Newsroom

Shaun completes 150 mile cycle tour

Newmarket Journal -

Shaun Whiter, who lost both legs after being hit by a dangerous driver in July last year, said it felt ‘amazing’ to have completed the 150-mile Tour of Suffolk cycle ride as part of the Ipswich Town Football Club team.

Swallowable gastric balloon could help with weight loss

NHS Choices - Behind the Headlines -

"Swallowable gastric balloon could help the obese lose weight without surgery," The Guardian reports. The news, which was widely reported, is based on a study presented at the European Congress of Obesity in Portugal.

Researchers in Italy found obese patients who used a swallowable gastric balloon lost on average about 15kg over a four-month period.

Gastric balloon treatment for obesity involves inserting a balloon in the stomach and filling it with air or liquid. This means you can't or won't need to eat as much to feel full.

Currently, deflated gastric balloons usually have to be inserted – and later removed – in a hospital setting. This involves being sedated or having a general anaesthetic and having an endoscopy, where a thin tube with a camera and light is passed down your throat.

The swallowable gastric balloon used in this study can be inserted without any invasive procedures such as endoscopy. The balloon is swallowed by the patient and then filled with liquid once it's in the stomach. The balloon stays in the stomach for four months, until it automatically deflates and is excreted.

Overall, the study found the swallowable gastric balloon was a safe procedure that led to weight loss in obese patients, when used alongside a low calorie diet. However, the rate of weight loss slowed down after 12 weeks of treatment, until the introduction of a very low calorie diet.

This is early stage research involving a small number of patients who were followed up for just 16 weeks. Long-term studies are needed to see if the swallowable gastric balloon can help people not only lose weight but also keep the weight off.

Where did the story come from?

This research was carried out by researchers from Sapienza University in Italy. No external sources of funding were mentioned.

The research was presented as a conference poster at the 24th European Congress on Obesity taking place in Portugal from May 17-20 2017. The poster is also available online (PDF, 530kb).

The media coverage around this research was generally accurate, though several reports made no mention of the fact that any weight loss achieved may not last beyond the period when the gastric balloon is in place, unless patients make long-term changes to their diet.

What kind of research was this?

This prospective non-randomised study investigated whether treatment with a swallowable gastric balloon is a safe and effective option to help obese people lose weight.

Used alongside a low calorie diet, the balloon can make it easier to adhere to the strict intake of the diet because it makes you feel fuller.

Non-randomised prospective studies like this one are useful to follow up on medical interventions, and assess their safety and effectiveness by looking at the number of adverse events. However, the best way to validate these findings would be by using a randomised controlled trial (RCT).

What did the research involve?

Researchers studied 38 obese patients (28 men and 10 women) for 16 weeks after insertion of the gastric balloon.

The mean age of the participants was 46, their mean initial weight was 110kg, and they had a mean BMI of 39.

The people recruited for the study had struggled to lose weight through dieting alone, and had refused other treatments involving gastric balloons because of the need for sedation and endoscopy.

The participants were asked to swallow the gastric balloon, which is packaged inside a capsule the size of a pill and attached to a thin tube. The capsule disintegrates when it's in the stomach, and the balloon is then filled with 550ml of liquid.

The thin tube is then detached and the gastric balloon remains in the stomach. After four months, the release valve in the balloon opens automatically, which empties the fluid, and the balloon is then excreted.

For the first 12 weeks of treatment, the patients were given a low calorie diet, which was then switched to a very low calorie ketogenic diet (~700 kcal/day) for the last four weeks.

Follow-up took place every two weeks. At the end of the 16 weeks, the balloon was excreted and participants were asked to follow a Mediterranean diet to maintain their weight loss.

What were the basic results?

Overall, treatment with the gastric balloon was well received by all the patients involved in the study. In all cases, the balloons were swallowed, filled and excreted successfully.

There were no reports of serious adverse events. Side effects such as nausea, vomiting and abdominal pain resolved on their own or with medication.

The participants lost weight throughout the 16 weeks of gastric balloon therapy:

  • at week 4: the mean weight loss was 5.4kg
  • at week 8: mean weight loss 8.9kg
  • at week 12: mean weight loss 11.5kg
  • at week 16: mean weight loss 15.2kg

Although weight loss decreased overall in the first 12 weeks, the rate of weight loss began to slow down at the end of the first 12 weeks. It then increased again in the last month, when the patients followed a very low calorie ketogenic diet (VLCKD) to boost weight loss.

