Can sweetened beverages cause heart failure

This is alarming and precise. Nutrition studies are often reported with greater certainty than is warranted. The relative risks of eating or drinking a certain food or beverage are not alarming when expressed as absolute numbers.

The 23% risk increase was calculated using a “hazard factor,” which is the risk that study participants will have heart failure at any time during the 12-year average period of the study.

Hazard ratios can be misleading. For this information to make sense, we must know which group we are talking about, their baseline heart failure risk, and the increase.

If you use hypothetical numbers, if the baseline heart failure risk for men is 4 per 1000, then a 23% risk increase means that one additional person will die by the age of fifty if they consume two or more sweet beverages a day.

It’s less alarming to discuss the risk in absolute rather than relative terms, but it makes for bad headlines.

Absolute figures don’t make good headlines.

Fallible memory

It is hard to study nutrition. Randomized placebo-controlled trials (RCT) are the gold standard for trial design. RCTs work well for studying medicine but not food, at least not over a long period. The cost of running them is high, and they do not have “ecological validity.” They don’t accurately represent everyday life because they add an extra level of control that is not found in real life. People tend to make different decisions when they are aware they are being observed.

Most nutrition studies are observational, and people are not randomly assigned to treatment groups. These studies are able to recruit a lot more participants than RCTs.

Large observational studies are not without their issues. They rely on surprisingly simple and naive methods of data collection, such as self-reporting and recollection. These produce notoriously unreliable results.

In addition to memory problems, people tend to underreport their consumption. This study collected data using a food frequency questionnaire. The participants were asked, “How many sweetened drinks or soft drinks do you consume per day or week?”.

It is important to be cautious when interpreting any study that relies on self-reported information, like this recent study from Sweden.

Accounting for Everything

An observational study cannot prove that drinking sweetened beverages causes heart failure. The study can only show that there is a correlation between the two.

Diabetes, high blood pressure, smoking, and body mass index are all associated with heart failure. Researchers took into account these “confounders” and others when calculating hazard ratios.

What if something was missed in the analysis? Those who drink a lot of sweetened beverages may have a poorer diet in general. Those who choose to avoid sweetened drinks likely have a better overall diet.

Confounding variables that are not accounted for can limit the predictive power of an observational study.

Sugar is not poison.

The study does not differentiate between drinks sweetened by sugar and those sweetened artificially, like aspartame or sucralose. We can’t say what role, if any, these artificial sweeteners have played in increasing heart disease risk.

In previous studies, sugar-sweetened drinks have been linked to a variety of health issues, including coronary artery disease or type two diabetes. Even if people in the study drank mainly sugar-sweetened beverages, it is important to be cautious when attempting to link one aspect of nutrition with a specific health outcome.

Sugar isn’t poisonous – it just contributes to an excess of energy, which is linked with metabolic disorders.

Sweetened beverages can increase the risk of heart failure. However, this must be considered in conjunction with a person’s overall diet and lifestyle. Concentrating on one nutrient can be counterproductive and misleading. This leads to seemingly endless debates about how much and what we should be eating. These controversies may sell newspapers and fake health products, but they do not help consumers make informed decisions.