US researchers have found that individuals with greater optimism are more likely to live longer and to achieve “exceptional longevity,” that is, living to age 85 or older.

Optimism refers to a general expectation that good things will happen, or believing that the future will be favourable because we can control important outcomes. Whereas research has identified many risk factors that increase the likelihood of diseases and premature death, much less is known about positive psychosocial factors that can promote healthy aging.

The large study, published in PNAS journal, was based on 69,744 women and 1,429 men. Both groups completed surveys to assess their level of optimism, as well as their overall health and health habits such as diet, smoking and alcohol use. Women were followed for 10 years, while the men were followed for 30 years.

When individuals were compared based on their initial levels of optimism, the researchers found that the most optimistic men and women demonstrated, on average, an 11-15% longer lifespan, and had 50-70% greater odds of reaching 85 years old compared to the least optimistic groups. The association between optimism and longevity held even after accounting for age, and other influential factors such as educational attainment, chronic diseases, depression and also health behaviours, such as alcohol use, exercise, diet and primary care visits.

The results are relevant to public health, explains co-author Lewina Lee, PhD, clinical research psychologist at the National Center for PTSD at VA Boston Healthcare System and assistant professor of psychiatry at Boston University School of Medicine (BUSM) because they show that optimism is a “psychosocial asset that has the potential to extend the human lifespan.” She suggests also that it is a kind of learned behaviour and that  levels of optimism can be modified using relatively simple techniques or therapies.

It is still unclear how exactly optimism helps people attain longer life. “Other research suggests that more optimistic people may be able to regulate emotions and behaviour as well as bounce back from stressors and difficulties more effectively,” said co-author Laura Kubzansky, PhD, MPH, Lee Kum Kee Professor of Social and Behavioral Sciences and co-director, Lee Kum Sheung Center for Health and Happiness at the Harvard T.H. Chan School of Public Health.

The researchers behind the current study suggest also that more optimistic people tend to have healthier habits, such as being more likely to engage in more exercise and less likely to smoke, which could extend lifespan.

The study, which looked at data from almost 46,000 people, provides convincing evidence that dietary improvement significantly reduces symptoms of depression, even in people without diagnosed depressive disorders.

According to lead researcher, Dr Joseph Firth, an Honorary Research fellow at The University of Manchester and Research Fellow at NICM Health Research Institute at Western Sydney University, existing research has been unable to definitively establish if dietary improvement could benefit mental health.

But this new analysis published in Psychosomatic Medicine, brought together existing data from large clinical trials of diets for mental health conditions to help provide better insight

“The overall evidence for the effects of diet on mood and mental well-being had up to now yet to be assessed. But our recent meta-analysis has done just that; showing that adopting a healthier diet can boost peoples’ mood. However, it has no clear effects on anxiety.”

Linking food to mood

The study combined data from 16 randomised controlled trials that examined the effects of dietary interventions on symptoms of depression and anxiety. The majority of these examined people with non-clinical depression.

The study found that all types of dietary improvement appeared to have equal effects on mental health, with weight-loss, fat reduction or nutrient-improving diets all having similar benefits for depressive symptoms.

“This is actually good news” said Dr Firth; “The similar effects from any type of dietary improvement suggests that highly-specific or specialised diets are unnecessary for the average individual.

“Instead, just making simple changes is equally beneficial for mental health. In particular, eating more nutrient-dense meals which are high in fibre and vegetables, while cutting back on fast-foods and refined sugars appears to be sufficient for avoiding the potentially negative psychological effects of a ‘junk food’ diet.

Support for a lifestyle approach

Dr Brendon Stubbs, co-author of the study and Clinical Lecturer at the NIHR Maudsley Biomedical Research Centre and King’s College London, added: “Our data add to the growing evidence to support lifestyle interventions as an important approach to tackle low mood and depression.

“Specifically, our results within this study found that when dietary interventions were combined with exercise, a greater improvement in depressive symptoms was experienced by people. Taken together, our data really highlight the central role of eating a healthier diet and taking regular exercise to act as a viable treatment to help people with low mood.”

Interestingly in the studies examined, women derived the greatest benefit from dietary interventions for symptoms of both depression and anxiety.

The analysis was not able to pinpoint why but according to Dr Firth added: “It could be through reducing obesity, inflammation, or fatigue – all of which are linked to diet and impact upon mental health.”

