Association of dietary amino acids with low mood

The use of diet for preventing and treating depression in young men: current evidence and existing challenges

Emerging evidence suggests that diet therapy (nutrients, foods and dietary patterns) could be effective as a potential adjunctive treatment option for major depressive disorder. Numerous mechanisms have been proposed, including the role inflammation, oxidative stress, brain-derived neurotrophic factor, the gastrointestinal tract microbiome and tryptophan/serotonin metabolism. Despite known differences in depression characteristics and treatment responses between males and females, there are limited sex-specific studies examining the role of diet in young men specifically. This is important as young men are often reluctant to seek mental health support, so finding treatment strategies which appeal to this demographic is crucial. This brief report provides an overview of the most recent advances in the use of diet for preventing and treating depression in young men, highlighting existing challenges and opportunities for future research. We recommend that clinicians discuss the role of diet with depressed young men, so that diet may be used alongside current treatment options.

Dietary Kynurenine Pathway Metabolites-Source, Fate, and Chromatographic Determinations

Tryptophan metabolism plays an essential role in human health. In mammals, about 95% of dietary tryptophan is metabolized through the kynurenine pathway, which is associated with the development of several pathologies, including neurodegeneration. Some of the kynurenine pathway metabolites are agonists of the aryl hydrocarbon receptor involved in metabolic functions, inflammation, and carcinogenesis. Thus, their origins, fates, and roles are of widespread interest. Except for being produced endogenously, these metabolites can originate from exogenous sources (e.g., food) and undergo absorption in the digestive tract. Recently, a special focus on exogenous sources of tryptophan metabolites was observed. This overview summarizes current knowledge about the occurrence of the kynurenine pathway metabolites (kynurenines) in food and the analytical method utilized for their determination in different food matrices. Special attention was paid to sample preparation and chromatographic analysis, which has proven to be a core technique for the detection and quantification of kynurenines. A discussion of the fate and role of dietary kynurenines has also been addressed. This review will, hopefully, guide further studies on the impact of dietary kynurenines on human health.

Genetic risk of depression is different in subgroups of dietary ratio of tryptophan to large neutral amino acids

Manipulation of intake of serotonin precursor tryptophan has been exploited to rapidly induce and alleviate depression symptoms. While studies show that this latter effect is dependent on genetic vulnerability to depression, the effect of habitual tryptophan intake in the context of predisposing genetic factors has not been explored. Our aim was to investigate the effect of habitual tryptophan intake on mood symptoms and to determine the effect of risk variants on depression in those with high and low tryptophan intake in the whole genome and specifically in serotonin and kynurenine pathways. 63,277 individuals in the UK Biobank with data on depressive symptoms and tryptophan intake were included. We compared two subpopulations defined by their habitual diet of a low versus a high ratio of tryptophan to other large amino acids (TLR). A modest protective effect of high dietary TLR against depression was found. NPBWR1 among serotonin genes and POLI in kynurenine pathway genes were significantly associated with depression in the low but not in the high TLR group. Pathway-level analyses identified significant associations for both serotonin and kynurenine pathways only in the low TLR group. In addition, significant association was found in the low TLR group between depressive symptoms and biological process related to adult neurogenesis. Our findings demonstrate a markedly distinct genetic risk profile for depression in groups with low and high dietary TLR, with association with serotonin and kynurenine pathway variants only in case of habitual food intake leading to low TLR. Our results confirm the relevance of the serotonin hypothesis in understanding the neurobiological background of depression and highlight the importance of understanding its differential role in the context of environmental variables such as complexity of diet in influencing mental health, pointing towards emerging possibilities of personalised prevention and intervention in mood disorders in those who are genetically vulnerable.

Tryptophan intake is related to a lower prevalence of depressive symptoms during pregnancy in Japan: baseline data from the Kyushu Okinawa Maternal and Child Health Study

OBJECTIVE

Tryptophan is an essential amino acid wholly derived from diet. While the majority of tryptophan is degraded through the kynurenine pathway into neuroactive metabolites like quinolinic acid and kynurenic acid, a small proportion of ingested tryptophan is metabolized into the neurotransmitter serotonin. The current cross-sectional study in Japan examined the association between tryptophan intake and depressive symptoms during pregnancy.

METHODS

Study subjects were 1744 pregnant women. Dietary intake during the preceding month was assessed using a self-administered diet history questionnaire. Depressive symptoms were defined as a score ≥ 16 on the Center for Epidemiologic Studies Depression Scale. Adjustment was made for age, gestation, region of residence, number of children, family structure, history of depression, family history of depression, smoking, secondhand smoke exposure at home and at work, employment, household income, education, body mass index, and intake of saturated fatty acids, eicosapentaenoic acid plus docosahexaenoic acid, calcium, vitamin D, and isoflavones.

