50 shocking facts about experts on TV…

Last night’s TV programme 50 Shocking Facts About Diet and Exercise presented poorly researched claims by a very mixed bunch of talking heads. Ironically, whilst the programme warned that 50% of personal trainers are not properly qualified (‘factoid’ number 16) it then went on wheel in ‘experts’, about half of whom were simply journalists or ‘nutritional therapists’ with flawed qualifications.

In this blog I examine the claims and evidence of two of the ‘experts’ appearing on the programme regarding artificial sweeteners.

Specifically two claims made by Stephanie Moore and Danni Levy.

First, I am unconvinced by Ms. Moore’s claims about aspartame (which she calls ‘aspartamine’) being a neurotoxic.

Second, I could not find any evidence for the throwaway remark by Danni Levy that drinks with artificial sweeteners cause insulin spikes. This is an important point to clear up: diabetics around the country should not take this ‘factoid’ seriously. (Even though there might – just might just be something in Danni’s statement that diet drinks make you fat…)

Let me explain…

Stephanie Moore – Nutritional Therapist

Stephanie Moore said:

“Artificial sweeteners are neurotoxic … the science will come out in the end, but it’s looking pretty bad from here”
(factoid #25)

Well at least Ms. Moore is being honest – she makes a statement, and then says that there is no scientific evidence for it! Which there isn’t.

Diploma in what?

Ms. Moore’s details displayed on the British Association for Nutritional Therapy (BANT) website claim that she has a Diploma in Nutritional Medicine from “Premier Training International”. When I checked the Premier Training International website they were only offering diplomas in Nutritional Therapy not Medicine. The Diploma is Nutritional Therapy is typically a home study course followed by a multiple choice exam. When I searched the Interweb I could find no-one else with a Diploma in Nutritional Medicine from “Premier Training International”. See here. Perhaps her claim of having a medical diploma is just a typo on the BANT website…

Degree from where?

Her business website claims a Bachelor’s degree nutritional medicine from Thames Valley University, which sounds reassuring, but some are not convinced of its value. Ben Goldacre simply states that Thames Valley University runs ‘degrees in quackery‘.

Ms. Moore appeared several times in the programme, and seemed to think that the most popular sweetener is called “aspartamine” – whoops! There is no such thing – it is “aspartame”.

The narrator, the professional and otherwise excellently entertaining Tracy-Ann Oberman, called it “aspartamane” – whoops again! Although she did slyly remark that there was some confusion in the name between the narrative text she was reading from and Ms. Moore’s ‘expert’ testimony.

And finally, the icing on the cake…

Stephanie is also a qualified life coach. (Be patient with that link – it takes 15 seconds for the video to start playing.)

Danni Levy – Fitness Writer, The Sun

One ‘factoid’ in the programme that seemed wrong to me was a throw-away remark from Danni Levy that fizzy diet-soda drinks with artificial sweeteners cause an insulin spike and this can lead you to eat more.

Now, I have some time for Danni because she not only has a very athletic body (which proves that she knows something about diet and exercise), and she also embraces the concept of regulating carbohydrates by reducing intake of high Glycemic Index foods – which is supported by good science (see the work of Professor Jennie Brand-Miller).

She also is not trying to blag any medical credentials.

But I don’t agree with Danni’s reasoning about diet drinks. Her logic goes like this:

1. Aspartame ingestion creates a substantive insulin response

2. That insulin response triggers a craving for carbohydrates

3. This craving then induces a greater subsequent calorie intake.

Professor Jennie Brand-Miller has told me that:

“This interpretation is controversial. If every insulin response were to make the body crave carbohydrate, then a high protein diet would stimulate enormous carbohydrate cravings and thereby defeat weight loss. In fact, we know that high protein diets induce satiety.”

Professor Roy Taylor told me bluntly that:

“Artificial sweeteners do not bring about an insulin response.”

So – what is the evidence?

Horwitz et al. (1988) ran a trial with 10 subjects and concluded that:

“Ingestion of aspartame- or saccharin-sweetened beverages by fasting subjects, with or without diabetes, did not affect blood glucose homeostasis.”

That study was some time ago, with a small sample group, not randomised against a control group and not double-blinded. The abstract states no statistical analysis.

So I did a quick (un)systematic review.

And I found these papers

The Horwitz study (see above) is stated as the most referenced paper on the search “aspartame insulin”.

I searched on http://www.ncbi.nlm.nih.gov/pubmed for articles linked by references (either earlier studies that Horwitz referenced, or later studies that referenced Horwitz.

In the 7 pages of referencing/referred to papers, I found these others that had the words ‘aspartame’ and ‘insulin’ in the title. Here are my one sentence summaries from their abstracts relating to Danni Levy’s theory that aspartame triggers an insulin spike.

Siegler (2012) Trial size not stated in abstract. No difference in insulin response between aspartame and placebo (water) during intense exercise.

Hall (2003) Only 6 subjects. Insulin concentrations were unaffected.

Nguyen (1998) Only 7 subjects. Aspartame did not alter glycaemia or insulinemia. (The subjects were stated to be healthy, so the term insulinemia may be misused)

Møller (1991) 6 males. Aspartame drinks had no impact on insulin levels.

Saravis (1990) 20 children. The empty sweetness of aspartame (my words) had an effect the short-term behavior of healthy 9- to 10-year-old children. This appears to be psycho-somatic (my words again) because there was an absence of any metabolic changes.

Tordoff (1990) 20 subjects chewed gum. The results were strange: medium levels of aspartame seemed to increase the subjective notion of ‘hunger’ in the subjects, but low and high levels of aspartame did not. Men and women seemed to react differently, and the perception of hunger over time was not consistent. Not a study that I would place too much reliance on.

Carlson (1989) Trial size not stated in abstract. “Doses of aspartame do not alter secretion of insulin in normal individuals.”

Shigeta (1985) Trial on diabetic humans and also diabetic rats. Trial size not stated in abstract. “Acute administration of aspartame has no influence on insulin levels”.

Stern (1976) 90 day study with 43 diabetic subjects subjected to 3 times normal daily aspartame levels. “No symptoms that could be traced to the administration of aspartame or the placebo , and diabetic control was unaffected by the chronic administration of these substances. Aspartame seems to be well tolerated by non-insulin-dependent diabetics.” BUT: No mention is made in the abstract of measurement of insulin levels, nor of effect on appetite or calorie consumption.

I found one other paper that did not appear in my Pubmed database search:

Melanson (1999) 10 healthy males. Strong proof here that low sugar levels make you hungry. The effects of aspartame ingestion seemed to me, if not the writers of the paper, to absolutely random. 4 of the men had blood sugar declines, 20 increases and 4 saw no effect at all. No measurements were taken of insulin levels.

Danni could be onto something though…

Her claim that diet drinks induce a greater subsequent calorie intake is, however, supported by one trial on fourteen female students “shown to have eating restraint ” found that “energy intake (the next day ) was significantly higher after the aspartame-sweetened lemonade”. This experiment compared with aspartame versus sugared drinks and water drinks.

This study by Lavin (1997) was not randomised or double blinded, but is interesting.

It is, however, only one trial on 14 people, so follow-up trials would be needed to confirm this…

To conclude

When you watch these programmes, do look at the qualifications of the people talking.

You may agree with many (medically qualified) people that ‘nutritional therapist’ = ‘quack’.

If you smell a rat, do some digging around the Interweb to find the facts for yourself…

Comment Below…

© Brian Wernham 2013 CC BY-NC-ND

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