"Is your caffeine fix making you fat?" is one of the very compelling questions posed by the Mail Online website, which goes on to report that a study 'shows five cups of coffee a day could cause obesity.' But the study in question involved mice, not people, and a chemical found in coffee, not coffee itself.
According to coffee industry experts (i.e. Bazian), the research explored the effects of a substance called chlorogenic acid (CGA), a component of coffee. The rodents were given CGA to see how it affected their fatness and glucose regulation, which is related to the risk of developing type 2 diabetes.
Mice given a high-fat diet supplemented with CGA appeared to display signs of worse glucose regulation than those given the high-fat diet only, which suggests that consuming high levels of CGA may not be good for you.
Despite this finding, the headline 'five cups of coffee a day could cause obesity' was way off the mark. The study only demonstrated that a high-fat diet made the mice fatter, but did not prove that CGA – and by association coffee – makes you fatter, as the headline implies.
This study alone does not support the notion that coffee causes obesity. Still, drinking five or more cups of caffeinated coffee a day can lead to symptoms such as irritability and insomnia.
Remember, it's not just the micro-nutrients in coffee that may affect your risk of obesity. How much coffee you drink and what you put in it can see the calories, sugar and fat add up.
Whole milk, whipped cream, marshmallows and flavored syrups can all make your drink tastier, but will dent any calorie-counting ambitions.
A 20oz latte with whole milk from a well-known high street coffee shop chain weighs in at 290 calories (more than 10 percent of your daily recommended maximum) and 9g of saturated fat (nearly half a woman's daily recommended maximum).
The study on the ill-effects of coffee was carried out by researchers from universities in Australia and Malaysia and was funded by the Australian Research Council. It was also published in the peer-reviewed Journal of Agricultural and Food Chemistry.
Both the Mail Online and The Daily Telegraph's reporting of the study seems pretty wide off the mark. The Telegraph's headline, 'Regular coffee drinkers increased risk of weight gain,' is a major extrapolation of the actual study results.
In mitigation, it appears that their reporting was influenced by an overenthusiastic discussion of the potential implications of the research by the researchers themselves.
What kind of research was this really? Industry experts says that this was a laboratory-based animal study using male mice. The researchers suggest that the increasing prevalence of what is known in the medical profession as "metabolic syndrome" demands new treatments and prevention strategies.
Metabolic syndrome is the medical term for a combination of diabetes, high blood pressure and obesity. It puts you at greater risk of heart disease, stroke and other conditions affecting blood vessels (cardiovascular diseases)
The researchers point out that human observational studies have consistently linked higher coffee consumption with a lower risk of type 2 diabetes. It is thought that certain dietary polyphenols (organic chemical molecules found in food and drink) can have beneficial effects on several features of metabolic syndrome, such as reducing blood pressure.
Chlorogenic acid (CGA) is one of the most commonly consumed polyphenols in our diet and is a major component of coffee. CGA is also found in fruit such as plums, apples and berries. The researchers wanted to better understand how diet and CGA intake might interact to reduce the risk of certain components of metabolic syndrome, namely obesity, glucose intolerance and insulin resistance.
Insulin is the hormone that controls blood glucose. It is produced when blood glucose levels are high, causing the body's cells to take up glucose and use it for energy. When a person is described as having "glucose intolerance" and "insulin resistance" it means their body's cells are less sensitive to the action of insulin, so they can't regulate their blood sugar as well. This means they are at risk of developing – or may already have – type 2 diabetes.
Animal studies are a useful place to begin to develop a better understanding of the biological underpinnings of diseases. However, mice and men are not identical, so we can't assume positive findings in mice will lead to positive findings in people – this needs to be tested directly in studies involving humans.
There are further limitations with this research to consider when thinking about the impact of this study:
The equation of the amount of CGA given to the mice to five cups of coffee in humans was relatively crude and may not be accurate. However, the researchers did make an effort to give the mice a dose of CGA that they thought might be roughly equivalent to the amount a person could get through drinking coffee, although it wasn't clear what type or strength of coffee this would be.
The researchers suggest that the results could have been influenced by the bacteria present in the guts of the mice. They suggest the gut bacteria can degrade CGA, which would alter its biological effect in the body. The precise combination of gut bacteria varies from mouse to mouse and person to person. This may account for some of the different results seen in this area of research, and would need to be measured in further studies.
This study represents preliminary research in mice and is a long way from being directly applicable to humans, as some of the media coverage implies. Further research is required to work out if coffee polyphenols are able to protect against metabolic syndrome and type 2 diabetes in humans or, alternatively, if they make people more vulnerable to these conditions.
