sweet potato

What is sweet potato

Sweet potato (Ipomoea batatas) is a member of the Convolvulaceae family; it is a dicotyledonous perennial plant found in the tropical and subtropical belts 1. Most varieties are edible, and all parts of the plants – shoots, leaves, vine and tubers – are consumed 2. The edible tuberous root is long and tapered, with a smooth skin whose color ranges between yellow, orange, red, brown, purple, and beige. Its flesh ranges from beige through white, red, pink, violet, yellow, orange, and purple. Sweet potato cultivars with white or pale yellow flesh are less sweet and moist than those with red, pink or orange flesh 3. The large, sweet-tasting tuberous roots, young leaves and shoots are common market vegetables. Although the soft, orange sweet potato is often called a “yam” in parts of North America, the sweet potato is botanically very distinct from a genuine yam (Dioscorea), which is native to Africa and Asia and belongs to the monocot family Dioscoreaceae 4. A true yam is a starchy edible root of the Dioscorea genus, and is generally imported to America from the Caribbean. It is rough and scaly and very low in beta carotene 5.

The centre of origin of sweet potato is Central America, but the crop is widely grown in many tropical and subtropical countries. Sweet potatoes are ranked seventh in world staple food production (expressed on a dry matter basis), after wheat, maize, rice, potato, barley and cassava. The crop is particularly important in South-East Asia, Oceania and Latin America. China still accounts for over 90% of total production; the other major sweet potato producing countries in Asia are: Indonesia, India, Japan, Vietnam, The Philippines and The Republic of Korea. Rwanda and Uganda are Africa’s largest producing countries. Sweet potato production in Latin America and The Caribbean is relatively small.

Figure 1. Sweet potato plant

sweet potato plant

Sweet potato is rich in nutrients and ranked highest in nutritional value amongst vegetables available in the United States of America 6. Among the important nutrients found in tubers are monosaccharides 7, complex carbohydrates 8, dietary fiber, beta-carotene (a source of vitamin A) 9, vitamin C, vitamin B6, anthocyanins 10, and minerals 11. The leaves of sweet potato are rich in protein, fibre, fat, vitamins, and minerals 11. Linoleic and alpha-linolenic acids 12, galactolipids 13, and bioactive substances (e.g. dietary antioxidants, including anthocyanins 14, polyphenols 15, flavonoids 16, and caffeic acid derivatives 17 are also present. These compounds have been extensively investigated for their role in health promotion in many countries.

Sweet potato nutrition facts

Besides simple starches, raw sweet potatoes are rich in complex carbohydrates, are a good source of potassium, dietary fiber and is a rich source of beta-carotene (a provitamin A carotenoid). In a 100 gram amount, raw sweet potato provides 88 calories and is a rich source of beta-carotene (a provitamin A carotenoid) that meets 100% of women and 80% of men Recommended Dietary Allowance 18. Vitamin A deficiency can erode the immune system and contribute to malnutrition, most seriously affecting pregnant women and young children in low-income countries. Somalia, like many developing countries, has a high prevalence of Vitamin A deficiency and malnutrition among its population. The use of orange-fleshed sweet potatoes – containing high levels of Vitamin A precursor – as animal fodder and food for humans has been successfully tested in southern Somalia 19.

While having moderate contents of other micronutrients, including vitamin B5, vitamin B6 and manganese (Table 1. Sweet potato nutrition facts) 20.

Sweet potato is 79% water, 20% carbohydrates, 1.6% protein, 3% dietary fiber and contains negligible amount of fat.

When cooked by baking, small variable changes in micronutrient density occur to include a higher content of vitamin C at 24% of the Daily Value per 100 g serving 21, 22.

The Center for Science in the Public Interest ranked the nutritional value of sweet potatoes as highest among several other foods 23.

