Most of us wouldn’t think twice about grabbing a prepackaged salad instead of uncut romaine or kale.
In fact, more than 70 percent of households in America consumed bagged greens in 2014.
But some recent studies have found the convenient shortcut may have a downside.
Prepackaged salads lose some minerals and vitamins – particularly vitamin B and C – when they are chopped, washed and bagged due to exposure to light, oxygen and heat.
While nutritionists warn these changes are minimal – and any greens on the plate should be applauded – we break down the details of what each grab-and-go salad sacrifices, and to what extent.
Researchers say nutrients like iron and calcium aren’t impacted by the washing and chopping of packaged greens
‘Prepackaged salad greens are nutritionally on par with other mixed baby greens that you by fresh and unpacked,’ registered dietitian Julie Upton, founder of the blog App for Health, told Daily Mail Online.
But she said there may be a slight reduction in nutrients due to salad greens being exposed to light.
In fact, some vitamins, such as vitamins A and E, found in greens are very sensitive to light and oxygen. Which means that by the time salads are bagged, they may have a reduced amount of these nutrients.
Many packaged spinach and kale are often prewashed. This may also diminish vitamins, such as vitamin C and B vitamin folate, that dissolve in water or are water-sensitive, according to New Jersey-based registered dietitian Vanessa Rissetto.
However, experts say the chopping of packaged salad greens may not directly affect the nutritious content.
‘However, you do create damage to plant cells, potentially releasing enzymes and other factors, as well as create more surface area for oxidation to occur,’ Mario Ferruzzi, a professor in the Department of Food, Bioprocessing and Nutrition Sciences at North Carolina State University, told CNN. This means the chopping of vegetables may cause them to turn brown prematurely.
Many factors are involved in the amount of nutrition packaged produce contain, including how long it sits in the fridge and what type of salad green it is.
For instance, a 2005 study published in the Journal of Food Science found spinach stored at 39 degrees loses much of its folate and carotenoid content – vitamins that have been shown to reduce heart disease and improve the immune system, respectively – after eight days.
However, a 2007 study published in Food and Nutrition Research found lettuce maintained most of its folate content after eight days of storage.
Furthermore, research published a 2017 issue of Food Chemistry found that after just three days of storage, spinach lost 80 percent of its vitamin C content while watercress maintained nearly 60 percent of its vitamin C content after 10 days of storage.
However, experts say the nutritional changes that occur are very small.
In fact, Rissetto added that minerals like iron and calcium are ‘pretty stable’ and wouldn’t degrade during the washing and cutting process ‘unless heat is applied which generally should not be.’
It seems water-soluble vitamins are the only ones impacted by the washing and chopping of prepackaged greens, but experts say salad-lovers shouldn’t be concerned.
‘As a rule people aren’t really deficient in B vitamins like folate or vitamin C for unless they are food compromised or just have a poor diet in general,’ Rissetto explained. ‘If you’re eating bagged salad I’m going to go out on a limb and say you’re likely eating other fruits/vegetables and whole grains so you shouldn’t worry about missing too much.’
But if the loss of vitamin C is a concern, people can find solace in how these greens are packaged.
Prewashed produce are usually bagged using technology called modified atmosphere packaging, Ferruzzi said.
This process significantly reduces the amount of oxygen in a package by replacing it with an inert gas such as nitrogen.
A 1999 study published in the Journal of Agricultural and Food Chemistry has shown that modified atmosphere packaging helped spinach retain most of its vitamin C content during storage.
This process also extends shelf life and helps prevent the browning of chopped vegetables, which makes packaged produce a great alternative to fresh salad greens, Upton said.
‘Salad greens are convenient and can get so many people to eat more vegetables,’ she said.
‘It can actually improve people’s diet more than regular, unpackaged salads and vegetables,’ she added. ‘Because many people buy fresh produce and let it sit in their fridge until it goes bad… But packaged greens are right there in your fridge, ready to eat.’