Skip the Wheatgrass Shots and Boost your Immunity Extra Virgin Olive Oil

In a recent post covering the 101 on fat-soluble vitamins, we reviewed the importance of eating fat with meals 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 have all grown up with someone in our lives saying, “Eat your fruits and veggies, they have vitamins that are good for you.” A few may know the basics like “carrots are good for your eyes,” and “calcium builds strong bones.” But, it isn’t always that simple. 

This article will provide a more in-depth guide to fat-soluble vitamins –– their purpose, sources, and specifically their role in immune health

Fat-Soluble Vitamin



Top Sources

Vitamin A

Retinoic Acid

Cell growth and differentiation
Bone development 
Immune health 

  1. Beef liver
  2. Herring
  3. Dairy products

Provitamin A



  1. Spinach
  2. Carrots
  3. Collard Greens

Vitamin D

Ergocalciferol (D2)
Cholecalciferol (D3) 

Bone metabolism
Blood calcium homeostasis
Cell differentiation and growth
Immune health 

  1. Cod liver oil
  2. Fish
  3. Fortified dairy

Vitamin E



  1. Wheat germ oil
  2. Extra virgin olive oil 
  3. Nuts and nut butters

Vitamin K

Phylloquinone Menaquinones

Blood clotting factors
Bone proteins

  1. Dark leafy greens
  2. Asparagus
  3. Legumes

 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.

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 regards 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 extra virgin olive oil 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, 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.

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 extra virgin olive oil (EVOO) to your meals:

  1. Massage extra virgin olive oil (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 extra virgin olive oil (EVOO) and roast them
  3. Pan fry shrimp in extra virgin olive oil (EVOO), 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.


  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

Written by Chloe Morrill

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 52 Weeks, a weekly meal plan program that helps users get back in the kitchen and feed themselves well. Kelly is also a co-founder of Olivaio.

Frequently Asked Questions

Q: What does fat-soluble mean?
Fat-soluble vitamins refers to vitamin that are soluble in organic solvents and absorbed and transported in a manner similar to that of fats. This means that unlike water-soluble vitamins like Vitamin B and C, Vitamins A, D, E, and K will metabolize just like other fats and can over-accumulate in your body. Because fat-soluble vitamins can over-accumulate and be stored in the body's fatty tissues, you should be careful not to over-consume on fat-soluble vitamins.

Q: Would taking multivitamin supplements be enough to fulfill my vitamin needs?
Yes, most multivitamin supplements are formulated to provide and fulfill most of your micronutrient needs, which include fat-soluble and water-soluble vitamins. However, these supplements can't replicate food and all of the nutrients and benefits of whole foods, such as fruits and vegetables, so try to get your micronutrients from food sources.