Mental Health Awareness Week – Special Focus on Depression (Heat)

Hot off the press is some brand new research in to the role of heat on alleviating the symptoms of depression. Turkish baths, saunas and sweat lodges have been a feature of cultures all over the world for hundreds of years. Full body heat has been used for therapeutic and sacred purposes by indigenous peoples across North America, Scandinavia, Central and South America, Central Europe where they are known to create a sense of relaxation. More recently research into the hormetic effects of heat on the body have uncovered many more health benefits. Hormesis is the term used to describe the beneficial effects of stress on the body. The most commonly understood example of this is exercise; the process of applying manageable stress to the body, by lifting weights for example, compels the body to respond by becoming stronger. Similarly, heat stress can activate biological pathways linked to improved health, longevity and neurogenesis (the formation of new brain cells).

In this paper the authors sought to clarify an earlier observation that a single session of infrared heat exposure reduced depression for five days post-treatment. Conducted over two years the participants in this current study all had a very high depression scores on a standard symptoms scale but were not taking any antidepressant medication. Participants were randomly allocated to one of two conditions: either one session of full body infrared heat treatment or one session of a placebo treatment; an identical set up just without sufficient heat to significantly raise core body temperature. The sham condition was so convincing that the majority of the people who received it believed they were receiving the real treatment. At the end of the intervention participants were reassessed at 1, 2 and 3 days, and 1, 2, 4 and 6 weeks after by assessors who did not know whether the participant had had the real or the sham treatment. Remarkably the participants who had received just one session of heat treatment showed significantly reduced depression scores up to six weeks after treatment and experienced only mild and short-lived side effects (such as dry mouth, headache or sweating). Though small, this study builds on previous research that showed a significant reduction in depression following heat treatment as well, of course, as the established therapeutic use of heat in many cultures.

Whole body heat treatment has the potential to be a powerful, safe, fast-acting and long-lasting treatment for depression. It means that a visit to the gym (see yesterday’s post) followed by a few minutes in the sauna could have tremendous positive effects on mood and depressive symptoms.

Janssen CW, Lowry CA, Mehl MR, et al. Whole-Body Hyperthermia for the Treatment of Major Depressive Disorder: A Randomized Clinical Trial. JAMA Psychiatry. Published online May 12, 2016. doi:10.1001/jamapsychiatry.2016.1031.

Hanusch, K. U., Janssen, C. H., Billheimer, D., Jenkins, I., Spurgeon, E., Lowry, C. A.  & Raison, C. L. (2013). Whole-body hyperthermia for the treatment of major depression: associations with thermoregulatory cooling. American Journal of Psychiatry, 170, 802-804.

Koltyn, K. F., Robins, H. I., Schmitt, C. L., Cohen, J. D. & Morgan, W. P. Changes in mood state following whole-body hyperthermia. International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group 8, 305-307 (1992).

Disclaimer

This information is provided for information purposes only and should not be taken as advice or instruction. This information does not replace the advice of your doctor. Please consult an appropriate health professional if you believe you are experiencing a mental or physical health concern. 

Mental Health Awareness Week – Special Focus on Depression (Exercise)

Many people will have heard that there are mood benefits of exercise. This is often linked to the ‘runners high’; the body’s release of endorphins and other ‘feel good’ chemicals during and just after exercise. There are also other neurological benefits of exercise that are linked to improved mood and wellbeing. For example, aerobic exercise increases the production of a protein called Brain Derived Neurotrophic Factor (BDNF). BDNF promotes the growth of new brain cells and is associated with improved memory, executive function and mood. Several studies and meta-analyses have demonstrated a positive effect of exercise on the symptoms of depression that are comparable to psychotherapy and antidepressant medication, and a new meta-analysis published last month, looking specifically at Quality of Life (QoL) adds to this body of research. QoL differs from illness symptoms in that it relates to a more global sense of wellbeing or satisfaction with life including where one perceives oneself to be in relation to peers or cultural expectations.

