What is fructose?
Fructose is a monosaccharide (simple sugar) that is found naturally in fruit. It is also used commercially as a sweetener in foods such as cake, candy, jams, beverage powders, and soft drinks. In these products, it may be listed on food labels as fructose or high-fructose corn syrup, a concentrated sweetener. (2) In table sugar, or sucrose, fructose is bound to glucose, another monosaccharide. (9) Fructose is absorbed in the small intestine and primarily metabolized by the liver. (2)
The health effects of fructose
Several adverse effects have been associated with a high intake of fructose, including:
- Increased risk of insulin resistance
- Increased triglyceride levels
- Weight gain and obesity
- Elevated blood pressure
- Hyperuricemia (a buildup of uric acid in the blood) (2)
A recent animal study published in 2019 has shed some light on the impact of fructose on mitochondrial function specifically. When consumed in combination with a high-fat diet, fructose intake was shown to impair the function and size of the mitochondria. This resulted in metabolic dysregulation and decreased fatty acid oxidation (fat burning). Interestingly, these outcomes were seen with fructose intake but not glucose. (7)
A diet containing fructose or high fat has also been linked to non-alcoholic fatty liver disease (NAFLD). An animal study examining the effects of these dietary components found that the severity of liver damage was correlated with the degree of dysfunction and oxidative damage to the mitochondria. (4) Similarly, a clinical trial in individuals with NAFLD found that daily fructose intake was associated with increased fibroids (scar tissue in the liver). (1)
Mitochondrial dysfunction and disease
Mitochondria are organelles found in your body’s cells that are essential to producing energy, maintaining the innate immune response, supporting protein synthesis by transcribing DNA to mRNA, managing the balance of calcium in cells, and signaling for apoptosis (cellular death) when necessary. (10) Mitochondrial dysfunction has been associated with conditions including:
- Aging (5)
- Cancer (3)
- Fatigue (5)
- Metabolic disorders (e.g., diabetes, metabolic syndrome) (5)
- Neurodegenerative diseases (e.g., Alzheimer’s, Huntington’s, Parkinson’s diseases) (3)
How to improve mitochondrial function
Preventative dietary changes may result in mitochondrial function improvement.
Diet
The above studies demonstrate the importance of minimizing the intake of added sugars in the diet, particularly fructose. The 2015-2020 Dietary Guidelines for Americans recommend consuming less than 10% of daily caloric intake from added sugars. (8) In a 2,000 calorie per day diet, this translates to less than 200 calories or 50 grams of added sugars. Limit the intake of foods high in fructose, including:
- Certain fruit (e.g., apples, cherries, raisins)
- Honey (9)
- Sweetened beverages (e.g., juices, soft drinks) (2)
- Syrups (e.g., high fructose corn syrup (HFCS), invert sugar syrup, isoglucose syrup)
- Table sugar (9)
The effects of fructose may be particularly harmful to mitochondria in the context of a high-fat diet. (7) This suggests that improving your overall dietary pattern may reduce the risk of mitochondrial damage. Consume less than 10% of your daily caloric intake from saturated fats, found in foods such as coconut oil, palm oil, butter, lard, and shortening. Lower your intake of trans fatty acids, found in partially hydrogenated oils (e.g., coffee creamers, desserts, margarine, microwave popcorn, frozen pizza) and naturally occurring in dairy and animal products. (8) Consuming lean meats while limiting the intake of processed foods and dairy can help reduce the intake of trans fats in your diet.
Antioxidant supplements
In addition to dietary changes, the best dietary supplements for mitochondrial function include antioxidants, such as alpha-lipoic acid, coenzyme Q10, and vitamins C and E. Antioxidants help to reduce oxidative stress in the body, protecting your cells and mitochondria from damage. (6)
The bottom line
The intake of fructose combined with a high-fat diet may contribute to mitochondrial dysfunction, resulting in negative metabolic effects. Prevent mitochondrial damage and dysfunction by reducing your intake of fructose and moderating fat intake. Consider incorporating key dietary supplements to support mitochondrial function, but we recommend speaking with your integrative healthcare practitioner for further guidance.
- Abdelmalek, M. F., Suzuki, A., Guy, C., Unalp-Arida, A., Colvin, R., Johnson, R. J., & Diehl, A. M. (2010). Increased fructose consumption is associated with fibrosis severity in patients with nonalcoholic fatty liver disease. Hepatology, 51(6), 1961–1971.
- Dornas, W. C., Lima, W. G. D., Pedrosa, M. L., & Silva, M. E. (2015). Health implications of high-fructose intake and current research. Advances in Nutrition, 6(6), 729–737.
- Friedman, J. R., & Nunnari, J. (2014). Mitochondrial form and function. Nature, 505(7483), 335–343.
- García-Berumen, C. I., Ortiz-Avila, O., Vargas-Vargas, M. A., Rosario-Tamayo, B. A. D., Guajardo-López, C., Saavedra-Molina, A., … Cortés-Rojo, C. (2019). The severity of rat liver injury by fructose and high fat depends on the degree of respiratory dysfunction and oxidative stress induced in mitochondria. Lipids in Health and Disease, 18(1).
- Gonzalez, M. J., Seyfried, T., Nicolson, G. L., Barclay, B. J., Matta, J., Vasquez, A., … Cintrón, A. (2018). Mitochondrial correction: A new therapeutic paradigm for cancer and degenerative diseases. Journal of Orthomolecular Medicine, 33(4).
- National Institutes of Health. (2018, April 24). Office of Dietary Supplements – Dietary Supplements for Primary Mitochondrial Disorders. Retrieved from https://ods.od.nih.gov/factsheets/.
- Softic, S., Meyer, J. G., Wang, G.-X., Gupta, M. K., Batista, T. M., Lauritzen, H. P., … Kahn, C. R. (2019). Dietary sugars alter hepatic fatty acid oxidation via transcriptional and post-translational modifications of mitochondrial proteins. Cell Metabolism, 30(4).
- U.S. Department of Health and Human Services and U.S. Department of Agriculture. (2015). 2015–2020 Dietary Guidelines for Americans. 8th Edition. Retrieved from http://health.gov/dietaryguidelines/2015/guidelines/.
- Ziesenitz, S. C. (2015). Authorised EU health claim for fructose. In Foods, nutrients and food ingredients with authorised EU health claims (Vol. 2, pp. 189–215). Mannheim, Germany: Woodhead Publishing.
- Zolkipli-Cunningham, Z., & Falk, M. J. (2017). Clinical effects of chemical exposures on mitochondrial function. Toxicology, 391, 90–99.
