Thursday, December 15, 2011

Sugar makes you look older than you really are

Lots of sugar is bad for you. While that is a general truth, a recent study has revealed an additional reason for cutting down on it: high levels of sugar make you look old. In some cases, independent observers perceived people's age almost two years higher than their actual age. Naturally, they used a large number of observers because assessing someone's age from the look of their skin is not quite an exact science. But the results are clear: glucose, which is the simple form of sugar that circulates in your body, makes you look older.

Glucose levels
For their experiments, the Dutch scientists working at Leiden, assessed participants' blood glucose levels after a meal, and divided them into three groups, based on low, medium and high levels of sugar. Sixty people were asked to determine age of the participants. The results show people that have higher levels of glucose after a meal look older, in general. Even when the results were corrected for confounders, such as smoking, body mass and real age, there was still a difference between perceived age and actual age. From calculations, the scientists derived a 5 month increase in age perception for each 0,18g/L increase in glucose concentration.

Naturally, the researchers also assessed differences between diabetics and non-diabetics. That is because these patients suffer from pathologically high glucose levels. They got the same result: people with diabetes look older on average than their healthy counterparts. This confirms the result found in the three groups with different glucose levels responses after a meal. In fact, people with diabetes were found to have the biggest gap between perceived age and real age.

Sugar and ageing
There seems to be a clear relationship between sugar and ageing of skin. More research is needed to uncover a possible causal relationship, though. One of the possible mechanisms include the formation of AGEs, a name that seems to fit. An AGE is a combination of a glucose molecule and an amino acid, the latter being a building block for proteins. The AGEs seem, through a rather complex process, able to make the skin look older by inducing connections between important molecules in the skin. This makes the skin more rigid, and reduces the possibility for efficient repair. All in all, that results in the skin looking older than its actual age. Though, we still need proof that this actually makes people look older.

Free sugars
For those wanting to keep their young look as long as possible, it might advisable to cut down on the amount of sugar you put in your coffee or tea. That is because this form of sugar is easily processable by the body, which results in higher concentrations in the blood after consumption. Actually, the body converts pretty much everything to glucose, because it is what we use as fuel. But for most types of food, the conversion takes quite a while, which spreads out the amount of glucose over a longer period of time. Consequently, the concentration does not reach high values. The glucose response that a specific type of food elicits in the body is quantified in the glycemic index. This food value has gotten more attention over the last decade: it is not just simply a story of carbohydrates, fats and kilojoules anymore. There is, like most things in biology, individual variation in glucose levels after consumption of specific foods.

Sugars that are easily processable are found in several sweet products, and are dubbed 'free sugars'. They pose an important risk factor for acquiring diabetes type II: because high levels of glucose need to be met with a high insulin response, the body loses its sensitivity for insulin. Because it is needed for uptake of glucose by cells, insensitivity means that glucose levels in the blood reach much higher values. This eventually leads to the disease we call diabetes.


  1. Fascinating read Bauke. As a *ahem* recovering sugar-holic (recovery which just happened to begin at the end of reading your post :P) I feel this has justified my decision to cut down very appropriately. Do you reckon it is possible then to regain insulin sensitivity overtime, as one decreases the sugar intake, or is the sensitivity damage done permanent?

  2. Insulin sensitivity is something that occurs after a long period of time. Diabetes Type II was normally associated with old people, as they have had the time to build up insensitivity. In our current society, even children get Type II Diabetes, which goes to show that our eating patterns have gotten worse: especially sweet and sugary things are responsible for that. (and then there's the thing with fatty foods and obesity, of course)

    As with everything in the body, once you gain it, it's hard to get rid of it. Same goes for insulin insensitivity. If you change your habits before you actually get Diabetes, it will probably be good enough. But people with Diabetes Type II can not be cured. There are some drugs that slow down the damage that a high level of glucose causes, but it won't prevent all symptoms.

    You're still young, so there is plenty of time for you to recover (if there is any damage at all, of course).

    The most important thing to remember is that habits of consuming lots of sugar make it more *likely* to get Diabetes, it doesn't mean you will get it ;)

    To end with a short answer: yes, I think it's possible to go back to normal levels of sensitivity when the changes are still minor.

  3. Hi,

    I have been following this research and so to make myself feel and look better as I get older, I have been cutting down my sugar intake and carb intake (which will turn into sugars). I must say I still enjoy my 85% cocoa chocolate which is not too high in sugar and eating berries....and of course a good night at the pub!

    I am a law student, thus I am a caffeine addict. I recently read that caffeine releases insulin! So I have made the baby step by opting for tea (a cup of tea has about half the amount of caffeine as a cup of coffee) and maybe someday I will be free from my addiction.

    Could you either confirm that what I read about the relationship between coffee and insulin is true, or better yet tell me it's wrong so I can go buy a double espresso asap!


  4. You know, eventually everything turns into sugars, because that's simply the body's fuel. So-called 'free sugars', the stuff that does not need to be modified much to take up, give a much higher diabetes risk, because the body needs to respond with larger amounts of insulin. Naturally, if the body has to modify stuff first before it gets turned into glucose (the fuel), it takes longer, and thus the concentration over time is lower. That corresponds with a lower concentration of insulin (over time), thus less chance of reaching insensitivity.

    As for caffeine, there have been a lot of studies regarding this issue, and this remains to be a hot topic. Most studies point out that caffeine *protect* against insulin resistance, and actually increases sensitivity. That's positive for us coffee drinkers ;)

    However, there have been some conflicting results found, indicating that caffeine is actually bad. Most of these studies focus on specific conditions, such as pregnancy, where caffeine is associated with increased insulin resistance. Or, they analyse specific tissues, and find impaired insulin signaling.

    Overall, if I had to make an educated guess, I would argue that caffeine is not bad for you. The conflicting results indicate we do not fully understand how it acts on our metabolism. As long as the scientists are quarrelling about it, I'm happily drinking my coffee.