Do Sweeteners Cause Cancer?

Sweeteners. A controversial topic to say the least.

Many take a hard line with sweeteners saying they can cause serious health risks like cancer.

Others say sweeteners can be a great use to take control of your weight without any adverse risks at all.

So who's right and who's wrong?

Lets first take a look at the evolution of sweetness and why we are so obsessed with the power of sweet sweet goodness…

The History Of Sweet

Rewind the clock to early hunter gather days and the first known use of sweetness came in the form of honey. 

Although not widely available around the world at the time, honey was a prime source of energy for a number Congo tribes for 2-3 months in the year, accounting for 80% of their daily calorie intake.

Fast forward and we moved onto another source, maple syrup.

This was introduced to native Americans, eventually becoming widely used throughout North America.

A century or two later and sugar cane was harvested and used throughout India of which it is still widely popular today all over the world.

In the turn of the 17th century, table sugar surpassed all of these other traditional products and became the leader in sweeteners all over the world. (1)

By 2012, the average Westerner was consuming approximately 24.7 teaspoons a day, a staggering 16% of their daily calories of which can mostly be associated to drinks and not solid food. (2)

As times have changed over the centuries, so have our attitudes to sweetness. Hunter-gatherers looked at foods like honey as a great way to get in dense amounts of energy without sickness. 

Fast-forward to today and sweetness is much more about satisfaction than survival.

This leads to the question, are natural sweeteners better than artificial?

Let's take a look at the most common natural sweeteners first…


Honey in its raw and pure form is essentially 38% fructose, 31% glucose and the rest primarily water.

Honey also contains a wide range of enzymes, trace minerals and other beneficial properties to the body.

When we look at honey, it's easy to think that it's just like table sugar and our intake should be kept to a minimum right? 

Well, the research actually points to some surprising benefits to honey intake.

First and foremost, two human studies show supplementing 3-5 tablespoons of honey a day for a month lowered LDL cholesterol, triglycerides, c-reactive protein & higher levels of HDL cholesterol. (3, 4)

Honey is also shown to have antibacterial properties and can shorten the duration of acute bacterial diarrhoea in children (5).

When choosing a honey, stick to raw which has not been exposed to heat or adulterated by other sweeteners.


Stevia has had its fair share of headlines over the years and rightly so. 

Many health advocates of a 'natural' diet sing the graces of stevia on a daily basis whilst others in the medical community caution against it. 

So whats the deal?

Given stevia has zero calories, many do tend to talk a lot about the insulin response caused in the body and what effects that may have. We will cover that shortly.

The studies done on stevia are vast in number and for the most part positive.

Stevia has been used as a traditional treatment for Diabetes for many years now with some positive results. (6)

In one study (7), participants were given a dose of sucrose (sugar) or Stevia before lunch. The results showed stevia lowered blood sugar after a meal and in turn lowered the insulin load.  

The study also tracked if the participants tended too over consume to make the calories back later in the day of which they DID NOT.

Another smaller study (8) showed that with 16 volunteers taking 5g doses of stevia every 6 hours for 3 days, improved glucose tolerance.

There has been talk in the past about stevia’s relationship with infertility, but at this stage, the research seems mixed.

Based on the evidence so far, it would seem stevia may be a great option for those that have blood sugar control issues and are looking to reduce their weight.

What About Artificial Sweeteners?

If there was ever a dividing topic in the health sector, artificial sweeteners are it!

With talk of sweeteners leading to cancer, let's dive into the literature and see what it has to say.

Artificial sweeteners were first talked about along side of cancer in 1970 when a very early type of sweetener (saccharin & cyclamate) caused bladder cancer in rats. (9, 10)

We later learnt that the condition of cancer was specific to the rats of which doses of vitamin C also caused the same outcome. 

Further studies later demonstrated that neither of the sweeteners were carcinogenic.

This particular study changed the way the media looked at sweeteners.

Another study done years later suggested links between aspartame and brain tumours. (11)

This study was based on the facts that aspartame consumption had increased along with brain cancer in humans despite not knowing if those with brain tumours had ever consumed the sweetener. (12)

Since then, the study has been dismissed by further research finding no correlation between aspartame and brain tumours. (13)

Although a lot of the research done so far doesn't seem to paint artificial sweeteners in bad light, caution is till advised.

Over recent years, artificial sweeteners have been tied to metabolic syndrome and related diseases like diabetes and cardiovascular disease. (14,15,16)

But again, for every study that comes out to show correlation, there's another that comes out finding no association.

It's clear that given there is no clinical evidence in humans to test a lot of these hypotheses, the effects of artificial sweeteners in relation to risk of disease remains inconclusive.

When it comes to weight loss, there have been positive associations that those with higher intakes of sweeteners do tend to be more overweight, but this is more than likely down to reverse-causality. (17,18)

In other words, those that tend to drink diet drinks or sweetened foods are consuming them in order to lose weight in the first place.

Based on the evidence so far, it's seem that artificial sweeteners may have their place in a weight loss diet over the short term. Due to the limited nature of studies, I wouldn't go banking on it.

Do artificial sweeteners confuse the body?

This point is always an interesting topic of discussion amongst the health world.

If our sweet taste receptors have evolved to tell us how to identify calorie rich sources, how would our body respond when our taste buds are bombarded with sweetness but no calorie surge?

Unfortunately this area is lacking in human trials, but some animal trials may tell us the answer.

Rats who are fed with artificial sweeteners consistently gain more weight than rats who are fed with sugar (glucose or sucrose). (19,20)

Also, the rats don't tend to lose the excess weight, even after the trials are switched back to glucose or sucrose to re-establish the calorie-predictive nature of sweet taste.

Interestingly, rats who were given a stevia solution gained significantly more weight than glucose fed rats. (21).

Rats fed with sweeteners also had impaired ability to respond to sugar containing foods. 

In one study, rats who had been fed artificial sweeteners were unable to compensate for calorie content of a sugar preload by eating less food afterwards, while rats who had been fed sugar containing food compensated almost perfectly for the extra calories in the preload by eating less food. (22)

Although animal evidence is fairly robust, human evidence is limited. 

In one particular human study looking at an MRI to measure brain responses to sucrose solutions indicate that artificial sweeteners may alter the brains response to sweet tastes in humans. (23)

People who regularly consume artificially sweetened drinks had higher reward responses to both saccharin and sucrose compared with people who didn't consume artificial sweeteners.

In conclusion

Although it may seem that artificial sweeteners are not as scary as the media makes out, I don't believe they have a place in a healthy diet.

Newer studies do tend to suggest detrimental effects to gut health (thats for another blog), and with human trails still limited, it's best to limit artificial sweeteners where possible.

If you’re looking for a bit of sweetness, stick to quality raw honey and remember, moderation is the key.

#sweeteners #artificialsweeteners #sugar

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