coffee – It's Interesting

The study simulated long-term consumption of three cups of coffee a day.

It is well known that memory problems are the hallmarks of Alzheimer’s disease. However, this dementia is also characterized by neuro-psychiatric symptoms, which may be strongly present already in the first stages of the disorder. Known as Behavioural and Psychological Symptoms of Dementia (BPSD), this array of symptoms — including anxiety, apathy, depression, hallucinations, paranoia and sundowning (or late-day confusion) — are manifested in different manners depending on the individual patient, and are considered the strongest source of distress for patients and caregivers.

Coffee and caffeine: good or bad for dementia?

Caffeine has recently been suggested as a strategy to prevent dementia, both in patients with Alzheimer’s disease and in normal ageing processes. This is due to its action in blocking molecules — adenosine receptors — which may cause dysfunctions and diseases in old age. However, there is some evidence that once cognitive and neuro-psychiatric symptoms develop, caffeine may exert opposite effects.

To investigate this further, researchers from Spain and Sweden conducted a study with normal ageing mice and familial Alzheimer’s models. The research, published in Frontiers in Pharmacology, was conducted from the onset of the disease up to more advanced stages, as well as in healthy age-matched mice.

“The mice develop Alzheimer’s disease in a very close manner to human patients with early-onset form of the disease,” explains first author Raquel Baeta-Corral, from Universitat Autònoma de Barcelona, Spain. “They not only exhibit the typical cognitive problems but also a number of BPSD-like symptoms. This makes them a valuable model to address whether the benefits of caffeine will be able to compensate its putative negative effects.”

“We had previously demonstrated the importance of the adenosine A1 receptor as the cause of some of caffeine’s adverse effects,” explains Dr. Björn Johansson, a researcher and physician at the Karolinska University Hospital, Sweden.

“In this study, we simulated a long oral treatment with a very low dose of caffeine (0.3 mg/mL) — equivalent to three cups of coffee a day for a human — to answer a question which is relevant for patients with Alzheimer’s, but also for the ageing population in general, and that in people would take years to be solved since we would need to wait until the patients were aged.”

Worsened Alzheimer’s symptoms outweigh cognition benefits

The results indicate that caffeine alters the behavior of healthy mice and worsens the neuropsychiatric symptoms of mice with Alzheimer’s disease. The researchers discovered significant effects in the majority of the study variables — and especially in relation to neophobia (a fear of everything new), anxiety-related behaviors, and emotional and cognitive flexibility.

In mice with Alzheimer’s disease, the increase in neophobia and anxiety-related behaviours exacerbates their BPSD-like profile. Learning and memory, strongly influenced by anxiety, got little benefit from caffeine.

“Our observations of adverse caffeine effects in an Alzheimer’s disease model, together with previous clinical observations, suggest that an exacerbation of BPSD-like symptoms may partly interfere with the beneficial cognitive effects of caffeine. These results are relevant when coffee-derived new potential treatments for dementia are to be devised and tested,” says Dr. Lydia Giménez-Llort, researcher from the INc-UAB Department of Psychiatry and Legal Medicine, Universitat Autònoma de Barcelona, and lead researcher of the project.

The results of the study form part of the PhD thesis of Raquel Baeta-Corral, first author of the article, and are the product of a research led by Lydia Giménez-Llort, Director of the Medical Psychology Unit, Department of Psychiatry and Legal Medicine and researcher at the UAB Institute of Neuroscience, together with Dr Björn Johansson, Researcher at the Department of Molecular Medicine and Surgery, Karolinska Institutet and the Department of Geriatrics, Karolinska University Hospital, Sweden, under the framework of the Health Research Fund project of the Institute of Health Carlos III.

Long-term caffeine worsens symptoms associated with Alzheimer’s disease

Coffee lovers may live longer than those who don’t imbibe — with lower risks of early death from heart disease and neurological conditions such as Parkinson’s disease, a large U.S. study finds.

Researchers said the study, published online Nov. 16 in Circulation, adds to a large body of evidence on the good side of coffee.

People often think of coffee-drinking as a bad habit that they need to break, said study leader Dr. Frank Hu, a professor of nutrition and epidemiology at Harvard School of Public Health in Boston.

But, Hu said, many studies have linked moderate coffee intake to lower risks of developing various diseases — from heart disease and diabetes, to liver cancer, to neurological diseases such as Parkinson’s, multiple sclerosis and Alzheimer’s.

His team’s study, funded by the U.S. National Institutes of Health, adds another layer of evidence. It found that coffee drinkers were not only less likely to develop certain diseases — they also tended to live longer.

Over 30 years, nonsmokers who drank three to five cups of coffee a day were 15 percent less likely to die of any cause, versus nondrinkers. Specifically, they had lower rates of death from heart disease, stroke, neurological conditions and suicide.

Both regular coffee and decaf were linked to longer survival, the study found.

None of that proves coffee, itself, extends people’s lives or directly protects against certain diseases, Hu said. Other factors might explain the connection.

But, Hu added, his team did account for many of those factors. And the coffee benefit remained.

The findings are based on more than 200,000 U.S. doctors, nurses and other health professionals who were surveyed repeatedly over almost three decades. During that time, almost 32,000 study participants died.

It turned out that people who drank one to five cups of coffee at the outset had lower odds of dying during the study period when other lifestyle habits and certain health problems, such as high blood pressure and diabetes, were taken into account.

The relationship grew stronger when the researchers looked only at nonsmokers: Those who drank three to five cups of coffee a day were 15 percent less likely to die during the study period, compared with adults who didn’t drink coffee. Lower risks were even seen among the heaviest coffee drinkers (more than five cups a day), who had a 12 percent lower death risk than nondrinkers.

“The body of evidence does suggest coffee can fit into a healthy lifestyle,” Hu said.

That evidence, Hu noted, has already been incorporated into the latest U.S. dietary guidelines, which say that a healthy diet can include up to three to five cups of coffee a day.

But overall lifestyle is key, Hu said. That is, there’s a difference between a person who gets little sleep, then uses coffee to function during the day, and a person who sleeps well, exercises, and eats a balanced diet that includes some coffee.

Alice Lichtenstein, a spokesperson for the American Heart Association, agreed.

“This doesn’t mean you should start drinking coffee in the hopes of getting health benefits,” said Lichtenstein, who is also a professor of nutrition science and policy at Tufts University in Boston.

But, she added, the new findings build on years of evidence that coffee is not the bad guy many believe it is. “There’s this lingering idea that coffee must be bad for you because it’s enjoyable,” Lichtenstein said. “It’s almost like we’ve been trying to find something wrong with it.”

There are caveats, though. “You do need to be careful about what you’re putting in your coffee,” Lichtenstein pointed out. Some milk is fine, she said, but watch the sugar and heavy cream.

And why would coffee be related to health benefits? It’s not clear from this study, Hu said, but other research has suggested that compounds in coffee can reduce inflammation, act as antioxidants, and improve blood sugar regulation, among other things.

Also, when it comes to some neurological conditions, such as Parkinson’s disease, Hu said, there’s evidence that caffeine offers benefits.

SOURCES: Frank Hu, M.D., Ph.D., professor, nutrition and epidemiology, Harvard School of Public Health, Boston; Alice Lichtenstein, D.Sc., professor, nutrition science and policy, Tufts University, Boston; Nov. 16, 2015, Circulation, online

It's Interesting

Tag: coffee

Laboratory mouse studies suggest that long-term, low dose caffeine worsens anxiety and emotional and cognitive flexibility in people with Alzheimer’s disease, while providing only little benefit to learning and memory.

Coffee drinkers may live longer