With Spring vying to make its move, my thoughts turn to those cold weather vegetables like spinach, a speedy-growing green, that can seed very quickly unless it’s grown in cold weather. Spinach has long been known as a vegetable rich in iron and other important nutrients that benefit the body if it’s cooked in just the right way.
Spinach is one of the richest sources of a natural occurring pigment and nutrient lutein. The retina of the human eye (specifically the macula) contains lutein and another caratonoid, zeaxanthin (Higdon & Drake, 2013). These important chemicals are responsible for protecting the eye from age-related macular degeneration and cataracts (Haas, 2006). Additionally, spinach is a good source of vitamins K, C and folic acid; and it contains the minerals calcium, manganese, magnesium and iron (Murray, et al., 2005 & Haas, 2006).
The complex interactions of various chemical and structural components in raw spinach prevent the human body from efficiently absorbing and using all of these nutrients. For example, because spinach contains oxalic acid, the ability for the body to use its iron and calcium content are limited (Wood, 2010).
Lutein and other carotenoids important for eye health are much better absorbed in the body after they are steamed or pureed, and served with a little fat. Processing spinach releases these nutrients from the complex molecular relationships among the fiber, protein and other nutrients in spinach
Though lutein absorption increases, boiled spinach yields far less antioxidant activity with losses in vitamin C and chlorophyl; and far less folate and vitamin K than the same amount of raw spinach (Fletcher & Hunter, 2002 & USDA, 2013). So for the body to get these nutrients, it’s important to continue to eat fresh spinach.
Four large studies found that people with the highest intakes of lutein and zeaxanthin from vegetables like spinach, kale and broccoli were 18 to 50 percent less likely to develop cataracts (Higdon & Drake, 2013).
Research suggests that consuming at least 6 milligrams of dietary lutein and zeaxanthin per day from vegetables like spinach may decrease the risk of age-related macular degeneration; more research is necessary to know the exact role that these two carotenoids play alone or with other carotenoids in promoting eye health (Higdon & Drake, 2013).
Haas, E. M. (2006). Staying healthy with nutrition: The complete guide to diet and nutritional medicine (21st century ed.). Celstial Arty: Berkley, CA.
Higdon, J., & Drake, V.J. (2013). An evidence-based approach to phytochemicals and other dietary factors (2nd ed.). Thieme: New York, NY.
McGee, H. (2004). On food and cooking: The science and lore of the kitchen (revised). Scribner: New York, NY.
Murray, M. Pizzorno, J., & Pizzorno, L. (2005). The encyclopedia of healing foods. Atria Books: New York, NY.
Wood, R. (2010). The new whole foods encyclopedia. Penguin Group: New York, NY.
USDA. (n.d.). National nutrient database for standard reference, release 26. Retrieved from: http://ndb.nal.usda.gov/ndb/foods/show/3214