HEALTH CORNER

Sugary drinks: To tax or not to tax

The price of your favorite sweet drink could more than double if the senate concurs with the House of Representatives. House Bill 5636 seeks to impose an excise tax of PhP10 per liter of sugar-sweetened beverages (SSBs), specifically, non-alcoholic drinks with added sugar or artificial sweetener like soft drinks, soda, fruit drinks, sports drinks, sweetened tea or coffee and energy drinks.

Excluded from the proposed tax are 100% natural fruit juice, 100% vegetable juice, yogurt, milk, meal replacements, weight loss and oral nutrition therapy products. Why single out sugar-sweetened beverages?

The World Health Organization (WHO) advocates for a tax on sugary drinks for a number of reasons. Sugar over-consumption is a key contributor to obesity, diabetes and tooth decay. SSBs are major sources of dietary sugar and are gulped down increasingly in many countries especially by children. Sugary drinks make it very easy to ingest excess sugar. On average, one can of soft drink contains about 40 grams or 10 teaspoons of sugar.

To prevent obesity and tooth decay, WHO guidelines recommend limiting free sugars to less than 10% of one’s total daily calorie intake (amounting to around 12 teaspoons of sugar a day for adults). For added health benefits, the WHO suggests cutting sugar further to below 5% of daily energy intake (about 6 teaspoons of sugar for adults). Free sugars are those added to foods and drinks by the manufacturer, cook, or consumer such as glucose, fructose and sucrose or table sugar and sugars naturally present in honey, syrups, fruit juices, and fruit juice concentrates.

Do sugary drinks cause diabetes?

SSB tax critics claim there is no direct link between SSBs and diabetes. Studies, they say, only prove correlation but not causation. Harvard School of Public Health Professors Malik and Hu have established that evidence for SSB consumption and diabetes risk have already fulfilled the Bradford Hill criteria for causality as follows:

1) Strength of association – Strong evidence from studies involving 310,819 participants showed 26% greater diabetes risk with 1 to 2 SSB servings a day compared to drinking none to less than 1 serving per month.

2) Consistency – The Nurses’ Health Study followed over 90,000 women for eight years and found that those who had 1 or more SSB servings a day were twice as likely to develop diabetes than those who rarely drank SSBs. Several other large studies have come to a similar conclusion.

3) Specificity – Besides raising blood sugars, SSBs have also escalated risk for related conditions like high blood pressure, abnormal blood cholesterol levels, lower bone mass, bulging waistlines, gout, inflammation and heart disease.

4) Temporality – Prospective studies like the Health Professionals Follow-up Study that tracked 40,000 men over 20 years saw a 24% higher diabetes risk with higher SSB intake.

5) Dose-response – Each SSB serving per day is tied to a 15% greater risk of diabetes.

6) Biological plausibility – Liquid calories generally don’t curb hunger as well as solid foods. Liquid sugars are also rapidly absorbed and acutely cause spikes in blood sugar. Excess sugar, particularly fructose, tends to turn into fat and accumulate in various organs, leading to poor insulin action and heart disease risk.

7) Experimental evidence – Randomized controlled trials are logistically challenging to do, but evidence measuring biomarkers for diabetes and heart disease risk reinforce the SSB-diabetes link. Have soda taxes worked?

The SSB tax passed in Mexico generated $1.4 billion in its first year; in Denmark, their saturated sugar tax raised €134 million from November 2011 to August 2012. Tax revenues could fund programs to promote health

and education, as well as accessibility of potable water and nutritious food like fruits and vegetables. One year after Mexico implemented its SSB tax, the lowest income households slashed sugary drink purchases by 17%, while the general population cut theirs by 12%. Would that make the SSB tax anti-poor?

On the contrary, the tax may actually be pro-poor. The economically disadvantaged are most vulnerable to the health threats of SSBs since they have the least resources to afford or access care. Harvard School of Public Health researchers project that SSB taxes will prevent 115,000 cases of obesity in 15 U.S. cities by the year 2025, avert diabetes, increase healthy life years and save on future health care costs. Cancer in a can?

Most sugary drinks are nothing more than empty calories. Usually devoid of nutrients like vitamins, minerals, fiber, antioxidants or ingredients of health value, some may even contain chemicals implicated to cause cancer. The caramel color in cola soft drinks may contain harmful chemicals such as 4-methylimidazole (4-MEI) and advanced glycation-end products (AGEs). 4-MEI has been found to cause cancer in animal studies and spur excess cancer risk in humans. Furthermore, AGEs interfere with many cell functions inducing damage to various organs like the brain, liver, heart and skeletal muscle.

Think before you drink.

What about drinks artificially sweetened with noncaloric sweeteners like aspartame, sucralose and stevia? Research findings have been inconsistent. Because artificially sweetened beverages (ASBs) like diet sodas contain little to no calories, they have been found in short-term studies to aid weight loss when substituted for SSBs. However, a recent pooled analysis of studies of almost 13,000 people saw a 1.59-fold higher risk of overweight and obesity in those who drank ASBs compared to those who did not.

Many posit that the reason why ASBs are tied to weight gain and diabetes risk is due to reverse causation -- overweight people are already at higher risk for obesity and diabetes, so are more likely to turn to diet soda than normal-weight ones. On the contrary, some evidence suggests the intense sweetness of artificial sweeteners may boost craving for sweets and enhance appetite. So, what makes for a healthy drink?

The best thirst quencher would still be clean water. You can also try infusing water with slices of citrus fruit, cucumber, crushed berries and mint for a little flavor. Other healthier alternatives to SSBs include unsweetened tea or coffee and unflavored low-fat or skim milk. The SSB tax is not a panacea.

Done in isolation, imposing tax on sugary drinks to trim obesity and diabetes rates is bound to fail. The SSB tax needs to be part of a comprehensive program to promote health. Alongside it must be initiatives to educate the masses about healthy lifestyle habits; improve food labeling; increase access to healthy food and drinks while curtailing SSB access in schools and workplaces; add warning labels on the health effects of SSBs; and restrict SSB marketing to children.

A tax on liquid candy may be bitter for business but certainly sweet for our nation’s health. So, let’s pass the SSB tax today for a healthier Philippines tomorrow. After all, soda is sweet, diabetes isn’t.

Dr. Joy Fontanilla heads the Center for Weight Intervention & Nutrition Services (WINS) at St. Luke’s Medical Center-Global City. She graduated from the University of the Philippines College of Medicine’s prestigious INTARMED program and finished Internal Medicine residency at the Cleveland Clinic, and Fellowship in Endocrinology, Diabetes and Metabolism at the University of Illinois in Chicago. She served as past president of the American Association of Clinical Endocrinologists Philippine Chapter and is the Editor-in-Chief of DiabetEASE magazine.