With our bodies frequently coming into contact with an endless variety of natural and synthetic chemicals, it is sometimes hard to tell which ones are friends and which ones are foes.

There are horror stories about everyday chemicals that are enough to make you swear off some of your favourite things altogether. But can these stories be supported by science?

Today, we’re looking at the chemistry behind the 5 most notorious everyday chemicals and whether they actually live up to their bad reputations.

  • Aspartame: Is it Sugarcoating the Truth?

Aspartame is an artificial sweetener with a bad name. Commonly used in fizzy drinks, it is 200 times sweeter than sugar. With headlines labelling it one of the most dangerous substances on the market, it is no wonder why health junkies worldwide are avoiding this wolf in sheep’s clothing.

In fact, it has been so widely criticised by the public that the FDA have conducted over 500 studies on this chemical; and in 2015, Pepsi removed it from one of their drinks.

The story goes that aspartame causes cancer, seizures, brain damage, neurotoxicity and a range of other horrors we don’t want anything to do with. This fear comes from the fact that aspartame breaks down in the body to form aspartic acid, phenylalanine and methanol.

While the breakdown products of this sweetener certainly sound dangerous, they pose no threat to your health when produced by aspartame.

  • Aspartic Acid

Aspartic acid has been said to inflict brain and nerve cell damage by over-stimulating glutamate production, leading to a condition known as excitotoxicity.

However, aspartic acid is one of the most common amino acids produced by a normal diet and we consume this chemical every day in the form of dairy products, meat, nuts and fish. These foods all contain a much higher dose of aspartic acid than aspartame does.

  • Methanol

Methanol is a very toxic chemical that should never be consumed in its pure form. The minimum lethal dose of methanol is 1 gram per kilogram of bodyweight.

Only 10% of aspartame is actually converted into methanol. This is the equivalent of 55 mg (0.055g) of methanol per litre. This may sound scary, but it is actually less than red wine (99-271 mg per litre) or even tomato juice (218 mg per litre).

  • Phenylalanine

Phenylalanine in aspartame is actually the only real cause for concern – but only for those who suffer from phenylketonuria, a condition where the body cannot break down phenylalanine.

Those who suffer from phenylketonuria should avoid phenylalanine-containing foods altogether, like dairy products, chicken, eggs and beans, to name a few. However, if you do not have this condition, then you are at no risk.

To round this off, drinking the occasional fizzy drink isn’t enough for aspartame to cause any negative health effects. In fact, you would have to drink over 32 cans of soda every day before this chemical would pose any threat.

“But aspartame isn’t the only dangerous chemical in fizzy drinks,” the public exclaim. “What about BPA?” Well, that is actually number 2 on our list.

  • Bisphenol-A (BPA): The Not-So-Silver Lining?

Sometimes with food and drink, it is the packaging you’ve got to be wary of. Nowadays, you will see an emergence of soda cans and plastic bottles that claim to be BPA free. But what does that mean for your health?

BPA is an organic synthetic compound used in the linings of soda cans, food cans and plastic bottles. It has a notorious reputation because of its ability to interfere with hormones, leading to the assumption that drinking a can of soda, for example, could have severe effects on fertility and overall health development.

However, while there are certainly many scary facts about this chemical, the reality is you would have to drink 8,000 cans of soda per day before BPA has any toxic effect on your health.

This is because the exposure limit of BPA is nearly impossible to reach given of the amount of it that is actually present in can linings (4.5 parts per trillion).

  • Propylene Glycol: What Food and Antifreeze Have in Common

This chemical is used in pharmaceuticals, food preservatives and antifreeze solutions. It is also “recognised as safe” by the FDA. So what is the problem with propylene glycol?

The controversy comes from the fact that people are wary that a chemical used in antifreeze is also used in food. However, the propylene glycol used in the food industry is a completely different grade to the one used in antifreeze, which is extremely high purity.

As well as this, propylene glycol is actually used in antifreeze to create a non-toxic alternative to the typical formulations that contain ethylene glycol, an extremely toxic chemical that has caused infant and pet death following the accidental consumption of spilt antifreeze.

