Six studies on strawberries’ health impacts will be presented at Nutrition 2020, the annual American Society for Nutrition meeting where professionals gather to advance nutrition science and its practical application.
The studies will be the subject of virtual presentations June 1-4. Covering the gut microbiota, cardiovascular, metabolic, and cognitive domains, the scientific research presented will highlight the potential outcomes strawberry consumption may have on human health.
Changes in the Gut Microbiome
Based on the polyphenol and fiber content of strawberries, one study investigated whether daily consumption of 26g of freeze-dried strawberry powder (FDSP) would lead to changes in the composition of the intestinal microbiota and concentration of fecal cholesterol and bile acid microbial metabolites (Henning, 2020). Results demonstrated that about two servings of strawberries daily for four weeks altered the gut microbiota, which was partially reversed two weeks after returning to a regular diet without strawberries.
A second study also aimed to evaluate the effects of four weeks of daily strawberry intake on bile acid metabolism (Zhao, 2020). The results indicate that regular strawberry consumption could lower pro-inflammatory lithocholic acid and other secondary bile acids, suggesting a potential role of strawberry in ameliorating colonic inflammation and promoting gut health.
Preliminary data from a third study suggests that 39g of FDSP intake is associated with a significant increase in propane-1, 2-diol, which is negatively correlated with Framingham reactive hyperemia index (fRHI), as well as the urinary metabolites 1-methylnicotinamide and hypoxanthine (Padhi, 2020). This study provides evidence that vascular improvements may be driven in part by changes in metabolism.
Cardiovascular Health
Two of the studies focus on determining how much strawberry is needed to improve cholesterol in high-risk adults. Both studies saw a significant decrease in low-density lipoprotein (LDL) cholesterol after participants consumed daily beverages of water mixed with FDSP.
One study suggested 2.5 servings per day were needed (Davis, 2020), while the other study saw significant improvements in LDL cholesterol with just one serving of strawberries per day (Skulas-Ray, 2020).
A third study’s initial data on strawberries’ effects on microvascular function showed that after four weeks of the equivalent of 3 servings of strawberries, there was a trend toward improved fRHI compared to the control (Padhi, 2020).
Metabolic Health
Two studies investigated strawberries’ impact on metabolic health.
Preliminary data on 30 participants with metabolic syndrome indicate a significant reduction in the homeostatic model of assessment of insulin resistance (HOMA-IR) following 32g of FDSP (the equivalent of 2.5 servings of strawberries) (Davis, 2020).
The other study’s initial review shows a decrease in fasting blood glucose after consuming the equivalent of 39g daily FDSP when individuals are stratified according to cardiovascular disease risk (Padhi, 2020).
Brain Health
The final project used data from the Rush Memory and Aging Project to look at associations between strawberry intake among older adults and the development of Alzheimer’s Disease (Agarwal, 2020). A trend emerged showing an association between increased strawberry intake and decreased neurofibrillary tangles, one of characteristic hallmarks of Alzheimer’s Disease.
The researchers concluded that higher intake of pelargonidin, a flavonoid, may reduce the risk of Alzheimer’s Disease. Strawberries, being the wealthiest source of pelargonidin, should be further assessed for their role to maintain brain health in older adults.
Conclusion
While strawberries are known for their complete daily value of vitamin C, 3g of fiber, and potassium and folate content, they are also rich in flavonoids- particularly pelargonidin. Because of these flavonoids, strawberries have been identified to have antioxidant and anti-inflammatory properties that improve gut microbiota, cardiovascular, metabolic, and neuronal function.
Sources:
Agarwal, P., Holland, T.M., Wang, Y., Schneider, J.A., & Morris, M.C. (2020). Pelargonidin in strawberries associated with reduced Alzheimer’s disease neuropathology: A community-based cohort. [Abstract]. Nutrition 2020, P18-002-20. https://www.eventscribe.com/2020/ASN/fsPopup.asp?Mode=posterinfo&PosterID=275364
Davis, D., Scofield, H., Betts, N., Izuora, K., & Basu, A. (2020). Dietary strawberries improve insulin resistance in adults with the metabolic syndrome. [Abstract]. Nutrition 2020, P06-021-20. https://www.eventscribe.com/2020/ASN/fsPopup.asp?Mode=posterinfo&PosterID=274632
Henning, S., Yang, J., Woo, S.L., Li, R., Huang, J., Thames, G., Gilbuena, I. Tseng, C. Ezzat-Zadeh, Z. Heber, D., & Li, Z. (2020). California strawberry consumption alters gut microbiome in healthy participants: A pilot study. [Abstract]. Nutrition 2020, P24-018-20. https://www.eventscribe.com/2020/ASN/fsPopup.asp?Mode=posterinfo&PosterID=275047
Padhi, E.M.T., Holt, R.R., Slupsky, C.M., & Keen, C.L (2020). A crossover study of freeze-dried strawberry powder on microvascular function, gut microbiota, and metabolic phenotype in overweight or obese postmenopausal women. [Abstract]. Nutrition 2020, P06-080-20. https://www.eventscribe.com/2020/ASN/fsPopup.asp?Mode=posterinfo&PosterID=276103
Skulas-Ray, A.C., Richter, C.K., Gaugler, T.L., Meily, S., Petersen, K. & Kris-Etherton, P.M. (2020). Dose-response effects of freeze-dried strawberry powder on atherogenic lipoproteins in overweight adults with elevated cholesterol: a randomized, double-blind crossover trial. [Abstract]. Nutrition 2020, P01-075-20. https://www.eventscribe.com/2020/ASN/fsPopup.asp?Mode=posterinfo&PosterID=274729
Zhao, A., Zhang, L., Zhang, X., Edirisinghe, I., Burton-Freeman, B., & Sandhu, A. (2020). Effects of daily strawberry intake (4 weeks) on plasma bile acid composition in humans: A randomized, placebo-controlled, crossover trial. [Abstract]. Nutrition 2020, P16-038-20. https://www.eventscribe.com/2020/ASN/fsPopup.asp?Mode=posterinfo&PosterID=275397