In this review the researchers collated exercise trials that assessed QoL in people with a diagnosis of Major Depressive Disorder (MDD). All trials included in this review had to include a non-exercise control group so that the effect of exercise could be established (as opposed to some other factor). The results indicated that moderate aerobic exercise, performed three times per week (the average across the studies) was associated with improved overall QoL for people with MDD. In addition, there were specific improvements in the psychological domain. The psychological domain (compared to the physical and social domains) has been shown have the greatest effect on overall QoL in long-term illness. There was no change in QoL in the non-exercising (control) groups. The authors state that exercise can be used as an effective treatment strategy for depression especially since antidepressant medication alone tends not to improve QoL even when depressive symptoms improve.

The evidence for the benefits of exercise in treating depression is robust and established. Regular exercisers have up to 30% reduced risk of developing the illness.  Of course, the experience of depression can make it difficult to find the motivation to exercise in the first place. For some people it may be important to start with smaller exercise goals such as a five minute walk three times a week to help build a sense of achievement and consistency. Walking with a friend or a group could potentially enhance the social domain of QoL as well as helping you to stay committed. Exercise can be a very effective, accessible, low-cost, low-risk (of side effects) weapon in the arsenal against depression.

Schuch, F. B., Vancampfort, D., Rosenbaum, S., Richards, J., Ward, P. B. & Stubbs, B. (2016). Exercise improves physical and psychological quality of life in people with depression: A meta-analysis including the evaluation of control group response. Psychiatry Research, 241, 47-54.

Arnold, R., Ranchor, A. V., Sanderman, R., Kempen, G. I., Ormel, J. & Suurmeijer, T. P. (2004). The relative contributions of domains of quality of life to overall quality of life for different chronic diseases. Quality of Life Research, 13, 883-896.

http://www.nhs.uk/Livewell/fitness/Pages/Whybeactive.aspx

Disclaimer

This information is provided for information purposes only and should not be taken as advice or instruction. This information does not replace the advice of your doctor. Please consult an appropriate health professional if you believe you are experiencing a mental or physical health concern. Speak to your GP or a trainer before making any significant changes to your exercise routine.

Mental Health Awareness Week – Special Focus on Depression (Omega-3)

Depression, or more technically Major Depressive Disorder (MDD), is a common and growing mental health concern, currently affecting 350 million people worldwide, making it one of the leading causes of global disability. Many people will be familiar with the symptoms of depression; low mood, loss of interest and enjoyment, disturbed sleep, change in appetite, low self-worth and fatigue, among others. This constellation of symptoms can rob sufferers of meaning from life, impair relationships and in severe cases lead to suicidal and self-harming thoughts and behaviours. Anybody who feels they might be experiencing these symptoms is strongly encouraged to talk to their GP about their symptoms and available treatments. Depression can be a very isolating experience but help is available and you are entitled to it.

A number of treatments have been shown to effectively treat depression including Cognitive Behavioural Therapy and Psychodynamic Psychotherapy. Anti-depressant medication can also be helpful if well tolerated, though side effects can be problematic for a number of patients. Recent research has started to identify other factors that can influence mood disorders or enhance the effectiveness of treatments. This week I will be presenting the latest research on lifestyle interventions that have been shown to alleviate the symptoms of depression.

The first in the series is the promising research on the efficacy of omega-3 fats in the reduction of severity of depressive symptoms. I have mentioned elsewhere the results of a meta-analysis showing that these fats have positive effects on depression. A new meta-analysis published in March this year builds on these results and addresses some of the limitations of previous papers.

In this latest analysis published in the journal Translational Psychiatry researchers reviewed the pooled results of over 1200 patients with a diagnosis of MDD. They found a significant beneficial effect of omega-3 supplementation on the depressive symptoms of MDD, comparable to the effects of anti-depressant medication. In particular, studies that included higher doses of the specific omega-3 eicosapentaenoic acid (EPA) showed the most benefit. Omega-3 supplementation also appeared to improve the effectiveness of antidepressant medication. The authors speculate that this effect might be mediated by EPA’s known anti-inflammatory action, though more research is needed to confirm this hypothesis. They also note that the long-term effects of high-dose omega-3 supplementation have not been fully analysed and should be before any clinical recommendations can be made.

