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Showing posts with label SCIENCE. Show all posts
Showing posts with label SCIENCE. Show all posts

Saturday, February 02, 2019

When taking probiotics could backfire, by Martha Henriques (From BBC FUTURE)

👉 GO TO FULL ARTICLE: When taking probiotics could backfire
👉 By Martha Henriques

Taking a course of antibiotics could harm the beneficial bacteria living inside us. So should we be taking probiotics after we finish them? The answer may not be so simple.
Taking probiotics when your gut health is weak may not be a good idea (Credit: Getty Images)
Probiotics have been touted as a treatment for a huge range of conditions, from obesity to mental health problems. One of their popular uses is to replenish the gut microbiome after a course of antibiotics. The logic is – antibiotics wipe out your gut bacteria along with the harmful bacteria that might be causing your infection, so a probiotic can help to restore order to your intestines.

But while it might sound like sense, there is scant solid evidence suggesting probiotics actually work if taken this way. Researchers have found that taking probiotics after antibiotics in fact delays gut health recovery.

Part of the problem when trying to figure out whether or not probiotics work is because different people can mean a variety of things with the term ‘probiotic’. To a scientist, it might be seen as a living culture of microorganisms that typically live in the healthy human gut. But the powdery substance blister packs on supermarket shelves can bear little resemblance to that definition.

Even when researchers use viable, living bacterial strains in their research, the cocktail varies from one lab to another making it tricky to compare.

“That’s the problem – there aren’t enough studies of any one particular probiotic to say this one works and this one doesn’t,” says Sydne Newberry of Rand Corporation, who carried out a large meta-analysis on the use of probiotics to treat antibiotic-induced diarrhoea in 2012.

[…] A particular concern is a lack of research on the safety of taking probiotics. While they are generally assumed to be safe in healthy people, there have been worrying case reports of probiotics causing problems – such as fungus spreading into the blood – among more vulnerable patients.

A recent study by scientists at the Weizmann Institute of Science in Israel found that even among healthy people, taking probiotics after antibiotics was not harmless. In fact, they hampered the very recovery processes that they are commonly thought to improve.

The researchers, led by Eran Elinav, gave 21 people a course of broad-spectrum antibiotics for one week. After this, they had a colonoscopy and an upper-gastrointestinal endoscopy to investigate the state of their microbiome throughout the gut.

[…] The volunteers were divided into three groups. The first was a wait-and-see group, with no intervention after the antibiotics. The second group was given a common probiotic for a month. The third was given perhaps the least savoury option: a faecal transplant. This group had a small sample of their own stool – taken before the antibiotic treatment – returned to their colon once the treatment was over.

The surprising finding was that the group who received the probiotic had the poorest response in terms of their microbiome. They were the slowest group to return to a healthy gut. Even at the end of the study – after five months of monitoring – this group had not yet reached their pre-antibiotic gut health.

“We have found a potentially alarming adverse effect of probiotics,” says Elinav.

The good news, incidentally, is that the group who received a faecal transplant did very well indeed. Within days, this group completely reconstituted their original microbiome.

“So many people are taking antibiotics all over the world,” says Elinav. “We can aim to better understand this potentially very important adverse effect that we didn’t realise existed.”

And the evidence is mounting that taking probiotics when gut health is weak is not such a good idea. Another recent study has found that probiotics don’t do any good for young children admitted to hospital for gastroenteritis. In a randomised controlled trial in the US, 886 children with gastroenteritis aged three months to four years were given either a five-day course of probiotics or a placebo.

The rate of continued moderate to severe gastroenteritis within two weeks was slightly higher (26.1%) in the probiotic group than in the placebo group (24.7%). And there was no difference between the two groups in terms of the duration of diarrhoea or vomiting.

Despite evidence such as this, the demand for probiotics is large and growing. In 2017, the market for probiotics was more than $1.8bn, and it is predicted to reach $66bn by 2024.

“Given the very heavy involvement of the industry, clear conclusions as to whether probiotics are truly helpful to humans remain to be proven,” says Elinav. “This is the reason why regulatory authorities such as the US’s Food and Drug Administration and European regulators have yet to approve a probiotic for clinical use.”

But that is not to write off probiotics completely. The problem with them may not be with the probiotics themselves, but the way we are using them. Often probiotics are bought off the shelf – consumers may not know exactly what they are getting, or even whether the culture they are buying is still alive. […]

👉 GO TO FULL ARTICLE: When taking probiotics could backfire
💡 MORE FROM BBC FUTURE:

Tuesday, October 09, 2018

The surprising truth about loneliness, by Claudia Hammond (From BBC FUTURE)

The reality of feeling alone is not what many people think. Claudia Hammond, who instigated a survey called the BBC Loneliness Experiment, explores five counterintuitive findings.