Sweet potato cultivars with dark orange flesh have more beta-carotene than those with light-colored flesh, and their increased cultivation is being encouraged in Africa where vitamin A deficiency is a serious health problem. A 2012 study of 10,000 households in Uganda found that children eating beta-carotene enriched sweet potatoes suffered less vitamin A deficiency than those not consuming as much beta-carotene 24.

Table 1. Sweet potato (raw with skin) nutrition facts

[Source: United States Department of Agriculture Agricultural Research Service 20]

Benefits of sweet potato

Sweet potato (Ipomoea batatas) ranks as the seventh most important crop worldwide. Sweet potato is a plant found in the tropical and subtropical belts and is one of the most nutritious tropical and subtropical vegetables.

Purple sweet potato, a special sweet potato cultivar, has been extensively investigated because large amounts of anthocyanin accumulate in its tuberous roots. Anthocyanin is well known for its free radical-scavenging activity and beneficial effects on human health. Its biosynthetic pathway has been well characterized in model plants. Although large-scale systematic studies have been performed to identify the anthocyanin proteins present in sweet potato, information on the regulation of anthocyanin synthesis in sweet potato is insufficient 25.

As well as being popular in cooking in countries in Asia-Pacific, Africa and North America, sweet potato is also used in traditional medicine for the treatment of diabetes mellitus. Research in animal and human models suggests a possible role of sweet potato in glycaemic control 26.

Sweet potato for type 2 diabetes mellitus

Diabetes mellitus is a metabolic disorder resulting from a defect in insulin secretion, insulin action, or both. A consequence of this is chronic hyperglycaemia (that is elevated levels of plasma glucose) with disturbances in carbohydrate, fat and protein metabolism. Long-term complications of diabetes mellitus include retinopathy, nephropathy and neuropathy (i.e. problems with the eyes, kidneys and peripheral nerves). Diabetes mellitus also increases the risk of cardiovascular disease.

Type 2 diabetes mellitus is a global public health issue 27, 28. The increase in numbers of people with type 2 diabetes mellitus across the age spectrum is of concern. Given the progressive nature of the disease, and the multiple pathophysiological (disease) abnormalities associated with it, accelerated ageing is suspected. This is supported by evidence both at molecular and functional levels 29.

The blood glucose-lowering activities of sweet potato were demonstrated in animal studies. A number of bioactive compounds were isolated from the leaves 30 and also the tubers 31, 32. These compounds, together with dietary fiber, contribute to blood glucose-lowering activitiy. Besides glycemic control, sweet potato has shown anti-sclerotic activity and inhibition of glycation in test tube studies 10, 33, as well as antihypertensive 34, antioxidative 35, 36, antimutagenic 37, chemopreventive 38, and cardioprotective properties 9. Finally, there is a suggestion that sweet potato may delay amyloid formation and prevent neuronal damage in the brain of mice 39, 40, 41, 42, 43.

This review 26 of randomised controlled trials found only three studies (with a total of 140 participants) that evaluated the effects of sweet potato for type 2 diabetes mellitus compared with a fake medicine (placebo). All these trials were of very low quality. Two studies with 122 participants showed improved long-term metabolic control of blood sugar levels as measured by glycosylated haemoglobin A1c (HbA1c) which was moderately lowered by 0.3% in participants who were given 4 g sweet potato tablets a day for three to five months. The duration of treatment ranged from six weeks to five months. No study investigated diabetic complications, death from any cause, health-related quality of life, well-being, functional outcomes or costs. Adverse effects were mostly mild, and included abdominal distension and pain. There are many varieties of sweet potatoes and sweet potato preparations. More trials are needed to assess the quality of the various sweet potato preparations as well as to evaluate further the use of different varieties of sweet potato in the diet of diabetic people. In conclusion there is insufficient evidence about the use of sweet potato for type 2 diabetes mellitus 26.

What is anthocyanin ?

