Shannon Wright MS, RD
Vitamin D has been emerged as a popular nutrient and supplement over the past decade. Discovered in the early 1900s as an anti-rickets compound and consequently added to several food sources (e.g. dairy) through mandatory U.S. fortification programs in the 1930s, vitamin D has long been considered a key fat-soluble vitamin essential for overall health.
Unfortunately 93% of Americans are failing to consume adequate vitamin D from food sources (including fortified foods)1, and this lack of vitamin D has led to approximately 1/3 of Americans having insufficient or deficient vitamin D levels.2 This is an important nutrient gap issue impacting individuals of all ages, from children to the elderly.
Why is vitamin D important?
• Builds and supports strong bones by enhancing calcium absorption†
• Helps regulate mineral concentrations of calcium and phosphorus in the body
• Supports a healthy immune system†
• Supports muscle health†
• Currently being researched for a variety of other important roles in the body
Where can I get vitamin D?
Our skin can actually make vitamin D by using the ultraviolet B rays in sunlight to convert a pre-vitamin D compound in our skin into vitamin D. However, because we use sunscreen and spend significant amounts of time indoors, our skin cannot be relied upon to provide adequate amounts of daily vitamin D.
Foods provide minimal amounts of vitamin D, which partially explains why low vitamin D levels are so prevalent. While certain foods naturally contain or are fortified with vitamin D, excessive amounts of such sources are required in order to meet our daily vitamin D needs. For example, to obtain just 1,000 IU of vitamin D, it would take approximately 10 glasses of milk or 10 ounces of salmon per day to fulfill the requirement. For many people, a daily vitamin D supplement is necessary to achieve and maintain healthy vitamin D levels in the body.
|Amount Per Serving
| Cod liver oil
| 1,360 IU per tablespoon
| Cooked salmon
| 360 IU per 3.5 ounces
| Fortified milk
| 100 IU per 8 oz. cup
| Fortified cereal
| 40 IU per ¾-1 cup
| 20 IU per 1 whole egg
In addition to sunshine and foods, nutritional supplements provide a convenient source of vitamin D.
How much vitamin D is right for me?
• For adults 19+ years old, 600 – 800 IU/day is the current Recommended Daily Allowance (RDA), which provides a minimum vitamin D requirement for bone health support.3
• For adults 19+ years old, 1,500 - 2,000 IU per day of vitamin D3 is the recommended dose by clinical practice guidelines, to raise vitamin D levels in your blood into the sufficient range (i.e. > 30 ng/ml).4
• 5,000 IU/day or more is often recommended by health care professionals if you have been identified as having low levels of vitamin D (i.e. < 30 ng/ml).4
Do you know the two types of vitamin D?
• Vitamin D is available in two forms: vitamin D2 and vitamin D3.
• Vitamin D3, which is of animal origin, is the preferred form because it raises and maintains vitamin D levels in your blood more efficiently than vitamin D2.5
• Vitamin D3 is the form most commonly found in nutritional supplements.
• Vitamin D2, which is of plant origin, is the common prescription form of vitamin D in the US.
Always let your personal health care professional know about all of your vitamin choices. They have the best perspective on your vitamin needs in relation to your overall health.
Are you at risk for vitamin D insufficiency or deficiency?
You may be at risk if you:
• don’t take a multivitamin or vitamin D supplement
• don’t regularly consume dairy products
• are overweight or obese
• are 50 years of age or older
• have darker skin
• have limited sun exposure:
• experience less than 10-30 minutes of sun exposure between 10 a.m. and 3 p.m. at least twice a week
• wear sunscreen on a regular basis
• are restricted to indoor activity or live in a nursing home
• live in a region with a long winter season
• live in a region with air pollution
• have a fat malabsorption, liver or kidney disorder
• take medications that affect vitamin D absorption or metabolism
Your doctor can arrange for a simple blood test (serum 25-hydroxyvitamin D) to determine your vitamin D status. Talk to your doctor about whether this blood test would be right for you. Be proactive with your health and consider taking a vitamin D supplement as part of a healthy supplement regimen.
1. Fulgoni VL, Keast DR, Bailey RL, et al. Foods, fortificants, and supplements: where do Americans get their nutrients? J Nutr. 2011;141:1847-1854.
2. Looker AC, Johnson CL, Lacher DA, et al. Vitamin D status: United States, 2001-2006. NCHS Data Brief. 2011(59):1-8.
3. Institute of Medicine. Food and Nutrition Board. Dietary Reference Intakes for Calcium and Vitamin D. National Academy Press. Washington, D.C. 2010.
4. Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol & Metab. 2011;96(7):1911-1930.
5. Tripkovic L, Lambert H, Hart K, et al. Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. Am J Clin Nutr 2012;95:1357-1364.