A recent study from the National University of Singapore revealed that regular tea drinkers have better organised brain regions – and this is associated with healthy cognitive function – compared to non-tea drinkers.

The discovery was made after examining neuroimaging data of 36 older adults.

“Our results offer the first evidence of positive contribution of tea drinking to brain structure, and suggest that drinking tea regularly has a protective effect against age-related decline in brain organisation,” explained team leader Assistant Professor Feng Lei, who is from the Department of Psychological Medicine at the National University of Singapore (NUS) Yong Loo Lin School of Medicine.

The research was carried out together with collaborators from the University of Essex and University of Cambridge, and the findings were published in scientific journal Aging.

Effect on brain networks

Past studies have demonstrated that tea intake is beneficial to human health, and the positive effects include mood improvement, reduced risk of glaucoma and cardiovascular disease prevention. In fact, results of a longitudinal study led by Asst Prof Feng which was published in 2017 showed that daily consumption of tea can reduce the risk of cognitive decline in older persons by 50%.

Following this discovery, Asst Prof Feng and his team further explored the direct effect of tea on brain networks.

The research team recruited 36 adults aged 60 and above, and gathered data about their health, lifestyle, and psychological well-being. The elderly participants also had to undergo neuropsychological tests and magnetic resonance imaging (MRI). The study was carried out from 2015 to 2018.

Upon analysing the participants’ cognitive performance and imaging results, the research team found that individuals who consumed either green tea, oolong tea, or black tea at least four times a week for about 25 years had brain regions that were interconnected in a more efficient way.

Keeping the flow of information going

“Take the analogy of road traffic as an example – consider brain regions as destinations, while the connections between brain regions are roads. When a road system is better organised, the movement of vehicles and passengers is more efficient and uses less resources. Similarly, when the connections between brain regions are more structured, information processing can be performed more efficiently,” explained Asst Prof Feng.

He added, “We have shown in our previous studies that tea drinkers had better cognitive function as compared to non-tea drinkers. Our current results relating to brain network indirectly support our previous findings by showing that the positive effects of regular tea drinking are the result of improved brain organisation brought about by preventing disruption to interregional connections.”

This small but interesting study needs to be repeated on a larger scale. The team next plans to examine the effects of tea, as well as the bioactive compounds in tea that can have on cognitive decline.

The scientists also implicate the neurodegenerative condition in a higher risk of depression, anxiety and a lower mean bone mass density (BMD) of the lumbar spine and femoral neck.

“These results indicate that vitamin D deficiency may play a role in Parkinson’s Disease [PD] pathogenesis, while vitamin D supplementation may be used to treat the non‐motor symptoms of PD,”​ says the team from Soochow University in China.

Initial findings

The team began by enrolling 182 patients with PD and 185 healthy controls. Serum vitamin D [25(OH)D] levels were measured along with BMD of the lumbar spine and femoral neck. They found that:

• Parkinson’s patients had significantly lower serum 25(OH)D levels relative to healthy controls
• Those with lower vitamin D levels had a significantly higher frequency of falls and insomnia
• They also had significantly more depression and anxiety
• People with Parkinson’s also had a significantly lower mean BMD of the lumbar spine and femoral neck

These findings remained true even after adjusting for  age, sex, and body mass index.

Symptoms of deficiency

Vitamin D deficiency is widespread in people with neurodegenerative diseases; studies showing around 55% of patients with Parkinson’s , 41% of those with Alzheimer’s have low levels – compared to 36% of a control population.

Vitamin D also has a vital role in bone metabolism and a lack of vitamin D which can help explain the increased risk of falls and fractures found in this study.

Studies have also shown that vitamin D levels are associated with cognition and mood in patients with Parkinson’s as well as gastrointestinal dysfunction, mainly delayed gastric emptying time.

Regarding the increase in falls, the authors write: “The most commonly cited theory for the connection between falls and vitamin D levels is related to reduced muscle mass and strength.”​

Connections between vitamin D, mood and sleep disorders are a little less clear.

The researchers also acknowledge a limitation of the study, having only evaluated 25(OH)D levels. An assortment of different sources of vitamin D, open up possibilities that different vitamin D forms may produce other results. They note, also, that vitamin D levels decrease and can be affected by many variables including  vitamin D‐rich food intake, sunlight exposure and skin colour.  These things, they say, require more careful study.