Propylene glycol based antifreeze, on the other hand, is not toxic and safeguards against this risk. When used in food products, this chemical is harmless and even has an E-Number (E1520).

  • Oxybenzone: The Chemical in Your Sunscreen

Oxybenzone is one of the most prolific and notorious ingredients in chemical absorber sunscreens. These are the types of sunscreens that disappear into the skin instead of leaving a white, greasy smear on top.

This chemical is used in sunscreen as a penetration enhancer, helping the skin to absorb other chemicals quickly. Oxybenzone is widely criticised as being:

  • A contact allergen, provoking things like eczema
  • An endocrine disruptor by mimicking, blocking and altering hormones

However, the health effects caused by oxybenzone in sunscreen have been widely debated because the concentration is not high enough to do any severe damage. This is because, while oxybenzone is a penetration enhancer, the chemicals inside sunscreen do not penetrate the skin deep enough to cause significant toxicity.

However, different skin types may react differently to certain chemicals. Just because oxybenzone-containing sunscreens do not harm one person, that doesn’t mean they will be suitable for everyone. It is always important to do your research beforehand and to be aware of your skin type.

  • Caffeine: A Psychoactive Drug

With 1.6 billion cups of coffee being consumed everyday around the world, caffeine is the most widely used psychoactive drug on the planet.

While many people are quick to point out the evils of artificial sweeteners or the toxicity of sunscreens, they seldom think about the chemical cocktail swirling inside their everyday Cup of Joe.

Some facts about caffeine include:

  • An average cup of coffee contains up 200mg of caffeine
  • Caffeine works by tricking adenosine receptors in the brain
  • Adenosine is a neurotransmitter that promotes sleep
  • Adenosine receptors mistake caffeine for adenosine
  • This uptake speeds up nerve cell activity instead of slowing it down
  • This increases neuron firing and adrenaline production
  • Caffeine appears in over 600 drinks, including berocca
  • Caffeine has the same effect on the brain as cocaine and heroin

While there are many apparent health benefits associated with caffeine, there are also many negative health effects that are a) more substantiated than other health problems mentioned on this list, and b) require a much lower dosage, making them more likely to be experienced:

  • A high intake of 500-600mg of caffeine per day, the equivalent of five or six cups of coffee, has been linked to insomnia, irritability, stomach problems, a fast heart rate and even muscle spasms
  • A moderate intake of 300mg of caffeine per day whilst pregnant has also been shown to increase the risk of low birth weights in babies

Let’s not also forget that caffeine is a psychoactive, and very addictive drug. This is because it is able to activate the reward system in the brain. This is the area that make us feel good and rewarded when we do something with an evolutionary benefit – like eating.

Drugs like cocaine, amphetamines, heroin and, you guessed it, caffeine can hijack this area of the brain. This can cause addiction by forcing us to associate rewarding feelings of wellbeing with that specific drug.

These feelings lead to a small percentage of people developing a caffeine addiction. But where there is an addiction, withdrawal swiftly follows; and caffeine withdrawal, like many drugs, triggers a variety of symptoms and health problems, including:

  • Headaches
  • Fatigue
  • Depression
  • Lack of concentration
  • Nausea
  • Vomiting

Caffeine also has the potential to drastically affect our sleep, which we know plays a crucial role in learning, memory and consolidating information. Therefore, it is considered dangerous for children or teenagers to consume high amounts of caffeine because it could impede their brain development.

With all of this in mind, caffeine poses a much more feasible danger than any other chemical on this list. But does this mean you now have to swear off your morning cup of coffee? No!

The Bottom Line

Our bodies are amazing. We come into contact with millions of harmless and harmful chemicals every single day, and the body has an evolved and complex defence system ready to deploy the militia and fight them off.

No matter what we do, we will always consume chemicals that have bad reputations. But as long you’re not surpassing normal dietary levels, whether that’s drinking under 8,000 cans of soda a day or just scaling back your coffee intake to 3 cups instead of 5, you can still consume your favourite things whilst staying healthy – everything in moderation, right?