Supermarket spinach may have some advantages

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Supermarket produce doesn’t compare to home-grown fruits and vegetables, or even the stuff found at farmers markets, right?

Maybe not. Spinach, it seems, might do better, nutrient-wise, under cool temperatures and continuous fluorescent light than in darkness, according to a new study in the Journal of Agricultural and Food Chemistry.


Researchers from the U.S. Department of Agriculture and the Atlantic Food and Horticulture Research Centre in Nova Scotia, Canada, put two varieties of spinach leaves (Lazio and Samish) through two scenarios. In one, supermarket conditions were simulated, with spinach leaves placed in a clear plastic box and stored at about 39 degrees Fahrenheit for up to nine days with continuous fluorescent light. Similar spinach leaves had similar conditions, but were kept in darkness.

All spinach leaves kept under light tended to have higher amounts of vitamin C, folate, vitamin K, vitamin E, and carotenoids lutein and zeaxanthin (carotenoids are yellow, red and orange pigments that plants synthesize). Only carotenoids beta-carotene and violaxanthin didn’t increase. In these leaves, folate levels increased between 84% and 100%, and vitamin K levels went up 50% to 100%, depending on the variety of leaf tested. Despite the boost in nutrients, the leaves did wilt after three days. Baby spinach leaves overall had higher levels of the compounds than did leaves growing lower down on the plant.

Leaves kept in the dark either held on to their levels of bioactive compounds, or saw them decrease.

Although the researchers aren’t sure of the exact mechanism that causes the nutrients to increase, the plants apparently continue to photosynthesize under UV light.

Considering what a powerhouse of nutrients spinach contains, it may be best to pick it up at the supermarket and eat it that day. Even Popeye might agree.

-- Jeannine Stein