Synonyms / Common Names / Related Terms
Allstar, Annapolis, Earliglow, Evangeline, Fragaria chiloensis ssp. Chiloensis, Fragaria x ananassa Duch., Fragaria x ananassa Duchesne, garden strawberry, Jewel, KYSt-4 (Nohime), KYSt-11 (Kurume IH-1), KYSt-17 (Kurume 58), Mesabi, Rosaceae (family), Sable, Sparkle, woodland strawberry.
Mechanism of Action
Constituents: 1-O-E-Cinnamoyl-beta-D-xylopyranoside, 1-O-E-cinnamoyl-beta-D-rhamnopyranoside, 1-O-E-cinnamoyl-alpha-xylofuranosyl-(1-->6)-beta-D-glucopyranose, tryptophan, and cyanidin-3-O-beta-D-glucopyranoside have been isolated from ripe fruits of the Chilean strawberry Fragaria chiloensis ssp. Chiloensis.18 The antioxidant effects from strawberries may be due to ellagic acid, and certain flavonoids: anthocyanin, catechin, quercetin, and kaempferol.1,18
In a laboratory study, frozen garden strawberries had a nitrate concentration of 57.38mg KNO3/kg and the concentrations in cherry, strawberry, black and red currant jams ranged from 6.30 to 97.38mg KNO3/kg.22
Anti-aging properties: In experiments using dietary supplementation, strawberry extracts were effective in forestalling and reversing the deleterious effects of behavioral aging in F344 rats.3
Anti-angiogenesis activity: In in vitro study, strawberry significantly inhibited both H2O2 as well as tumor necrosis factor (TNF) alpha-induced vascular endothelial growth factor expression by the human keratinocytes.14
Antibacterial activity: In in vitro study, strawberry showed clear antimicrobial effects against Salmonella and Staphylococcus.5 This activity may be due to strawberry's somplex phenolic polymers, such as ellagitannins, that are strong antibacterial agents, and also to the antiadherence activity of the berries. In laboratory study, fresh strawberries and strawberry juice inhibited the growth of Enterobacter sakazakii.4
Anticancer activity: Individual compounds in strawberries have demonstrated anticancer activity in several different studies, blocking initiation of carcinogenesis, dose-dependently inducing apoptosis, and suppressing progression and proliferation of tumors.1,8,9,10,11 This activity may be due to the strawberry extracts' antioxidant properties and their ability to reduce oxidative stress.10
Anti-inflammatory properties: In an in vitro study, strawberry extracts inhibited COX enzymes.1
Antileukemia activity: In an in vitro study, strawberry extracts exhibited high cytotoxic activity against a sensitive leukemia HL60 cell line as well as its multidrug-resistant sublines.15 The values of resistance factor found for these extracts were very low lying in the range 0.32/2.0.
Anti-oxidant activity: Plants in the Rosaceae family (dog rose, sour cherry, blackberry, strawberry, raspberry) are thought to have strong antioxidants properties.16 This is supported by work in humans, animals, and in the laboratory. A retrospective survey of elderly Japanese found that frequent intake of orange or other citrus fruits, or persimmon, strawberry, or kiwi fruit was associated with lower plasma 8-iso-PGF(2alpha) concentrations, possibly due to their vitamin C content17, although another researcher states that strawberry's free radical scavenging effect is associated with the anthocyanin content18. A third researcher found that strawberries have high activities of glutathione peroxidase, superoxide dismutase, guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase.10 In a pig model, strawberries decreased oxidative stress by decreasing malondialdehyde formation in the body and by protecting mononuclear blood cells against increased DNA damage.19 One of the reasons behind the different theories of antioxidant activity may be due to the different varieties of strawberry. An in vitro study found that free phenolic content of strawberry cultivars differed by 65% and flavonoid and anthocyanin content could differ by 100%.13 However, this researcher found that free phenolic content was weakly correlated with total antioxidant activity, and flavonoid and anthocyanin content did not correlate with total antioxidant activity.