The study appeared in the journal Acta Neurologica Scandinavica​.

A diet rich in B vitamins is recommended to maintain optimal health of body and mind. Insufficient intake, on the other hand, has been linked with elevated levels of oxidative stress and neural inflammation, as indicated by abnormally high blood levels of the amino acid homocysteine.

At the same time, the effect of increased oxidative stress in the brain is not well studied, thus researchers at Swinburne University and Austin Hospital in Melbourne (backed by supplement manufacturers Blackmores) conducted a small randomised controlled trial to assess the direct impact of six months of high-dose B vitamin supplementation on brain health and levels of homocysteine and other biomarkers in the brain.

They recruited 32 healthy adults (12 male, 20 female) between the ages of 30 and 65, who were given either Blackmores’ Executive B Stress Formula tablets, or placebo that contained a small amount of glucose and riboflavin (2mg of B2).

The findings were published in the journal Nutrients.

Brain changes

Each participant took two tablets daily – one at breakfast and one at lunch – for six months. The researchers performed a series of blood tests, including tests for vitamins B6 and B12, folate and homocysteine levels at baseline and after the trial.

The team also used magnetic resonance spectroscopy to look at the posterior cingulate cortex (PCC, linked to memory and emotions) and dorsolateral prefrontal cortex (DLPFC, involved in as working memory, cognitive flexibility, planning, inhibition, and abstract reasoning) in the study participants before and after supplementation.

What they found was that the supplemented group experienced an increase in blood plasma vitamin B6 and B12 levels, as well as a decrease in blood plasma homocysteine.

Additionally, the researchers observed significant relationships between vitamin B6 and N-acetylaspartate (NAA, the second-most concentrated molecule in the brain), creatine and choline, as well as between vitamin B12 and creatine.

They also found that within the supplemented group, NAA in the PCC increased, though not enough to be considered statistically significant.

There was, however, no change in the group’s folate levels. However the paper notes that many foods sold in Australia, such as bread and milk, are already fortified with folate which could explain why folate levels did not change with supplementation.

Beyond folate

While folate is usually credited with reducing homocysteine levels, this study found that that although vitamins B6 and B12, along with folate, usually worked together to maintain cardiovascular, neural and psychological health by regulating homocysteine, the results suggested that the higher levels of blood plasma vitamin B6 and B12 was responsible for lowering blood plasma homocysteine levels.

They concluded that since vitamin B6- and B12-dependent enzymes – cystathionine B-synthase and methionine synthase, respectively – drove homocysteine catalysis, supplementation with a high-dose vitamin B multivitamin could “promote the breakdown of homocysteine to a greater extent than folate​”.

Follow-up needed

This was a small study, and the researchers suggest its findings should be treated as “preliminary findings that warrant further investigation with a larger sample”​.

They stated that this was the first study to have assessed the efficacy of high-dose vitamin B multivitamin supplementation in regulating the relationship between blood and neural biomarkers of oxidative stress.

In conclusion, they wrote: “Increasing levels of blood high-dose B-group vitamins were also associated with increased neural metabolism. These findings suggest that high-dose B-group vitamin supplementation might be effective in reducing oxidative stress and inflammation through increasing oxidative metabolism, and may promote myelination, cellular metabolism, and energy storage.​

“Together, these findings highlight the importance of B-group vitamins in the maintenance of brain health in healthy adults, and may have important implications in the prevention and alleviation of disease and disability.”

Researchers from the University of California, Los Angeles (UCLA) have linked long stretches of sedentary behaviour – for instance, spending all day sitting at a desk – to changes in a part of the adult brain that’s critical for memory.

Earlier research has linked sedentary behaviour to an increased risk of heart disease, diabetes and premature death in middle-age and older adults. The new study, published in the journal PLOS One, builds on what we know, focusing on inactivity’s impacts on the brain function.

Specifically, the new study linked sedentary behaviour to thinning of the medial temporal lobe, a region of the brain region in the formation of new memories. According to the researchers there is now good evidence to suggest that sedentary behaviour may be a risk factor for the development of age-related cognitive decline and dementia but the mechanism behind this is less clear than with other effects.