The safest way to ensure you are getting enough omega-3 is through your diet. EPA is found primarily in oily fish such as mackerel, herring, trout, salmon and sardines. The body is able to convert it from the essential fat alpha-linolenic acid (ALA) but not very efficiently and only in small amounts; it is much more easily absorbed from marine sources. The NHS recommends that a healthy diet should include at least one serving of oily fish per week but the most recent National Diet and Nutrition Survey published by Public Health England showed that Britons are not consuming anywhere close to the recommended amounts. The research is encouraging but there is still work to be done. Until then trying to eat the recommended amounts of oily fish could be a useful adjunct to prescribed treatment.

Mocking, R. J. T., Harmsen, I., Assies, J., Koeter, M. W. J, Ruhé, H. G. & Schene, A. H. (2016). Meta-analysis and meta-regression of omega-3 polyunsaturated fatty acid supplementation for major depressive disorder. Translational Psychiatry, 6, e756; doi:10.1038/tp.2016.29

http://www.nhs.uk/Livewell/Goodfood/Pages/fish-shellfish.aspx

https://www.bda.uk.com/foodfacts/omega3.pdf

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/310997/NDNS_Y1_to_4_UK_report_Executive_summary.pdf

https://www.sciencedaily.com/releases/2016/04/160426091725.htm

Disclaimer

This information is provided for information purposes only and should not be taken as advice or instruction. This information does not replace the advice of your doctor. Please consult an appropriate health professional if you believe you are experiencing a mental or physical health concern.

Dietary Fibre Linked with Improved Cognitive Control in Children

A correlation study conducted with small group of 7 and 9 year olds demonstrated a positive relationship between diet quality, in particular dietary fibre content, and performance on a task designed to assess attention and the ability to disregard distracting stimuli.

65 children undertook a modified version of the Erikson Flanker Test in which they were asked to pay attention to the direction of a fish in the centre of a computer screen and to try to ignore other fish that appeared on the screen at the same time that were facing either the same direction or the opposite direction of the target fish. Their results were correlated against food diaries that tracked a range of nutrients and subsets of nutrients. For example fats were broken down in to saturated fatty acids, cholesterol, omega-3s and DHA .

They found that children who had higher fibre diets had significantly improved accuracy scores on the Flanker test. The results showed that soluble fibre was associated with overall accuracy and pectin was particularly linked to accuracy in the version of the test that required greater effort. The researchers postulate that the effects might be linked to better control of blood sugar and/or the interaction of the gut microbiota. Fibre cannot be assimilated into the body but is highly fermentable by the bacteria in the gut. Some of the important end products of this fermentation are short-chain fatty acids, which have been linked to reduced inflammation in the brain and increased BDNF, compound associated with the creation of new brain cells.

Whilst this study was conducted on children it is highly likely that the outcomes will be similar in adults.

• High soluble fibre foods: Oats and oat bran, beans, lentils, apples, pears.
• High insoluble fibre foods: Wheat bran and wholegrains, brown rice, seeds, fruit and vegetable skins.
• High pectin foods: Apples, pears, quince, peaches, plums, oranges, lemons, grapefruit, gooseberries, apricots, guava, carrots, tomatoes.

Reference

Khan, N. A., Raine, L. B., Drollette, E. S., Scudder, M. R., Kramer, A. F., & Hillman, C. H. (2015). Dietary Fiber Is Positively Associated with Cognitive Control among Prepubertal Children. The Journal of Nutrition, 145(1), 143–149. http://doi.org/10.3945/jn.114.198457

Gut Microbes Regulate Nerve Cell Myelination (Animal Model)

The prefrontal cortex (PFC), the foremost part of the brain, is the seat of what is called ‘executive function’. Executive functions are the higher order tasks of the brain (beyond regulating the systems and processes of the body) such as attention, planning, decision-making, memory, managing social interactions, making moral judgements and anticipating the consequences of a particular behaviour. The PFC also plays an important role in emotional functioning; regulating fear, anxiety, normal guilt, and PFC dysfunction is implicated in the development of mental disorders such as schizophrenia and autism spectrum disorders.