Anthocyanins are members of the flavonoid group of phytochemicals, a group predominant in teas, honey, wines, fruits, vegetables, nuts, olive oil, cocoa, and cereals 44. Anthocyanins occur ubiquitously in the plant kingdom and confer the bright red, blue and purple colors to fruits and vegetables such as purple sweet potato, berries, grapes, apples, purple cabbage and corn 45. Epidemiologic studies suggest that the consumption of anthocyanins lowers the risk of cardiovascular disease, diabetes, arthritis and cancer due, at least in part, to their anti-oxidant and anti-inflammatory activities 46. The daily intake of anthocyanins in residents of the United States is is estimated to be between 180 and 215 mg or about 9-fold higher than that of other dietary flavonoids 45.

In both in vitro and in vivo research trials, anthocyanins have demonstrated marked ability to reduce cancer cell proliferation and to inhibit tumor formation 47, 48, 49, 50. The capacity of anthocyanin pigments to interfere with the process of carcinogenesis seems to be linked to multiple potential mechanisms of action including inhibition of cyclooxygenase enzymes and potent antioxidant potential. Hou et al. 51 revealed that anthocyanins inhibit tumorigenesis by blocking activation of a mitogen-activated protein kinase pathway. This report provided the first indication of a molecular basis for why anthocyanins demonstrate anticarcinogenic properties. In other research, fruit extracts with significant anthocyanin concentrations proved to be effective against various stages of carcinogenesis 52, 48, 53, 54, but the individual role of anthocyanins versus other components was not determined, in part because the anthocyanins were too easily degraded during bioassays if separated from stabilizing cofactors such as other phenolic constituents 55. In vivo studies have shown that dietary anthocyanins inhibit cancers of the gastrointestinal tract and topically applied anthocyanins inhibit skin cancer. Although experimental studies have clearly demonstrated the anti-cancer activity of anthocyanins, epidemiological studies have not revealed protective effects of anthocyanin consumption on cancer risk in humans, and their antioxidant activity in humans remains questionable 45.

The roles of anthocyanin pigments as medicinal agents have been well-accepted dogma in folk medicine throughout the world, and, in fact, these pigments are linked to an amazingly broad-based range of health benefits. For example, visual acuity can be markedly improved through administration of anthocyanin pigments to animal and human subjects, and the role of these pigments in enhancing night vision or overall vision has been particularly well documented 56. Oral intake of anthocyanosides from black currants resulted in significantly improved night vision adaptation in human subjects 57, and similar benefits were gained after administration of anthocyanins from bilberries 58. Three anthocyanins from black currant stimulated regeneration of rhodopsin (a G-protein-coupled receptor localized in the retina of the eye), and formation of a regeneration intermediate was accelerated by cyanidin 3-rutinoside 59. These studies strongly suggest that enhancement of rhodopsin regeneration is at least one mechanism by which anthocyanins enhance visual acuity.

