The good news: The salad dressing you might despise for adding extra calories actually makes up the superfood on your plate.
A recent study published in the scientific journal Food Nutrition concludes that oil-based dressings or sauces (including mayonnaise-based sauces) can help the body absorb kale’s valuable nutrients.
Kale contains many beneficial compounds that promote overall well-being, but these nutrients are fat soluble. This essentially means that they break down only in the presence of fat. In other words, it is hard for the body to absorb the nutrients in kale – unless the kale is eaten with fat.
Ruojie “Vanessa” Zhang, one of the study authors, explains in a Summary Among the findings:
“Kale is a nutrient-rich vegetable that contains carotenoids, including lutein, alpha-carotene, and beta-carotene, which have beneficial effects on overall health. The problem is that our bodies have difficulty absorbing these nutrients because they are fat soluble rather than water soluble.”
carotenoids Nutrient-rich pigments are what give some fruits and vegetables their color. They are linked to better vision, a stronger immune system, and a lower risk of conditions like diabetes, heart disease and some cancers.
In the study, researchers put kale through a simulated gastrointestinal tract model that mimics human digestion. They tested it in several ways:
- Raw
- ripe
- raw or cooked with dressing or sauce
- cooked in sauce
The results showed that raw kale on its own had very little nutrient absorption, and simply cooking the kale actually worsened absorption.
But once the researchers added an oil-based “nanoemulsion” sauce — basically a finely mixed oil-based dressing, though not one you or I have in the fridge — the models absorbed far more of the carotenoids that give kale its health reputation.
This will be the case whether the kale is raw or cooked, and whether the sauce is added before or after cooking. This suggests that cooking the kale in an oil-based sauce works as well as throwing the sauce in later, so you have flexibility in how you prepare it.
Kale also contains vitamins C and E and other plant compounds that support overall health.
But again – they are largely fat soluble. Therefore, downing kale directly is not as helpful as some people may think.
Instead, you can (thankfully) use modest amounts of olive oil vinaigrette, an oil-based sauce or a mayonnaise-based dressing to make the nutrients in kale more accessible to your body.
Learn more about why you might want to add kale to your regular diet in “5 Nutrients That May Prevent Alzheimer’s – and Foods Rich in Them.”