About the results: The findings in this article are based on an online survey of 55,000 people from around the world, called the BBC Loneliness Experiment. It was created by academics at three British universities in collaboration with Wellcome Collection. - Find out more: The Anatomy of Loneliness
  1. Younger people feel lonelier than older people
  2. 41% of people think loneliness can be positive
  3. People who feel lonely have social skills that are no better or worse than average
  4. Winter is no lonelier than any other time of year
  5. People who often feel lonely have higher levels of empathy than everyone else
1) Younger people feel lonelier than older people

When you picture someone who’s lonely, the stereotype is often an older person who lives alone and hardly sees anyone. Indeed, in the BBC Loneliness Experiment, 27% of over 75s said they often or very often feel lonely. This is higher than in some surveys, but because the survey was online, we had a self-selecting sample and might have attracted more people who feel lonely.

Yet the differences between age groups are striking. Levels of loneliness were actually highest among 16-24 year olds, with 40% saying they often or very often feel lonely.

Monday, July 30, 2018

Why you really are as old as you think, by David Robson (from BBC Future)

Most people feel younger or older than they really are – and this 'subjective age' has a big effect on their physical and mental health.

As they get older, people with a younger subjective age are less likely to develop dementia and they even have a reduced risk of mortality (Credit: Javier Hirschfeld/Getty Images)
Imagine, for a moment, that you had no birth certificate and your age was simply based on the way you feel inside. How old would you say you are?

Like your height or shoe size, the number of years that have passed since you first entered the world is an unchangeable fact. But everyday experience suggests that we often don’t experience ageing the same way, with many people feeling older or younger than they really are.

Scientists are increasingly interested in this quality. They are finding that your ‘subjective age’ may be essential for understanding the reasons that some people appear to flourish as they age – while others fade. “The extent to which older adults feel much younger than they are may determine important daily or life decisions for what they will do next,” says Brian Nosek at the University of Virginia.

Its importance doesn’t end there. Various studies have even shown that your subjective age also can predict various important health outcomes, including your risk of death. In some very real ways, you really are ‘only as old as you feel’.

Given these enticing results, many researchers are now trying to unpick the many biological, psychological, and social factors that shape the individual experience of ageing – and how this knowledge might help us live longer, healthier lives.

This new understanding of the ageing process has been decades in the making. Some of the earliest studies charting the gap between felt and chronological age appeared in the 1970s and 1980s. That trickle of initial interest has now turned into a flood. A torrent of new studies during the last 10 years have explored the potential psychological and physiological consequences of this discrepancy.

One of the most intriguing strands of this research has explored the way subjective age interacts with our personality. It is now well accepted that people tend to mellow as they get older, becoming less extroverted and less open to new experiences – personality changes which are less pronounced in people who are younger at heart and accentuated in people with older subjective ages.

Interestingly, however, the people with younger subjective ages also became more conscientious and less neurotic – positive changes that come with normal ageing. So they still seem to gain the wisdom that comes with greater life experience. But it doesn’t come at the cost of the energy and exuberance of youth. It’s not as if having a lower subjective age leaves us frozen in a state of permanent immaturity.

Feeling younger than your years also seems to come with a lower risk of depression and greater mental wellbeing as we age. It also means better physical health, including your risk of dementia, and less of a chance that you will be hospitalised for illness.

Yannick Stephan at the University of Montpellier examined the data from three longitudinal studies which together tracked more than 17,000 middle-aged and elderly participants.

Most people felt about eight years younger than their actual chronological age. But some felt they had aged – and the consequences were serious. Feeling between 8 and 13 years older than your actual age resulted in an 18-25% greater risk of death over the study periods, and greater disease burden – even when you control for other demographic factors such as education, race or marital status.

There are many reasons why subjective age tells us so much about our health. It may be a direct result of those accompanying personality changes, with a lower subjective age meaning that you enjoy a greater range of activities (such as travelling or learning a new hobby) as you age. “Studies have found, for example, that subjective age is predictive of physical activity patterns,” Stephan says.

But the mechanism linking physical and mental wellbeing to subjective age almost certainly acts in both directions. If you feel depressed, forgetful, and physically vulnerable, you are likely to feel older. The result could be a vicious cycle, with psychological and physiological factors both contributing to a higher subjective age and worse health, which makes us feel even older and more vulnerable. (Continue reading)

💡David Robson is a science writer based in London, UK. He is d_a_robson on Twitter.

Wednesday, March 07, 2007

A Window into the Interior of the Earth, by Juan Manuel Pardellas

Scientists study Earth's missing crust

By JUAN MANUEL PARDELLAS, Associated Press Writer Tue Mar 6, 5:53 PM ET


British scientists have embarked on a mission to study a huge area on the Atlantic seabed where the Earth's crust is mysteriously missing and instead is covered with dark green rock from deep inside the planet.

Thursday, December 21, 2006

PARALLEL UNIVERSES

Published by BBC Two 9.00 p.m. Thursday 14 February 2002

Everything you're about to read here seems impossible and insane, beyond science fiction. Yet it's all true.

Scientists now believe there may really be a parallel universe - in fact, there may be an infinite number of parallel universes, and we just happen to live in one of them. These other universes contain space, time and strange forms of exotic matter. Some of them may even contain you, in a slightly different form. Astonishingly, scientists believe that these parallel universes exist less than one millimetre away from us. In fact, our gravity is just a weak signal leaking out of another universe into ours.