Maybe you tested low for vitamin D so you want to start taking vitamin D supplement or you have been reading about the various health benefits of Vitamin D including immune support and have decided you want to increase your daily vitamin D intake. Whatever your reason may be, these are the top three things you should know before you start taking a vitamin D supplement.
1. Sources of Vitamin D: Are you getting Enough?
Your body makes Vitamin D from sunlight. Basically the UVB rays in sunlight is responsible for converting a form of cholesterol that is present in your body, 7-dehydrocholesterol to Vitamin D3. This form of vitamin D3 gets further converted in the liver and then ultimately in the kidney to the most active form, calcitriol.
If you live in a region where sunlight is scarce especially in winter months, then you are likely to become deficient. Even if you live in an area where there is abundant sunshine through the year, you may be spending most of your time indoors in which case you are likely to at least have insufficient levels of Vitamin D.
You can also get vitamin D3 from food especially animal food sources such as salmon, trout, mackerel or egg yolk. But it is difficult to eat enough of these foods to meet your daily vitamin D needs. For example, a can of light tuna will provide 150 IU of vitamin D or 1 egg yolk can provide approximately 40 IU of vitamin D.
Plant forms such as mushroom and foods fortified with vitamin D2 provide even less vitamin D.
The Recommended Dietary Allowance of vitamin D for an adult is 600IU and if you are 70 years older, the RDA is 800IU.
Diet can help when there is limited sun exposure but unlikely to meet these daily goals. You cannot eat several eggs or cans of tuna per day without going over your daily limit of other nutrients such as cholesterol in the case of eggs. You may need to take a supplement to get adequate vitamin D.
2. Take Vitamin D3 instead of vitamin D2.
Vitamin D is available in 2 different supplement forms vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D3 is better absorbed in the body than vitamin D2.
Research studies have shown that vitamin D2 supplementation is less effective than vitamin D3 supplementation in increasing blood level of the vitamin. Vitamin D2 has lower potency and shorter duration of action compared to vitamin D3.
3. What is the “right amount” to take
Before you start looking for vitamin D supplements, remember to check your multivitamin content, if you take one daily. Most multivitamins contain about 400IU. Vitamin D is a fat-soluble vitamin and like all fat-soluble vitamins, excess amounts when taken will be stored in fat tissue and has the potential to buildup to unsafe levels. Vitamin D toxicity is rare and usually takes intake of very high amounts over a period of time.
Research studies recommend 1000 IU vitamin D3 in supplement form per day on average for most adults. But to know exactly how much Vitamin D supplement you need and can safely take especially if you have health issues, it is best to have your doctor order test to check blood levels of 25-hydroxy vitamin D.
If you liked this article you might find our blog on Top 10 foods to boost your immune system naturally below.
The information and other content provided in this blog are for information purpose only, and not intended and should not be considered as medical advice. If you have a medical concern, you should consult with your health care provider before you make any changes to your diet or lifestyle.
- 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(6):1357-1364. doi:10.3945/ajcn.111.031070
- Armas LA, Hollis BW, Heaney RP. Vitamin D2 is much less effective than vitamin D3 in humans. J Clin Endocrinol Metab. 2004 Nov;89(11):5387-91. doi: 10.1210/jc.2004-0360.
- Amrein, K., Scherkl, M., Hoffmann, M. et al. Vitamin D deficiency 2.0: an update on the current status worldwide. Eur J Clin Nutr 74, 1498–1513 (2020). https://doi.org/10.1038/s41430-020-0558-y
- Tsiaras WG, Weinstock MA. Factors influencing vitamin D status. Acta Derm Venereol. 2011;91(2):115-124. doi:10.2340/00015555-0980
- Vitamin D, Fact sheet for Health professionals by Office of Dietary supplements, NIH, updated October 9, 2020. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/