Sunday, 26 October 2008

Sugar, Sugars and Sweeteners - Spotlight on Aspartame

Summary
Alternative Names
Chemistry and Origins
Classification
Regulation
Where it can be Found
Taste, Calories and Digestion
Health Implications and Safety
My Opinion


How could you resist putting something this cool on your food?
As part of the Definitive Guide to Sugar, Sugars and Sweeteners, each month I will try to cover one in detail so that eventually the guide becomes a one-stop shop for all you ever wanted to know...
Summary
Aspartame is an artificial sweetener with negligible calories used widely to sweeten food or drink marketed as low calorie or sugar free. Studies have linked aspartame to a number of health problems, but none have been compelling enough persuade regulators to restrict its use and it remains a legal additive in the US, Europe and probably worldwide.
Alternative Names
Tropicana Slim, Equal, NutraSweet, Canderel, E951
Chemistry and Origins
It was stumbled upon in 1965 by James Schlatter, a chemist working for a pharmaceutical company, who created it while researching drugs to treat ulcers. When he licked his finger, which had accidentally come into contact with aspartame, he noticed the sweet taste.

Aspartame is a dipeptide, which means it is a molecule made up of two amino acids joined by a single peptide bond. The two amino acids are aspartic acid and phenylalanine. In fact strictly speaking, it is a methyl ester of the dipepetide of these two amino acids and as such has the full name aspartyl-phenylalanine-1-methyl ester. Still awake?
Classification
Aspartame is a non-saccharide sweetener - this means non-carbohydrate and differentiates it from other sweeteners like sucrose and glucose. It is also classified as artificial and non-nutritive.

A question for the chemists amongst you: are sugar alcohols disaccharides, strictly speaking? I know they are hydrogenated disccharides, but does that still qualify them as a disaccharides? I am looking for a simple term that differentiates nutritive sweeteners like glucose and sorbitol from others. Answers in the comments please!
Regulation
Between 1980 and 1996 applications to the FDA for aspartame's use in food and drink in the US were variously turned down, re-stated and eventually granted for all food and drink amid questions about the validity of study data and its availability to a board of enquiry set up to consider its safety. Interestingly, Donald Rumsfeld was involved at one point in the 80s. It is not clear whether at the time he regarded the eventual approval of aspartame's use as a known unknown, unknown unknown, or a dead cert because he'd backhanded the Reagan-appointed FDA commissioner. Just kidding Don, please don't sue me ;-)

Meanwhile, a number of European countries approved it in the 1980s, and in 1994 it was granted EU-wide approval.
Where it Can be Found
Aspartame is not found naturally, but is added as an ingredient to thousands of foods and drinks, as well as being marketed as a sweetener under a number of trade names. It is also used to sweeten chewing gum and pharmaceutical products like cough syrup. It is apparently also used like sugar as a condiment in some countries. Typically it used as a way to sweeten foods that are marketed as being sugar free, low calorie or good for people who need to watch their blood sugar levels.
Taste, Calories and Digestion
Aspartame is roughly 200 times sweeter than sucrose and is fully digested by the body. It has roughly 4 calories per gram but because so little of it is needed to create a sweet taste it can be regarded as having negligible calories.

Although it has a sweet taste, Aspartame is often blended with other sweeteners such as acesulfame potassium since these combinations are seen as creating a more authentic sugar substitute.
Health Implications and Safety
Few food ingredients have undergone the scrutiny aspartame has been subjected to. It has been studied for decades and controversy continues to rage over its safety.

Theories about the Effects of its By-Products
Aspartame is broken down into a number of substances when digested - these are methanol, formaldehyde, formic acid, phenylalanine and aspartic acid. In addition, a substance called aspartylphenylalanine diketopiperazine is created when aspartame breaks over time in carbonated drinks, so this joins the list of substances to consider.

There is some concern around all these chemicals. For example - methanol from aspartame digestion is believed by some scientists to be safe because it is not harmful in small amounts and is in any case already part of the human metabolism process and can be found naturally in fruit juices. On the other hand, other scientists believe we are protected from the naturally occurring methanol by other substances in fruit juice not found in aspartame and that chronic poisoning from aspartame is possible.

However, this and theories around the dangers of the other substances listed are largely theoretical and although there is research to support some of them, nothing concrete has emerged.