  1. Woolfe, Jennifer A. (5 March 1992). Sweet Potato: An Untapped Food Resource. Cambridge, UK: Cambridge University Press and the International Potato Center (CIP). ISBN 9780521402958.[]
  2. Purseglove, John Williams (1968). Tropical crops: Dicotyledons. Longman Scientific and Technical. New York: John Wiley and Sons. ISBN 978-0-582-46666-1[]
  3. Gad Loebenstein; George Thottappilly (2009). The sweetpotato. pp. 391–425. ISBN 978-1-4020-9475-0[]
  4. Wikipedia. Sweet potato. https://en.wikipedia.org/wiki/Sweet_potato[]
  5. Food Reference. THE CONFUSION BETWEEN SWEET POTATOES & YAMS. http://www.foodreference.com/html/art-sweet-potato-yam.html[]
  6. USDA National Nutrient Database for Standard Reference 2010, Release 23. U.S. Department of Agriculture, Agricultural Research Service; Nutrient Data Laboratory Home Page. https://www.ars.usda.gov/northeast-area/beltsville-md/beltsville-human-nutrition-research-center/nutrient-data-laboratory/[]
  7. Salvador LD, Suganuma T, Kitahara K, Tanoue H, Ichiki M. Monosaccharide composition of sweet potato fiber and cell wall polysaccharides from sweet potato, cassava, and potato analyzed by the high-performance anion exchange chromatography with pulsed amperometric detection method. Journal of Agricultural and Food Chemistry 2000;48(8):3448-54. https://www.ncbi.nlm.nih.gov/pubmed/10956132[]
  8. Sabater-Molina M, Larque E, Torrella F, Zamora S. Dietary fructo-oligosaccharides and potential benefits on health. Journal of Physiology and Biochemistry 2009;65(3):315-28. https://www.ncbi.nlm.nih.gov/pubmed/20119826[]
  9. Maiani G, Caston MJ, Catasta G, Toti E, Cambrodon IG, Bysted A, et al. Carotenoids: actual knowledge on food sources, intakes, stability and bioavailability and their protective role in humans. Molecular Nutrition & Food Research 2009;53 Suppl 2:S194-218. https://www.ncbi.nlm.nih.gov/pubmed/19035552[][]
  10. Miyazaki K, Makino K, Iwadate E, Deguchi Y, Ishikawa F. Anthocyanins from purple sweet potato Ipomoea batatas cultivar Ayamurasaki suppress the development of atherosclerotic lesions and both enhancements of oxidative stress and soluble vascular cell adhesion molecule-1 in apolipoprotein E-deficient mice. Journal of Agricultural and Food Chemistry 2008;56(23):11485-92. https://www.ncbi.nlm.nih.gov/pubmed/18986148[][]
  11. Antia BS, Akpan EJ, Okon PA, Umoren IU. Nutritive and anti-nutritive evaluation of sweet potatoes (Ipomoea batatas) leaves. Pakistan Journal of Nutrition 2006;5(2):166-8.[][]
  12. Almazan AM, Adeyeye SO. Fat and fatty acid concentrations in some green vegetables. Journal of Food Composition and Analysis 1998;11(4):375-80.[]
  13. Napolitano A, Carbone V, Saggese P, Takagaki K, Pizza C. Novel galactolipids from the leaves of Ipomoea batatas L.: characterization by liquid chromatography coupled with electrospray ionization-quadrupole time-of-flight tandem mass spectrometry. Journal of Agricultural and Food Chemistry 2007;55(25):10289-97. https://www.ncbi.nlm.nih.gov/pubmed/17988089[]
  14. Islam MS, Yoshimoto M, Terahara N, Yamakawa O. Anthocyanin compositions in sweet potato (Ipomoea batatas L.) leaves. Bioscience, Biotechnology, and Biochemistry 2002;66(11):2483-6. https://www.jstage.jst.go.jp/article/bbb/66/11/66_11_2483/_pdf[]
  15. Thu NN, Sakurai C, Uto H, Van Chuyen N, Lien DT, Yamamoto S, et al. The polyphenol content and antioxidant activities of the main edible vegetables in northern Vietnam. Journal of Nutritional Science and Vitaminology 2004;50(3):203-10. https://www.ncbi.nlm.nih.gov/pubmed/15386933[]
