A recent study conducted by UC San Francisco reveals a significant reduction in the consumption of sugar-sweetened beverages (SSBs) in Oakland, California, following the implementation of a local soda tax. This decline is likely to contribute to improved public health and financial savings for the city. The findings support previous recommendations by the National Clinical Care Commission (NCCC) to implement a national tax on SSBs and may reignite the debate around the issue.
Published in PLOS Medicine, the study found that purchases of SSBs in Oakland dropped by 26.8 percent between July 2017, when the one-cent-per-ounce tax went into effect, and December 31, 2019. This decrease was in comparison to similar cities without a tax, such as Richmond, California, and Los Angeles.
The NCCC, established by Congress to provide guidance on diabetes policy, had advised the introduction of a nationwide tax on SSBs just over a year ago. However, California state legislators have prohibited new taxes on SSBs for the past five years. Existing taxes in Oakland, San Francisco, Berkeley, and Albany were permitted to remain in place.
“These results suggest SSB taxes can meaningfully improve diet and health and generate substantial cost savings over a sustained period of time, all of which support the case for a national tax on SSBs,” said study senior author Dr. Dean Schillinger.
“The American Beverage Association cornered the California legislature into passing the law barring further SSB taxes in our state. Voters now have evidence that allowing such taxes can yield significant benefits to society, and we hope that legislators at the state and national level act on these findings.”
To assess the impact of the soda tax, researchers compared sugary drink purchases in Oakland to those in nearby Richmond and Los Angeles, which do not have a beverage tax. They analyzed consumer behavior in these cities in the 30 months before and after the tax went into effect on July 1, 2017.
The study also employed computer modeling to estimate the consequences of reduced SSB consumption on community health, using quality-adjusted life-years (QALYs) as a measure. QALYs represent a year of perfect health and are often used to quantify the benefits of health interventions. Additionally, the researchers calculated the health care cost savings associated with preventing or controlling diseases linked to SSB consumption, such as diabetes, heart disease, stroke, and gum disease.
According to the findings, a 26.8% reduction in SSB consumption over a decade added 94 QALYs per 10,000 residents and saved Oakland more than $100,000 per 10,000 residents in health care costs. The researchers expect these gains to increase over a lifetime.
Furthermore, they discovered no evidence that consumers traveled to neighboring untaxed locations to purchase sugary drinks or substituted sweet snacks for taxed SSBs.
“Our estimates suggest this tax is at least as cost-effective as other widely recognized public health interventions such as smoke-free workplace policies and air pollution control measures,” noted study first author Professor Justin White.
The study also revealed a significant decrease in the consumption of sugar-sweetened beverages (SSBs) across all categories, including sweetened soda, fruit drinks, sports drinks, and sweetened teas.
The findings suggest that the local soda tax implemented in the city has had positive effects on public health, which may be underestimated due to the study not accounting for additional benefits from nutrition and public health programs funded by the tax revenue.
The research discovered that purchases of various types of SSBs declined significantly, with sweetened soda dropping by 23.1 percent, fruit drinks by 30.4%, sports drinks by 42.4 percent, and sweetened teas by 24.4 percent. The declines were consistent for both individual- and family-sized products and were similar in both lower-income and higher-income areas.
“Studies of other U.S. cities have found similar reductions in SSB purchases as this one,” said Dr. Schillinger. “The sustained impact of Oakland’s tax is particularly important. It suggests that, were an SSB tax to be scaled nationally, our country would enjoy better health and lower healthcare costs.”
According to Dr. Schillinger, the current findings might underestimate the health benefits of the SSB tax. He stated that the researchers “did not account for the positive impacts of the local nutrition and public health programs funded by the tax revenue in Oakland.”
As of 2021, seven U.S. cities and over 35 countries had implemented SSB taxes to reduce the risk of diet-sensitive chronic diseases and increase government revenue for health promotion initiatives.
Past research has shown that consuming sugar-sweetened beverages is linked to a higher risk of obesity, type 2 diabetes, and cardiovascular disease. In fact, a recent UCSF study found that SSB taxes in five cities, including Oakland, significantly lowered the risk of diabetes and unhealthy weight gain in pregnant mothers and reduced the risk of having an overly small fetus.
While previous studies have established that SSB taxes lead to fewer purchases and reduced intake of SSBs in the short term, this study is among the first to examine sustained declines alongside other purchasing behavior, such as “substitute” purchases of sweet snacks. It is also the first study to evaluate cost-effectiveness in relation to SSB taxes.
This research contributes valuable insights into the potential benefits of SSB taxes in promoting public health and reducing the risks associated with chronic diet-sensitive diseases. As more cities and countries adopt similar measures, the findings of this study may play an essential role in shaping future policies and strategies aimed at decreasing SSB consumption and promoting healthier lifestyles.
Sugar-heavy diets can have numerous negative health impacts on humans and pose a significant burden on the health care system. Some of the key health issues associated with excessive sugar consumption include:
Consuming excessive amounts of added sugars, particularly in the form of sugar-sweetened beverages and processed foods, can lead to weight gain and an increased risk of obesity. Obesity is associated with numerous health problems, such as heart disease, type 2 diabetes, and certain types of cancer.
High sugar consumption can lead to insulin resistance, a major risk factor for type 2 diabetes. Over time, this can cause elevated blood sugar levels, which can damage organs, blood vessels, and nerves, leading to further health complications.
Diets high in added sugars have been linked to an increased risk of developing heart disease, the leading cause of death worldwide. Excessive sugar intake can lead to high blood pressure, increased levels of unhealthy cholesterol (LDL), and inflammation, all of which contribute to the development of cardiovascular disease.
Sugary foods and drinks promote the growth of harmful bacteria in the mouth, which can lead to tooth decay and cavities. Poor dental health can also contribute to other health issues, such as gum disease and tooth loss.
Excessive sugar intake, particularly in the form of fructose, can lead to fat accumulation in the liver, resulting in NAFLD. This condition can progress to more severe liver diseases, such as non-alcoholic steatohepatitis (NASH), cirrhosis, and liver cancer.
High sugar consumption has been linked to the development of metabolic syndrome, a cluster of conditions that increase the risk of heart disease, stroke, and type 2 diabetes. These conditions include high blood pressure, elevated blood sugar levels, excess body fat around the waist, and abnormal cholesterol levels.
The increased prevalence of obesity, type 2 diabetes, cardiovascular disease, and other conditions related to sugar-heavy diets places a significant burden on the health care system. This includes higher health care costs, increased demand for medical services and resources, and a greater need for chronic disease management and prevention programs.
Additionally, the economic impact of lost productivity due to illness, disability, and premature death associated with sugar-related health issues can be substantial. To address these challenges, health care systems must invest in public health initiatives, such as educational campaigns, nutritional guidelines, and policies aimed at reducing sugar consumption and promoting healthier lifestyles.
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