- Blending spinach smoothies with coconut or cow milk could increase the nutrient content.
- Researchers tested smoothie ingredients and found a certain antioxidant dissolved better with fats.
If you want to get the most out of leafy greens in your smoothies, you may want to add in high-fat liquids such as coconut milk or whole milk, recent research suggests.
The liquid you add in to help blend your ingredients may affect how certain nutrients are available for your body to absorb, according to a study published February 2 in the journal Nutrients.
Researchers from Linköping University is Sweden tested 14 different types of liquid in smoothies to see how they affected the nutritional content. They specifically measured how much of a specific antioxidant they were able to extract from spinach in the smoothies. The antioxidant, called lutein, is a type of nutrient known as a phytochemical, also found in kale, broccoli, and herbs like basil, as well as eggs, kiwi fruit, and grapes. Lutein is linked to benefits such as reduced risk of heart disease, lower inflammation, and healthy aging, specifically protecting the eyes, brain, and skin from cellular damage over time.
Data from the study showed the smoothies made with whole milk and coconut milk had significantly higher levels of available lutein than smoothies made with water. That's partly explained by the fact that the nutrient dissolves in fat but not in water. However, other factors like protein and fiber content may also make a difference, according to the study.
The researchers were surprised to find, however, that yogurt was not as effective for making lutein available for absorption, possibly because of the fermentation process involved in producing it.
They found that plant-based milks were also ineffective for optimizing the amount of lutein in a smoothie. Both oat milk and almond milk smoothies had about the same levels of lutein as smoothies made with water. Soy milk smoothies were significantly lower in lutein than those made with water, researchers found.
"Plant-based liquids have become increasingly common in smoothies. We saw that soy milk was actually less effective than water when it comes to liberating lutein in spinach smoothies," Jan Neelissen, co-author of the study and doctorate student at Linköping University said in a press release.
While the study measured the amount of lutein available in smoothies, it did not directly measure how much humans were able to absorb from the different drinks, so more research is needed to determine how it might help or hurt our nutrition goals.
Pro athletes, dietitians, and celebs swear by spinach smoothies
To start boosting your blender game now, try adding a hit of milk or coconut to one of the smoothie recipes that pro athletes use after a workout, mixing spinach with ingredients like protein powder, berries, other veggies, and spices.
NBA champ Steph Curry, for instance, drinks a mixture of spinach, kale, blueberries, cinnamon, mango, and vanilla extract with coconut water and Greek yogurt.
Tennis great Naomi Osaka gets her dose of spinach along with cucumbers, apples, pineapples, lemon, ginger, electrolytes, and protein powder.
For a flavorful, high-fiber option, registered dietitian Meghan Pendleton recommends a blueberry basil smoothie with blueberries, banana, basil, spinach, avocado, protein powder, and milk.
Celebrities also love smoothies with leafy greens, like a combo of lettuce, spinach, apple, banana, pear, and coconut water the Reese Witherspoon said she drinks "every single day."