Antiplatelet properties: In an in vitro study, strawberry had relatively high antiplatelet activity.6 This finding is supported by a later study that found strawberry varieties KYSt-4 (Nohime), KYSt-11 (Kurume IH-1), and KYSt-17 (Kurume 58) showed significant antiplatelet activity both in vitro and, after oral administration to mice, in vivo.7
Antiproliferative activity: In in vitro studies, strawberry extract has shown dose-dependent antiproliferative activity, which can vary from cultivar to cultivar.12,13 Interestingly, one study found that extracts from organically grown strawberries had a higher antiproliferative activity.12
Gastrointestinal effects: In in vitro studies, strawberry extract exerted an inhibitory effect on intestinal P-glycoprotein-related functionality and interfered with the absorptive transport across Caco-2 monolayers.20,21
Insecticide photodegradation effects: In laboratory study, the cuticle and epicuticular wax of strawberry increased the photodegredation half-life of the insecticide chlorpyrifos-methyl, but did not prevent the insecticide from penetrating into the fruit.23
Iron absorption effects: In a study of parous women, strawberry (Fragaria spp.) and other fruits had a mild to moderate enhancing effect on iron absorption.2
Nitrosation inhibition: In an in vitro study, strawberry inhibited nitrosation.24 To test its effects in humans, healthy male and female volunteers were administered nitrate (400mg daily day) in combination with an amine-rich diet and whole strawberries (300g). After the administration of strawberries, NDMA excretion was decreased by 70%, compared with NDMA excretion after ingestion of an amine-rich diet with a nitrate.
Pharmacodynamics/Kinetics:
Six healthy volunteers (three women and three men) consumed a meal containing 200g strawberries (providing 179microM pelargonidin-3-glucoside).25 Urine samples were collected before and after the meal and rapidly treated by solid-phase extraction. Identification and quantification of anthocyanin metabolites were carried out by HPLC-ESI-MS-MS and HPLC with UV-visible detection, respectively. In addition to pelargonidin-3-glucoside, five anthocyanin metabolites were identified in urine: three monoglucuronides of pelargonidin, one sulfoconjugate of pelargonidin and pelargonidin itself. Total urinary excretion of strawberry anthocyanin metabolites corresponded to 1.80 ± 0.29% (mean ± SEM, N=6) of pelargonidin-3-glucoside ingested. More than 80% of this excretion was related to a monoglucuronide. Four hours after the meal, more than two-thirds of anthocyanin metabolites had been excreted, although urinary excretion of the metabolites continued until the end of the 24-hour experiment. This study demonstrated that anthocyanins were glucuro- and sulfo-conjugated in humans and that the main metabolite of strawberry anthocyanins in human urine was a monoglucuronide of pelargonidin.
After a 72-hour period of a phytoestrogen-free regimen, five healthy women and two men consumed a single strawberry-meal containing known amounts of plant lignans.26 Basal and post-meal blood and urine samples were collected at short intervals. The samples were analyzed using time-resolved fluoroimmunoassay of enterolactone. The strawberry meal increased plasma concentration of enterolactone after eight to 24 hours and in urine in the 13 to 24-hour and 25 to 36-hour urine collections. High individual variability of the metabolic response was observed. Enterolactone excreted in the urine collected throughout the 48-hour post-meal yielded on average 114% of the plant lignans consumed.
