Micronutrient Series: Vitamin D

Written By Emily Pomfrey Wells, fact checked by Holley Samuel MEd, RD, LD, CPT

After a long cold winter of running in multiple layers runners may be looking forward to warmer weather right around the corner. Think of all the time that will be saved getting out the door with lack of needing to bundle up alone! Spring and summer for most runners means more sunshine and one of the most important vitamins: calciferol, better known as Vitamin D.

Vitamin D should wear a super hero cape because of everything it does for the human body. It helps us build strong bones, helps control muscles, and even supports immune response. This is pretty important stuff, especially for runners who are hoping to perform at their best and remain injury free. Vitamin D is so important for bone health and development that research strongly suggests that athletes who are deficient in vitamin D are at an increased risk for developing bone injuries such as stress fractures. 

Vitamin D blood levels can be checked to better understand and prevent vitamin D deficiencies as vitamin D insufficiency and deficiency are common in athletes. It’s recommended that athletes have 40 ng/mL of blood level vitamin D although optimal levels are still being debated. Another recent study suggests female athletes should have blood levels over 50 ng/mL to reduce the risk of bone stress injury. For those above the age of eighteen, it’s recommended to consume 600 IU of vitamin D each day, but if you’re a runner, you are probably going to need more.

It’s pretty common knowledge that one source of vitamin D is from sunlight, but which foods are good sources of vitamin D? Here are three to try this week:

  1. Cooked salmon 3oz. provides 570 IU

  2. Fortified vitamin D milk (soy, almond or dairy) can provide between 100-120 IU/serving. Add some fortified cereal to increase vitamin D content by around 80 IU

  3. Omelet (2 eggs-make sure to include the yolks) with white mushrooms (½ cup) that have been grown while exposed to sunlight can provide around 450 IU 

When sunshine and food isn’t enough (for many athletes this is the case) to maintain adequate vitamin D levels, supplementation may be needed. It’s important to work with a healthcare professional before starting any supplementation because taking the wrong supplement or taking too much could be harmful to health and unnecessarily expensive. Supplemental doses range anywhere from 400IU to 50,000IU prescriptions, so identifying what individual levels are through blood testing and the correct supplement dose is imperative. 

References: 

  1. Vitamin D Fact Sheet for Professionals. National Institute of Health. Updated August 17, 2021. Accessed March 2, 2022. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

  2. Yoon S, Kwon O, Kim J. Vitamin D in athletes: focus on physical performance and musculoskeletal injuries. Physical Activity and Nutrition. 2021;25(2):020-025. DOI: https://doi.org/10.20463/pan.2021.0011

  3. Sale C, Elliot-Sale KS. Nutrition and Athlete Bone Health. Sports Medicine. 2019;49(2):139–S151. https://doi.org/10.1007/s40279-019-01161-2


Holley Samuel