumption predict hyperhomocysteinemia (> P97.5 of reference range). Two patients exhibited biochemical EFA deficiency and seven showed biochemical signs of omega3/docosahexaenoic acid (DHA) marginality. Four patients exhibited moderate hyperhomocysteinemia with plasma values ranging from 57.5 to 74.8 micromol/L. None of the five patients with either moderate hyperhomocysteinemia, biochemical EFA deficiency, or both, was predicted by their clinicians to have poor diets. That diet was nevertheless at the basis of these abnormalities became confirmed after supplementing 4 of them with B vitamins and with soybean and fish oils. We conclude that a subgroup of patients with schizophrenia has biochemical EFA deficiency, omega3/DHA marginality, moderate hyperhomocysteinemia, or combinations. Correction seems indicated in view of the possible relation of poor EFA and B-vitamin status with some of their psychiatric symptoms, but notably to reduce their high risk of cardiovascular disease.

Mediterranean diet and depression.

OBJECTIVE: The adherence to a Mediterranean Dietary Pattern ensures an adequate intake of B vitamins and w-3 fatty acids. A protective role on depression has been suggested for both nutrients. DESIGN: Cross-sectional analysis from the SUN (Seguimiento Universidad de Navarra) prospective cohort study. Data from 9670 participants (4211 men and 5459 women) were analised. Logistic regression analyses were fitted to assess the association between B-vitamins and w-3 fatty acids intake (quintiles) and the prevalence of depression. RESULTS: Folate intake was inversely associated with depression prevalence among men, especially smokers. Among women, B12 vitamin intake was inversely associated with depression, especially among smokers and physically active women. No significant associations were observed for w-3 fatty acids intake. CONCLUSIONS: The adherence to a Mediterranean Dietary Pattern ensures an adequate intake of fruits, nuts, vegetables, cereals, legumes or fish, important sources of nutrients linked to depression prevention.

Role of nutritional supplementation in reducing the levels of homocysteine.

Elevated plasma homocysteine level is a risk factor for atherosclerotic disease. Plasma homocysteine levels are influenced by genetic, physiological and lifestyle factors. Among the lifestyle factors, diet plays a significant role. Dietary intakes of folate, vitamins B12, B6 and B2 have been reported to be inversely related to plasma homocysteine concentration. Prevalence of subclinical deficiencies of these vitamins is high in Indian population. Folate status is the major determinant of plasma homocysteine level and there is a strong inverse correlationship between plasma homocysteine level and serum or erythrocyte folate levels. A combination therapy with B vitamins--folate, vitamins B12 and B6 is an effective means to reduce elevated homocysteine levels in general people and in patients with myocardial infarction. To maintain low plasma homocysteine concentration, people should be advised to increase their consumption of pulses, eggs, green leafy vegetables and fruits which are rich in B vitamins.