References
Hannum, S. M. Potential impact of strawberries on human health: a review of the science. Crit Rev Food Sci Nutr 2004;44(1):1-17. 15077879
Ballot, D., Baynes, R. D., Bothwell, T. H., Gillooly, M., MacFarlane, B. J., MacPhail, A. P., Lyons, G., Derman, D. P., Bezwoda, W. R., Torrance, J. D., and . The effects of fruit juices and fruits on the absorption of iron from a rice meal. Br J Nutr 1987;57(3):331-343. 3593665
Joseph, J. A., Denisova, N. A., Bielinski, D., Fisher, D. R., and Shukitt-Hale, B. Oxidative stress protection and vulnerability in aging: putative nutritional implications for intervention. Mech Ageing Dev 7-31-2000;116(2-3):141-153. 10996014
Kim, H. and Beuchat, L. R. Survival and growth of Enterobacter sakazakii on fresh-cut fruits and vegetables and in unpasteurized juices as affected by storage temperature. J Food Prot 2005;68(12):2541-2552. 16355824
Puupponen-Pimia, R., Nohynek, L., Alakomi, H. L., and Oksman-Caldentey, K. M. The action of berry phenolics against human intestinal pathogens. Biofactors 2005;23(4):243-251. 16498212
Dutta-Roy, A. K., Crosbie, L., and Gordon, M. J. Effects of tomato extract on human platelet aggregation in vitro. Platelets 2001;12(4):218-227. 11454256
Naemura, A., Mitani, T., Ijiri, Y., Tamura, Y., Yamashita, T., Okimura, M., and Yamamoto, J. Anti-thrombotic effect of strawberries. Blood Coagul Fibrinolysis 2005;16(7):501-509. 16175010
Chen, M. S., Chen, D., and Dou, Q. P. Inhibition of proteasome activity by various fruits and vegetables is associated with cancer cell death. In Vivo 2004;18(1):73-80. ViewAbstract
Choi, S. Y., Chung, M. J., and Sung, N. J. Volatile N-nitrosamine 15011755 after intake Korean green tea and Maesil (Prunus mume SIEB. et ZACC.) extracts with an amine-rich diet in subjects ingesting nitrate. Food Chem Toxicol 2002;40(7):949-957. 12065217
Wang, S. Y., Feng, R., Lu, Y., Bowman, L., and Ding, M. Inhibitory effect on activator protein-1, nuclear factor-kappaB, and cell transformation by extracts of strawberries (Fragaria x ananassa Duch.). J Agric Food Chem 5-18-2005;53(10):4187-4193. 15884858
Ramos, S., Alia, M., Bravo, L., and Goya, L. Comparative effects of food-derived polyphenols on the viability and apoptosis of a human hepatoma cell line (HepG2). J Agric Food Chem 2-23-2005;53(4):1271-1280. 15713052
Olsson, M. E., Andersson, C. S., Oredsson, S., Berglund, R. H., and Gustavsson, K. E. Antioxidant levels and inhibition of cancer cell proliferation in vitro by extracts from organically and conventionally cultivated strawberries. J Agric Food Chem 2-22-2006;54(4):1248-1255. 16478244
Meyers, K. J., Watkins, C. B., Pritts, M. P., and Liu, R. H. Antioxidant and antiproliferative activities of strawberries. J Agric Food Chem 11-5-2003;51(23):6887-6892. 14582991
Roy, S., Khanna, S., Alessio, H. M., Vider, J., Bagchi, D., Bagchi, M., and Sen, C. K. Anti-angiogenic property of edible berries. Free Radic Res 2002;36(9):1023-1031. 12448828
Skupien, K., Oszmianski, J., Kostrzewa-Nowak, D., and Tarasiuk, J. In vitro antileukaemic activity of extracts from berry plant leaves against sensitive and multidrug resistant HL60 cells. Cancer Lett 5-18-2006;236(2):282-291. 16039042
Halvorsen, B. L., Holte, K., Myhrstad, M. C., Barikmo, I., Hvattum, E., Remberg, S. F., Wold, A. B., Haffner, K., Baugerod, H., Andersen, L. F., Moskaug, O., Jacobs, D. R., Jr., and Blomhoff, R. A systematic screening of total antioxidants in dietary plants. J Nutr 2002;132(3):461-471. 11880572
Kuriyama, S., Ebihara, S., Hozawa, A., Ohmori, K., Kurashima, K., Nakaya, N., Matsui, T., Arai, H., Tsubono, Y., Sasaki, H., and Tsuji, I. Dietary intakes and plasma 8-iso-prostaglandin F2alpha concentrations in community-dwelling elderly Japanese: the Tsurugaya project. Int J Vitam Nutr Res 2006;76(2):87-94. 16941420
