Think you’re getting all those vitamins and minerals from your food? Maybe not.


“You are what you eat” is a very famous saying . . . although, you may have heard the more accurate version of it: “You are what you eat and absorb.” Absorption is important because it’s possible to eat a variety of highly nutrient-dense foods but not get the full benefit from these nutrients simply because of your gene. Not absorbing nutrients is similar to not getting them in the first place. Nutrients can’t help your body if they never truly make it inside to support your reproductive health. Take for example Vitamin D.

Vitamin D and Reproductive Health

You may already know vitamin D is essential for bone health because it promotes absorption of calcium and is needed by bone cells for growth and repair. It also plays an important role in fertility and reproduction. Vitamin D is essential for the fertilization of an egg and sperm. In men, vitamin D promotes sperm motility and viability. Vitamin D also helps reduce inflammation and helps to regulate the immune system and carbohydrate metabolism. Optimal level of vitamin D contributes to a healthy immune system and reduced risk for endometriosis. Changes in the immune system and the presence of endometriosis can affect embryo implantation. Higher levels of vitamin D have been linked to higher in vitro fertilization success rates. The risk for spontaneous abortion during the first trimester is higher in those with Vitamin D deficiency. So not consuming enough vitamin D can negatively affect your reproductive health.

Risk of Vitamin D Deficiency

According to a study published in the journal Nutrients, researchers found that “Nearly one-third of the U.S. population is at risk of deficiency in at least one vitamin, or has anemia.” The top five most common nutrient deficiencies were for Vitamins B6, B12, C, and D, and the mineral iron. Many factors can influence the absorption of nutrients in our food. Your gene is one factor in determining how efficiently your body absorbs and utilizes certain nutrients, including vitamin D.

Sources of Vitamin D

You can get vitamin D from sunlight, foods, and supplements. Vitamin D is known as the sunshine vitamin because your skin makes Vitamin D when exposed to UV light. Fatty fish such as salmon, and fortified dairy products are the best sources of vitamin D. However, it can be difficult to reach needs through sunlight and food alone, so supplementation may be beneficial. For women of childbearing age and pregnant women, the RDA for vitamin D is 15 micrograms per day.

How Much Do You Need?

Vitamin D deficiency is diagnosed by measuring the most common form of vitamin D in the blood, which is 25-hydroxyvitamin D. Research shows that variations in the CYP2R1 and GC genes can affect your risk for low circulating 25-hydroxyvitamin D levels. Low level of 25-hydoxyvitamin D can affect your reproductive health. If you have one or more elevatedrisk variant gene, you are at an increased risk for low circulating vitamin D levels. In this case aim for 1000 IU (25 mcg) vitamin D per day. This can help to maintain or improve your likelihood of conceiving by enhancing calcium absorption and metabolism, immune function, and sperm or oocyte ability to fertilize and grow. Do not exceed 2000 IU (50 mcg) per day without having a conversation with your physician. You will need to have your blood levels of vitamin D assessed and monitored since it’s a fat soluble vitamin.

If you are interested in the Nutrigenomix test for a better insight into your fertility health, we offer the fertility gene test with our service.


  • Hou, W., Yan, X., Bai, C., Zhang, X., Hui, L., Yu, X. Decreased serum vitamin D levels in early spontaneous pregnancy loss. European Journal of Clinical Nutrition. 2016;70(9):1004-1008.
  • Jensin, MB., Bjerrum, PJ., Jessen, TE., Nielsen, JE., Joensen, UN., Olesen, IA., Petersen, IH.. Juul, A., Dissing, S., & Jorgensen, N. Vitamin D is positively associated with sperm motility and increases intracellular calcium in human spermatozoa. Human Reproduction. 2011;26(6):1307-1317.
  • Karsenty, G., Oury, F. Regulation of male fertility by the bone-derived hormone osteocalcin. Molecular and Cellular Endocrinology, 2014;382(1):521-526.
  • Bird, JK., Murphy, RA., Crappie, ED., & McBurney, MI. Risk of Deficiency in Multiple Concurrent Micronutrients in Children and Adults in the United States. Nutrients. 2017. 1-20.
  • Slater, NA., Rager, ML., Havrda, DE., & Harralson, AF. Genetic Variation in CYP2R1 and GC Genes Associated With Vitamin D Deficiency Status. Journal of Pharmacy Practice. 2015:1-6.
  • Wang TJ et al. Common genetic determinants of vitamin D insufficiency: a genome-wide association study. Lancet. 2010;376(9736):180-88.

Hi, I’m Katelyn! Empowering your fertility journey with tailored nutrition guidance, A&N Nutrition Service offers specialized support for women undergoing fertility treatments.

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