How did the researchers interpret the results?

The researchers concluded: "The Elipse balloon appears to be a safe and effective weight loss method. Furthermore, the introduction of a VLCKD (very low calorie ketogenic diet) improves weight loss."

They added: "The procedureless nature of the Elipse balloon may make it amenable to a larger population of obese patients not responding to diet treatment and a variety of clinicians (e.g. nutritionists, dieticians and internists) who currently do not have access to endoscopic or surgical weight loss devices."

Conclusion

This research investigated whether treatment with a swallowable gastric balloon is a safe and effective option to help obese people lose weight.

Overall, the study found the gastric balloon led to weight loss when used alongside a low calorie diet, with a mean weight loss of 15.2kg by the end of the 16-week treatment period.

However, the rate of weight loss declined after 12 weeks of treatment, before going up again in the last month with the introduction of a very low calorie diet.

This is an interesting piece of research, but it has a number of limitations.

  • This is a very small study, and the findings would have to be observed on a large scale before it can be decided whether this swallowable gastric balloon is a safe and cost-effective option compared with other gastric balloon procedures.
  • The study only looks at the effects of the gastric balloon after 16 weeks of treatment. The effects of the gastric balloon for long-term weight loss would have to be studied before it's decided whether this could be a sustainable weight loss treatment.
  • Because the study has only been presented as a poster at a conference, only limited information on the findings is currently available. A full research paper would provide more information on the methods and limitations of the study. 

Dr Simon Cork, Research Fellow at the Department of Investigative Medicine at Imperial College London, commented: "This is an interesting study with interesting outcomes for clinical practice. It is a small study (only 38 people); however, in terms of proof of concept this is acceptable.

"It is also noteworthy that weight loss begins to slow down as the trial goes on (until the introduction of a low calorie diet). This is not surprising, but shows that in itself, gastric balloons are not long-term solutions for weight loss.

"Sadly, the weight lost through this balloon will undoubtedly be put back on soon after the balloon is removed. Nevertheless, gastric balloons are still useful for some patients, and the introduction of a device which doesn't require surgery to implant is a positive step forward."

Read more on weight loss and weight loss surgery.

Links To The Headlines

'Gastric band in a pill' can help obese lose two stone. The Daily Telegraph, May 18 2017

Gastric band in a pill provides quick fix for ballooning weight. The Times. May 18 2018

Diet pill balloon can lose you 2st. The Sun, May 18 2017

The balloon you swallow to help you shed weight. Daily Mirror, May 18 2017

Balloons could help patients to avoid gastric band surgery. The Guardian. May 18 2017

'Fat but fit' still at higher risk of heart disease

NHS Choices - Behind the Headlines -

"The idea that people can be fat but medically fit is a myth," reports BBC News.

The story is based on research from scientists at the University of Birmingham, reported at a medical conference but not yet published.

The researchers used information from a UK database of GP records covering 3.5 million people, to calculate people's chances of getting cardiovascular disease, such as a heart attack or stroke.

They focused on people who were obese based on a body mass index (BMI) over 30, but who did not have the associated risk factors of high blood pressure, diabetes or abnormal fats in their blood.

The researchers wanted to know if this group, sometimes called "metabolically healthy obese" people, had a raised risk of cardiovascular disease compared to people of recommended weight (a BMI of 18.5 to 24.9).

The research found they had a higher chance of heart disease, stroke or transient ischaemic attack (mini stroke) and heart failure, compared to those of recommended weight. However, their risk was not as high as for obese people who also had diabetes, high blood pressure or abnormal fats.

The research is unpublished, which means we can't check the validity of the study. However, it confirms that keeping to a healthy weight is likely to lower your chances of cardiovascular disease, which is not a surprising finding.

Where did the story come from?

The study was carried out by researchers from the University of Birmingham. It was presented at the European Congress on Obesity in Portugal.

Sources of funding were not declared.

Some sections of the UK media seized on the study with glee. "Think you're fat AND fit? There's no such thing!" crowed the Daily Mail, illustrating its article with fat-shaming photographs of overweight people at the gym.

