Diet Drinks vs Regular Sodas: Mortality
While we have known for a while that sugary drinks are harmful to your health, these data provide some of the best evidence so far on the effects of sugary drinks and health.
Participants who drank more sugary drinks had a significantly higher risk of death, even after adjustment for BMI, diet, age, smoking, drinking, and physical activity.
Participants who drank more than 2 sugary drinks a week had a 6% higher risk of death from any cause. Individuals who drank more than 2 sugary drinks a day had a 21% higher risk of death from any cause.
Meanwhile, individuals occasionally who drank diet drinks, a.k.a. artificially sweetened beverages, had a lower risk of death than individuals who never drank artificially sweetened beverages.
Those who drank more than 2 diet drinks a day had a slightly higher mortality rate than those who never drank diet drinks.
Researchers used data from two studies that followed over 100,000 participants from 1986 to 2010. These studies were two of the most comprehensive studies in medical research.
The Nurses Health Study continues to follow hundreds of thousands of nurses to see what factors contribute to the health of women.
The Health Professionals Follow-Up Study continues to survey male medical professionals to see which nutritional factors contribute to men's health
For this particular paper, researchers took data from 118,363 participants across both studies and looked specifically at the effects of drinking sugary drinks and diet drinks.
They excluded participants who had diabetes, cancer, or heart disease at baseline.
Information on dietary habits was collected through detailed surveys every 4 years.
Information on medical conditions and deaths were collected through medical records and mortality records.
Source: Long-Term Consumption of Sugar-Sweetened and Artificially Sweetened Beverages and Risk of Mortality in US Adults
Diet Drinks vs Regular Sodas: Heart Disease Mortality
A similar pattern was seen in the analysis of heart disease mortality, where researchers looked at how often individuals died of heart disease.
Individuals who drank more than 1 sugary drink a month had a significantly higher risk of dying from heart disease compared to individuals who never drank sugary drinks. Individuals who drank more than 2 sugary drinks a day had a 31% higher rate of heart disease.
Those who drank 1-6 diet drinks a week actually had a lower rate of heart disease compared to those who rarely or never drank diet drinks. Individuals who drank 2 or more diet drinks a month had a slightly higher risk of heart disease death.
Diet Drinks vs Regular Sodas: Cancer Mortality
Sugary drinks showed a clear and significant association with the risk of dying from cancer. Individuals who drank more than 1 sugary drink a day had a 10%+ higher risk of dying from cancer, even after adjustment for BMI, diet, age, smoking, drinking, and physical activity.
Diet drinks did not significant affect cancer risk in any direction.
The data presented here, as part of an observational study, can only show correlations. They do not show causations.
However, they do provide good evidence that people who drink more sugary drinks have a higher risk of dying from heart disease and cancer, as well as higher overall mortality.
We can also see that diet drinks are associated with lower risk across the board compared to sugary drinks and sodas. Even after accounting for BMI, among other factors, individuals who drank diet drinks had better health outcomes than individuals who drank sugary drinks.
One somewhat concerning result for diet sodas was the slight increase in mortality among individuals who drank more than 2 diet drinks a day. One possibility is that diet drinks are dangerous in a way that we don't yet understand. However, this is not supported by other research. Additionally, it doesn't account for the apparent lower risk of death for individuals who drank 1-7 diet drinks a week.
Another more likely explanation for this result is that diet drinks correlate with lifestyle. Individuals who drank a few diet drinks here and there may have had a better lifestyle. Likewise, individuals who drank a lot of diet drinks may have had a less healthy lifestyle.