The thinning brain

The study included 35 people between the ages of 45 and 75. Researchers used a questionnaire to ask the participants about their physical activity levels and the average number of hours per day they had spent sitting over the previous week.

Some physical measures were taken, and they were all tested for the “Alzheimer’s gene” variants (APOE). Researchers also scanned the participants’ brains using a high-resolution MRI scan. This gave the scientists a detailed look at the medial temporal lobe of each participant and allowed them to identified relationships among this region’s thickness, the participants’ physical activity levels and their sitting behaviour.

With every hour of sitting each day, the researchers observed a decrease in brain thickness. Time spent sitting was not only linked to less thickness in the medial temporal lobe, but to certain areas within it, including the entorhinal cortex, the parahippocampal cortex, and the subiculum.

The study was not able to explain why this thinning occurs. Interestingly, while sitting was significantly linked to thinning of the medial temporal lobe, more physically active participants did not show any greater thickness in this region, suggesting that exercise might not be able to undo the damage that excessive sitting brings.

Any movement may be healthful

Even so the researchers suggest that “reducing sedentary behaviour may be a possible target for interventions designed to improve brain health in people at risk for Alzheimer’s disease.”

This is because sedentary behaviour is known to be a predictor of Alzheimer’s risk. In fact, the team points out that previous studies suggest that around 13% of Alzheimer’s cases may be due to inactivity, and that even a 25% reduction in sedentary behaviour would reduce Alzheimer’s prevalence by about one million cases worldwide. One recent study found that a variety of physical activities from walking to gardening and dancing can improve brain volume and cut the risk of Alzheimer’s disease by 50%.

There is also evidence to suggest that more time spent sitting may be linked to worse cognitive performance, which could be a symptom of changes to the brain.

It also suggests that reducing the amount of sitting that people do may be a more effective intervention than adding specific exercise regimens – something that has been shown to benefit physical health as well.

Going forward, the researchers said they plan to survey people that sit for longer periods of time each day, in order to determine if sitting causes the observed thinning. They would also like to explore the role gender, weight and race play in the effect on brain health to sitting.

• For more on this topic see our articles Stand up for good health and Don’t just sit there!

Melatonin’s main function is to separate day and night in the body’s internal biological clock. This hormone is produced as night falls, preparing the body for sleep by lowering the blood pressure and body temperature.

Since darkness is a trigger of melatonin, strong fluorescent lights – and even ‘eco-friendly’ LED lights – are known to interfere with its production. But other factors can also stop the body making it, including anxiety and depression. The efficiency of the circadian system, and thus melatonin production can also decrease with age and in certain diseases, according to a new review published in the British Journal of Pharmacology.

Supporting the ageing brain

The review, which explores the relationship between melatonin and health as we age, suggests that supplementing the hormone might have broad health benefits.

“Deviant circadian rhythms and poor sleep quality are associated with increased risks of cardiovascular, metabolic and cognitive diseases, as well poor quality of life and increased risks of premature death,” says lead researcher Dr Nava Zisapel, of Israel’s Tel Aviv University.

“The brain structure changes with age,” says Zisapel, whose company Neurim Pharmaceuticals, produces prolonged release melatonin supplement called Circadin, “and may lose the ability to produce melatonin if the pineal gland becomes calcified. It doesn’t happen to everyone at the same age, but in general, people who begin to get grey hair are losing the ability to produce melatonin.”

Help for Alzheimer’s?

In particular the review looks at evidence for melatonin supplementation in Alzheimer’s disease (AD).

With Alzheimer’s the build-up of beta-amyloid plaque in pre-clinical AD has been correlated with poor sleep quality, while early neuropathological changes at this stage of AD are accompanied by lower melatonin levels.

Studies also suggest that sleep disruption may reduce the body’s ability to clear toxic beta-amyloid plaques, particularly in an area of the brain known as the precuneus, which is involved in the speed of reaction time to a verbal memory task.

Research into melatonin supplements has shown that they may help realign a person’s circadian rhythm and sleep, and can improve cardiovascular and cognitive health, including in patients with Alzheimer’s disease, who may start producing less melatonin in the early stages of their illness.