New research from University College Cork has uncovered an important role of the gut microbiome on the structure and functions of neurones in the PFC. In this study the researchers compared the brains of mice raised in ‘germ free’ conditions (i.e. no gut microbiome) with mice raised conventionally and those who spent the first part of their lives germ-free then were later introduced to the conventionally-raised animals, which would lead to some colonisation of the gut microbiome.

They found that over 221 genes behaved differently in the brains of the germ-free and ex-germ-free mice compared to those raised conventionally. The germ-free vs the conventional mice made up the biggest difference accounting for 190 of the 221 differently expressed genes. Many of these genes were involved in the task of myelination and these changes were confined to the PFC region of the brain. Myelin is the fatty sheath that surrounds a nerve cell, like the protective plastic coating around an electrical wire. Myelin aids the conductivity of the nerve cell, helping it to send messages faster and more efficiently. Failure in myelination is the cause for the loss of muscle function and control in Multiple Sclerosis, for example. This study was looking at the underlying biological mechanism so the researchers did not make any comment on the potential implications of these changes other than to note previous research showing increased anxiety in germ-free mice and stating ‘Our results further highlight the microbiota as a viable therapeutic target in psychiatric disorders’. They also note that the unusual changes in the myelin of the germ-free mice was corrected in the ex-germ-free mice, indicating that later colonisation of the gut microbiome normalised myelin gene expression in this important region of the brain.

Reference

Hoban, A. E., Stilling, R. M., Ryan, F. J., Shanahan, F., Dinan, T. G., Claesson, M. J., Clarke, G. & Cryan, J. F. (2016). Regulation of prefrontal cortex myelination by the microbiota. Translational Psychiatry, 6, e774. doi:10.1038/tp.2016.4

http://www.nature.com/tp/journal/v6/n4/full/tp201642a.html

Short-Term Psychodynamic Psychotherapy Effective at Reducing Depressive Symptoms and Inflammatory Markers

Depression is rapidly becoming the leading cause of disease burden (negative effects on quality of life) in the world. Psychologists and biologists have been trying to understand the underlying mechanisms of depression for a long time, wondering whether it is mainly biological or psychological in nature; a disease of the body or of the mind? My clinical experience is that it can be either or both, which is why a thorough assessment is essential. For some people the roots of their depression lie in difficult early circumstances, abusive relationships or a traumatic event. For others there may be a genetic predisposition to the illness, it ‘runs in the family’, or some other physiological factor.

Several studies have demonstrated a relationship between inflammation in the body and depression. Inflammation is your body’s response to illness or infection and can be activated by a number of factors such as poor diet, underlying illness and chronic stress. Many studies have illustrated that the higher the degree of inflammation in the body the more severe the depressive symptoms and vice versa. The consistency of this finding has led to the ‘Inflammatory Hypothesis of Depression’, proposing that inflammation is the driving force in depression in many people, and that it can increase symptom severity in those already dealing with low mood.

In a trial thought to be the first of its kind researchers from Brazil and the USA looked at the levels of inflammation in patients' blood as well as the severity of their depression before and after 16 standard (50 minutes) sessions of psychotherapy (plus an extra two for data collection). The result demonstrated a relationship between the levels of markers for inflammation and the severity of symptoms such that after psychotherapy treatment patients were less depressed and their inflammation had reduced. Previous research had looked at the ways that medication and CBT could reduce inflammation but this was the first study to look at the role of psychodynamic psychotherapy and the results are interesting enough to warrant further research.

The implications are powerful because, as the upward trend of depression continues, it will become increasingly important to find effective and low-cost treatments for the illness. This study suggests that patients could potentially gain relief from their mild or moderate depression in as little as four months and without the side-effects associated with medication.