RESULTS

The prevalence of depressive symptoms during pregnancy was 19.2%. After adjustment for confounding factors, higher tryptophan intake was independently inversely associated with the prevalence of depressive symptoms during pregnancy: the adjusted prevalence ratios (95% confidence intervals) for depressive symptoms during pregnancy in the first, second, third, and fourth quartiles of tryptophan intake were 1 (reference), 0.99 (0.76-1.28), 0.94 (0.71-1.25), and 0.64 (0.44-0.93), respectively (p for trend = 0.04).

CONCLUSIONS

Higher estimated tryptophan intake was cross-sectionally independently associated with a lower prevalence of depressive symptoms during pregnancy in Japanese women.

Deficiency in the Essential Amino Acids l-Isoleucine, l-Leucine and l-Histidine and Clinical Measures as Predictors of Moderate Depression in Elderly Women: A Discriminant Analysis Study

Increases in depression are common in some elderly women. Elderly women often show moderate depressive symptoms, while others display minimal depressive symptoms. These discrepancies have produced contradictory and inconclusive outcomes, which have not been explained entirely by deficits in neurotransmitter precursors. Deficiency in some amino acids have been implicated in major depression, but its role in non-clinical elderly women is not well known. An analysis of essential amino acids, depression and the use of discriminant analysis can help to clarify the variation in depressive symptoms exhibited by some elderly women. The aim was to investigate the relationship of essential amino acids with affective, cognitive and comorbidity measures in elderly women without major depression nor severe mood disorders or psychosis, specifically thirty-six with moderate depressive symptoms and seventy-one with minimal depressive symptoms. The plasma concentrations of nineteen amino acids, Beck Depression Inventory (BDI) scores, Geriatric Depression Scale (GDS) scores, global cognitive scores and comorbidities were submitted to stepwise discriminant analysis to identify predictor variables. Seven predictors arose as important for belong to the group based on amino acid concentrations, with the moderate depressive symptoms group characterized by higher BDI, GDS and cognitive scores; fewer comorbidities; and lower levels of l-histidine, l-isoleucine and l-leucine. These findings suggest that elderly women classified as having moderate depressive symptoms displayed a deficiency in essential amino acids involved in metabolism, protein synthesis, inflammation and neurotransmission.

Evaluation of serum amino acids and non-enzymatic antioxidants in drug-naïve first-episode major depressive disorder

BACKGROUND

The alterations of biological markers are thought to be effective tools to understand the pathophysiology and management of major depressive disorder (MDD). A lot of researches has implied many markers for depression, but any of them fully discovered the association between the markers and depression. The present study investigated the serum levels of amino acids and non-enzymatic antioxidants in major depression, and also explained their association with depression.

METHODS

This study examined 247 MDD patients and 248 healthy controls (HCs) matched by age and sex. The Hamilton Depression Rating Scale (Ham-D) was used to all the participants to measure the severity of depression. Quantification of serum amino acids, vitamin A and E were carried out using the HPLC system whereas vitamin C levels were measured by UV-spectrophotometer. All the statistical analysis was performed by SPSS statistical software (version 23.0). The independent sample t-test, the Mann-Whitney U test, and the Fisher's exact test were applied to detect the group differences where a Bonferroni correction applied to the p value.

RESULTS

It was observed that serum levels of four amino acids (methionine, phenylalanine, tryptophan, and tyrosine) along with three non-enzymatic antioxidants (vitamin A, E, and C) were significantly dropped in MDD patients compared to HCs (Cohen's d (d): - 0.45, - 0.50, - 0.68, - 0.21, - 0.27, - 0.65, and - 0.24, respectively). Furthermore, Ham-D scores of cases were negatively correlated with serum levels of methionine (r = - 0.155, p = 0.015) and tyrosine (r = - 0.172, p = 0.007).

CONCLUSION

The present study suggests that lowered serum methionine, phenylalanine, tryptophan, tyrosine, and non-enzymatic antioxidants are associated with depression. The reduction of these parameters in MDD patients may be the consequence, and not the cause, of major depression.

Body-weight and psychological well-being in the UK general population

Background

While the consequences of body weight for physical health are well explored, the evidence for psychological well-being is less straightforward. An instrumental variable approach is used to address the endogenous relationship between body weight and well-being in the UK general population.

Methods

Data from the Health Survey for England (2003, 2004 and 2006) are used to fit linear and ordered probit instrument variable models for a sample of 13 862 individuals, with frequent white meat consumption instrumenting for body-weight. Non-linearities in the relationship, robustness to weak instruments and relaxation of strict exogeneity assumption are further examined.

