September 2015 Issue
Added Sugars and Heart Health
By Judith C. Thalheimer, RD, LDN
Vol. 17 No. 9 P. 38
Recent research shows added sugars contribute to cardiovascular disease risk and mortality.
A growing body of evidence indicates that added sugars may have a significant impact on cardiovascular health. According to a study in the April 2014 issue of JAMA Internal Medicine, people who consume more added sugars have a much higher risk of death from cardiovascular disease (CVD). Subjects who consumed 10% to 25% of their calories from added sugars were 30% more likely to die from CVD than those who consumed less than 10%.1
In this article, Today's Dietitian delves into the research to determine how added sugars may increase CVD risk, and what nutrition professionals can do to help clients and patients tame their sweet tooth.
Actual vs Recommended Intake
The average American consumes around 22 teaspoons of added sugars every day.2 That's more than 88 g of sugar or nearly 352 calories. Approximately one-half of that sugar comes from sugar-sweetened beverages such as sodas, energy drinks, sports drinks, fruit drinks, and teas. Grain-based desserts such as cakes and cookies also are big contributors.3
The Institute of Medicine (IOM) has set the upper limit for added sugar intake at 25% of daily calories.4 There's general consensus from other public health organizations that this limit is too high. The 2015 Dietary Guidelines for Americans is expected to recommend limiting intake of added sugars to a maximum of 10% of daily calories.5 In 2014, the World Health Organization lowered its recommended intake from 10% to 5% of calories.6 To put those recommendations in perspective, for a 2,000 kcal diet, 10% is 200 kcal/day, or about 12 teaspoons (approximately 50 g) of added sugars, and 5% is 100 kcal, or about 6 teaspoons (25 g). The American Heart Association (AHA) has been recommending that women get no more than 6 teaspoons of added sugars per day since 2009. For men, the AHA's upper limit is 9 teaspoons per day.7
What Are Added Sugars?
"Americans are confused about what 'added sugar' means," says Janet Bond Brill, PhD, RDN, FAND, a cardiovascular nutritionist and author. Part of that confusion stems from the word "sugar" itself. The word typically is used to refer to sucrose, the glucose-fructose disaccharide that composes the white crystals in the sugar bowl. Scientifically, however, a sugar is defined as any monosaccharide (glucose, fructose, and galactose) or disaccharide, such as sucrose, lactose, and maltose.8 All caloric sweeteners get their sweetness from some combination of mono- and disaccharides.
The term "added sugars" refers to any caloric sweetener added to a food during processing, cooking, or at the table.
"Sugars are found naturally in foods like plants and dairy, but humans have extracted these sugars and added them to every conceivable type of processed food," Brill says. Added sugars are used to enhance the flavor and texture of foods and to increase shelf life.9 "Whether it's a so-called 'natural' sweetener like honey or raw sugar, a refined product like table sugar, or something manufactured like high-fructose corn syrup, all added sugars are problematic," Brill says. "They're cheap and ubiquitous, and we simply consume too many of them for our own good."
In addition to helping the public understand what's classified as an added sugar, it's important to make a distinction between added sugars and sugars as they exist in nature. "It's okay to eat sweet fruits and vegetables," Brill continues. "It's all the different sugars used in the manufacturing process or sprinkled on at the table that we need to limit. Sugar in fruit is bound up with fiber and lots of nutrients and water, and it doesn't have the same negative physiological effects."
Obesity and the Heart
The 2009 AHA recommendations, laid out in the scientific statement Dietary Sugar Intake and Cardiovascular Health, primarily were based on evidence available at the time that linked high intake of added sugars with higher body weight and lower intake of essential nutrients.7 "High intakes of added sugars, particularly sugary drinks, are associated with obesity. That's settled science," says Rachel Johnson, PhD, MPH, RD, a professor of nutrition at the University of Vermont and a spokesperson for the AHA, "and obesity is a primary risk factor for cardiovascular disease."
