Do I Need A Vitamin D Supplement?

by Stephanie Skinner-Lucas, MS, RDN, LDN

Last Updated: April 12, 2021

With more sunny days on the horizon, warmer temperatures on the way, and more outdoor activities to look forward to, this is a good time to review the benefits of the ‘sunshine vitamin,’ which is vitamin D. It is called the ‘sunshine vitamin’ because it is produced when your bare skin is directly exposed to sunlight. Sun exposure is the best way to boost vitamin D levels because very few foods contain significant amounts. While most people get some vitamin D this way, clouds, smog, older adults, using sunscreen, spending more time indoors, and having dark-colored skin reduce the amount of vitamin D your skin can make. Therefore, this could increase the possibility of having a vitamin D deficiency. Time to do a little exploration to see if you may need a vitamin D supplement.

What is Vitamin D and What Does It Do?
Vitamin D is a fat-soluble vitamin that has various forms, including D-1, D-2, D-3.

One of Vitamin D’s body functions is to maintain proper calcium and phosphorus levels, which help build and maintain bones. More than 90 percent of women older than age 19 do not consume enough vitamin D. Having proper vitamin D levels during adult years helps protect you from developing osteoporosis, a disease that thins and weakens the bones and makes them more likely to break. Adequate intake of calcium and vitamin D is important for adults when peak bone mass is still actively accruing (ages 19 through about 30) and, for women, in the post-menopausal period of life, when rapid bone remodeling occurs.

Vitamin D is needed to move your muscles, and it is used by your nerves to carry messages between your brain and your body.

Your immune system uses Vitamin D to fight off invading bacteria and viruses. A 2017 study published in the American Journal of Clinical Nutrition found that vitamin D levels were inversely associated with cardiovascular events. Scientists are still studying vitamin D to better understand how it affects our health.

How Much Vitamin D Do I Need?
Life Stage Recommended Amount
Birth to 12 months 10 mcg (400 IU)
Children 1–13 years 15 mcg (400 IU)
Teens 14–18 years 15 mcg (600 IU)
Adults 19–70 years 15 mcg (600 IU)
Adults 71 years and older 20 mcg (800 IU)
Pregnant and breastfeeding women 15 mcg (600 IU)
What Foods Provide Vitamin D?
Very few foods naturally contain vitamin D. Fortified foods provide most of the vitamin D in the American diet. The Nutrition Facts label can inform you of the amount of vitamin D there is in your food!
  • Most of the U. S. milk supply is fortified with vitamin D. Many plant-based alternatives such as soy milk, almond milk, and oat milk are fortified as well.
  • Fatty fish like trout, salmon, tuna, and mackerel and fish liver oils are among the best natural food sources of vitamin D.
  • Beef liver, cheese, and egg yolk have a small amount of vitamin D.
  • Mushrooms provide a little vitamin D. Some mushrooms have been exposed to ultraviolet light to increase their vitamin D content.

Am I Getting Enough Vitamin D?
A blood test can identify whether you are getting enough vitamin D. In the blood, Vitamin D exists in a form called 25-hydroxyvitamin D. It is measured in either nanomoles per liter (nmol/L) or nanograms per milliliter (ng/dl). Levels of 50 nmol/L (20ng/mL) or higher are adequate for most people for bone and overall health Levels below 30 nmol/L (12ng/mL) are too low and might weaken your bones and affect your health Most people have adequate vitamin D blood levels. However, almost 1 out of 4 people have abnormal levels inadequate for bone and overall health.

What Kinds of Vitamin D Dietary Supplements are Available?
If your level of vitamin D is below the normal range, there are supplements available. Vitamin D is found in multivitamin/multimineral supplements, in vitamin D form only, or vitamin D combined with other nutrients.

There are 2 forms of vitamin D in supplements: D2 (ergocalciferol) and D3 (cholecalciferol). Both forms increase vitamin D in your bloodstream and create calcifediol, the main form of vitamin D and the form that your body stores. However, the liver metabolizes vitamin D2 and D3 differently. h When vitamin D2 is metabolized, it produces less calcifediol than vitamin D3. Your skin makes vitamin D3 when it is exposed to ultraviolet B(UVB) radiation from sunlight. For these reasons, D3 is the more powerful of the two types. It raises blood levels of vitamin D almost twice as much and for longer than D2.

Since Vitamin D is fat-soluble, it is best absorbed when taken with a meal or snack that includes some fat. Your healthcare provider can guide you to the form of Vitamin D that is best for you, including the amount and frequency that will work to get your Vitamin D level back to normal.

People should strive to get most of their nutrients from food and beverages. Foods contain vitamins, minerals, dietary fiber, and other components that benefit health. In certain cases, fortified foods and dietary supplements are useful when it is impossible to meet the need for certain nutrients. Keep in mind there are many options available to help you to achieve a normal vitamin D blood level. For more information on how to get enough nutrients from the food you eat, schedule an appointment with a Kroger Health Dietitian.

Disclaimer: This information is educational only and not providing healthcare recommendations. Please see a healthcare provider.


Stephanie Skinner-Lucas, MS, RDN, LDN

Stephanie Skinner-Lucas, MS, RDN, LDN

Stephanie is a proactive dietitian who believes healthy lifestyle changes are made one habit at a time. Small intentional steps early in life can lead to long-term victories for the rest of your life. With a background from geriatric nutrition to meal planning, renal disease to weight management, Stephanie has had the opportunity to serve many populations. She believes success is achieved by listening, mentoring and partnering with each individual to find what they need to live their healthiest life. Stephanie loves preparing meals with spice, crunch & texture that awakens the palate! In her free time, she enjoys helping others, walking for charity and improving her golf swing.