One intervention study reviewed found improved cognitive function in people with mild to moderate AD using 2milligrams/ day (mg/d) of prolonged release melatonin over 6 months.

Though encouraging, more studies are needed to prove this effect. Nevertheless, Zisapel says, clinically meaningful effects of melatonin treatment have been demonstrated in placebo-controlled trials in humans, and the balance of evidence to-date warrants further research in this area.

The study, published in the journal Neurology, also suggested that older adults who ate at least one serving of leafy green vegetables had minds that were significantly ‘younger’ than their physical age.

Researchers at Rush University Medical Center in Chicago used a food questionnaire to survey 960 people with an average age of 81 who had not been diagnosed with any form of dementia. The participants were asked about how often they ate certain foods. Participants then had their thinking and memory skills tested every year and were followed for nearly 5 years.

On the basis of their answers to the food questionnaire – which assessed how often and how many half-cup servings they ate of either spinach, kale/collards/greens, or a one-cup serving of lettuce/salad – participants were divided into groups based on their consumption of green, leafy vegetables.

The group that ate the most servings averaged 1.3 servings per day, while the group with the fewest servings ate on average 0.1 servings per day.

Younger brains

Overall, the participants’ scores on the thinking and memory tests declined over time at a rate of 0.08 standardised units per year. Over 10 years of follow-up, the rate of decline for those who ate the most leafy greens was slower by 0.05 standardized units per year than the rate for those who ate the least leafy greens. This difference was equivalent to their minds being 11 years younger in age.

The results remained valid after accounting for other factors that could affect brain health, such as seafood and alcohol consumption, smoking, high blood pressure, obesity, education level and amount of physical and cognitive activities.

Study author Martha Clare Morris, ScD, a nutritional epidemiologist at Rush commented:  “The study results do not prove that eating green, leafy vegetables slows brain aging, but it does show an association. She adds: “There continue to be sharp increases in the percentage of people with dementia as the oldest age groups continue to grow in number. Effective strategies to prevent dementia are critically needed.”

In a first of its kind international collaboration, researchers from Australia and the UK examined the effects of aerobic exercise on a region of the brain called the hippocampus, which is critical for memory and other brain functions.

Brain health decreases with age, with the average brain shrinking by approximately five per cent per decade after the age of 40.

Looking for clarity

Studies in laboratory animals have consistently shown that physical exercise increases the size of the hippocampus but until now evidence in humans has been inconsistent.

To gain some clarity on potential benefits in humans, the researchers systematically reviewed 14 clinical trials which examined the brain scans of 737 people before and after aerobic exercise programs or in control conditions.

The participants included a mix of healthy adults, people with mild cognitive impairment such as Alzheimer’s and people with a clinical diagnosis of mental illness including depression and schizophrenia. Ages ranged from 24 to 76 years with an average age of 66.

The researchers examined effects of aerobic exercise, including stationary cycling, walking, and treadmill running. The length of the interventions ranged from three to 24 months with a range of 2-5 sessions per week.

Overall, the results – published in the journal NeuroImage – showed that, while exercise had no effect on total hippocampal volume, it did significantly increase the size of the left region of the hippocampus in humans.

Lead author Joseph Firth, a postdoctoral research fellow at Australia’s National Institute of Complementary Medicine at Western Sydney University, said the study provides some of the most definitive evidence to date on the benefits of exercise for brain health.

Long term benefits

“When you exercise you produce a chemical called brain-derived neurotrophic factor (BDNF), which may help to prevent age-related decline by reducing the deterioration of the brain,” Mr Firth said.

“Our data showed that, rather than actually increasing the size of the hippocampus per se, the main ‘brain benefits’ are due to aerobic exercise slowing down the deterioration in brain size. In other words, exercise can be seen as a maintenance program for the brain.”

Mr Firth said along with improving regular ‘healthy’ ageing, the results have implications for the prevention of ageing-related neurodegenerative disorders such as Alzheimer’s and dementia – however further research is needed to establish this.

Interestingly, he adds that physical exercise is one of the very few ‘proven’ methods for maintaining brain size and functioning into older age.