  16. Miean KH, Mohamed S. Flavonoid (myricetin, quercetin, kaempferol, luteolin, and apigenin) content of edible tropical plants. Journal of Agricultural and Food Chemistry 2001;49(6):3106-12. https://www.ncbi.nlm.nih.gov/pubmed/11410016[]
  17. Islam MS, Yoshimoto M, Yamakawa O. Distribution and physiological functions of caffeoylquinic acid derivatives in leaves of sweet potato genotypes. Journal of Food Science 2003;68(1):111-6. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2621.2003.tb14124.x/pdf []
  18. Institute of Medicine, US Panel on Micronutrients. Dietary reference intakes for vitamin A, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc. National Academies Press. Washington, DC, 2001. PMID: 25057538 www.ncbi.nlm.nih.gov/pubmed/25057538[]
  19. Food and Agriculture Organization of the United Nations. Sweet potatoes – cultivating resilience, fighting malnutrition in Somalia. http://www.fao.org/emergencies/fao-in-action/stories/stories-detail/en/c/266043/[]
  20. United States Department of Agriculture Agricultural Research Service. USDA Food Composition Databases. https://ndb.nal.usda.gov/ndb/search/list[][]
  21. “Sweet potato, cooked, baked in skin, without salt”. Nutritiondata.com. Conde Nast. 2013. http://nutritiondata.self.com/facts/vegetables-and-vegetable-products/2667/2[]
  22. Dincer, C; Karaoglan, M; Erden, F; Tetik, N; Topuz, A; Ozdemir, F (Nov 2011). “Effects of baking and boiling on the nutritional and antioxidant properties of sweet potato [Ipomoea batatas (L.) Lam.] cultivars”. Plant Foods for Human Nutrition. 66 (4): 341–7. https://link.springer.com/article/10.1007%2Fs11130-011-0262-0[]
  23. Center for Science in the Public Interest. 10 Best Foods. https://cspinet.org/eating-healthy/what-eat/10-best-foods[]
  24. “Nutrient-boosted foods protect against blindness”. New Scientist, Health. https://www.newscientist.com/article/mg21528784-200-nutrient-boosted-foods-protect-against-blindness/[]
  25. Proteomic approach reveals that starch degradation contributes to anthocyanin accumulation in tuberous root of purple sweet potato. J Proteomics. 2016 Jun 30;143:298-305. doi: 10.1016/j.jprot.2016.03.010. Epub 2016 Mar 6. https://www.ncbi.nlm.nih.gov/pubmed/26957144[]
  26. Ooi CP, Loke SC. Sweet potato for type 2 diabetes mellitus. Cochrane Database of Systematic Reviews 2013, Issue 9. Art. No.: CD009128. DOI: 10.1002/14651858.CD009128.pub3. http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD009128.pub3/full[][][]
  27. Abegunde DO, Mathers CD, Adam T, Ortegon M, Strong K. The burden and costs of chronic diseases in low-income and middle-income countries. The Lancet 2007;370(9603):1929-38. https://www.ncbi.nlm.nih.gov/pubmed/18063029[]
  28. Wild S, Roglic G, Green A, Sicree R, King H. Global prevalence of diabetes: estimates for the year 2000 and projections for 2030. Diabetes Care 2004;27(5):1047-53. http://care.diabetesjournals.org/content/27/5/1047.long[]
  29. Monnier VM, Mustata GT, Biemel KL, Reihl O, Lederer MO, Zhenyu D, et al. Cross-linking of the extracellular matrix by the Maillard reaction in aging and diabetes: an update on “a puzzle nearing resolution”. Annals of the New York Academy of Sciences 2005;1043(Jun):533-44. https://www.ncbi.nlm.nih.gov/pubmed/16037276[]
  30. Li F, Li Q, Gao D, Peng Y. The optimal extraction parameters and anti-diabetic activity of flavonoids from Ipomoea batatas leaf. African Journal of Traditional, Complementary, and Alternative Medicines : AJTCAM / African Networks on Ethnomedicines 2009;6(2):195-202.[]