Silva, G. D. G. d., Wiener, C. D., Barbosa, L. B., Araujo, J. M. G., Molina, M. L., Martin, P. S., Oses, J. P., Jansen, K., Souza, L. D. d. M. & Silva, R. A. d. (2016). Pro-inflammatory cytokines and psychotherapy in depression: Results from a randomised clinical trial. Journal of Psychiatric Research, 75, 57-64. 

Probiotic Relieves Anxiety in Chronic Fatigue Syndrome (Pilot Study)

Chronic Fatigue Syndrome (CFS) or Myalgic Encephalopathy (ME) is a complex illness of unknown cause that has both physical and psychological symptoms. The major physical symptom is intense bodily fatigue, which is made worse by bouts of physical or mental exertion and is not relieved by sleep. Muscle and joint pain and bowel conditions such IBS are often also seen. Psychologically, people with a diagnosis of CFS often report feeling depressed and/or anxious and find it hard to concentrate. Although it is not clear what causes CFS there is a strong link to increased markers of inflammation (the body’s immune response to illness or infection) and disturbances in the gut microbiome. This observation is interesting because the gut is the crucible of the immune system and plays an important role in ‘teaching’ the immune system to respond appropriately to pathogens and in distinguishing the body’s own cells from invaders.

In a small but well-designed pilot study, participants with a diagnosis of CFS and comorbid depression and/or anxiety were randomly assigned to two experimental groups. The test group took three sachets a day of a probiotic (Lactobacillus casei Shirota) totalling 24 billion bacteria per day. The control group ingested three sachets of an identical looking placebo product. After eight weeks the patients were reassessed on the depression and anxiety scales.

At the end of the test period not only had there been an increase in the number of Lactobacillus in the patients’ guts but also increased numbers of Bifidobacteria, a different strain of bacteria that is associated with a healthy digestive system. This is noteworthy a) because it indicates that the introduction of one helpful strain can encourage the proliferation of another, b) because CFS patients tend to have low levels of Bifidobateria and c) because some strains of Bifidobacteria are known to improve blood levels of tryptophan, an essential amino acid that is the precursor of serotonin, a neurotransmitter linked to happiness and good mood.

The researchers also found that patients who had been taking the probiotic were significantly less anxious than at the start of the study, a valuable finding considering the significant burden of anxiety in this patient group. Importantly, the probiotic was well tolerated, which means that it did not cause any unwanted or unpleasant side-effects.

Rao, A. V., Bested, A. C., Bealune, T. M., Katzman, M. A., Iorio, C., Berardi, J. M. & Logan, A. C. (2009). A randomized, double-blind, placebo-controlled pilot study of a probiotic in emotional symptoms of chronic fatigue syndrome. Gut Pathogens, 1:6.

Healthy Diet Linked to Reduced Risk of Depression

In 2015 a large Spanish study reported results showing that improvements in diet reduced a person's likelihood of developing depression. Similarly, a new correlation study of Iranian adults (average age 36 years) has demonstrated a statistically significant relationship between healthy diet and reduced rates of depression. The researchers assessed the diet and lifestyle of over 3000 people - looking at their eating habits, weight, BMI, smoking status and levels of psychological distress - and compared them against measures for anxiety and depression. They found that non-smokers were less likely to be anxious than smokers and those with healthier diets were 29% less inclined to be depressed than those with poor diets. Further research is required to understand the predictive features of these results.

Saneei, P., Esmaillzadeh, A., Keshteli, A. H., Reza Roohafza, H., Afshar, H., Feizi, A. & Adibi, P. (2016). Combined healthy lifestyle is inversely associated with psychological disorders in adults. PLoS One. DOI: 10.1371/journal.pone.0146888

Psychotherapy Reduces Physical Symptoms in Irritable Bowel Syndrome

Irritable Bowel Syndrome (IBS) is the name given to a collection of abdominal and digestive symptoms. Typically suffers present abdominal pain and bloating, diarrhoea or constipation. Doctors are unclear as to what causes the symptoms but have linked the syndrome to altered immune function, stress and inflammation and, in some instances, abnormalities in the gut microbiome. Additionally, there is no known cure for IBS leaving sufferers in ongoing pain and discomfort that significantly impairs their quality of life.