Most of the coverage repeated the line that it is not possible to be overweight and healthy, which is not what the study found.

The study results showed obese people were at an increased risk of certain diseases, but that doesn't mean they will all get these diseases.

What kind of research was this?

This was a prospective cohort study.

This type of study is good at finding links between factors – such as weight, metabolic indicators and cardiovascular disease, in this case – but cannot prove that one causes another.

So the study does not prove that being obese but metabolically healthy causes cardiovascular disease, only that there's a link between the two.   

What did the research involve?

Researchers used electronic health records from 1995 to 2015 from the Health Improvement Network database of UK general practice records.

They looked at records of people aged 18 and over, without cardiovascular disease at the start of the study. People were grouped according to their BMI and whether they had any of three metabolic risk factors: diabetes, high blood pressure or abnormal blood fats.

Researchers then calculated the relative risk for each group of getting one of four cardiovascular disease conditions:

  • coronary heart disease (including angina and heart attack)
  • cerebrovascular disease (including stroke and transient ischaemic attack or TIA)
  • heart failure, where the heart muscle is unable to pump sufficient blood around the body
  • peripheral vascular disease, where blood vessels in the legs narrow and cause pain while walking

They compared the risks of people with recommended weight and no metabolic risk factors with people who were obese and had no, one, two or three metabolic risk factors.

They adjusted their figures to take account of confounding factors including age, sex, smoking and socioeconomic status.

What were the basic results?

Of the 3.5 million people in the study, 766,900 (21.9%) were obese – of whom 518,000 (14.8%) were obese with no additional risk factors (metabolically healthy).

The researchers found that, compared to people of recommended weight, metabolically-healthy obese people were:

  • 50% more likely to get heart disease
  • 7% more likely to get cerebrovascular disease
  • twice as likely to get heart failure

The findings for peripheral vascular disease were mixed. Overall, metabolically-healthy obese people were 9% less likely to get peripheral vascular disease. However, excluding smokers, the risk was 11% higher.

Metabolic risk factors raised the chances of getting any of these conditions, in addition to obesity.

Compared to recommended weight, metabolically-healthy people, those who were obese and had all three risk factors were:

  • 2.6 times more likely to get heart disease
  • 58% more likely to get cerebrovascular disease
  • 3.8 times more likely to get heart failure
  • 2.2 times more likely to get peripheral vascular disease

The researchers say their figures were statistically significant; however they were unable to supply the full data with confidence intervals, so we can't check this.

How did the researchers interpret the results?

The researchers said their study showed that "metabolically-healthy obese individuals are at higher risk" of the diseases studied and that "The priority of health professionals should be to promote and facilitate weight loss among obese persons, regardless of the presence or absence of metabolic abnormalities."

Study author Dr Rishi Caleyachetty added: "So-called metabolically healthy obesity is not a harmless condition and perhaps it is better not to use this term to describe an obese person."

Conclusion

The question of whether someone can be "fat but fit" has been much debated. If you're obese but exercise, eat well and don't have metabolic risk factors, the theory goes, you could be just as healthy as someone of recommended weight. This study suggests that may not be true.

It is definitely worth adopting a healthy lifestyle, whatever your weight. The study found that, the more metabolic risk factors people had, the more likely they were to develop heart disease, cardiovascular disease and so on. Metabolic risk factors do make a difference.

But in this large study, on average, people who were obese with no metabolic risk factors had a higher risk of disease than people of recommended weight with no metabolic risk factors.

The study has some strengths. It is very large, and uses data from records that are thought to be reasonably reliable. However, we need to remain cautious about the strength of the study until we can see the full data. The researchers say the paper is under peer review and is expected to be published in a medical journal.

If you are worried about your weight, talk to your doctor and take a look at our weight loss programme.

Links To The Headlines

It is not possible to be 'fat and fit', major study finds. Independent, May 17 2017

Think you're fat AND fit? There's no such thing! Mail Online, May 17 2017

Being 'fat but fit' is a myth, claims study. Sky News, May 17 2017

Can you be fat and fit? No you can't be both obese and healthy, says study of 3.5 million people. Metro, May 17 2017

No such thing as 'fat but fit', major study finds. Guardian, May 17 2017

'Fat but fit' idea is a medical myth, researchers find. Telegraph, May 17 2017

'Fat but fit is a big fat myth'. BBC News, May 17 2017

Lack of sleep knocks your social appeal, says research

NHS Choices - Behind the Headlines -

"A couple of bad nights is enough to make a person look 'significantly' more ugly," reports BBC News.