  31. Kusano S, Abe H, Tamura H. Isolation of antidiabetic components from white-skinned sweet potato (Ipomoea batatas L.). Bioscience, Biotechnology, and Biochemistry 2001;65(1):109-14. https://www.jstage.jst.go.jp/article/bbb/65/1/65_1_109/_pdf[]
  32. Sakuramata Y, Oe H, Kusano S, Aki O. Effects of combination of Caiapo with other plant-derived substance on anti-diabetic efficacy in KK-Ay mice. BioFactors (Oxford, England) 2004;22(1-4):149-52. https://www.ncbi.nlm.nih.gov/pubmed/15630271[]
  33. Park KH, Kim JR, Lee JS, Lee H, Cho KH. Ethanol and water extract of purple sweet potato exhibits anti-atherosclerotic activity and inhibits protein glycation. Journal of Medicinal Food 2010;13(1):91-8. https://www.ncbi.nlm.nih.gov/pubmed/20136441[]
  34. Egert S, Bosy-Westphal A, Seiberl J, Kurbitz C, Settler U, Plachta-Danielzik S, et al. Quercetin reduces systolic blood pressure and plasma oxidised low-density lipoprotein concentrations in overweight subjects with a high-cardiovascular disease risk phenotype: a double-blinded, placebo-controlled cross-over study. British Journal of Nutrition 2009;102(7):1065-74. https://www.ncbi.nlm.nih.gov/pubmed/19402938[]
  35. Huang Z, Wang B, Eaves DH, Shikany JM, Pace RD. Phenolic compound profile of selected vegetables frequently consumed by African Americans in the southeast United States. Food Chemistry 2007;103(4):1395-402.[]
  36. Islam I, Shaikh AU, Shahidul IM. Antioxidative and antimutagenic potentials of phytochemicals from Ipomoea batatas (L.) lam. International Journal of Cancer Research 2009;5(3):83-94.[]
  37. Kurata R, Adachi M, Yamakawa O, Yoshimoto M. Growth suppression of human cancer cells by polyphenolics from sweet potato (Ipomoea batatas L.) leaves. Journal of Agricultural and Food Chemistry 2007;55(1):185-90. https://www.ncbi.nlm.nih.gov/pubmed/17199331[]
  38. Wang LS, Stoner GD. Anthocyanins and their role in cancer prevention. Cancer Letters 2008;269(2):281-90. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2582525/[]
  39. Kim JK, Choi SJ, Cho HY, Kim YJ, Lim ST, Kim CJ, et al. Ipomoea batatas attenuates amyloid beta peptide-induced neurotoxicity in ICR mice. Journal of Medicinal Food 2011;14:1-6. https://www.ncbi.nlm.nih.gov/pubmed/21244238[]
  40. Lu J, Wu DM, Zheng YL, Hu B, Zhang ZF. Purple sweet potato color alleviates D-galactose-induced brain aging in old mice by promoting survival of neurons via PI3K pathway and inhibiting cytochrome C-mediated apoptosis. Brain Pathology (Zurich, Switzerland) 2010;20(3):598-612. https://www.ncbi.nlm.nih.gov/pubmed/19863544[]
  41. Wang YJ, Zheng YL, Lu J, Chen GQ, Wang XH, Feng J, et al. Purple sweet potato colour suppresses lipopolysaccharide-induced acute inflammatory response in mouse brain. Neurochemistry International 2010;56(3):424-30. https://www.ncbi.nlm.nih.gov/pubmed/19941923[]
  42. Wu DM, Lu J, Zheng YL, Zhou Z, Shan Q, Ma DF. Purple sweet potato colour repairs d-galactose-induced spatial learning and memory impairment by regulating the expression of synaptic proteins. Neurobiology of Learning and Memory 2008;90(1):19-27. https://www.ncbi.nlm.nih.gov/pubmed/18316211[]
  43. Ye J, Meng X, Yan C, Wang C. Effect of purple sweet potato anthocyanins on beta-amyloid-mediated PC-12 cells death by inhibition of oxidative stress. Neurochemical Research 2010;35(3):357-65. https://www.ncbi.nlm.nih.gov/pubmed/19771514[]