Results

Accounting for endogeneity and conditional on health a protective effect on well-being is observed. A unit increase in body mass index (BMI) improves General Health Questionnaire (GHQ) by 0.17 (95% CI: 0.02-0.31) points and reduces the probability of reporting very low GHQ by 2.5% (95% CI: 0.01-0.05). Empirical testing showed that the instrument performs well, with increased meat consumption adding 0.58 points (95% CI: 0.42-0.74) to ones' BMI.

Conclusions

We present support for the jolly-fat hypothesis, however, caution is recommended in drawing inferences. Further research needs to resolve the mixed findings in the literature.

Egg consumption and prevalence of psychological disorders in adults

PURPOSE

No previous study has examined the associations between egg consumption and prevalence of psychological disorders. The present study was conducted to determine the association between egg consumption and depression in a large sample of Iranian adults.

METHODS

This cross-sectional study was conducted on 3172 adults in Isfahan, Iran. Egg consumption was assessed by using a validated, self-administered, dish-based, semi-quantitative food frequency questionnaire. The Iranian validated version of Hospital Anxiety and Depression Scale was used to screen for anxiety and depression. The Iranian validated version of General Health Questionnaire with 12 items was used to assess psychological distress. Depression, anxiety and psychological distress were defined according to standard criteria.

RESULTS

The mean age of the study participants was 36.5 ± 7.9 years. Depression, anxiety and psychological distress were prevalent among 28.4, 13.6 and 23% of the study subjects, respectively. After controlling for potential confounders, no significant association was observed between egg intake and depression (OR for comparing extreme quartiles: 1.08; 95% CIs 0.80-1.45) and anxiety (OR 0.79; 95% CIs 0.54-1.16), as well as psychological distress (OR 1.03; 95% CIs 0.76-1.41) in the whole population. In men, significant positive associations were observed between egg intake and depression before controlling for BMI (OR 1.68; 95% CIs 1.01-2.80); however, the associations became non-significant after taking BMI into account (OR 1.62; 95% CIs 0.96-2.72).

CONCLUSIONS

We found no significant association between egg intake and psychological disorders. Further studies, in particular of prospective design, are warranted.

Association between habitual tryptophan intake and depressive symptoms in young and middle-aged women

BACKGROUND

The intake of tryptophan, the precursor of serotonin, is assumed to affect serotonin availability and depression onset. Nevertheless, a definitive relationship between dietary tryptophan intake and depressive symptoms has not been established. We examined the association between tryptophan intake and depressive symptoms screened in a group of 4272 first-year female dietetic students and 3651 their mothers.

METHODS

Dietary tryptophan intake during the preceding month was assessed with a validated, self-administered diet history questionnaire. Depressive symptoms were assessed with the Center for Epidemiologic Studies Depression Scale (CES-D) using two cutoff scores: CES-D score ≥ 16 and CES-D score ≥ 19 (the optimal cutoff score for Japanese people). The multivariate adjusted prevalence ratio (PR) and 95% confidence interval (CI) for depressive symptoms were calculated using Poisson regression analysis.

RESULTS

The prevalence of depressive symptoms (CES-D score ≥ 16) was 50.0% for young women and 26.5% for middle-aged women. The adjusted PR (95% CI) for depressive symptoms in the highest versus lowest quintile of tryptophan intake was 0.84 (0.75, 0.93) in young women (P for trend < 0.0001) and 0.83 (0.64, 1.01) in middle-aged women (P for trend < 0.0001). These associations were stable even when depressive symptoms were defined as a CES-D score ≥ 19.

LIMITATIONS

This is a cross-sectional study. Depressive symptoms were assessed using a self-reported questionnaire.

CONCLUSIONS

This cross-sectional study showed that a higher tryptophan intake was independently associated with a lower prevalence of depressive symptoms in young Japanese women.

Possible relationship between amino acids, aggression and psychopathy

OBJECTIVE

Aggressive behaviour is associated with reduced serotonin metabolism in the brain, but there is not enough knowledge on potential changes of the serotonin precursor levels among violent offenders. In this study, we aimed to evaluate the relationships among the tendency of psychopathy, anger and the basic amino acids.

METHODS

Fifty-two young adult male patients with antisocial personality disorder (APD) and 30 healthy men included the study. Serum amino acid levels were measured by HPLC method. Aggression questionnaire and Hare Psychopathology Scale were used for all participants.