A meta-analysis published this year has shown that psychotherapy is an effective long term treatment for reducing symptom severity in IBS. The researchers included only high-quality (random controlled trial) studies and the final analysis included data from a pool of 2290 individuals. Trials included standard psychological therapy as well as relaxation technique training, individual and group treatments and therapy provided in-person or by a therapist online.

Psychological treatments were shown to be effective both at short term (1-6 months) and long-term follow (6 month-one year); the treatment worked and the effects lasted. This study follows an earlier(2) meta-analysis that showed psychotherapy to be as effective as antidepressant medication at improving quality of life for IBS sufferers, but that psychotherapy was more effective than medication at reducing subsequent healthcare costs.

1. Laird KT, Tanner-Smith EE, Russell AC, Hollon SD, Walker LS, Short- and Long- Term Efficacy of Psychological Therapies for Irritable Bowel Syndrome: A Systematic Review and Meta-analysis, Clinical Gastroenterology and Hepatology (2016), doi: 10.1016/j.cgh.2015.11.020.

2. Creed, F., Fernandes, L., Guthrie, E., Palmer, S., Ratcliffe, J., Read, N., Rigby, C., Thompson, D., Tomenson, B. on behalf of the North of England IBS Research Group. The cost-effectiveness of psychotherapy and paroxetine for severe irritable bowel syndrome.  Gastroenterology, 124, 303-317.

Omega-3 Fats Are Effective Treatment for Depression – Meta Analysis

The varied literature on the effects of omega-3 supplementation on depression can throw up conflicting results depending on the structure and size of the individual studies. Some researchers will look at the components of omega-3s together, some separately; some for two weeks and some for two months. In order to arrive at a coherent answer to the questions of the role of omega-3 fats on depression a group of Italian researchers conducted a meta-analysis. They pooled the studies conducted on patients with a diagnosis of major depressive disorder (MDD) and those who exhibited depressive symptoms but who did not have a clinical diagnosis. The average length of treatment with fish oils was 16 weeks. The analysis revealed a significantly positive effect of fish oils (particularly EPA) in alleviating symptoms in both patients with MDD and those without a diagnosis showing that these essential fats are an effective treatment for primary depression. 

Grosso, G., Pajak, A., Marventano, S., Castellano, S., Galvano, F., Bucolo, C., Drago, F. & Caraci, F. (2014). Role of omega-3 fatty acids in the treatment of depressive disorders: a comprehensive meta-analysis of randomized clinical trials. PLoS One, 9 (5), e96905. ECollection.

Serum Vitamin D Predicts Cognitive Performance in Adults

Much of the research on the relationship between vitamin D and cognitive function has been conducted on older people or individuals who have a diagnosis of Alzheimer’s Disease or other dementia. This is because older people are less able to synthesise vitamin D in their skin and because dementia is typically a disease of aging. A study published in August 2015 looked at the relationship between vitamin D status and cognitive function in two cohorts of healthy individuals; those aged 30-60 and 60+. Research on disease-free groups is important because it allows us to look at the potential effect that nutritional deficiency has on the general population and on sub-clinical (no diagnosis) functioning. That is to say that we can learn more about how dietary insufficiencies might be affecting the general population long before disease onset. This information allows us more opportunity to intervene with treatment.

In this study of vitamin D in the blood were strongly associated with the degree of cognitive impairment on tests of visual spatial memory (recalling and recreating a complex shape) and processing speed. In this study lower levels of vitamin D were associated with poorer performance on these tests even in people aged 30.  This study complements a growing body of research that is demonstrating a relationship between vitamin D status and brain function (including influence on mood and anxiety disorders).

There is also growing concern worldwide about the ‘pandemic’ of vitamin D deficiency and the many health concerns it is associated with such as osteoporosis, fractures, and increased risk of some cancers and autoimmune diseases. It is estimated that at least 50% of people are vitamin D deficient and the situation is worse for those of with dark skin as the melanin pigment blocks the action of vitamin D synthesis in the skin. Food sources of vitamin D include oily fish (salmon, sardines and mackerel), eggs and fortified cereals, though few people are eating sufficient amounts of these foods to keep their levels topped up, and vegetarians and vegans need to be very thoughtful about their food/supplement choices to ensure adequate levels.