  44. Lila MA. Anthocyanins and Human Health: An In Vitro Investigative Approach. Journal of Biomedicine and Biotechnology. 2004;2004(5):306-313. doi:10.1155/S111072430440401X. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1082894/[]
  45. Wang L-S, Stoner GD. Anthocyanins and their role in cancer prevention. Cancer letters. 2008;269(2):281-290. doi:10.1016/j.canlet.2008.05.020. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2582525/[][][]
  46. Anthocyanins: structural characteristics that result in unique metabolic patterns and biological activities. Prior RL, Wu X. Free Radic Res. 2006 Oct; 40(10):1014-28. https://www.ncbi.nlm.nih.gov/pubmed/17015246/[]
  47. Hou D.X. Potential mechanisms of cancer chemoprevention by anthocyanins. Curr Mol Med. 2003;3(2):149–159. https://www.ncbi.nlm.nih.gov/pubmed/12630561[]
  48. Kang S, Seeram N, Nair M, Bourquin L. Tart cherry anthocyanins inhibit tumor development in Apc(Min) mice and reduce proliferation of human colon cancer cells. Cancer Lett. 2003;194(1):13–19. https://www.ncbi.nlm.nih.gov/pubmed/12706854[][]
  49. Koide T, Hashimoto Y, Kamei H, Kojima T, Hasegawa M, Terabe K. Antitumor effect of anthocyanin fractions extracted from red soybeans and red beans in vitro and in vivo. Cancer Biother Radiopharm. 1997;12(4):277–280. https://www.ncbi.nlm.nih.gov/pubmed/10851476[]
  50. Meiers S, Kemeny M, Weyand U, Gastpar R, von Angerer E, Marko D. The anthocyanidins cyanidin and delphinidin are potent inhibitors of the epidermal growth-factor receptor. J Agric Food Chem. 2001;49(2):958–962. https://www.ncbi.nlm.nih.gov/pubmed/11262056[]
  51. Hou D.X, Kai K, Li J.J, et al. Anthocyanidins inhibit activator protein 1 activity and cell transformation: structure-activity relationship and molecular mechanisms. Carcinogenesis. 2004;25(1):29–36. https://www.ncbi.nlm.nih.gov/pubmed/14514663[]
  52. Smith M, Marley K, Seigler D, Singletary K, Meline B. Bioactive properties of wild blueberry fruits. J Food Sci. 2000;65:352–356.[]
  53. Bomser J, Madhavi D, Singletary K, Smith M.A. In vitro anticancer activity of fruit extracts from Vaccinium species. Planta Med. 1996;62(3):212–216. https://www.ncbi.nlm.nih.gov/pubmed/8693031[]
  54. Kandil F, Song L, Pezzuto J, Seigler D, Smith M.A. Isolation of oligomeric proanthocyanidins from flavonoid-producing cell cultures. In Vitro Cell Dev Biol Plant. 2000;36:492–500.[]
  55. Mazza G, Miniati E. Boca Raton, Fla: CRC Press; 1993. Anthocyanins in Fruits, Vegetables, and Grains.[]
  56. Orally administered delphinidin 3-rutinoside and cyanidin 3-rutinoside are directly absorbed in rats and humans and appear in the blood as the intact forms. Matsumoto H, Inaba H, Kishi M, Tominaga S, Hirayama M, Tsuda T. J Agric Food Chem. 2001 Mar; 49(3):1546-51. https://www.ncbi.nlm.nih.gov/pubmed/11312894/[]
  57. Effects of black current anthocyanoside intake on dark adaptation and VDT work-induced transient refractive alteration in healthy humans. Nakaishi H, Matsumoto H, Tominaga S, Hirayama M. Altern Med Rev. 2000 Dec; 5(6):553-62. https://www.ncbi.nlm.nih.gov/pubmed/11134978/[]
  58. The effect of bilberry nutritional supplementation on night visual acuity and contrast sensitivity. Muth ER, Laurent JM, Jasper P. Altern Med Rev. 2000 Apr; 5(2):164-73. https://www.ncbi.nlm.nih.gov/pubmed/10767671/[]
  59. Stimulatory effect of cyanidin 3-glycosides on the regeneration of rhodopsin. Matsumoto H, Nakamura Y, Tachibanaki S, Kawamura S, Hirayama M. J Agric Food Chem. 2003 Jun 4; 51(12):3560-3. https://www.ncbi.nlm.nih.gov/pubmed/12769524/[]
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