Carbohydrates and Sugars 101

Sugar gets a bad rap, regardless of the type of sugar. What we forget is there is actually sugar that is not “bad.”

Sure, the monosaccharide glucose is the best common form of sugar.  It generally makes up the majority of starchy root vegetables carbohydrate content and is far more compatible with human physiology.  Although excess glucose from some sources can still produce high blood glucose levels and may create problems with our corresponding insulin production, this form of sugar is metabolized much more cleanly than fructose.  Fructose metabolism generates uric acid production and creates oxidative stress within our cells’ mitochondria.  Our liver has to clean up the metabolic clutter produced by fructose and this contributes to fatty liver deposits and ultimately non alcoholic fatty liver disease (NAFLD), which is now at unprecedented levels across all demographics, even young children, here in the US.  In addition, a significant number of people suffer from fructose intolerance and suffer significantly with even modest amounts of this sugar.

What is the difference between “good” vs “bad” sugars (or is that even a thing)?

The better sugars are those that are metabolized without significant harmful byproducts.  Glucose can be helpful to many organs in the body such as the thyroid gland, the brain, and our adrenals, when consumed in moderation.  These organs have higher needs for glucose and although any people can follow very low carb diets indefinitely with no observable side effects, others may see aberrations in their thyroid or adrenal function.  Glucose produces very few free radicals when it is converted to energy. In comparison, fructose generates a host of undesirable free radicals that in turn damage the mitochondrial membrane and create oxidative stress.

What are some sources/examples of “good sugar” and why are they on the ok list — why are they healthy (or at least not unhealthy)?

The best sources of sugar would be the starch found in most root vegetables, as well as a few grains or grain-like foods/ pseudo grains, which is almost entirely made up of glucose.  Examples would be potatoes, sweet potatoes, yams, carrots, and parsnips. Rice and buckwheat are also almost entirely glucose based with respect to their starch content.

The worst sources of sugar would be any sweetener with high fructose contents such as corn syrup, fruit juice concentrates, agave, and cane sugar (where half of the sugar will be in the form of fructose).  Fruit juice is typically very high in its fructose content and should be avoided. Even some fruits have very high fructose contents and should be eaten in limited quantities such as one piece or 1 cup per day and only when in season. Examples of these fruits are mangoes, pears, grapes/raisins, apples, bananas, and pineapple.  It is better to choose those fruits with very low fructose content most often. Examples of these better choices would be raspberries, blackberries, grapefruits, and tangerines.

~ John Bagnulo MPH, PhD.

Resources:

1.  Lambertz J, Weiskirchen S, Landert S, Weiskirchen R. Fructose: A Dietary Sugar in Crosstalk with Microbiota Contributing to the Development and Progression of Non-Alcoholic Liver Disease. Frontiers in Immunology. 2017;8:1159. doi:10.3389/fimmu.2017.01159

2.  Jegatheesan P, De Bandt J-P. Fructose and NAFLD: The Multifaceted Aspects of Fructose Metabolism. Nutrients. 2017;9(3):230. doi:10.3390/nu9030230.

3.  Jensen T, Abdelmalek MF, Sullivan S, et al. Fructose and Sugar: A Major Mediator of Nonalcoholic Fatty Liver Disease. Journal of hepatology. 2018;68(5):1063-1075. doi:10.1016/j.jhep.2018.01.019.

4.  Siqueira JH et al. Sugar-Sweetened Soft Drinks and Fructose Consumption Are Associated with Hyperuricemia: Cross-Sectional Analysis from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). Nutrients. 2018 Jul 27;10(8). pii: E981. doi: 10.3390/nu10080981.

5.  Sara J White, Emma L Carran, Andrew N Reynolds, Jillian J Haszard, Bernard J Venn; The effects of apples and apple juice on acute plasma uric acid concentration: a randomized controlled trial, The American Journal of Clinical Nutrition, Volume 107, Issue 2, 1 February 2018, Pages 165–172

6.  Orlando A, Cazzaniga E, Giussani M, Palestini P, Genovesi S. Hypertension in Children: Role of Obesity, Simple Carbohydrates, and Uric Acid. Frontiers in Public Health. 2018;6:129. doi:10.3389/fpubh.2018.00129.