The benefits, the experts suggest, could be because heat restores the body’s natural temperature rhythm over the course of a day, which can be disrupted in depressed patients.

Scientists from the University of Freiburg in Germany tested the effects of thermal baths on 45 people with depression. The people in the study group (average age 48) all had moderate to severe depression, which was measured on the commonly used HAM-D scale.

On this scale a score of 19 or higher out of 50 indicates someone has severe depression – the average score among participants was 21.7.

Participants were randomly assigned to either twice-weekly spa bathing, or two sessions of moderate exercise a week over a two week period, after which time their depression retested.

The bath group were asked to sit in a 40°C (104°F) bath for 30 minutes, then relax with hot water bottles for 20 minutes. People in the exercise group had to do a moderate aerobic workout, such as running, dancing or swimming, for 40 to 45 minutes.

Better than exercise

Those in the bathing group saw an average drop of six points on the HAM-D scale within a fortnight, suggesting someone with severe depression could cut their symptoms to moderate depression, or somebody already on a moderate score could drop to mild by bathing. In contrast exercise patients only shaved three points off their score.

In addition, while 13 out of 23 people dropped out of the exercise group, only two out of 22 failed to complete the hot bath treatments.

Because baths are easy, enjoyable and have a fast acting effect, the team notes, people are more likely to keep up the habit over the long term.

Heat may rest the ‘clock’

Although the exact causes of depression are not clear, one theory is that it is linked to a disruption in our circadian rhythm – or body clock – which dictates our cycles of hormones, body temperature and sleep, among other things.

In those with depression, body temperature may not be well regulated and the heat from the baths and hot water bottles may have helped correct this. Results of this study, for instance, showed that the body temperatures of those in the bath group increased by around 2°C (3.6°F) after bathing.

• For more information on the benefits of baths see The health benefits of a hot bath. For more on the benefits of heat see Feel the heat – the benefits of a sauna

A study conducted by researchers from the US, Canada, France and Israel, has discovered that adults over the age of 60 are significantly cleverer at the start of autumn compared with spring. The difference between the autumn and spring equinox say the scientists, was equivalent to four years of ageing.

The study analysed data involving more than 3,000 people in North America and Europe, most of whom were over 70. They had each been given annual tests of memory and processing speed, with their testing spread randomly throughout the year.

Doctors had assumed that the month the testing occurred was irrelevant, but the paper in the online journal Plos Medicine found that the seasons did matter. In fact, cognitive performance was shown to be higher in the summer and autumn compared with winter and spring. It peaked at the autumn equinox then dropped off until the spring equinox six months later.

Important considerations for dementia testing

For some participants, the researchers also looked at levels of proteins associated with Alzheimer’s disease. This revealed seasonal rhythms in Alzheimer-disease-related proteins in the spinal fluid, and in the expression of specific genes in the brain, giving us a window into the underlying mechanisms.

They found a 30% greater chance of meeting diagnostic criteria for mild cognitive impairment or dementia if cognitive tests are carried out in late-winter or early-spring. “The difference in performance was enough to impact the clinical impression of what diagnostic category a patient was going to be in,” said one of the researchers Andrew Lim, from the University of Toronto.

The team could only speculate on the cause of such a change. Light, temperature, the body’s hormone levels or vitamin D consumption could be to blame, Lim said. But on the bright side, the study opens up the possibility that “good cognition” could be extended beyond that peak time to prevent or slow the onset of Alzheimer’s disease.

One theory is that our lifestyle and health habits vary with the season, we may for instance eat, sleep and exercise differently.

Lead researcher Philip De Jager, from Columbia University, said another theory was that during winter our brains experienced something akin to a mild hibernation. “The underlying rhythms are similar to those that regulate many other mammals and animals,” he said. “They probably help us minimise activity in months when fewer resources are available and take advantage of them at a time when they are abundant.”

• For more on the connection between weather and health see our article Must be the weather

A new UK study has found that staying in sync with natural circadian rhythms – our daily sleep-wake and light-dark cycles – is linked to improvements in mood and cognitive functioning as well as a decreased likelihood of developing major depression and bipolar disorder.