Cheel, J., Theoduloz, C., Rodriguez, J., Saud, G., Caligari, P. D., and Schmeda-Hirschmann, G. E-cinnamic acid derivatives and phenolics from Chilean strawberry fruits, Fragaria chiloensis ssp. chiloensis. J Agric Food Chem 11-2-2005;53(22):8512-8518. 16248546
Pajk, T., Rezar, V., Levart, A., and Salobir, J. Efficiency of apples, strawberries, and tomatoes for reduction of oxidative stress in pigs as a model for humans. Nutrition 2006;22(4):376-384. 16413749
Deferme, S., Van Gelder, J., and Augustijns, P. Inhibitory effect of fruit extracts on P-glycoprotein-related efflux carriers: an in-vitro screening. J Pharm Pharmacol 2002;54(9):1213-1219. 12356275
Van Gelder, J., Deferme, S., Naesens, L., De Clercq, E., van den, Mooter G., Kinget, R., and Augustijns, P. Intestinal absorption enhancement of the ester prodrug tenofovir disoproxil fumarate through modulation of the biochemical barrier by defined ester mixtures. Drug Metab Dispos 2002;30(8):924-930. 12124311
Gajewska, R., Nabrzyski, M., and Szajek, L. [Occurrence of nitrates and nitrites in certain frozen fruits, jams, stewed fruit and fruit-vegetable juices for children and in certain types of bee honey]. Rocz Panstw Zakl Hig 1989;40(4-6):266-273. 2637478
Riccio, R., Trevisan, M., and Capri, E. Effect of surface waxes on the persistence of chlorpyrifos-methyl in apples, strawberries and grapefruits. Food Addit Contam 2006;23(7):683-692. 16751145
Chung, M. J., Lee, S. H., and Sung, N. J. Inhibitory effect of whole strawberries, garlic juice or kale juice on endogenous formation of N-nitrosodimethylamine in humans. Cancer Lett 8-8-2002;182(1):1-10. 12175517
Felgines, C., Talavera, S., Gonthier, M. P., Texier, O., Scalbert, A., Lamaison, J. L., and Remesy, C. Strawberry anthocyanins are recovered in urine as glucuro- and sulfoconjugates in humans. J Nutr 2003;133(5):1296-1301. 12730413
Mazur, W. M., Uehara, M., Wahala, K., and Adlercreutz, H. Phyto-oestrogen content of berries, and plasma concentrations and urinary excretion of enterolactone after a single strawberry-meal in human subjects. Br J Nutr 2000;83(4):381-387. 10858696
Published Strawberry Nutrition Studies
High anthocyanin intake is associated with a reduced risk of myocardial infarction in young and middle-aged women. Cassidy, A. et al, 2013. http://circ.ahajournals.org/content/127/2/188
Effects of dietary strawberry powder on blood lipids and inflammatory markers in obese human subjects. Zunino, SJ, et al, 2011.
http://www.ncbi.nlm.nih.gov/pubmed/22068016
Strawberries decrease atherosclerotic markers in subjects with metabolic syndrome. Basu A 2010.http://www.ncbi.nlm.nih.gov/pubmed/20797478
Freeze-dried strawberry powder improves lipid profile and lipid peroxidation in women with metabolic syndrome: baseline and post intervention effects
Basu A, Wilkinson M, Penugonda K, Simmons B, Betts NM, Lyons TJ.
http://www.ncbi.nlm.nih.gov/pubmed/19785767
Strawberry Modulates LDL Oxidation and Postprandial Lipemia in Response to High-Fat Meal in Overweight Hyperlipidemic Men and Women. Burton-Freeman B et al. Journal of the American College of Nutrition 2010 Feb. http://www.jacn.org/content/29/1/46.abstract?sid=0eaae02e-46ff-4152-b20c-a90658fa2c6f
Serum Antioxidant Capacity Is Increased by Consumption of Strawberries, Spinach, Red Wine or Vitamin C in Elderly Women
Cao, Guohua, et al.
http://jn.nutrition.org/cgi/content/full/128/12/2383
Anthocyanin Excretion by Humans Increases Linearly with Increasing Strawberry Dose
Carkett, Colleen, et al.
http://jn.nutrition.org/cgi/content/abstract/138/5/897
Metabolism of Antioxidant and Chemopreventive Ellagitannins from Strawberries, Raspberries, Walnuts, and Oak-Aged Wine in Humans: Identification of Biomarkers and Individual Variability
Cerdá, Begoña, et al.
http://pubs.acs.org/doi/abs/10.1021/jf049144d
Strawberry Extract Caused Endothelium-Dependent Relaxation through the Activation of P13 Kinase/Akt,
Edirisinghe, Indika, et al.
http://www.ncbi.nlm.nih.gov/pubmed/18816058
Strawberry anthocyanin and its association with postprandial inflammation and insulin.
