Currently browsing posts about: Artificial-sweeteners

I’ve been asked repeatedly this week to comment on the huge press outcry about a study that links diet sodas to an increased risk of stroke and heart disease.

I have not seen the study and neither has anyone else. It is not yet published.

It was presented at the American Stroke Association’s International Stroke Conference 2011.  The American Heart Association has a short summary on its website.  And Rosie Mestel has an excellent account in the Los Angeles Times.

Here’s what I can glean from the limited information available:

• The study started in 2003.  It was designed to determine risk factors for heart disease and stroke in a multi-ethnic New York City population.
• It used a food frequency questionnaire to ask about 2,500 people how often they drank diet sodas (among many other questions).
• Nine years later, it assessed rates of stroke and heart disease.
• The result: people who said they habitually drank diet sodas had a 60% higher rate of stroke and heart attacks.
• They had a 48% higher rate when the data were controlled for contributing factors: age, sex, race, smoking, exercise, alcohol, daily calories, and metabolic syndrome.

That is all we know.

Does this study really mean that “diet soda may not be the optimal substitute for sugar-sweetened beverages for protection against vascular outcomes,” as the lead author is quoted as saying?

As Rosie Mestel puts it:

It’s worth noting, as some scientists did, that this is a link, not proof of cause and effect. After all, there are many things that people who slurp diet sodas every day are apt to do – like eat a lousy diet — and not all of these can be adjusted for, no matter how hard researchers try. Maybe those other factors are responsible for the stroke and heart attack risk, not the diet drinks. (Those who drink daily soda of any stripe, diet or otherwise, are probably not the most healthful among us.)

Leaving questions about the accuracy of dietary information obtained by questionnaire, the study raises more important questions:

1. Could this finding simply be a statistical result of a “fishing expedition?”  The food frequency questionnaire undoubtedly asked hundreds of questions about diet and other matters.  Just by chance, some of them are going to give results that look meaningful.  The increase in stroke risk seems astonishingly high and that also suggests a need for skepticism.
2. What is the mechanism by which diet sodas lead to stroke or heart disease?  I can’t think of any particular reason why they would unless they are a marker for some known risk factor for those conditions.

Please understand that I am no fan of diet sodas.  I don’t like the metallic taste of artificial sweeteners and they are excluded by  my “don’t eat” rule: never eat anything artificial.

But before I believe that this study means that artificial sweeteners cause cardiovascular problems, I want to see a study designed to test this particular hypothesis and a plausible biological reason for how diet sodas might cause such problems.

FoodNavigator.com has a special issue on obesity research.  Its reports are based on single studies that may or may not agree with previous research and, therefore, require some interpretation.

Zero-calorie sweeteners do not prompt overeating, finds study: People do not compensate with extra calories after consuming foods and drinks sweetened with zero-calorie sweeteners, suggests a new study published in the journal Appetite…

Fruit flies help explain why diet success varies: A study on fruit flies has indicated that genetic interaction with diet has a greater impact on body weight than diet alone, which the researchers say can help explain different reactions to similar diets….

Sucralose does not promote weight gain: Human study: Consumption of sucralose and sucralose-sweetened products does not affect gut hormones linked to hunger, or detrimentally affect blood sugar levels, says a new study from Australia….

Food addiction: Fat may rewire brain like hard drugs: Overeating may be driven by a same neurobiological mechanism in the brain as drug addition, says a new study from the US that adds clout to the theory ‘food addiction’….

Overeating drives fat gain at the hips, says obesity-related study: Fat tissues in the upper and lower body may gain weight differently, says a new study which deepens our understanding of fat accumulation and obesity….

Two of these studies are about the effects of artificial sweeteners on hunger, satiety, calorie intake, and weight gain.  In contrast to previous studies, both of these find that sweeteners do not cause people to eat more to compensate for the reduced calories.

I’m guessing we will be hearing more about this topic, as new research results come in.  Stay tuned.

Oh those British libel laws.   According to FoodNavigator.com, a judge in Britain has just ruled that Asda, a grocery company in the UK, may not legally describe aspartame, the artificial sweetener, as “nasty.”

This decision is a reversal of a previous High Court ruling that “nasty” has only a vague meeting and does not constitute “malicious falsehood.”  The Court of Appeals reversed that ruling.

A spokeswoman for the maker of aspartame, Ajinomoto, said: “Asda can no longer deny that describing aspartame as a ‘nasty’ denigrates a safe and beneficial food ingredient.” Ajinomoto will now proceed with its malicious falsehood case… We will continue to pursue our case and defend the reputation of aspartame.”

This parsing of the meaning of “nasty” would be deliciously academic if we didn’t have our own veggie libel laws to contend with.

And as FoodNavigator puts it:

The case could have wider implications for firms employing emotive rhetoric about additives in marketing materials, notably Pret A Manger, which last year urged shoppers to “avoid hairy chemicals”, which were defined as “obscure chemicals, additives and preservatives … the nasties we avoid at all costs”.