RESULTS

Blood levels of phosphoserine, aspartic acid, glutamic acid, aminoadipic acid and 1-methylhistidine in group of patients with APD were significantly higher than the control group. Blood levels of TRP, asparagine, citrulline, cystine, isoleucine, tyrosine, histidine, hydroxylysine, lysine, ethanolamine and arginine in the group of patients were found lower than the control group. A significant positive correlation between anger scores and histidine, methionine and GABA was found. GABA and methionine showed a significant correlation with the indirect aggression score.

CONCLUSION

Our study showed a relationship between serum amino acid levels and the scores of aggression and psychopathy. We think that this is a productive research area for understanding the relationship among biochemical factors, aggression and psychopathy.

The effects of dietary tryptophan on affective disorders

Using a randomized crossover study design, 25 healthy young adults were examined for differences in anxiety, depression, and mood after consuming a high tryptophan and a low tryptophan diet for 4days each. There was a 2week washout between the diets. A within-subjects analysis of the participants' mood indicated significantly (p<.01) more positive affect scores after consuming a high tryptophan diet as compared to a low tryptophan diet. Negative affect differences between the diets were not statistically significant (p>.05). Also, consuming more dietary tryptophan resulted in (p<.05) less depressive symptoms and decreased anxiety.

Canadian Network for Mood and Anxiety Treatments (CANMAT) Clinical guidelines for the management of major depressive disorder in adults. V. Complementary and alternative medicine treatments

BACKGROUND

In 2001, the Canadian Psychiatric Association and the Canadian Network for Mood and Anxiety Treatments (CANMAT) partnered to produce evidence-based clinical guidelines for the treatment of depressive disorders. A revision of these guidelines was undertaken by CANMAT in 2008-2009 to reflect advances in the field. There is widespread interest in complementary and alternative medicine (CAM) therapies in the treatment of major depressive disorder (MDD).

METHODS

The CANMAT guidelines are based on a question-answer format to enhance accessibility to clinicians. An evidence-based format was used with updated systematic reviews of the literature and recommendations were graded according to Level of Evidence using pre-defined criteria. Lines of Treatment were identified based on criteria that included evidence and expert clinical support. This section on "Complementary and Alternative Medicine Treatments" is one of 5 guideline articles.

RESULTS

There is Level 1 evidence to support light therapy in seasonal MDD and St. John's wort in mild to moderate MDD. There is also some evidence for the use of exercise, yoga and sleep deprivation, as well as for omega-3 fatty acids and SAM-e . Support for other natural health products and therapies is still limited.

LIMITATIONS

The evidence base remains limited and studies often have methodological problems, including small samples, variability in dose, short duration of treatment, unknown quality of the agent and limited long-term data. Safety data are also sparse with little information about drug interactions.

CONCLUSIONS

Some CAM treatments have evidence of benefit in MDD. However, problems with standardization and safety concerns may limit their applicability in clinical practice.

Nutrition and geriatric psychiatry: a neglected field

PURPOSE OF REVIEW

Nutritional issues have received little attention in geriatric psychiatry research. This review focuses on literature published in 2003 and 2004 on nutritional factors in mental illness in the elderly and proposes directions for future research.

RECENT FINDINGS

There has been more research on the role of micronutrients in psychiatric disorders of older adults but studies examining nutritional state in this population are lacking. The former research suggests associations between low folic acid/vitamin B12 status and depression in older adults whereas evidence for other micronutrients is still tentative. In the latter work, there is only one study that examines malnutrition in psychogeriatric patients despite the availability of well-validated screening tools for assessing nutritional state in the elderly and the known impact of undernutrition in ageing and the development of frailty. The role of obesity in ageing is also relevant especially as more people with schizophrenia live longer, although the current evidence in the non-mentally ill elderly suggests that being overweight may have protective effects in the elderly.

SUMMARY

Malnutrition is likely to have considerable impact on the mental and physical state of the elderly.

Food and nutrient intake in relation to mental wellbeing

Background

We studied food consumption and nutrient intake in subjects with depressed mood, anxiety and insomnia as indices of compromised mental wellbeing.

Methods

The study population consisted of 29,133 male smokers aged 50 to 69 years who entered the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study in 1985–1988. This was a placebo-controlled trial to test whether supplementation with alpha-tocopherol or beta-carotene prevents lung cancer. At baseline 27,111 men completed a diet history questionnaire from which food and alcohol consumption and nutrient intake were calculated. The questionnaire on background and medical history included three symptoms on mental wellbeing, anxiety, depression and insomnia experienced in the past four months.

Results

Energy intake was higher in men who reported anxiety or depressed mood, and those reporting any such symptoms consumed more alcohol. Subjects reporting anxiety or depressed mood had higher intake of omega-3 fatty acids and omega-6 fatty acids.

Conclusions

Our findings conflict with the previous reports of beneficial effects of omega-3 fatty acids on mood.