Our internal body clock regulates multiple functions including body temperature and eating habits. Disruption of this clock, for instance through long-term night-shift work, has previously been associated with an increased risk of cancer, heart disease and obesity.

The observational study of over 91,000 people, aged 37 to 73, was conducted at the University of Glasgow and published in The Lancet Psychiatry.  It measured disruptions in sleep-wake cycles using a device called an accelerometer that is worn on the wrist and measures a person’s daily activity levels. Moods and mental well-being were measured using a standardised questionnaire.

Disruption leads to depression

Those with more circadian rhythm disruptions – defined as increased activity at night, decreased activity during the day or both – were significantly more likely to have symptoms consistent with bipolar disorder or major depression. They were also more likely to have decreased feelings of well-being and to have reduced cognitive functioning, based on a computer-generated reaction time test.

Lead researcher Professor Daniel Smith, professor of psychiatry at the university, noted: “It’s widely known that a good night’s sleep is a good thing for well-being and health. That’s not a big surprise. But I think what’s less well-known and what comes out of this work is that not only is a good night’s sleep important, but having a regular rhythm of being active in daylight and inactive in darkness over time is important for mental well-being.”

Aim for better sleep hygiene

Smith also says that it is still not certain whether an out-of-kilter body clock causes mental health problems, or if the mental health problems are causing disturbances to people’s daytime and night-time cycles.

However, findings from this study – the largest of its kind so far – are consistent with research indicating a link between sleep disruptions and mood disorders. Another British study in, for example, showed that men who worked night shifts for four years or more were more likely to have anxiety and depression than those who work during the day.

There is also evidence that the body clocks of people who suffer from depression are ‘out of sync’.

He adds that better sleep hygiene is key. ‘There are a lot of things people can do, especially during the winter, such as getting out of the house in the morning to get exposed to light and take exercise, so that by evening they are tired.

‘You can also turn off your mobile phone around 10pm because the light in it is telling your brain it’s daytime. But it is hard for some people, such as shift workers, because of their job or because of their family circumstances.’

Again this advice links to recent findings that taking a more mindful approach to using our phones, computers and tablets can make us happier.

• For more on circadian rhythms see our article The ancient clock that rules our lives – and determines our health

Researchers from Binghamton University in New York surveyed 463 people who were either under 30s (young adults) and over 30s (mature adults). Standard questionnaires were used to assess diet and exercise habits, as well as mental states. In particular, they looked at consumption of food groups containing constituents known to be associated with neurochemistry and neurobiology.

Published in the journal Nutritional Neuroscience ​the results suggest that the mood and healthy behaviour of young adults appears to be driven by diet and lifestyle elements that increase concentration and availability of neurotransmitter precursors in the brain. A higher meat intake and regular exercise may be the best choice, say the scientists.

In mature adults the critical determinants of mood and healthy behaviour were the availability of dietary antioxidants  and the avoidance of foods and dietary practices that activate the sympathetic nervous system. These include coffee, high-carbohydrate intake (particularly high glycaemic index carbs) and skipping breakfast.

Different ages, different needs

According to leading author Lina Begdache, assistant professor of health and wellness studies: “Regular consumption of meat leads to build-up of two brain chemicals (serotonin and dopamine) known to promote mood. Regular exercise leads to build-up of these and other neurotransmitters as well.​”

In this study, young adults who ate meat (red or white) less than three times a week and exercised less than three times week showed a significant mental distress, she said.

Conversely, says Begdache, as we age there is an increase in free radical (oxidant) formation, so our need for antioxidants increases.​ Not getting a steady supply of these in the diet can trigger our innate fight-or-flight response (commonly known as the stress response).​

“Free radicals cause disturbances in the brain, which increases the risk for mental distress. Also, our ability to regulate stress decreases, so if we consume food that activates the stress response (such as coffee and too much carbohydrates), we are more likely to experience mental distress.”​

The reason for the age-dependent response to different types of diet may be explained by brain maturity, she suggests, which may not bw complete until after the age of 30, and which may explain the different responses to food in otherwise healthy people.

The researchers note that, as this was an observational study, more information would be needed to draw firm conclusions. Even so, these preliminary results open the door to potential new insights into how our dietary needs, as they relate to overall wellbeing, change over time and how a one-size fits all approach to nutrition can let (some of) us down.