Edirisinghe, Indika, et al. British Journal of Nutrition 2011 May.
http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8376140
Attenuation of meal-induced inflammatory and thrombotic responses in overweight men and women after 6-week daily strawberry (Fragaria) intake. A randomized placebo-controlled trial.
Ellis, CL, et al.
http://www.ncbi.nlm.nih.gov/pubmed/21242652
Strawberry Anthocyanins Are Recovered in Urine as Glucuro- and Sulfoconjugates in Humans
Felgines, Catherine, et al.
http://jn.nutrition.org/cgi/content/full/133/5/1296
Potential Impact of Strawberries on Human Health: A Review of the Science
Hannum, Sandra M
http://www.ncbi.nlm.nih.gov/pubmed/15077879
Strawberry and its Anthocyanins Reduce Oxidative Stress-Induced Apoptosis in PC12 Cells
Heo, Ho Jin, et al.
http://www.ncbi.nlm.nih.gov/pubmed/15769124
Strawberry Consumption Is Associated with Increased Antioxidant Capacity in Serum
Henning, Susanne, et al.
http://www.ncbi.nlm.nih.gov/pubmed/20136444
The Effect of Strawberries in a Cholesterol-Lowering Dietary Portfolio
Jenkins, David JA, et al.
http://www.ncbi.nlm.nih.gov/pubmed/19013285
Fruit Polyphenols and Their Effects on Neuronal Signaling and Behavior in Senescence
Joseph, James A., et al.
http://onlinelibrary.wiley.com/doi/10.1196/annals.1395.052/abstract
Processing Strawberries to Different Products Alters Contents of Vitamin C, Total Phenolics, Total Anthocyanins, and Antioxidant Capacity.
Klopotek, Yvonne, et al.
http://www.ncbi.nlm.nih.gov/pubmed/15998127
Compositional Changes of Strawberry Due to Dehydration, Cold Storage and Freezing-Thawing Processes
Moraga, G, et al.
http://onlinelibrary.wiley.com/doi/10.1111/j.1745-4549.2006.00079.x/abstract
Bioavailability of Pelargonidin-3-O-glucoside and Its Metabolites in Humans Following the Ingestion of Strawberries with and without Cream
Mullen, William, et al.
http://pubs.acs.org/doi/abs/10.1021/jf072000p
Extracts from Organically and Conventionally Cultivated Strawberries Inhibit Cancer Cell Proliferation In Vitro
Olsson, ME, et al.
http://pubs.acs.org/doi/abs/10.1021/jf0524776
Whole Berries versus Berry Anthocyanins: Interactions with Dietary Fat Levels in the C57BL/6J Mouse Model of Obesity
Prior, Ronald L., et al.
http://pubs.acs.org/doi/abs/10.1021/jf071993o
Dietary Modulation of the Effects of Exposure to Fe Particles
Rabin, BM, et al.
http://ddr.nal.usda.gov/bitstream/10113/10633/1/IND44021269.pdf
Berry Fruits for Cancer Prevention: Current Status and Future Prospects
Seeram, Navindra P
http://www.ncbi.nlm.nih.gov/pubmed/18211019
Berry Fruits: Compositional Elements, Biochemical Activities, and the Impact of Their Intake on Human Health, Performance, and Disease
Seeram, Navindra P
http://www.ncbi.nlm.nih.gov/pubmed/18211023
Identification of Phenolic Compounds in Strawberries by Liquid Chromatography Electrospray Ionization Mass Spectroscopy
Seeram, Navindra P, et al.
http://www.sciencedirect.com/science
Strawberry Phytochemicals and Human Health: A Review
Seeram, Navindra P
http://pubs.acs.org/doi/abs/10.1021/bk-2007-0956.ch021
Strawberry Intake, Lipids, C-Reactive Protein, and the Risk of Cardiovascular Disease in Women
Sesso, Howard D, et al.
