Testing the Nutritional Value of Carbohydrates

Experts established a new set of guidelines to determine the quality and nutritional value of carbohydrates. 

Carbohydrates are found in all sorts of foods including fruits, vegetables, legumes, and grains, among others. Carbohydrates are broken down into simple sugars like glucose to often be used as the brain and body’s primary fuel source.  Dietary fiber is also a carbohydrate, but it is not digested; instead, it stimulates movement throughout the intestines and helps feed the good bacteria in the gut.¹  

Testing the nutritional value of carbohydrates is important as they are a vital macronutrient. According to guidelines set by the Institutes of Medicine, it is recommended that most individuals aim to get between 45 and 65 percent of their calories from carbohydrates.²  

However, not all carbohydrates are created equal, and some sources are more nutrient-dense than others. For example, refined sugars and grains are often considered less nutritious than fruits, vegetables, legumes, and whole grains.³  Assessing the nutritional value of carbohydrates is often based on the content of simple sugars and the amount of fiber found in a food.^4,5  Although these are valuable metrics, foods contain vitamins, minerals, and other macronutrients; each of these are important factors that might not be accounted for with this approach. 

Considering more nutritional factors could potentially yield more accurate measures of the nutritional value of carbohydrate-containing foods.  A group of experts and researchers addressed this gap and established two new ways of testing carbohydrate food quality.  The guidelines were summarized in a report published by Nutrients.⁵

The first set of guidelines is the Carbohydrate Food Quality Score (CFQS) – 4.  This evaluates the content of four nutrients: dietary fiber, free sugar, sodium, and potassium.  The nutritional guidelines of the CFQS-4 recommend that in every 100g of dry weight, the food contains less than 600 milligrams (mg) of sodium and more than 300mg of potassium.  Moreover, in 100g of carbohydrates, the CFQS-4 recommends that there should be less than 10g of free sugar and more than 10g of dietary fiber. Carbohydrate-containing foods are ranked on a scale of 0-4, where one point is obtained for meeting the nutritional guideline for each nutrient.⁵

The second set of guidelines is the CFQS-5; this evaluates all components of the CFQS-4 as well as the food’s content of whole grains.  The guidelines recommend that the food contains more than 25g of whole grains in every 100g of dry weight.  For this model, carbohydrate-containing foods are ranked on a scale of 0-5, where one point is obtained for meeting the nutritional guideline for each nutrient.

These models consider a food’s content of sodium and potassium, which are key electrolytes.  Maintaining a healthy balance between potassium and sodium is important, as consuming too much sodium and too little potassium may be associated with increased blood pressure.⁶  Having one model consider whole grain content may also be helpful in determining the carbohydrate quality of grain products specifically.  

More research is needed to determine the accuracy of the CFQS-4 and CFQS-5 in assessing the nutritional value of a greater variety of carbohydrate-containing foods.  Moreover, more research is needed to determine whether factoring other nutrients, vitamins, and minerals, would be feasible for future guidelines. 

References

1. EUFIC: Food facts for healthy choices (2020, January 14). The Functions of Carbohydrates in the Body. EUFIC. Accessed 2022, April 11, from https://www.eufic.org/en/whats-in-food/article/the-basics-carbohydrates#:~:text=Introduction,whole%20grains%2C%20fruit%20and%20vegetables.
2. Manore MM. Exercise and the Institute of Medicine recommendations for nutrition. Curr Sports Med Rep. 2005;4(4):193-198. doi:10.1097/01.csmr.0000306206.72186.00
3. American Heart Association (2018, April 16). Nutrition Basics: Carbohydrates. American Heart Association. Accessed 2022, April 12, from https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/carbohydrates
4. Liu, J., Rehm, C.D., Shi, P. (2020, May 21). A comparison of different practical indices for assessing carbohydrate quality among carbohydrate-rich processed products in the US. PLoS ONE. doi: 10.1371/journal.pone.0231572
5. Drewnowski A, Maillot M, Papanikolaou Y, et al. A New Carbohydrate Food Quality Scoring System to Reflect Dietary Guidelines: An Expert Panel Report. Nutrients. 2022;14(7):1485. Published 2022 Apr 2. doi:10.3390/nu14071485
6. Centers for Disease Control and Prevention (CDC) (2021, April 12). The role of potassium and sodium in your diet. U.S. Department of Health & Human Services. Accessed 2022, April 16, from https://www.cdc.gov/salt/potassium.htm