In a recent post covering the 101 on fat-soluble vitamins, we reviewed the importance of incorporating fat in your diet to help the body absorb and store vitamins. Today, we'll dive a bit deeper by discussing the role of fat-soluble vitamin absorption in immune health.

We've all been cautious the past few years. Immune-boosting foods and supplements have been at the center of the nutrition and wellness world, and for good reason — we’ve been in a global pandemic. Though no diet or single food can keep you from catching covid or getting the flu, you can increase your overall health by taking care of your mind and body.

This article will provide a more in-depth guide to fat-soluble vitamins — their purpose, sources, and specifically their role in immune health (2,3).

As you can see, each fat-soluble vitamin plays a role in various bodily functions. Though they are all crucial, when it comes to immune health, Vitamin A and Vitamin D are the most important. We’ll discuss both below.

Vitamin A

As discussed above, Vitamin A (and pro-vitamin A) can be found in a wide variety of foods. Pro-vitamin A is typically found in carotenoids, foods that contain a specific pigment that provides powerful antioxidants. In regard to immune health, Vitamin A, specifically retinoic acid, has been observed as a key player in immune function on a cellular level.

According to Gropper & Smith (2), “Dendritic cells are involved in the immune response, retinoic acid regulates the proliferation and differentiation of them.” In addition to this, Gropper & Smith (2) discuss that “Vitamin A is needed for T-lymphocyte function and for antibody response to viral, parasitic, and bacterial infections.”

As we can see, vitamin A has a particular role in immune health. However, it is essential to consume vitamin A with fat so the body can actually absorb it. About 70-90% of vitamin A is absorbed as long as the meal contains (~10 g or more) some fat (2).

Keep reading for easy ways to combine EVOO and vitamin A to support maximum absorption.

Vitamin D

Commonly referred to as the “sunshine vitamin,” vitamin D can be produced in the skin with direct sunlight or ingested through fish products or fortified foods. Vitamin D is usually associated with calcium, as they both work together to build strong bones, however, vitamin D has a lesser-known role as a start player in immune health.

Arranow (1), a lead investigator of vitamin D’s roles in the body, states, “Vitamin D can modulate the innate and adaptive immune responses.” She elaborated that “Deficiency in vitamin D is associated with increased autoimmunity and an increased susceptibility to infection.” Furthermore, immune cells were found to have vitamin D receptors on them, providing more evidence of vitamin D’s direct role in immune function (1).

We know vitamin A and D are key players in immune function and health. Both of these vitamins are critical to support a healthy immune system, so make sure to consume them with fat so that they can be better absorbed and stored!

Here are 3 easy ways to add EVOO to your meals:

1. Massage EVOO into your fish filet before you bake or broil it.

2. Lightly coat a carotene-based vegetable medley (think carrots, squash, sweet potatoes) in EVOO and roast them.

3. Pan fry shrimp in EVOO and add them to your favorite pasta dish or salad.

For more tips on how to practice using the Mediterranean diet in your everyday cooking, click here.

Written by Chloe Morrill, RD

Reviewed by Kelly Powers, MA, RDN, a Registered Dietitian Nutritionist who takes a holistic approach to nutrition and health. Kelly is a recipe developer with a food blog highlighting whole foods, simple recipes, and her life in San Francisco. She’s the creator of Weeknight Dinners, a weekly meal plan program that helps users get back in the kitchen and feed themselves well.

References

1. Aranow C. (2011). Vitamin D and the immune system. Journal of investigative medicine: the official publication of the American Federation for Clinical Research, 59(6), 881–886. https://doi.org/10.2310/JIM.0b013e31821b8755

2. Gropper, S. S. & Smith, J. L. (2018). Advanced Nutrition and Human Metabolism: Seventh edition. Cengage Learning.  

3. Harvard Medical School. (2018, November 14). Listing of Vitamins. Harvard Health. Retrieved from: https://www.health.harvard.edu/staying-healthy/listing_of_vitamins