by Whitney Crouch, RDN, CLT
Sugar is a hot topic. It’s one of the recently
recognized, major culprits for increasing rates of overweight and obesity, type
2 diabetes, and heart disease and contributes to a multitude of other health
conditions related to inflammation in the body.1
Sugar
intake in America
42% of Americans at 2 years meet the 2015-2020 Dietary
Guidelines for Americans recommendation for limiting added sugars intake to 10%
of daily calories from added sugars, and the actual amount of sugar consumed by
these individuals is staggering.
On average, those who met the Dietary Guidelines
recommendation consumed almost 7 teaspoons of added sugars daily, and those who
did not consumed about 25 teaspoons of added sugars/day (1 tsp of added sugar =
4.2 grams of sugar),1 which is about 420 calories/day from added sugars alone.
Examples of added sugars include brown sugar, corn
sweetener, corn syrup, dextrose, fructose, glucose, high-fructose corn syrup,
honey, lactose, malt syrup, maltose, molasses, raw sugar, and sucrose.2
Excessive
sugar intake: long-term consequences
Sugar is thought to be a pro-inflammatory agent in the
body. When blood sugar levels are elevated for extended periods of time, the
body may be placed into an inflammatory state, which can lead to cellular
dysfunction and changes to both the innate and adaptive immune systems. It is
postulated that elevated sugar intake produces elevated free fatty acid
production by the liver, which may trigger the inflammatory process and
increase reactive oxidative species (ROS) formation.3
The innate immune system represents the dominant defense
system against most organisms; it has a fast response to infection but no
immunological memory.4 In contrast, the adaptive immune system has
immunological memory that promotes quick elimination of pathogens when
reinfection with the same pathogen occurs. It includes T and B lymphocytes and
antibodies.5
Obesity, physical inactivity, and consumption of excess
refined sugars have been associated with an increased risk of type 2 diabetes,
as well as autoimmune and inflammatory diseases.6,7 Obese individuals have
fewer white blood cells to fight infections, and the cells they do possess have
reduced phagocytic capability.8 Sustained hyperglycemia, such as in diabetes,
is associated with an elevated risk of autoimmune and inflammatory diseases
(i.e., rheumatoid arthritis, asthma, psoriasis), as well as cancer.9
Excessive
sugar intake: short-term consequences
The link between excess body weight, type 2 diabetes,
tooth decay, and heart disease from overconsumption of sugar are well
established.5 But what does too much sugar do to the fast-acting, innate immune
system? Studies have looked at what happens in the blood after consumption of
large amounts of sugar, and in short, depressing effects on the innate immune
system were seen.10,12
One such study looked at the blood after healthy study
participants consumed 100 g (25 teaspoons) of sucrose, glucose, or fructose.10
As a result of the high sugar intake (which also happens to be the average
intake of added sugars in 58% of Americans), there was a transient 50% decrease
in neutrophils’ capacity to engulf bacteria in the 1-2 hours after the sugary
drink was consumed.10 Neutrophils are the most common type of white blood cell
(WBC), comprising 55-70% of the WBC count, and are responsible for immediate
responses to infection or attacks on the body’s cells.11
Another study looked at the phagocytic capacity of
neutrophils in healthy students who either ingested a sugar-containing or
sugar-free beverage. No neutrophil abnormalities were found after drinking the
sugar-free drink, however there was a significant decrease in the mean
phagocytic (ability to engulf pathogens) index after in the group ingesting the
sugar-containing drink.12
Together, these studies shine light on the body’s
impaired ability to fight off bacterial invaders when high sugar drinks are
consumed – a trend that is prevalent in the Standard American Diets.1
The leading sources of added sugars in the US diet are
sugar-sweetened beverages, grain-based desserts like cakes and cookies, candy,
and dairy desserts such as ice cream.13 For reference, one 16-oz bottle of
Coca-Cola contains 52 g of added sugar (or ~13 tsp of added sugar).14
Sugar
intake and your health
Added sugars are ubiquitous in processed foods. To limit
intake of sugar to achieve the recommended 1
In addition to dietary awareness, maintaining regular
exercise helps support healthy blood glucose levels. Exercise is the most
potent physiological inducer of efficient glucose storage and reduces the
severity of hyperglycemic events, in addition to the risk and severity of
autoimmune diseases.9 Muscular uptake of blood glucose helps to regulate
circulating blood post-prandial blood sugars, and the greater the muscle mass,
the greater the uptake of blood sugars.15
Citations
- Bowman SA et al. Added sugars intake of Americans: What we eat in America, NHANES 2013-2014. Food Surveys Research Group. Dietary Data Brief No. 18. May 2017.