Researchers in Sweden found people rated photographs of strangers as less attractive and healthy when the people in the photographs had less sleep.

The study used photographs of healthy, mainly young, students taken after either two nights of normal sleep (around eight hours a night) or two nights of restricted sleep (around four hours a night).

The photos were rated by 122 strangers, who were asked how much they would like to socialise with the people in the photographs, and how healthy, attractive, trustworthy and sleepy they looked.

The study found that on average, people were 2.1% less likely to want to socialise with people who'd had less sleep.

It's unclear how significant this finding is in real life, or what effect it might have on people not getting enough sleep.

If you're having difficulty sleeping, whether or not other people want to socialise with you may be the least of your worries.

Persistently poor sleep can increase the chances of obesity and diabetes, and worsen conditions like depression and anxiety.

Find out more about getting a good night's sleep.

Where did the story come from?

The study was carried out by researchers from Karolinska Institute and Stockholm University in Sweden and was funded by the two institutions. 

It was published in the peer-reviewed journal Royal Society Open Science on an open access basis, meaning it's free to read online.

BBC News gave a balanced overview of the study, but didn't mention the small size of the effect of sleep deprivation.

What kind of research was this?

This was an experimental psychological study, using volunteers. This type of study can show the effects of experimental conditions on volunteers, but doesn't necessarily tell us what happens to people with sleep problems in real life.

What did the research involve?

Researchers recruited 14 female and 11 male students, mostly in their early 20s but ranging from 18-47 years old. 

All 25 students had their photograph taken twice – once after two nights of sleep restriction and once after two nights of normal sleep.

The photos were viewed by 122 members of the general public from Stockholm, 65 of them women, who gave ratings on a number of questions.

The researchers looked at the results to see if there was a difference between people's ratings of photos taken when people were sleep restricted, or when they'd had normal sleep.

For the photographs after normal sleep, people were told to go to bed for around eight hours, between 10pm and midnight until between 6am and 8am.

Before the sleep deprivation photographs, people were told to go to bed for around four hours, between midnight and 2am until between 4am and 6am.

They used actigraphs (special monitors) to measure activity so the researchers could check the students had followed the instructions properly.

The average difference in hours of sleep between the normal and restricted sleep was 3.5 hours a night, adding up to seven hours less sleep than normal over two nights.

All photographs were taken at the same time of day by the same photographer, with people wearing no make-up and hair scraped back from the face.

Raters were asked to look at 50 photos (two from each person) and say on a scale of one to seven:

  • how much they would like to socialise with them
  • how attractive they were
  • how healthy they looked
  • how sleepy they looked
  • how trustworthy they looked

Students were paid for taking part and raters were offered cinema tickets.

The researchers excluded ratings from people whose ratings showed low variability (less than 0.5 standard deviation between scores on normal sleep and restricted sleep photos) because they say this could indicate "low motivation to adhere to the instructions of the task".

What were the basic results?

People's average ratings were mostly in the middle of the seven-point scale on all questions, with averages between three and five for people who'd had normal sleep.

Raters' scores suggested they were less willing to socialise with people who'd been sleep restricted, but only by 0.15 points on a seven-point scale (around 2.1%).

Compared with average ratings after normal sleep, average ratings on a seven-point scale were:

  • 0.09 points lower for attractiveness
  • 0.11 points lower for health
  • 0.25 points higher for sleepiness

There was no difference in the trustworthiness scores between normal sleep and sleep deprivation.

Analysis showed only about a third of people's reduced willingness to socialise with sleep-restricted people was explained by the findings on attractiveness, health and sleepiness. In other words, something other than attractiveness, health or sleepiness was putting people off.

How did the researchers interpret the results?

The researchers say their study "indicates that restricted sleep affects facial appearance negatively and decreases others' willingness to socialise with the sleep deprived person".

They say it confirms previous findings that people completely deprived of sleep for one or two nights are judged to look less healthy and attractive, and extends the findings to "less substantial and more natural" sleep loss conditions.