http://www.jacn.org/cgi/content/abstract/26/4/303
Beneficial Effects of Fruit Extracts on Neuronal Function and Behavior in a Rodent Model of Accelerated Aging
Shukitt-Hale, Barbara, et al.
http://www.neurobiologyofaging.org/article/S0197-4580(06)00192-8/abstract
Berry Fruit Supplementation and the Aging Brain
Shukitt-Hale, Barbara, et al.
http://www.ncbi.nlm.nih.gov/pubmed/18211020
Antimutagenic Activity of Berry Extracts
Smith, S. Hope, et al.
http://www.ncbi.nlm.nih.gov/pubmed/15671688
Inhibitory Effect on Activator Protein-1, Nuclear Factor-KappaB, and Cell Transformation by Extracts of Strawberries (Fragaria x ananassa Duch.)
Wang, Shiow Y, et al.
http://www.ncbi.nlm.nih.gov/pubmed/15884858
Recent Advances in Berry Supplementation and Age-Related Cognitive Decline
Willis, Lauren M; Shukitt-Hale, Barbara; Joseph, James A
Lipophilic and Hydrophilic Antioxidant Capacities of Common Foods in the United States
Wu, Xianli, et al.
http://www.ncbi.nlm.nih.gov/pubmed/15186133
Phenolic Acid Profiles in Some Small Berries
Zadernowski, Ryszard, et al.
http://pubs.acs.org/doi/abs/10.1021/jf040411p
Isolation and Identification of Strawberry Phenolics with Antioxidant and Human Cancer Cell Antiproliferative Properties
Zhang, Yanjun, et al.
http://pubs.acs.org/doi/abs/10.1021/jf071989c
Strawberry Studies Show Possible Cardiovascular Benefits
Two recent studies, one published in March and the other as yet unpublished, have examined the role that fresh strawberries (Fragaria vesca) play in cardiovascular health, and the results suggest potential benefits of increased consumption.1,2 Led by Maurizio Battino, PhD, and conducted by researchers from Università Politecnica delle Marche in Ancona, Italy, and the Universities of Salamanca, Granada, and Seville in Spain, the studies used blood tests to track specific health markers in the test subjects. Both studies required participants to consume a strawberry-rich diet. The first study examined cholesterol levels in the blood, while the second evaluated red blood cells and their response to both spontaneous and induced hemolysis (the breakdown of red blood cells). The results of these studies could lead to a greater understanding of how the antioxidant phytochemicals present in the fruit interact with the human body and “[encourage] further evaluation on a population with higher cardiovascular disease risk.”1
The cholesterol study, published in the March 2014 issue of the Journal of Nutritional Biochemistry, tracked 23 healthy adult subjects as they ate approximately 500 grams (roughly 1 pound) of strawberries per day. Blood tests were taken before and after treatment to compare levels of low-density lipoproteins (LDL cholesterol), high-density lipoproteins (HDL cholesterol), and triglycerides. After 30 days, the results demonstrated a statistically significant (P < 0.05) response to treatment. LDL cholesterol levels fell by 13.7% and triglyceride levels fell by 20.8% compared to baseline.1 The levels of beneficial HDL cholesterol remained steady. Fifteen days after stopping treatment, further tests indicated that all measurements had returned to their pre-treatment values.
The second study by Battino et al. included a smaller sample size (n = 18) of different subjects and a shorter trial period of two weeks to assess the effect of the same amount of strawberries on immune response against oxidative hemolysis. Red blood cells collected from subjects were separated from plasma and suspended in a control solution to induce hemolysis.2 They observed “no significant changes” in total plasma antioxidant capacity or in serum concentrations of vitamin C or uric acid, but did note a “highly pronounced reduction in [solution]-induced hemolysis (P < 0.001)” in the red blood cells.2 The results, which will be published in the August 2014 issue of Food Chemistry, “[suggest] that a regular consumption of strawberries may enhance body defences against oxidative challenges.”2
As with all research, these studies’ findings of potential health benefits of strawberries should be interpreted prudently. The relatively small sample sizes, lack of control groups, and the amount of fresh strawberries consumed by the subjects mean that more research must be conducted before anyone claims that strawberries should be marketed or professionally recommended for those at risk of cardiovascular disease. Further, no direct evidence exists about what specifically was responsible for the observed beneficial effects in the subjects. The researchers, however, say that anthocyanins bear further scrutiny.
