Sugar: it's not just adding inches - it's aging you

Dr Hannah Sweilam

We all know smoking, pollution and too much sun exposure ages you, but now there’s another culprit to add to the list; according to research, sugar causes wrinkles too. Dr Hannah Sweilam.

It’s hard to avoid, and lets face it, it tastes good. But every time you devour a sugary treat or a giant bowl of pasta, it’s doing you harm. It’s not just adding inches to your waitline, raising your blood sugar levels and increasing inflammation around your body, it’s also affecting your skin. Sugar damages collagen, a protein in skin which gives it its firmness, suppleness and elasticity.  The word ‘collagen’ is derived from the Greek ‘kolla’ meaning glue: it gives skin its strength and structure.  Sugar damages this protein by a process called ‘glycation’.

What is Glycation?

Bear with me while we get some science out of the way. Glycation happens when a sugar molecule binds to a protein, in this case, a collagen fibre.  The newly created sugar-collagen hybrid then sticks itself irreversibly to a second collagen fibre, forming what’s known as an ‘advanced glycation end product’ (or ‘AGE’). The result is an AGE comprised of two cross-linked collagen fibres and the process is repeated multiple times across our skin cells.

What effects do AGEs have on skin?

First, this cross-linking of collagen fibres damages their structure. The collagen becomes stiff and malformed which shows up as wrinkles, sagginess and loss of radiance.  The cross-linked collagen can’t repair itself and builds-up in the skin over time.

Second, the process of glycation and AGEs themselves produce free radicals.  Free radicals are highly unstable molecules which bombard and react with other molecules, causing inflammation, and further damage and loss of skin structure.

In addition to distorting collagen fibres and producing free radicals, AGEs also target fibroblasts which are cells in skin that produce collagen.  AGEs have been shown to reduce the ability of fibroblasts to grow and renew, impeding their ability to produce collagen, and in some casesthey can destroy fibroblasts altogether.

The result is that AGEs hinder the formation of new collagen, accelerating the rate at which skin becomes thinner, drier, and less elastic.

And if that weren’t enough, AGEs also appear to render skin more vulnerable to the damaging effects of UV light and smoking.  The mechanism of this is not fully understood though it appears to be related to the tendency of AGEs to produce free radicals.

When you put all of this together it’s easy to see how  lifestyle choices can have a significant effect on the skin.


But it’s not just skin

Like collagen, proteins are present throughout our body and so it’s not surprising that the effects of glycation and AGEs extend beyond our skin.

AGEs were first identified in people with diabetes, where they are formed in excess due to high blood sugar levels.  Researchers began to understand that AGEs contribute to the complications of diabetes including heart disease, kidney failure, Alzheimer’s, and loss of vision (macular degeneration). These complications mirror the diseases that occur more generally in old age and evidence supports the idea that a build-up of AGEs in organs over time contributes to the multisystem decline that occurs as we grow older.

AGEs cross-link proteins throughout the body, increasing the stiffness of tissues such as the major arteries and heart, and accumulating in organs including the brain.  The harmful effects of AGEs on various organs have been demonstrated in animal studies and research suggests that lower levels of AGEs are associated with healthier ageing and greater longevity.


What can you do?

You can’t avoid this process completely but glycation can be reduced by avoiding sugary foods. This includes simple carbohydrates such as white bread and pasta, which are quickly converted into sugar in the body.

Should you cut carbs altogether?

No. Although all carbohydrates are converted into sugar, some dietary carbohydrate is necessary for our cells to function normally. But you can swap the simple ones for complex carbohydrates, such as brown rice and vegetables. Complex carbohydrates are converted into less sugar, and are converted more slowly, which helps control blood sugar levels and limit bursts of glycation activity.



Other low-glycaemic foods, that is foods that release less sugar and do it slowly, include beans, nuts and grains.  Incorporating protein, such as chicken, into a meal can also help to slow down the rate at which sugar is released, and adding foods that are rich in antioxidants, such as berries, help clear damaging free radicals from the body.

As we cook food, sugars and protein in food react to form AGEs. It is becoming increasingly evident that food-derived AGEs contribute to AGE levels in our body.  Steamed and boiled food contains smaller amounts of AGEs than fried food, or food that has been browned or caramelised.


The race to find an ‘AGE eliminator’

The prevention of AGE accumulation is a hot field for research.  Substances able to affect formation of AGEs, or break already formed AGEs, have been identified and some are being tested in clinical trials.  Time will tell whether any of these substances are effective in humans and tolerable in terms of any side-effects.  Meanwhile, if we want to slow down the skin ageing process and promote greater longevity, a healthy diet and lifestyle remain key.


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Does Accumulation of Advanced Glycation End Products Contribute to the Aging Phenotype?; J Gerontol A Biol Sci Med Sci. 2010 Sep; 65A(9): 963–975

Generation of active oxygen species from advanced glycation end-products (AGE) under ultraviolet light A (UVA) irradiation; Biochem Biophys Res Commun. 1997 Jun 18;235(2):306-10

Dietary Advanced Glycation End Products and Their Role in Health and Disease; Adv Nutr July 2015 Adv Nutr vol. 6: 461-473, 2015

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