Sugar

Every living organism needs sugar, one way or another. Most plants produce glucose (C₆H₁₂O₆) through photosynthesis, and plants that don't photosynthesise (holoparasites) get their sugars through parasitic means. Animals require glucose for respiration, and this is as it's the main source of energy for cells. But there's obviously more to sugars than just glucose.  

It's easy to identify if a substance is a sugar or not - it has the suffix "ose". Contrary to what I believed, this doesn't designate any functional groups. Beyond that, names can be oblique and don't reveal much. Take lactose (C₁₁H₂₂O₁₂), which doesn't have a name indicating any number of carbon atoms or its shape, but rather the fact that it only forms naturally in breast milk - lactis in Latin means milk. And of course, sugars will have various names depending on the context - glucose is synonymous to dextrose, which is like but not exactly glucose. Along with this, all sugars are very soluble (due to them containing weak intermolecular forces), which explains why they're often used as sweeteners.

 

Every sugar is a saccharide, and can take up different forms - if it's a monomer, it's a monosaccharide (like glucose), and if two monosaccharides are linked, it's a disaccharide (such as sucrose, which consists of glucose and fructose bonded together). These are considered simple sugars. There aren't seemingly any strict general formulae surrounding these - many monosaccharides follow the general formula C_n(H₂O)_2n, but not all - deoxy sugars replace a hydroxyl group with a hydrogen atom (like deoxyribose, found in DNA), and amino sugars have a hydroxyl group replaced with an amine group.

If multiple monosaccharides are linked together as a lengthy polymer, it may be considered a polysaccharide, with examples including starch (found in countless food products) and glycogen (which is how sugars are stored in the body). Should only a few monosaccharides (usually up to ten) be linked to each other, it's defined as an oligosaccharide. Both of these aren't formally considered sugars, as sugars are generally considered sweet, and starch for instance isn't. Instead, all four come under the carbohydrate umbrella term, which simply denotes compounds containing carbon, hydrogen and oxygen atoms.

 

Simple sugars are commonly found naturally - fructose, for instance, naturally occurs in fruits, whereas sucrose is produced in plants such as sugar cane and is the main component of white sugar. They are easy for the body to metabolise, since they have such simple structures, so therefore can lead to an increase in blood sugar levels, as energy is released in the process. Most people's blood sugar levels naturally vary over time, usually changing in a cycle as hormones like insulin and glucagon are secreted, thus altering how much sugar is found in the bloodstream and in cells for respiration.

 

However, people with either Type 1 or Type 2 diabetes have problems with insulin, either as not enough is secreted by the pancreas (in the case of Type 2) or the insulin isn't effective (in the case of Type 1) - and in the case of conditions like diabetes, sugar intake is recommended to be moderated. NHS article on diabetes here.

 

That's where another form of sugars, known as sugar alcohols, could come in. These consist of a sugar which is bonded to a hydroxyl group. These are commonly used as sugar substitutes in food production, since they're incompletely absorbed in the small intestine, so therefore result in a lower increase in blood sugar, and have thus been suggested as an alternative sugar source for diabetics. As well as this, studies which took place in 1969 claimed that sugar alcohols like xylitol reduced the growth of dental plaque compared to sucrose, though this alone shouldn't be used to claim sugar alcohols are better than sugars at reducing plaque. Whether sugar alcohols are healthier or not is still up to debate.

 

It's easy to focus on how sugar is used in food, and indeed it's all over the place - from fruit to pasta to honey to cakes, it's a fundamental part of all our diets. However, sugar's also everywhere in industry - about 185 million tonnes are produced globally each year.

Take the polysaccharide cellulose - it can be found in large quantities in wood and cotton, so technically there's sugar in lots of clothes, paper and furniture. It's also the most abundant organic compound, so unsurprisingly the industry is massive, and is expected to accelerate in growth in the future. This is partially as it becomes a popular substitute for plastic, as it is more biodegradeable and not sourced from fossil fuels. Unsurprisingly, this also means that a growing industry may also exacerbate the damage the industry is doing to the environment, such as through increased deforestation and any resultant industrial waste (point 2) produced. 

 

As time goes on, more studies suggest the effects of sugar are more sour than we'd hope they'd be. Possible health issues from overconsumption of sugar include high blood pressure and obesity, and governments continue to pass bills on sugar taxes and limiting how much can be added in soft drinks (to the anger of consumers). Chemically, though, sugar will remain as sweet as it's always been.

Ending a blogpost on a pun - that always goes down well.