Being overweight increases risk of high blood pressure, atherosclerosis, and diabetes, conditions which all raise the risk of CVD. According to the World Heart Federation, 58% of diabetes cases and 21% of ischemic heart disease cases are attributable to being overweight.10 "The number one problem with added sugars is their connection to obesity," Brill says. "It's so easy to drink high amounts of sugar, and so tempting to eat the sweet treats that are all around us; it's just calorie overload."
More Than Just Weight Gain
But evidence is mounting that added sugars do more to increase CVD risk than just add to Americans' waistlines. A 2014 review in the American Journal of Clinical Nutrition concluded that the more added sugars people consumed, the higher their triglyceride levels, total and LDL cholesterol, and blood pressure, and that this association was independent of sugars' effect on body weight.11 A 2011 study by Stanhope and colleagues found that LDL cholesterol levels of healthy young subjects increased 20% after just two weeks of consuming added sugars at the IOM-recommended upper limit of 25% of daily calories.12 In that same year, the International Study of Macro/Micronutrients and Blood Pressure found a direct link between consumption of added sugars and blood pressure. The more sugar sweetened beverages people in the study drank, the higher their blood pressure.13
High added sugar intake also is associated with evidence of increased inflammation and oxidative stress, which are important factors in the development of atherosclerosis.7,14 A 2014 review article by Prasad and Dhar detailed evidence that sugar causes the generation of reactive oxygen species, an overabundance of which may result in oxidative stress, which is involved in all stages of the development of artery-hardening plaque.14,15
Sugars also may add to cardiovascular risk by increasing fat synthesis by the liver, a process known as de novo lipogenesis (DNL). Excessive fructose metabolism can cause the liver to make new fat, an effect which possibly could be greater when fructose is paired with glucose, as it is in most added sugars.16 DNL is linked to increased triglyceride and cholesterol levels.16 It also is associated with increased inflammatory factors, such as C-reactive protein, in the blood, which play a role in the development of arterial plaque.17 Fructose metabolism by the liver may even contribute directly to hypertension by causing increased urate synthesis, which leads to higher blood pressure.11
The evidence for a link between added sugars and CVD was so compelling to Kolderup and Svihus in their 2015 review, "Fructose Metabolism and Relation to Atherosclerosis, Type 2 Diabetes, and Obesity," they concluded that data support an association between added sugars and atherosclerosis, peripheral vascular disease, coronary artery disease, cardiomyopathy, heart failure, and cardiac arrhythmias.16
How Low Can You Go?
It seems clear that reducing added sugar intake would benefit cardiovascular health, but decreasing added sugars can be challenging in today's food environment. In a study of packaged foods, 75% were found to contain added sugars.18 "One 12-oz can of soda averages around 10 teaspoons of sugar," Brill says. "One small soda and you're over the daily recommended limit." Other sweetened beverages, including lemonade and sweetened iced teas, are no better. Cinnamon rolls can have more than 14 teaspoons of added sugars, and a small two-tablespoon serving of barbecue sauce can have more than 21/2 teaspoons.19,20 It's no surprise that most Americans don't meet the AHA recommendations of no more than 6 teaspoons per day for women and no more than 9 teaspoons for men.
Nevertheless, it's possible to change behavior. In a randomized trial, overweight and obese adolescents who had water and sugar-free beverages delivered to their homes for a year gained less weight than their free-drinking peers.21 Unfortunately, their good habits didn't persist when the home delivery stopped, which indicates the importance of permanently changing the environment. "We've come a long way in recognizing the advantages of recommending a diet lower in added sugars," Johnson says. "High added sugar consumption is being recognized for the public health problem that it is, and we're seeing an increase in awareness and initiatives. The idea of taxing sugary drinks, removal of sugar-sweetened beverages from schools, and even the FDA's proposal to list added sugars on the Nutrition Facts label are all steps in the right direction." In March 2014, the FDA proposed inserting an "added sugars" category on all Nutrition Facts labels. In July 2015, a supplemental proposal was issued that would include a DV percentage of added sugars based on the recommendation that the daily intake of calories from added sugars should not exceed 10% of total calories.22
If adopted, these new FDA rules would address the fact that Nutrition Facts labels currently list only total sugars, meaning there's no way to know how much sugar in a strawberry yogurt, for example, is from the milk, how much is from the strawberries, and how much is actually added sugars. To complicate matters further, sugar content is listed in grams, which aren't second nature to most consumers. "It can help to teach clients that there are around 4 g of sugar in a teaspoon," Brill says. "Dividing the number on the package label by four and comparing the outcome to how much sugar they typically add to their morning coffee can really put things into perspective."