Conclusion

Most people who have looked in the mirror after a sleepless night won't be surprised to hear that a poor night's sleep makes you look less attractive and healthy.

It may not be particularly welcome news that your appearance could also put people off talking to you.

But the study results show only a very small impact of sleep deprivation on people's perceptions of appearance.

While the results are statistically significant, it's hard to know how you would notice a 2% drop in a stranger's willingness to socialise with you.

And studies like this, which include only a limited demographic (in this case Swedish students aged around 22, mostly white) may have little relevance to anyone who doesn't fit that profile.

More important are the known health effects of sleep problems. An occasional late night is very different from persistent difficulties in getting to sleep or staying asleep.

Regular poor sleep can raise your risk of diabetes, heart disease and obesity, and is linked to mental health problems like anxiety and depression.

There are plenty of things you can try yourself to increase your chances of getting a good night's sleep. But if you've tried these and you're still struggling to sleep, talk to your GP.

Good ways to sleep well include:

  • regular sleep hours for going to bed and getting up
  • keeping your bedroom calm, cool, comfortable and quiet
  • taking regular exercise, but not late in the evening
  • cutting down on caffeine
  • avoiding too much alcohol, especially late at night
  • relaxing before going to bed with a bath or a good book, or listening to calming music

Read more about getting to sleep.  

Links To The Headlines

Beauty sleep is a real thing, research shows. BBC News, May 17 2017

Links To Science

Sundelin T, Lekander M, Sorjonen K, Axelsson J. Negative effects of restricted sleep on facial appearance and social appeal. Royal Society Open Science. Published online May 17 2017.

Hope for plant-based contraceptive, study claims

NHS Choices - Behind the Headlines -

"Forget Plan B – try aloe vera, controversial study claims: Scientists insist pills made from dandelions and mangoes can prevent pregnancy without a hit of hormones," reports the Mail Online.

The news is based on a study investigating whether chemicals found in certain plants can reduce sperm's ability to fertilise a woman's egg.

Sperm get a boost of energy from the hormone progesterone as they approach the egg. This activation increases their swimming speed in the female reproductive tract, enabling them to penetrate the egg.

Using donor sperm samples, this research showed how two plant chemicals – pristimerin (found in thunder god vine) and lupeol (found in mango, dandelion root and aloe vera) – were able to prevent sperm activation.

This raises the possibility that these natural substances could act as an alternative to hormone-based contraceptives, which are known to have side effects.

More laboratory research is needed to show if this type of contraceptive method has the potential to be safe and effective before researchers can consider moving on to human trials.

The researchers are currently working on developing a contraceptive patch and pill. But it's likely to be many years before we know if this could lead to a new licensed contraceptive.

Where did the story come from?

The study was carried out by researchers from the University of California.

It was funded by a US National Institutes of Health grant, a Pew Biomedical Scholars Award, an Alfred P Sloan Award, and Packer Wentz Endowment Will.

The researchers declare a conflict of interest in that two of the authors are inventors on a patent application filed by the University of California.

The study was published in the peer-reviewed journal Proceedings of the National Academy of Sciences and is free to read online.

The news stories have broadly reported the story accurately, but don't state that any potential new contraceptive would take years to develop. 

What kind of research was this?

This laboratory study aimed to assess whether it's possible to use plant chemicals to restrict sperm movement, thereby preventing them from moving effectively towards the egg.

The researchers explain how the sperm calcium channel, CatSper, which is found in the tail, is a key part of male fertility.

The female hormone progesterone activates CatSper by binding to a particular receptor (ABHD2), energising the sperm and boosting fertility.

In theory, any chemical that blocks this receptor has the potential to behave like a contraceptive and prevent fertilisation.

This type of research is useful for further understanding how biological mechanisms work and identifying potential new therapies.

But even if it's shown to work in the laboratory, much more testing is needed before we can conclude that this is a safe and effective alternative form of contraception.  

What did the research involve?

Four healthy donors provided sperm samples for this research. The researchers analysed the effects different hormones and substances have on calcium channels (CatSper) and consequently sperm movement. All tests were performed at normal body temperature (37C). 

Sperm samples were exposed to the following hormones:

  • testosterone
  • oestrogen
  • progesterone
  • hydrocortisone (a steroid hormone)
  • pregnenolone sulphate (a steroid hormone)
What were the basic results?

