Sweeteners Hiding Behind GRAS

Historically, sweetening agents in foods and drinks have been Generally Regarded As Safe, coming under the acronym of GRAS.

Now, this is not necessarily the case and sweeteners can be classed as an additive. But it seems there remains a bias towards a need to ‘prove’ harm, rather than to err on the side of caution and establish safety.

Since the 1980s a sweetener to continually come under question (which does not equate to rigorous testing) is aspartame, the active ingredient of which is the amino acid/neurotransmitter phenylalanine (phe) – never normally found isolated from protein (i.phe).

There are very good reasons why the use of i.phe has come under academic scrutiny:

• We know from study of the inherited metabolic condition phenylketonuria (PKU) that high levels of phe in the blood can lead to excess crossing the blood/brain barrier and causing severe neurological damage (especially in the developing brain of a foetus or child but also to some extent in an adult).
• Since the 1950s we have learned, and continue to learn more of the mechanisms involved, including something of the role of gut microbiota and the negative effects of i.phe.
• In non-PKU persons excesses are controlled, in large part, by production and release of enzymes that convert, in the liver, phe to a different amino acid. Importantly, the mechanisms have not yet been fully elucidated.
• The gaps in our knowledge are particularly important regarding i.phe as opposed to phe as part of protein. Because …
• We have no evidence that i.phe will trigger the safety mechanisms in play from protein-phe intake for non-PKU persons.
• Key is the fact that because of the possibility of irreversible brain damage it, obviously, would be unethical to carry out the type of testing required to provide ‘evidence of harm’.

The above points are at the centre of objections to the UK’s policy of 2016 to promote diet drinks, the replacement of sugar with sweeteners, as a healthy option; with a stated plan to extend the same principle to many other products that are popular with children. (There are additional flaws in the 2016 policy and its promotion but the focus here is on sweeteners.)

Sweeteners that use i.phe include aspartame, neotame, and advantame, but I am not familiar with the full list of trade names they may come under.

To end on a positive note, at least for those within the PKU community. Not in any way to underestimate the great difficulties in following the therapeutic diet low in phenylalanine, they do have the advantage of receiving professional, individual dietetic guidance and support. And, I note with pleasure the number of those with PKU who have followed the therapeutic treatment from birth and are now adults, qualified in various spheres, and who have chosen to be advocates for the PKU community on an international stage.

29th May 2024