- USDHHS and USDA. Added sugars. 2015–2020 Dietary Guidelines for Americans. http://health.gov/dietaryguidelines/2015/. Accessed November 29, 2018.
- Della Corte KW et al. Effect of dietary sugar intake on biomarkers of subclinical inflammation: a systematic review and meta-analysis of intervention studies. Nutrients. 2018;10(5):606.
- Inweregbu K et al. Nosocomial infections. Contin Educ Anaesth Crit Care Pain. 2005;5(1):14–17.
- Janeway CA Jr et al. Immunobiology: The Immune System in Health and Disease: Principles of Innate and Adaptive Immunity. 5th ed. New York:2001.
- Malik VS et al. Sugar-sweetened beverages, obesity, type 2 diabetes mellitus, and cardiovascular disease risk. Circulation. 2010;121(11):1356-1364.
- Gaby A. A review of the fundamentals of diet. Glob Adv Health Med. 2013;2(1):58-63.
- Nieman DC et al. Influence of obesity on immune function. J Am Diet Assoc. 1999;99(3):294–299.
- Hansen NW et al. The endothelial border to health: Mechanistic evidence of the hyperglycemic culprit of inflammatory disease acceleration. IUBMB Life. 2017;69(3)L148–L161.
- Sanchez A et al. Role of sugars in human neutrophilic phagocytosis. Am J Clin Nutr. 1973;26:1180–1184.
- American Society of Hematology. Blood Basics. http://www.hematology.org/Patients/Basics/. Accessed November 16, 2018.
- Ringsdorf WM Jr et al. Sucrose, neutrophilic phagocytosis and resistance to disease. Dental Survey.1976;52:46-48.
- Drewnowski A et al. Consumption of added sugars among US children and adults by food purchase location and food source. Am J Clin Nutr. 2014;100(3):901-907.
- Coca-colaproductfacts.com. How Much Sugar In Coke Is There? | Product Facts. https://www.coca-colaproductfacts.com/en/faq/sugar/how-much-sugar-in-coke/. Accessed November 16, 2018.
- Sylow L et al. Exercise-stimulated glucose uptake – regulation and implications for glycaemic control. Nat Rev Endocrinol. 2017;13(3):133-148.
Whitney Crouch, RDN, CLT
Whitney Crouch is a Registered Dietitian who received her undergraduate degree in Clinical Nutrition from the University of California, Davis. She has over 10 years of experience across multiple areas of dietetics, specializing in integrative and functional nutrition and food sensitivities. When she’s not writing about nutrition or educating others, she’s spending time with her husband and young son. She’s often found running around the bay near her home with the family’s dog or in the kitchen cooking up new ideas to help her picky eater expand his palate.
Whitney Crouch is a Registered Dietitian who received her undergraduate degree in Clinical Nutrition from the University of California, Davis. She has over 10 years of experience across multiple areas of dietetics, specializing in integrative and functional nutrition and food sensitivities. When she’s not writing about nutrition or educating others, she’s spending time with her husband and young son. She’s often found running around the bay near her home with the family’s dog or in the kitchen cooking up new ideas to help her picky eater expand his palate.
