Thursday, July 26, 2018

19th Annual Harvard Nutrition and Obesity Symposium: Sugar

The 19th Annual Harvard Nutrition and Obesity Symposium was held on July 11th and 12th. This year’s topic was Sugar: Epidemiologic, Physiologic, and Policy Considerations of the Sugar Epidemic.

The 19th Annual Harvard Nutrition and Obesity Symposium: Sugar
According to research from the National Cancer Institute, Americans consume around 22 teaspoons of added sugar per day, with ~50% of added sugar coming from beverages. Because sugar-sweetened beverages are the largest source of added sugar in the American diet, many studies have delved into this topic. Increased intake of sugary beverages has been associated with negative health effects, such as weight gain, obesity, cardiovascular disease, diabetes, metabolic syndrome, non-alcoholic fatty liver disease, gout, and tooth decay. Higher intake of sugary beverages has also been associated with decreased student academic performance, including the areas of grammar, reading, writing, and math.

To address some of the negative effects of sugar, a number of cities in the U.S. and other countries have added soda/sugar sweetened beverage taxes to discourage their purchase. Some have even taken it a step further, with junk food taxes added in Mexico and Hungary. Meanwhile, Chile is taking an impressive and large-scale approach to confront the obesity epidemic. High sugar beverages have a hefty 18% tax. Warning labels are put on the front of food and beverage packages with added sugars, sodium, saturated fats, or calories that surpass certain thresholds. Restrictions are placed on child marketing. In addition, there is a total advertising ban on all TV and cinema from 6 am – 10 am, with warning messages on TV outside of this time. 

Funds raised from sugar sweetened beverage taxes and similar taxes may be used for public health initiatives, such as supporting nutrition and physical activities in schools. Benefits of these taxes can include decreased consumption of unhealthy foods, decreased rates of overweight and obesity leading to healthcare cost savings, decreased mortality rates, increased number of quality of life years, and increased years of life for individuals.

Conflicting results have been found regarding whether low/zero calorie sweeteners are better or not compared to caloric sweeteners. Dr. Richard Mattes suggested that rather than lumping  sweeteners into a category, each type of sweetener presents a unique metabolic challenge. Taste receptors are located all over the body, and the signaling cascades they initiate vary depending on the sweetener type and where it binds to in the body. Dr. Eran Elinav noted how the human microbiome varies according to the individual, and how consumption of the same food or beverage has different effects on different people.

Overall, the fewer added sweeteners you consume, the better it is for your health. Different guidelines exist for recommended limitations on added sugar intake. The 2015-2020 Dietary Guidelines for Americans suggests limiting added sugars to less than 10% of total caloric intake. The American Heart Association recommends an intake of no more than half of one’s daily discretionary calories to come from added sugar. For most women, that's approximately 6 teaspoons per day, or 100 calories from sugar. For men, it's about 9 teaspoons per day, or 150 calories. While it may be difficult to determine the amount of added sugars in your foods and beverages, changes are coming to nutrition facts labels. Added sugars are scheduled to be declared on nutrition facts labels by 2020 for large manufacturers and by 2021 for small companies. Some manufacturers have already begun updating their nutrition facts labels!

The New Nutrition Facts Label