It’s easy to assume that as long as you’re eating healthy foods, your body is getting all the nutrition it needs for optimal health. To that end, smoothies filled with greens, fruits and powder add-ons have become incredibly popular.

But there’s a problem with that assumption…

The truth is what your body absorbs from food can range from 10 to 90 percent. And many factors, such as time of day, other foods eaten at the same meal, preparation methods, the health of your digestive system and your age, affect how much nutrition you may or may not be getting.

Ease of absorption — or bioavailability — can also depend on the nutrient. Certain vitamins like A, D, E and K are all fat-soluble vitamins, meaning they dissolve in fat. If you want to soak up those important nutrients, you need to consume supplements or foods containing them with some dietary fat.

Then there are phytochemicals (or phytonutrients), which may be the most powerful source of antioxidants. Their potential benefits include strengthening the immune system, reducing inflammation, preventing DNA damage (and repairing it!), regulating hormones and preventing damaged cells from reproducing and spreading.

They come from plants, but unfortunately, phytochemicals can be tough to free up from the fruits and vegetables that contain them. But because they’re far too important for us to miss out on, researchers looked into what we can do to make that easier…

Help your smoothie give up the goods

According to Rosanna Chung, assistant professor in the Department of Health, Medicine and Caring Sciences at Linköping University, “Lutein is a bio-active compound. We have studied lutein in a similar way to studying a pharmaceutical drug.”

That means lutein is one powerful phytochemical…

In the world of science, a bio-active compound is a type of chemical found in small amounts in certain foods that have action in the body that may promote good health. These compounds are being studied in the prevention of cancer, heart disease and other diseases. 

Spinach is a great source of lutein, but as we discussed earlier, just eating spinach, even lots of it, doesn’t ensure you’ll get your fair share of lutein. Plus, there are additional complications…

Previous research has found that lutein degrades when heated. So cooking spinach can cheat you of this powerful compound.

That’s why Prof. Chung and fellow researchers at Linköping University (LiU) decided to explore different ways to prepare smoothies using raw spinach.

One thing they discovered was that lutein is fat-soluble, not water-soluble. So lutein requires gastric juice and/or other food components to free it from the plant material and allow it to be absorbed in the intestines.

They also discovered that the liquid you choose to blend up with your spinach makes a huge impact on how much lutein gets freed up…

Out of 14 different dairy and plant-based liquids used in the smoothie preparations, only four increased the release of lutein from spinach compared to water:

• Smoothies made with high-fat cow’s milk and medium-fat cow’s milk increased lutein liberation by 36 percent and 30 percent, respectively.
• Coconut milk was even more effective, increasing lutein release by 42 percent.
• Coconut milk with additives showed a 25 percent increase in lutein liberation.

Most plant-based “milk” beverages did not affect lutein release. Neither did yogurt, which could be due to the fermentation process. And soymilk actually reduced lutein liberation by 61 percent compared with water.

Remember the fat

One reason the cow’s milk and coconut milk were so effective at increasing lutein release could be because they both contain fat. It works for fat-soluble vitamins, so makes perfect sense.

If you’re not a fan of smoothies, consider a raw spinach salad made with a dressing made from olive oil. Remember to steer clear of cooking it — if the nutrition is what you’re after.

One more important note the researchers made: Spinach smoothies should be consumed as soon as possible because lutein breaks down quickly. So don’t let it sit around too long or store in the refrigerator, or else all your hard work liberating lutein goes down the drain.

Sources:

The best liquids to maximise antioxidant content in spinach smoothies — Linköping University

The Effects of Dairy and Plant-Based Liquid Components on Lutein Liberation in Spinach Smoothies — Nutrients

How Much Nutrition Do You Absorb from Food? — Scientific American

Fat-Soluble Vitamins — National Library of Medicine

Are You Eating Too Many Antioxidants? — Prevention

Nanoscale Delivery Systems of Lutein: An Updated Review from a Pharmaceutical Perspective — Pharmaceutics