Spinach: Health Benefits of this Green Vegetable
Spinach, like all dark green vegetables, is packed full of beneficial nutrients. Although well known for being an excellent source of iron and folic acid, spinach also contains many protective carotenoids, beneficial for healthy eyesight and other eye-related conditions, as well as having anti-carcinogenic properties.
Spinach belongs to the same family as beets and chard. The three main types of spinach are smooth leaf, savoy (this has wrinkled, curly leaves) and semi savoy (a hybrid between the two types). All are rich in nutrients, especially baby spinach leaves, which have 90 percent more antioxidants that an iceberg lettuce.
This vegetable is an excellent source of fiber, vitamin K and Vitamin C. It is a rich source of minerals such as calcium, iron, magnesium and manganese. It is also a good source of folate, a water-soluble B vitamin which is important for good cognitive function. Spinach is especially high in carotenoids, which the body converts to the antioxidant Vitamin A to help trigger immune response to fight infections. These carotenoids, including Beta-carotene, zeaxanthin, and lutein also act as protection for eye-related conditions like macular degeneration. Spinach is one of the richest sources of lutein, and is also rich in glycolipids, powerful phytochemicals known to have cancer cell growth suppression qualities.
Researchers have identified at least 13 different flavonoid compounds in spinach that function as antioxidants and as anti-cancer agents. The anticancer properties of these spinach flavonoids have been sufficiently impressive to prompt researchers to create specialized spinach extracts that have been used in controlled studies. Here is a selection of some of the findings.
age-related macular degeneration
A study involving 356 subjects with advanced macular degeneration (vision loss) found that higher intake of spinach resulted in significantly lower risk for age-related macular degeneration.
A study of human liver cancer cells found that spinach had the highest antiproliferative effect (inhibited cell growth) as compared to other vegetables.
Another study found a significant relationship between spinach consumption and the risk of gallbladder cancer.
A natural antioxidant in spinach leaves was found to slow prostate cancer in both animal and human prostate cancer cells.
Retinoids in spinach were found to have chemotherapeutic and chemopreventative potential for cervical cancer.
A study of more than 36.000 Americans found that spinach was correlated with a lower risk of developing cataracts.
Rats that had suffered brain damage and were fed a spinach diet showed a reduction in damaged tissue and increased brain function.
Tips for Using Spinach
- Store fresh spinach in the refrigerator, as it will retain more nutrients this way. A 2005 study found that commercially packed fresh spinach stored at refrigerator temperatures retained folate and carotenoid content at a slower rate than spinach stored at higher temperatures, but when it was kept for longer than 8 days it lost much of its nutrient content.
- Spinach is extremely versatile. The baby leaves can be eaten raw in salads, or it can be wilted for a few minutes in butter, olive oil or lemon juice, to accompany any dish.
- Moeller, S.M., Jacques, P.F., & Blumberg, J.B. (2000, October). The potential role of dietary xanthophylls in cataract and age-related macular degeneration. J Am Coll Nutr, (5 Suppl): 522S-527S.
- Kuriyama, I., Musumi, K., Yonezawa, Y., Takemura, M., Maeda, N., Iijima, H., Hada, T., Yoshida, H., & Mizushina, Y. (2005, October). Inhibitory effects of glycolipids fraction from spinach on mammalian DNA polymerase activity and human cancer cell proliferation. Journal of Nutritional Biochemistry, 16(10), 594-601.
- Seddon, J.M., Ajani, U.A., Sperduto, R.D., Hiller, R., Blair, N., Burton, T.C., Farber, M.D., Gragoudas, E.X., Haller, J., & Miller, D.T. (1994, November 9). Dietary carotenoids, vitamins A,C, and E, and advanced age-related macular degeneration. Eye disease case-control study group. JAMA, 272(18), 1413-1420.
- Chu, Y.F., sun, J., Wu, X., & Liu, R.H. (2002, November 6). Antioxidant and antiproliferative activities of common vegetables. J Agric Food Chem, 50(23), 6910-6.
- Rai, A., Mohapatra, S.C. & Shukla, H.S. (2006, April). Correlates between vegetable consumption and gallbladder cancer. Eur J cancer Prev, 15(2), 134-137.
- Sani, H.A., Rahmat, A., Ismail, M., Rosli, R., & Endrini, S. (2004). Potential anticancer effect of red spinach (Amaranthus gangeticus) extract. Asia Pacific Journal of Clinical nutrition, 13(4), 396-400.
- Nyska, A., Suttie, A., Bakshi, S., Lomnitskia, L., Grossman, S., Bergman, M., Ben-Shaul, V., Crocket, P., Haseman, J.K., Moser, G., Goldsworthy, T.L., & Maronpot, R.R. (2003, January/February). Slowing Tumorigenic Progression in TRAMP Mice and Prostatic Carcinoma Cell Lines Using Natural Anti-Oxidant from spinach, NAO--A Comparative Study of Three Anti-Oxidants. Toxicologic Pathology, 31(1), 39-51.
- Abu, J., Batuwangala, M., Herbert, K., & Symonds, P. (2005, September). Retinoic acid and retinoid receptors: potential chemopreventive and therapeutic role in cervical cancer. Lancet Oncol, 6(9), 712-720.
- Brown, L., Rimm, E.B., Seddon, J.M., Giovannucci, E.L, Chasan-Taber, L., Spiegelman, D., Willett, W.C., & Hankinson, S.E. (1999, October). A prospective study of carotenoid intake and risk of cataract extraction in US men. Am J Clin Nutr, 70(4), 431-432.
- Wang, Y., Chang, C., Chou, J., Chen, H., Deng, X., Harvey, B., Cadet, J.L., Bickford, P.C. (2005, May). Dietary supplementation with blueberries, spinach, or spirulina reduces ischemic brain damage. Experimental Neurology, 193(1), 75-84.
- Kelemen et al. vegetables, fruit, and antioxidant-related nutrients and risk of non-Hodgkin lymphoma: a National cancer Institute-Surveillance, Epidemiology, and End Results population-based case-control study. Am J Clin Nutr. 2006 Jun;83(6):1401-10.
- Pandrangi S, Laborde LF. Retention of folate, carotenoids, and other quality characteristics in commercially packaged fresh spinach. Journal of Food Science, Vol. 69, No. 9, 2004.