Anthocyanins, members of the flavonoid group of phytochemicals, are pigments that give berries their bright colors, ranging from red-orange to blue-violet.3,4 Research exploring the role of anthocyanins in health has grown during recent years, with their “free-radical scavenging and antioxidant capacities” being “the most highly publicized” aspect.3 More research is being conducted to ascertain what role they play in keeping the heart healthy, with much larger studies scrutinizing a variety of sources for anthocyanins, including strawberries. One review published in 2011 in Advances in Nutrition notes “a decreasing trend” for cardiovascular disease in the results of these studies.4
Because both of Professor Battino’s studies focused on whole-fruit consumption, there exists the question of how to translate these preliminary findings into practical applications. The study in Food Chemistry notes this particular limitation, suggesting that reduced servings may create a more reasonable continuation of the experiment.2 Similar studies have observed positive effects of heart-healthy foods such as walnuts while still using an average serving size per day, such as the study by Katz et al in Journal of the American College of Nutrition.5 In this study, subjects consumed 56 grams (about two ounces) of walnuts per day for eight weeks, with highly significant results (P = 0.019).5 Aside from portion sizes, creating a control group for a trial that uses fresh, whole fruit would present a considerable challenge, as opposed to administering the fruit in a supplement form such as a capsule, for example.
In a study to be published in the June 2014 issue of the Journal of Nutrition, researchers from Oklahoma State University, the University of Oklahoma, and Queen’s University of Belfast in Northern Ireland conducted a more controlled study by using different dosages (25 mg and 50 mg) of powdered freeze-dried strawberries in drink form.6 The placebo-controlled study examined 60 overweight adults for 12 weeks. Outcomes for this study showed a similar statistically significant (P < 0.05) trend toward the reduction of LDL cholesterol with subjects in the high-dosage group recording an average reduction of 28 mg/dL.6
Future research on the cardiovascular benefits of strawberries could use these results and limitations to move forward with well-designed human trials. Working to isolate anthocyanins and regulate the amount would remove the uncontrollable factors of the experiments, such as the variable amount of anthocyanins present in fresh, whole fruit; their interactions with other compounds of the fruit; and the effects of those compounds in humans, as the amount of dietary fiber present in strawberries also may have affected the subjects’ cholesterol levels.1 If anthocyanins are responsible for the observed outcomes, researchers could work to standardize the anthocyanin levels for a more controlled study with results that are easier to replicate.
—Hannah Bauman
References
1. Alvarez-suarez JM, Giampieri F, Tulipani S, et al. One-month strawberry-rich anthocyanin supplementation ameliorates cardiovascular risk, oxidative stress markers and platelet activation in humans. J Nutr Biochem. 2014;25(3):289-94. Available here. Accessed April 2, 2014.
2. Tulipani S, Armeni T, Giampieri F, et al. Strawberry intake increases blood fluid, erythrocyte and mononuclear cell defenses against oxidative challenge. Food Chem. 2014;156:87-93. Available here. Accessed April 2, 2014.
3. Lila MA. Anthocyanins and human health: an in vitro investigative approach. J Biomed Biotechnol. 2004;2004(5):306-313. Available here. Accessed April 2, 2014.
4. Wallace TC. Anthocyanins in cardiovascular disease. Adv Nutr. 2011;2(1):1-7. Available here. Accessed April 2, 2014.
5. Katz DL, Davidhi A, Ma Y, Kavak Y, Bifulco L, Njike VY. Effects of walnuts on endothelial function in overweight adults with visceral obesity: a randomized, controlled, crossover trial. J Am Coll Nutr. 2012;31(6):415-23. Available here. Accessed April 2, 2014.
6. Basu A, Betts NM, Nguyen A, Newman ED, Fu D, Lyons TJ. Freeze-dried strawberries lower serum cholesterol and lipid peroxidation in adults with abdominal adiposity and elevated serum lipids. J Nutr. 2014. Available here. Accessed April 2, 2014.