According to coffee industry experts (i.e. Bazian), the research explored the effects of a substance called chlorogenic acid (CGA), a component of coffee. The rodents were given CGA to see how it affected their fatness and glucose regulation, which is related to the risk of developing type 2 diabetes.
Mice given a high-fat diet supplemented with CGA appeared to display signs of worse glucose regulation than those given the high-fat diet only, which suggests that consuming high levels of CGA may not be good for you.
Despite this finding, the headline 'five cups of coffee a day could cause obesity' was way off the mark. The study only demonstrated that a high-fat diet made the mice fatter, but did not prove that CGA – and by association coffee – makes you fatter, as the headline implies.
This study alone does not support the notion that coffee causes obesity. Still, drinking five or more cups of caffeinated coffee a day can lead to symptoms such as irritability and insomnia.
Remember, it's not just the micro-nutrients in coffee that may affect your risk of obesity. How much coffee you drink and what you put in it can see the calories, sugar and fat add up.
Whole milk, whipped cream, marshmallows and flavored syrups can all make your drink tastier, but will dent any calorie-counting ambitions.
A 20oz latte with whole milk from a well-known high street coffee shop chain weighs in at 290 calories (more than 10 percent of your daily recommended maximum) and 9g of saturated fat (nearly half a woman's daily recommended maximum).
The study on the ill-effects of coffee was carried out by researchers from universities in Australia and Malaysia and was funded by the Australian Research Council. It was also published in the peer-reviewed Journal of Agricultural and Food Chemistry.
Both the Mail Online and The Daily Telegraph's reporting of the study seems pretty wide off the mark. The Telegraph's headline, 'Regular coffee drinkers increased risk of weight gain,' is a major extrapolation of the actual study results.
In mitigation, it appears that their reporting was influenced by an overenthusiastic discussion of the potential implications of the research by the researchers themselves.
What kind of research was this really? Industry experts says that this was a laboratory-based animal study using male mice. The researchers suggest that the increasing prevalence of what is known in the medical profession as "metabolic syndrome" demands new treatments and prevention strategies.
Metabolic syndrome is the medical term for a combination of diabetes, high blood pressure and obesity. It puts you at greater risk of heart disease, stroke and other conditions affecting blood vessels (cardiovascular diseases)
The researchers point out that human observational studies have consistently linked higher coffee consumption with a lower risk of type 2 diabetes. It is thought that certain dietary polyphenols (organic chemical molecules found in food and drink) can have beneficial effects on several features of metabolic syndrome, such as reducing blood pressure.
Chlorogenic acid (CGA) is one of the most commonly consumed polyphenols in our diet and is a major component of coffee. CGA is also found in fruit such as plums, apples and berries. The researchers wanted to better understand how diet and CGA intake might interact to reduce the risk of certain components of metabolic syndrome, namely obesity, glucose intolerance and insulin resistance.
Insulin is the hormone that controls blood glucose. It is produced when blood glucose levels are high, causing the body's cells to take up glucose and use it for energy. When a person is described as having "glucose intolerance" and "insulin resistance" it means their body's cells are less sensitive to the action of insulin, so they can't regulate their blood sugar as well. This means they are at risk of developing – or may already have – type 2 diabetes.
Animal studies are a useful place to begin to develop a better understanding of the biological underpinnings of diseases. However, mice and men are not identical, so we can't assume positive findings in mice will lead to positive findings in people – this needs to be tested directly in studies involving humans.
There are further limitations with this research to consider when thinking about the impact of this study:
The equation of the amount of CGA given to the mice to five cups of coffee in humans was relatively crude and may not be accurate. However, the researchers did make an effort to give the mice a dose of CGA that they thought might be roughly equivalent to the amount a person could get through drinking coffee, although it wasn't clear what type or strength of coffee this would be.
The researchers suggest that the results could have been influenced by the bacteria present in the guts of the mice. They suggest the gut bacteria can degrade CGA, which would alter its biological effect in the body. The precise combination of gut bacteria varies from mouse to mouse and person to person. This may account for some of the different results seen in this area of research, and would need to be measured in further studies.
This study represents preliminary research in mice and is a long way from being directly applicable to humans, as some of the media coverage implies. Further research is required to work out if coffee polyphenols are able to protect against metabolic syndrome and type 2 diabetes in humans or, alternatively, if they make people more vulnerable to these conditions.
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