Is Your Prenatal Doing Its Job?


As you navigate the world of fertility and pregnancy, you may have come across the term ‘bioavailability’ when researching a prenatal vitamin. But what does it mean, and why does it matter, especially when it comes to choosing the ideal prenatal vitamin? 

Let’s explore the significance of bioavailability and highlight some of the most absorbable forms of essential nutrients so you can make the best decision for both your body and your growing baby when eyeing the nutrient label on your next prenatal vitamin.

prenatal vitamin

What is bioavailability?

Bioavailability is a fancy word that describes how well your body can absorb and use the nutrients you consume. It's not just about the quantity of nutrients, but how readily the nutrients can be absorbed by your body. When a nutrient has high bioavailability, it means your body can easily absorb and utilize it, giving you the maximum benefits. So, when it comes to choosing the ideal prenatal vitamin, it's important to consider the forms of nutrients that are easily absorbed by your body for optimal health and well-being during pregnancy.

Choosing the ideal forms of nutrients

Let's take a closer look at some key nutrients commonly found in prenatal vitamins and the sources from which they are derived.

Folate or Folic Acid

Folate and folic acid are often used interchangeably. While they are both Vitamin B9, they’re not exactly the same thing.  Folate is the naturally occurring form of this essential B vitamin found in foods, while folic acid is the synthetic version commonly used in supplements and fortified foods. 

Folate has higher bioavailability since it is already in the active form that your body can readily absorb and utilize. Folic acid, on the other hand, requires conversion into its active form, methylfolate, before it can be effectively used by your body. Some individuals have genetic variations, like MTHFR, that make this conversion less efficient, leading to lower bioavailability of folic acid compared to folate in these individuals.

  • Opt for a prenatal vitamin that contains methylated folate rather than folic acid.

  • Vitamin D

    When your skin is exposed to sunlight, your body naturally produces vitamin D3 (cholecalciferol), which is highly bioavailable. However, dietary sources and supplements can provide either vitamin D3 or vitamin D2 (ergocalciferol). Vitamin D3 has been found to have superior bioavailability and is more effective at raising blood levels of vitamin D compared to vitamin D2.

  • Opt for a prenatal vitamin that includes Vitamin D3 and don’t forget to enjoy some sunshine.

  • Iron

    Who knew there were so many forms of iron? Iron glycinate, compared to other forms of iron, such as ferrous sulfate or ferrous gluconate, is believed to have higher bioavailability. Iron glycinate is generally well-tolerated and less likely to cause gastrointestinal side effects like constipation and stomach upset, which are commonly associated with other iron supplements. 

    Iron glycinate has also been found to be less affected by dietary factors that can hinder iron absorption, such as the presence of certain foods or medications. This further contributes to its superior absorbability, helping your body to efficiently utilize the iron.

  • Opt for a prenatal that includes iron glycinate.

  • B Vitamins

    Different forms of B vitamins can have varying bioavailability. We’re going to use some big, fancy words here, but don’t worry, there won’t be a spelling test later! 

    Methylcobalamin, the active form of vitamin B12, has higher bioavailability compared to cyanocobalamin, a commonly used inexpensive synthetic form of B12. Similarly, pyridoxal-5-phosphate (P5P), the active form of vitamin B6, has superior bioavailability than pyridoxine. Choosing B vitamins in their active forms can ensure optimal bioavailability and utilization by your body.

  • Opt for active forms of B vitamins (methylcobalamin and pyridoxal-5-phosphate).

  • Wrapping it up

    Think of bioavailability as your own nutrient treasure hunt. You want to find those gems of readily absorbed nutrients that your body can readily snatch up and put to good use. It's like giving your body a VIP pass to the most exclusive nutrient party!

    Since every woman and every pregnancy is unique, it's always best to consult with your healthcare provider to determine the most suitable prenatal vitamin that meets your specific needs. 



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    Martineau AR, Thummel KE, Wang Z, Jolliffe DA, Boucher BJ, Griffin SJ, Forouhi NG, Hitman GA. Differential Effects of Oral Boluses of Vitamin D2 vs Vitamin D3 on Vitamin D Metabolism: A Randomized Controlled Trial. J Clin Endocrinol Metab. 2019 Dec 1;104(12):5831-5839. doi: 10.1210/jc.2019-00207. PMID: 31199458; PMCID: PMC6797055.

    Szarfarc SC, de Cassana LM, Fujimori E, Guerra-Shinohara EM, de Oliveira IM. Relative effectiveness of iron bis-glycinate chelate (Ferrochel) and ferrous sulfate in the control of iron deficiency in pregnant women. Arch Latinoam Nutr. 2001 Mar;51(1 Suppl 1):42-7. PMID: 11688081.

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