Reference

Darwish, H., Zeinoun, P., Ghusn, H., Khoury, B., Tamim, H., and Khoury, S. J. (2015). Serum 25-hydroxy vitamin D predicts cognitive performance in adults. Neuropsychiatric Disease and Treatment, 11, 2217–2223.

Healthy Diets Reduce Risk of Depression

A large (15,000 participants) Spanish study has shown that diets high in nutrients are linked to a reduced risk of depression. This study has generated a lot of interest not only because of the large cohort size, which makes the results more generalisable, but because it is thought to be the first to follow healthy individuals and track, over 10 years, those who went on to develop illness and disease.

The researchers looked at three diets:

• Mediterranean Diet – characterised by the consumption of vegetables, legumes, fruits and nuts, cereals, fish and seafood; low intake of meat and dairy products, and moderate alcohol intake.

• Vegetarian Dietary Pattern – a kind of ‘flexitarian’ diet that promotes eating plant foods (including potatoes) most of the time but allowing for a little meat

• Healthy Eating Index- promotes eating larger amounts of vegetables, fruits, whole-grain bread, nuts, beans and pulses, omega 3s and unsaturated fats, and smaller amounts of sugar-sweetened beverages and fruit juice, red/processed meat, trans fats, and alcohol.

As part of the study the researchers also looked at activity levels, BMI, health history and vitamin supplementation, and the analysis was controlled for a number of variables including age, sex and smoking status.

For the statistical analysis the levels of adherence were split in to five groups (quintiles). So on a scale of 1-5, those in group 1 ate the least healthy diets while those in group 5 were paragons of healthy eating. The results showed that those in groups 2-5 had a 25-30% reduced risk of developing depression than those in group 1. Interestingly, there was a plateau in this effect once the respondents had moderately good diets. The researchers believed this to be due to a threshold effect; once you are consuming adequate amounts of a nutrient there is no additional benefit of consuming larger quantities of it.

The researches did not highlight any individual food or nutrient as being particularly important or protective. In fact they pointed out in their discussion the inconclusive results from other studies that looked at the relationship between individual nutrients (vitamins, minerals or fats) and depression. However, this and other studies have demonstrated the strong relationship between the quality of the overall diet and risk of depression. It is likely that it is the interaction of different compounds from various foods that offers most protection not just to depression but to overall health. 

Reference

Sánchez-Villegas, A., Henríquez-Sánchez, P., Ruiz-Canela, M., Lahortiga, F., Molero, P., Toledo, E., & Martínez-González, M. (2015). A longitudinal analysis of diet quality scores and the risk of incident depression in the SUN Project. BMC Medicine, 13, 197-197.

Probiotic Alleviates Stress and Anxiety

We have known for some years now that there is a comorbidity between psychological problems such as depression and anxiety and gastrointestinal disorders. That is to say people who present with these psychological problems often have a gut issue at the same time and vice versa. Recent research that has started to explain some of the processes underlying this relationship and the term given to this connection is the ‘gut-brain axis’. The community of bacteria in the gut is central to the gut-brain axis with the bacteria playing an essential role in nutrient absorption and production, inflammation and immunity amongst many others.

Much of the research into the gut-brain axis is of potential treatments: the researchers are looking to relieve a particular disorder and so the results can often only accurately be applied to groups who suffer from that disorder. However, a recently presented study looked at the effects of probiotic (beneficial bacteria) supplementation on healthy people.

Researchers from Ireland put 22 male participants through a battery of tests to assess their cognitive performance, perceived stress and stress hormone levels before and after a four-week course of a daily supplement of the bacteria Bifidobacteria longum. At the end of the study the participants reported feeling less anxious and stressed, had significantly improved cognition scores and were producing lower levels of stress hormones.