Johnson recommends people use their daily sugar allotment to enhance the palatability of nutritious foods. "Buy plain yogurt and sweeten it yourself with fruit or a little honey or maple syrup, or mix plain yogurt half-and-half with sweetened yogurt," Johnson says. "Another example is oatmeal. It's a great food, but a lot of people won't eat it plain, so adding a sprinkling of sugar along with some fruit is fine if that's what it takes to make it palatable." Moreover, using fruit as a basis for snacks and desserts can help satisfy a sweet tooth without added sugars.
Since sugar-sweetened beverages provide the vast majority of added sugars in the Western diet, cutting out those drinks would make the biggest impact. "Most Americans aren't going to switch to water and unsweetened iced tea," Brill says. "If artificial sweeteners work for someone, diet soda is preferable to sugar-sweetened. Or recommend a splash of 100% fruit juice with seltzer."
More than 2,200 Americans die of heart disease every day.23 Calls to limit sodium and saturated fat intake to decrease CVD risk have been in place for decades. Now, data implicating high intake of added sugars in the development of CVD risk factors such as increased blood lipid levels and high blood pressure argue strongly for a decrease in dietary added sugars. Moving the American diet away from processed foods toward a dietary pattern emphasizing fruits, vegetables, whole grains, and lean proteins, as recommended by the Dietary Guidelines for Americans, the AHA, and many other public health organizations, would cut added sugars (along with added salt) and simultaneously increase overall intake of healthful nutrients.
While breaking the sugar habit is difficult, nutrition professionals can educate the public on the importance of decreasing intake of added sugars and provide practical tips to move sugar from a regular part of the diet to an occasional treat.
— Judith C. Thalheimer, RD, LDN, is a freelance nutrition writer, a community educator, and the principal of JTRD Nutrition Education Services.
SUGAR BY ANY OTHER NAME …
Added sugars appear on ingredient lists by many names, but the body metabolizes them all in essentially the same way. On Nutrition Facts labels, added sugars include the following:
• any ingredient with the word "sugar," such as white granulated sugar, brown sugar, beet sugar, raw sugar, or sugar cane juice;
• any ingredient with the word "nectar," such as agave nectar, peach nectar, or fruit nectar;
• any ingredient with the word "syrup," such as corn syrup, high fructose corn syrup, carob syrup, maple syrup, or malt syrup;
• any ingredient containing a word ending in "-ose," including sucrose, dextrose, glucose, fructose, maltose, lactose, galactose, saccharose, and mannose;
• cane juice/evaporated cane juice/cane juice crystals;
• corn sweetener/evaporated corn sweetener;
• fruit juice/fruit juice concentrate;
• panela (raspadora);
• sweet sorghum; and
1. Yang Q, Zhang Z, Gregg EW, Flanders WD, Merritt R, Hu FB. Added sugar intake and cardiovascular diseases mortality among US adults. JAMA Intern Med. 2014;174(4):516-524.
2. Added sugars add to your risk of dying from heart disease. American Heart Association website. http://www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/HealthyEating/Added-Sugars-Add-to-Your-Risk-of-Dying-from-Heart-Disease_UCM_460319_Article.jsp. Updated December 2, 2014.