Studies have shown that meditation can have long-term effects on the brain and how it works, and numerous studies on the potential benefits of meditation have been published.

This prompted the AHA to review current high-quality scientific studies to determine whether the practice has a role in reducing heart disease.

Although the practice of meditation dates back as far as 5000 BC and is associated with certain philosophies and religions, meditation is increasingly practiced as a secular and therapeutic activity.

Around 8% of Americans practice some sort of meditation, according to the 2012 National Health Interview Survey, conducted by the National Center for Complementary and Integrative Health, which is part of the National Institutes of Health. The same survey also found that 17% of patients with cardiovascular disease expressed an interest in participating in a clinical trial of meditation.

Health and well-being benefits

The current research review for the AHA was done by cardiovascular disease experts and a neuroscientist who reviewed existing research on whether common types of sitting meditation had an impact on cardiovascular risk factors and disease.

The analysis excluded studies on combination mind-body practices, such as yoga and Tai Chi, since the physical activity included in these practices has an established positive impact on heart disease risk.

The studies of sitting meditation, including a variety of common forms such as: Samatha; Vipassana (Insight Meditation); Mindful Meditation; Zen Meditation (Zazen); Raja Yoga; Loving-Kindness (Metta); Transcendental Meditation; and Relaxation Response showed that meditation may:

• Be associated with decreased levels of stress, anxiety and depression, and improved quality of sleep and overall well-being
• Help lower blood pressure, although more evidence is needed to determine whether or how much it may lower blood pressure in a given individual
• Help individuals stop smoking

Meditation might be associated with a decreased risk of heart attack, although there are only a few studies on this, and more studies are needed before any conclusions can be made.

A low risk treatment

“Despite numerous advances in the prevention and treatment of atherosclerosis, cardiovascular disease remains a leading cause of morbidity and mortality in the US and developing world,” said Glenn N. Levine, MD, a professor of medicine at Baylor College of Medicine in Houston, Texas and chair of the writing group of the AHA Scientific Statement that is published in the Journal of the American Heart Association

“Since education on how to meditate is widely available and meditation has little if any risk associated with it, interested people may want to use these techniques, in addition to established medical and lifestyle interventions, as a possible way to lower heart disease risk.”

Levine notes that the gold standard for the prevention and treatment of heart disease remains lifestyle advice and medical treatment that has been carefully studied and shown to work, including cholesterol therapy, blood pressure control, smoking cessation and regular physical activity.

However, he adds, “Meditation, which is becoming increasingly popular and recognized for its benefits, may be an inexpensive and widely available adjunct to standard therapies for reduction of cardiovascular risk.”

• For more on this topic see the relates story Meditation protects against premature death from heart disease

But new research from the UK suggests that brief training in mindfulness strategies could help.

After a short training session and encouragement to continue practising mindfulness – which involves focusing on what’s happening in the present moment – heavy drinkers drank less over the next week than people who were taught relaxation techniques, according to the study published in the International Journal of Neuropsychopharmacology.

“We found that a very brief, simple exercise in mindfulness can help drinkers cut back, and the benefits can be seen quite quickly,” said the study’s lead author, Dr Sunjeev Kamboj of University College London’s Clinical Psychopharmacology Unit.

The researchers brought in 68 drinkers, who drink heavily but not to the point of having an alcohol use disorder.

Half of them were trained, using an 11 minute audio recording, to practise mindfulness, which teaches a heightened awareness of one’s feelings and bodily sensations, so that they pay attention to cravings instead of suppressing them.

The other half were taught relaxation strategies, chosen as a control condition that appeared to be just as credible as the mindfulness exercise for reducing alcohol use.

A significant reduction

At the end of the training participants were encouraged to continue practising the techniques for the next week.

The mindfulness group drank 9.3 fewer units of alcohol (roughly equivalent to three pints of beer) in the following week compared to the week preceding the study. There was no significant reduction in alcohol consumption among those who had learned relaxation techniques.

“Practising mindfulness can make a person more aware of their tendency to respond reflexively to urges. By being more aware of their cravings, we think the study participants were able to bring intention back into the equation, instead of automatically reaching for the drink when they feel a craving,” Dr Kamboj said.

Severe alcohol problems are often preceded by patterns of heavy drinking, so the researchers are hopeful that mindfulness could help to reduce drinking before more severe problems develop.