Conventional nutritional wisdom dictates that heart disease risk can be influenced through our intake of fat. Specifically, saturated fat (found in foods such as meat, dairy products, eggs and coconut) promotes heart disease, while certain foods (for example, omega-3 fats found in oily fish) do the reverse. I do think there’s a good deal of evidence linking omega-3 fats with benefits for heart health, but don’t believe that there is good evidence that saturated causes heart disease. Whatever the truth of the matter is, the point is that in discussions of the effect of diet on heart disease, the focus here is very much on fat.
However, in recent years there has been growing interest in the role that carbohydrate might have on risk of heart disease and stroke (cardiovascular disease). Last year I blogged about a specific study which linked the consumption of certain carbohydrates with an increased risk of cardiovascular disease. Specifically, the problem foods here seem to be those that are most disruptive of blood sugar and hormones such as insulin (high glycaemic index/high glycaemic load foods). Through their ability to cause spikes in blood sugar, these foods can induce changes in the biochemistry of the body that would be expected to enhance cardiovascular disease risk such as increased ‘oxidative stress’ (free radical damage), inflammation, protein glycation (glucose ‘bonding’ to proteins in the body and damaging them) and coagulation (essentially, making the blood ‘stickier’ and more likely to clot).
Carbohydrates may also contribute to cardiovascular disease risk through their potential ability to cause weight gain (particularly around the abdomen) and increase the risk of type 2 diabetes. One type of carbohydrate-rich foodstuff that has been the subject of research focusing on weight and type 2 diabetes are sugary soft drinks. They can contribute to the glycaemic load of the diet too, which as mentioned above, may contribute to cardiovascular disease through a variety of mechanisms.
In a recent study, the relationship between sugary soft drink consumption and risk of heart disease was assessed in a group of more than 85,000 women monitored over a 24-year period [1]. The researchers accounted for so-called confounding factors including age, smoking habits, family history of heart disease, and blood pressure and cholesterol levels. The effort here was to help ensure that any relationship between heart disease and sugary soft drink consumption is likely to be due to the soft drink, and not factors associated with soft drink consumption.
What this study found was that compared to women drinking less than one soft drink per month, those drinking 1 soft drink and 2 or more soft drinks a day were at a 23 and 35 per cent increased risk of heart diseased respectively. The enhanced risk was statistically significant.
This study adds to the considerable body of evidence linking the consumption of certain carbohydrates and an increased risk of chronic disease. And it also might cause us to remember that while fat consumption may affect heart disease risk, this appears to be true for carbohydrate too.
References:
1. Fung TT, et al. Sweetened beverage consumption and risk of coronary heart disease in women. Am J Clin Nutr (February 11, 2009). doi:10.3945/ajcn.2008.27140