The single issue about which there appears to be universal agreement is the dangers of phenylalanine to a small number of people. It is considered unsafe for those born with phenylketonuria, a rare genetic condition. Sufferers are not able to metabolise phenylalanine and its accumulation can lead to problems with brain development. Phenylketonuria affects only one out of several thousand people, but this number which varies significantly between countries - Finland, for example, appears to have a very low incidence of around 1 in 100,000.

Reported Symptoms
In 1995 this US Department of Health and Human Services document was submitted to the FDA listing 92 symptoms it had received reports about from consumers. Whilst this anecdotal evidence will be regarded largely meaningless from a scientific perspective, it nevertheless gives an idea of the range of problems aspartame consumption may cause.

Evidence of Harm
Scientific studies have tended to focus on the long term effects of consumption, in particular looking at the possibility of an increased risk of cancer. These have been both epidemiological studies of humans and controlled studies with rats.

Some of the studies have been claimed to prove a link, others have been claimed to show no link. In most cases, there have been methodological concerns or suggestions of potential conflicts of interest that have made impossible any definitive conclusion about the safety or otherwise of aspartame.

For example, a 2005 study that fed aspartame to rats for seven years (conducted by the European Ramazzini Foundation for cancer research in Italy) found a statistically significant increase of malignant tumors of peripheral nerves in male rats and of lymphomas-leukemias and malignant tumors of the kidneys in female rats. There were 1800 rats involved in the study. The European Food Safety Authority questioned the validity of the results, as did the American Food & Drug Administration. The Foundation issued a rebuttal. Later, questions about conflicts of interest for the EFSA Executive Director were raised. The ERF did another study in 2007 which they said confirmed their original results. So far, a New Zealand health authority cast doubt on the results.

For whatever reason, the research to date has not convinced regulatory bodies anywhere in the world to restrict the use of aspartame beyond recommendations about daily intake.

ADI (Acceptable Daily Intake)
America's FDA has set the ADI for aspartame at 50 mg/kg of body weight/day. In contrast, the European Commission’s Scientific Committee on Food (SCF) has set it at 40. It is not clear how this is calculated, but it is described as a conservative estimate, based on the idea that this amount can be consumed daily over a person's lifetime. As a guide, an adult would need to consume 20 aspartame-sweetened 12oz carbonated soft drinks to reach their ADI.

Other Information
Aspartame does not promote tooth decay and its digestion does not significantly affect blood sugar levels.
My Opinion
There may be insufficient evidence to get aspartame banned, but it's hard to feel good about consuming it with this much controversy about its potential effects. Just reading how it breaks down in the body is enough to raise alarm bells. Sure, you could describe the digestion of any food in chemical-sounding terms - but the difference here is that aspartame does not occur in nature so it feels like the chances are low that our bodies are totally happy with the types and proportions of the chemicals aspartame introduces.

As for the ADI, it seems paradoxical that regulators can, amid a deluge of reported symptoms and disputed evidence, describe aspartame as safe, yet so precisely prescribe limits for its consumption.

If I had to consume food that had been sweetened and if I had to avoid higher-calorie sweeteners, I would be inclined to seek substances that are less removed from nature and not associated with so many health issues.

That said, I believe we should exercise caution about all sweeteners, particularly those recently introduced or discovered. Aspartame is in some ways the grandfather of sweeteners and we should not rule out the possibility that many of the newer sweeteners we are hearing about will in decades to come attract as much controversy once there has been enough time for them to be fully studied.

Summary
Alternative Names
Chemistry and Origins
Classification
Regulation
Where it can be Found
Taste, Calories and Digestion
Health Implications and Safety
My Opinion

See Also:
Sugar, Sugars and Sweeteners: The Definitive Guide

2 comments:

Carrie Tucker said...

Concentrated fruit juice is the only sweetener I trust, and then again, fresh fruit would be a better way to satisfy that sweet tooth, yes?

Sugar and salt seem to be American's favorite comfort food. Eat real food, and you won't need as much comforting. Get out there and live life to the fullest, that way real food tastes just right!

Methuselah said...

Caroline - agreed, fresh fruit is the best way. When we get to 'Spotlight on Fructose' we'll see why concentrated forms like fruit juice are not ideal. But still way better than aspartame (IMHO)!

By coincidence my next planned post is about comfort eating...

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