The researchers found testosterone, oestrogen and hydrocortisone had no effect on the mobility of sperm and its ability to penetrate the egg.

They confirmed that progesterone activates the sperm for fertilisation by binding to the ABHD2 receptor. They also found pregnenolone sulphate had a similar effect in activating sperm, likely by binding to the same site.

The researchers then identified two steroid-like plant chemicals, pristimerin and lupeol, which appeared to block the action of the progesterone and pregnenolone sulphate on sperm.

By preventing the action of the other hormones, they reduced the sperm's ability to activate and then penetrate and fertilise an egg. 

How did the researchers interpret the results?

The researchers concluded that their results indicate pregnenolone sulphate and progesterone are the main steroids that initiate sperm activation.

Pristimerin and lupeol, found in plants, can act as contraceptives by reducing sperm movement and preventing fertilisation.  

Conclusion

This laboratory study aimed to investigate a variety of steroid hormones and plant compounds to look at their effect on sperm activation and ability to fertilise an egg.

The researchers confirmed that the hormone progesterone present in the female reproductive tract seems to be needed to activate sperm and make them able to fertilise an egg.

The also found that two plant compounds, pristimerin and lupeol, were able to block the sites on the sperm that are activated by progesterone. This means these two compounds could have a potential contraceptive action.

But it's far too early to say whether new contraceptives could become available as a result of this research. More laboratory research would be needed to show their potential to be safe and effective before considering trials in humans.

For example, at the current stage it's not actually known whether these compounds would incapacitate all sperm and prevent them fertilising an egg.

It's also unclear what method of exposure would be needed (like a pill, patch or vaginal ring) and whether the compounds have toxic side effects.

Most potential new treatments identified at such an early experimental stage don't make it all the way to becoming licensed treatments available to the general public. 

Find out more about contraception.

Links To The Headlines

Plant chemicals hope for 'alternative contraceptives'. BBC News, May 16 2017

Forget Plan B – try aloe vera, controversial study claims: Scientists insist pills made from dandelions and mangoes can prevent pregnancy without a hit of hormones. Mail Online, May 15 2016

Contraceptive pill without side-effects could be created using aloe vera extract, scientists say. The Daily Telegraph, May 15 2017

Links To Science

Mannowetza N, Millera M and Lishkoa P. Regulation of the sperm calcium channel CatSper by endogenous steroids and plant triterpenoids. Proceedings of the National Academy of Sciences of the United States of America. Published online May 15 2017

Can fizzy water make you fat?

NHS Choices - Behind the Headlines -

“Fizzy water could cause obesity by encouraging you to eat more,” The Daily Telegraph reports.

Researchers aimed to see whether it could be the carbonation in soft drinks – rather than the sugar – that explains the link between soft drinks and obesity.

Overall, they found rats that drank diet or regular fizzy drinks ate more and gained more weight over six months than rats that drank flat soda or water. The weight gain was associated with increased production of the appetite hormone ghrelin, which is produced by both rodents and humans.

The researchers then looked at the effects of carbonated drinks in 20 young men and found they also had higher blood ghrelin levels after drinking fizzy drinks than after flat soda or water.

But we can’t say from the results of this study alone that carbonation or ghrelin production is the full answer to the link between soft drink consumption and obesity.

It is likely that obesity is caused by multiple environmental, social and lifestyle factors, rather than carbonation on its own.

People who consume lots of fizzy drinks may also be more likely to have a less healthy diet and to be doing less exercise. The safest and cheapest bet for refreshment is plain old tap water.

Where did the story come from?

The study was carried out by researchers from Birzeit University in Palestine and was funded by grants from the same institution. 

It was published in the peer-reviewed journal Obesity Research and Clinical Practice.

The coverage of the study in the UK media was accurate.

 

What kind of research was this?

This animal research aimed to see whether having fizzy drinks could contribute to weight gain.

The authors state that arguably there are many causes of obesity, including environmental, social and genetic factors. They say numerous studies have observed links between obesity and soft drink consumption, mostly believed to be due to the sugar content in these drinks.

But there’s another element to both sugar sweetened and diet fizzy drinks: carbon dioxide. This study  aimed to look at the effects of carbonation.

