Fructose in the firing line again...

Last week, one of my blogs explored the potential for the sugar fructose to provoke unwanted bowel symptoms including abdominal discomfort and bloating. I mentioned, albeit in passing, that there were likely other reasons to be somewhat wary of fructose. It has, for instance, been implicated as a potentially potent cause of weight gain and type 2 diabetes. For the original post, see here.

Since then, I came across a study which assessed the relationship between an often fructose-filled foodstuff – soft drinks – and risk of type 2 diabetes. In this study, the relationship between soft drink consumption and risk of metabolic syndrome was also assessed. Metabolic syndrome is usually characterised by a constellation of several features including abdominal obesity, raised levels of blood fats known as triglycerides, raised blood pressure, raised blood sugar and/type 2 diabetes, and low levels of ‘healthy’ HDL cholesterol.

The study itself was a ‘meta-analysis’, which means it lumped together several similar studies. It discovered that compared to those consuming less than one serving of soft drinks per month, those consuming 1-2 servings a day were at a 26 per cent increased risk of diabetes, and a 20 per cent increased risk of metabolic syndrome [1].

Now, as I’ve stressed before, so-called ‘epidemiological’ studies of this nature can really tell us only about the associations between things. They cannot be used to prove that one is causing the other.

This latest meta-analysis is just yet another piece to add to the ever-burgeoning ‘evidence-base’ that fructose, far from being the healthy ‘fruit sugar’ some have promoted it as, is a potentially quite toxic substance that needs to be consumed with come considerable caution.

Just before this latest meta-analysis was published, some French scientists wrote a review of the evidence on fructose, insofar as its relationship to ‘cardiometabolic’ disorders including obesity, cardiovascular disease, type 2 diabetes and metabolic syndrome [2]. This review, I think, quite nicely summarises what is known about fructose, and highlights it’s potential for damage in a way that seems balanced and without undue bias. You can read the full text of this review here.

Fructose is found in fruit, but I don’t see a huge issue with individuals eating fruit, unless they are fructose intolerant (see last week’s post), or are eating what looks like excessive quantities of it. At least with fruit, one has the benefit of consuming, along with the fructose, some likely health-giving components including soluble fibre, phytochemicals and vitamins.

The same, unfortunately, cannot be said for foodstuffs which contain fructose in the form of ‘high fructose corn syrup’ (HFCS) – and soft drinks are a prime example here. If fructose or high fructose corn syrup is listed as an ingredient, the likelihood it’s something you would do well to pass on. Come to think of it, though, if you’re scrutinising the ingredients label of a foodstuff, chances are you’ve got the wrong food in your hands.

References:

1. Malik VS, et al. Sugar Sweetened Beverages and Risk of Metabolic Syndrome and Type 2 Diabetes: A Meta-analysis. Diabetes Care 2010 Aug 6. [Epub ahead of print]

2. Wiernsperger N, et al. Fructose and Cardiometabolic Disorders: The Controversy Will, and Must, Continue. Clinics (Sao Paulo). 2010;65(7): 729–738