3. Center for Science in the Public Interest. Sugar: too much of a sweet thing. Accessed at http://cspinet.org/new/pdf/combined_infographic.pdf
4. Institutes of Medicine Food and Nutrition Board. Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids. http://iom.nationalacademies.org/Reports/2002/Dietary-Reference-Intakes-for-Energy-Carbohydrate-Fiber-Fat-Fatty-Acids-Cholesterol-Protein-and-Amino-Acids.aspx. Published September 5, 2002.
5. US Department of Agriculture. Scientific Report of the 2015 Dietary Guidelines Advisory Committee. http://www.health.gov/dietaryguidelines/2015-scientific-report/PDFs/Scientific-Report-of-the-2015-Dietary-Guidelines-Advisory-Committee.pdf. Published February 2015.
6. Jaslow R. World Health Organization lowers sugar intake recommendations. CBS News website. http://www.cbsnews.com/news/world-health-organization-lowers-sugar-intake-recommendations/. Updated March 5, 2014.
7. Johnson RK, Appel LJ, Brands M, et al. Dietary sugars intake and cardiovascular health: a scientific statement from the American Heart Association. Circulation. 2009;120(11):1011-1020.
8. Sugar. Biology Online website. http://www.biology-online.org/dictionary/Sugar. Updated April 1, 2009.
9. Nutritive and nonnutritive sweetener resources. USDA National Agricultural Library website. http://fnic.nal.usda.gov/food-composition/nutritive-and-nonnutritive-sweetener-resources. Updated June 15, 2015.
10. Obesity. World Heart Federation website. http://www.world-heart-federation.org/cardiovascular-health/cardiovascular-disease-risk-factors/obesity/
11. Te Morenga LA, Howatson AJ, Jones RM, Mann J. Dietary sugars and cardiometabolic risk: systematic review and meta-analyses of randomized controlled trials of the effects on blood pressure and lipids. Am J Clin Nutr. 2014;100(1):65-79.
12. Stanhope KL, Bremer AA, Medici V, et al. Consumption of fructose and high fructose corn syrup increase postprandial triglycerides, LDL-cholesterol, and apolipoprotein-B in young men and women. J Clin Endocrinol Metab. 2011;96(10):E1596-E1605.
13. Brown IJ, Stamler J, Van Horn L, et al. Sugar-sweetened beverage, sugar intake of individuals, and their blood pressure: international study of macro/micronutrients and blood pressure. Hypertension. 2011;57(4):695-701.
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15. Prasad K, Dhar I. Oxidative stress as a mechanism of added sugar-induced cardiovascular disease. Int J Angiol. 2014;23(4):217-226.
16. Kolderup A, Svihus B. Fructose metabolism and relation to atherosclerosis, type 2 diabetes, and obesity. J Nutr Metab. 2015;2015:823081.
17. Monsour HP Jr, Frenette CT, Wyne K. Fatty liver: a link to cardiovascular disease — its natural history, pathogenesis, and treatment. Methodist Debakey Cardiovasc J. 2012;8(3):21-25.
18. Ng SW, Slining MM, Popkin BM. Use of caloric and noncaloric sweeteners in US consumer packaged foods, 2005-2009. J Acad Nutr Diet. 2012;112(11):1828-1834.e1-6.
19. How many calories in Cinnabon Classic roll. CalorieKing website. http://www.calorieking.com/foods/calories-in-bakery-classic-roll_f-ZmlkPTE3MDM5Nw.html
20. United States Department of Agriculture. National Nutrient Database for Standard Reference, Release 27.
21. Ebbeling CB, Feldman HA, Chomitz VR, et al. A randomized trial of sugar-sweetened beverages and adolescent body weight. N Engl J Med. 2012;367:1407-1416.
22. Proposed changes to the nutrition facts label. US Food and Drug Administration website. http://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/
LabelingNutrition/ucm385663.htm. Updated July 24, 2015. Accessed July 31, 2015.
23. Heart disease research. Go Red for Women website. https://www.goredforwomen.org/home/about-heart-disease-in-women/research/