Animal research is a useful step to see how biological processes may work in humans, as we share many similarities.

That said, we aren’t identical to rodents, so any findings would always need to be validated in human trials. Preliminary attempts at validation were made in this study. There are still likely to be many other issues involved with dietary intake and weight gain.   

What did the research involve?

The study involved groups of male rats who were all fed a standard diet, but given one of four different drinks:

  • tap water
  • regular degassed (flat)
  • soda regular carbonated soda
  • diet carbonated soda

The researchers assessed food consumption, weighed the rats, and analysed blood sugar and cholesterol after six months on the diet.

They also looked at blood levels of the hormone ghrelin, which is released from the digestive system in response to hunger.

After death, the rats’ stomachs were also examined to see how much ghrelin had been produced and their liver was examined for fatty deposits.

In a second part of the study, 20 healthy human male students aged 18-23 were given a light breakfast followed one hour later by each of the four drinks.

The students repeated this experiment on different days so they were all trying the same drinks. They then had blood samples taken to measure ghrelin. Ghrelin is a hormone that’s “used” by the digestive system to simulate feelings of hunger.

What were the basic results?

Rats that drank tap water or flat soda weighed significantly less than those drinking the carbonated drinks. Rats that drank both the diet and sugary fizzy drinks gained a similar amount of weight. Weight gain was slowest in the water-drinking rats compared with all three groups drinking soda.

Rats drinking the fizzy drinks ate significantly more food than those drinking water and flat soda. This was associated with increased blood levels of ghrelin, further supported by evidence of increased ghrelin secretion from the stomach.

There was no difference in blood sugar or cholesterol levels, but those that drank fizzy drinks had more fat in the liver.

In the human volunteers, ghrelin levels were higher after drinking fizzy drinks one hour after food – three-folds higher than after flat soda, and six-folds higher than after water.

How did the researchers interpret the results?
The researchers concluded that, “This study clearly shows discernible effect of the carbon dioxide gas in carbonated drinks on increased food ingestion and heightened risk of weight gain, obesity and fatty liver disease by inducing ghrelin release.”

Conclusion

There seemed to be a clear distinction in this study between fizzy and non-fizzy-drink consumption in terms of weight gain, appetite and ghrelin production.

These findings were further supported by the study in healthy adult volunteers, which similarly showed that the fizzy drinks increased ghrelin production.

But does this mean that carbonation and ghrelin production provide the whole answer to why soft drink consumption is linked with obesity?

But this doesn’t account for the link between weight gain and diet drinks which don’t contain sugar’They suggest carbonation could be the common link between the two.

This is possible. But it may also be that other unhealthy lifestyle factors, which this study didn’t look at, could also be a common link between sugary and diet fizzy drinks..

In real life, people who drink soda lots of fizzy drinks could also be more likely to have a less healthy diet and exercise less.

It could still be argued that even if people drinking soft drinks do eat more unhealthy food, this is caused by the carbonation making them eat more, but this isn’t proven.

Another point to bear in mind is that this research was conducted primarily in rats. Human beings may not have identical biology.

And although the researchers did follow this up with a human study, they only looked at a very small sample of young men. We can’t necessarily apply their results to women or other populations.

Even in the rats, they found though the rats had increased levels of the appetite hormone, there was no effect on the levels of another satiety hormone that tells them they’re full. This means we can’t be certain that ghrelin provides the whole answer to weight gain.

Overall, this study raises an interesting possibility that fizzy drinks could stimulate the appetite and cause weight gain, which is definitely worthy of further research.

The best way to achieve a healthy weight is through eating a balanced diet and exercising regularly And as unexciting as it may seem, water straight from the tap is the best option to quench your thirst. 

Links To The Headlines

Fizzy water could cause obesity by encouraging you to eat more. The Daily Telegraph, May 15 2017

 Fizzy water could make you FAT, reveal scientists…and you could be better off drinking ‘flat’ sugary drinks. The Sun, May 15 2017

Fizzy water could be making you fat – here's how. Daily Mirror, May 15 2017

Links To Science

Eweis SD, Abed F, Stiban J. Carbon dioxide in carbonated beverages induces ghrelin release and increased food consumption in male rats: Implications on the onset of obesity. Obesity Research and Clinical Practice. Published online February 19 2017

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