Nutritional levels found in spinach may improve when exposed to fluorescent lighting used in grocery stores, according to findings published in the Journal of Agriculture and Food Chemistry. Prior studies have found that spinach is a high source of antioxidants, folate and vitamins C, D and K.

Spinach is normally sold in clear plastic containers and kept at39 degrees Fahrenheit. Also, in many grocery stores, the vegetable can be exposed to lighting for up to 24 hours a day.

To see how the nutritional levels of spinach were affected by the fluorescent bulbs, a team of researchers from the American Chemical Society conducted a study that lasted between three to nine days that exposed the vegetable to either constant light sources or complete darkness.

The investigators discovered that spinach exposed to the lighting for three days was found to have higher nutrition levels, and the vegetables that were under the lighting for nine days had between 84 and 100 percent more folate. The study also showed that the spinach had an increase in vitamin K between 50 and 100 percent.

However, spinach that was kept in the dark during the trial experienced no change or contained lower levels of the nutrients.

In addition to eating spinach, consuming foods such as blueberries, pistachios and tomatoes, which are high sources of antioxidants, can help improve optimal health.