Aspartame is an artificial sweetener that is almost 200 times sweeter than sugar. 

It is a protein and as such is not calorie free, it contains 4 calories per gram. However it is so sweet that only a tiny amount is needed and consequently any typical serving will contain approx zero calories.

It has a quite a good flavor with little aftertaste. However it breaks down under heat and so is not suitable for cooking. It has virtually replaced saccharin as the main sweetener used in soft drinks etc.

It has provoked considerable controversy, with many people complaining about side effects, including dizziness, blurred vision and headaches. Yet despite this millions use it every day with no obvious short term side effects. But longer term side effects may be an issue. We will explore this further.

It is used a sweetener in sodas, cookies, chewing gum and just about any diet product. It is also used as a table top sweetener. It is not heat stable and so is not suitable for cooking. It also has a rather poor shelf life, particularly in warm temperatures, causing it to break down into it's component part, reducing the sweetness of the product. Cans of soda stored in warm locations can deteriorate quickly.

It has zero calories per serving and zero glycemic index. This makes it suitable as part of a diabetic diet. It also has a taste very close to sugar particularly if mixed with Acesulfame K. This seems to be it's biggest advantage, and why it is so widely used, despite generating more complaints to the FDA regarding side effects than any other food additive.

As a chemical salt, combined with Acesulfame K, it is particularly useful for manufacturers of chewing gum, as it gives a duration of sweetness way in excess of any other substance, natural or artificial. 

Just type aspartame into google and see what comes up on the first page of results! Clearly many people are concerned about this product, and this alone will almost certainly see it being phased out over the next few years as better sweeteners arrive on the market.

Some tests seem to have shown it to be safe, though critics question the thoroughness and funding of the testing procedures. In addition a by-product of the metabolism of aspartame is phenoanalyne and people with a genetic disorder called phenylketonuria (PKU) are unable to metabolize it. Consequently all products that contain it must carry a warning on the label. 

A report to the FDA summarized a listing of the adverse health effects which were found in a survey of 551 persons. It also states that pilots are particularly susceptible to the effects.

Video by Mercola:

Safety Guideline:
The FDA has issued a guideline ADI of 50mg of this substance per kg of body weight. For the average person this would be equivalent to about 37 cans of soda sweetened with it.

CSPI (US) Recommendation

The recommendation issued by the Center for Science in the Public Interest (US) for this substance is - AVOID

Unlike all other artificial sweeteners Aspartame is fully metabolized by the body during digestion. It is broken in 3 parts: Aspartic Acid 40%, Phenylalanine 50% and Methanol 10%. It is the last two that are particularly of interest. There are three types of Phenylalanine, all have an effect on the brain and nervous system, and at high doses are toxic.

The human body can tolerate only small doses of methanol, such as may exist naturally in fruit. It is certainly not beneficial!

Weight Loss:
Although artificial sweeteners contain zero calories, they do not always appear to be effective against obesity and diabetes. Statistical and clinical tests have repeatedly shown this to be so, though, until now the reason has been a mystery. However a new trial, conducted at the Weizmann Institute of Science in Rehovot, Israel and published Sept 17th 2014, sheds more light on the situation. It appears that these sweeteners affect the bacteria in the bowel in adverse ways. Tests showed impaired glucose metabolism in subjects, human and animal following moderate consumption over several weeks. 

More information is available in Science News. While further testing is needed, including natural zero calorie sweeteners, the results are indeed worrying. Perhaps these sweeteners have no role at all to play in weight loss and may be a poorer choice than regular sugar! Watch this space! 

It is an artificial product manufactured in a chemical process.

Sold As:
Sold as NutraSweet, Equal, Canderel, AminoSweet, NatraTaste. It is usually in the little Blue Packets next to the sugar bowl.

How Expensive?
On the world market it is one of the cheapest sweeteners available, costing about 8% the price of sugar for the same unit of sweetness. The patent expired in 1992 so it is now a commodity product with many factories in China producing it at a very low cost.

Aspartame Market Share:
In 2012 it  sold approx 4.3 million tonnes equivalent out of a total world market of approx 188 million tonnes. (Sugar was about 155 million tonnes) This would give it about 2.28% of the total market by unit of sweetness. By value it would be significantly less.

Interesting facts:
It was discovered by accident in 1965 by a Chemist employed by Searle while working on an anti ulcer drug. It would be a further 30 years before it received FDA approval for use in all foods. It is often used with acesulfame-K as the two sweeteners seem to compliment each other.

Pepsi have recently announced that they will discontinue the use of aspartame in their diet product due to customer concern. Having experienced 5% fall in sales in 2014 the decision has been made to reformulate the product with a combination of acesulfame K and sucralose. They say the taste is the same but the 'mouthfeel' slightly different. It will be interesting to see if this reverses the fall in sales. If it does, we can expect other manufacturers to follow.

Approved for use in all foods in the USA in 1996. Must carry a warning that it contains phenylalanine. Gained EU approval in 1994 as E951.


Conclusions for Aspartame

One of most common artificial sweeteners in use today, though its star is on the wane. Is useful for diabetics and it is harmless to teeth.

However, many concerns have been raised and side effects reported. It is the single biggest source of complaints to the FDA, no other product or drug comes close. Best advice would be to avoid if possible or at least to limit consumption. If no side effects are experienced it would still be well to avoid excessive amounts. New and better sweeteners are on the way!

Some critics of this product even claim that it does not help to reduce weight. However it does help reduce calorie consumption and so is very likely to assist in weight loss as part of a controlled diet - but at what cost?

Name Calories / Gram Sweetness Index Glycemic Index Calories / Spoon-Equiv
Aspartame 4 200 0 0

Taste: -------- Good
Aftertaste: ---- No
Concerns: ----- Yes

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