Hopefully you read my last article on choosing between Over the Counter vs Prescription Vitamins. If you are deciding to choose your own prenatal vitamins, as most people do, you need to know what to look for. I’ve done the research and summarized the top 9 things to look for in prenatal vitamins.
#1 Folate (Folic Acid)
This is the main ingredient that differentiates regular vitamins from prenatal vitamins. Folate is imperative in decreasing the risk of neural tube defects (such as spina bifida). Folate is so important that even women who could become pregnant (such as those women having unprotected sex) should consider folate supplementation.
The recommended dose is at least 0.4mg or 400mcg per day. Many vitamins will have more than 400mcg. Any supplementation from 400mcg-1mg is within the normal range.
Women who are at high risk of having a child with a neural tube defect should supplement with 4mg of folate per day. They should begin the supplement 3 months before pregnancy and continue until 12 weeks of pregnancy. After 12 weeks (the 1st trimester) they should switch to 0.4mg for the remainder of pregnancy. Women who are at high risk include women who have had a child in the past with a neural tube defect. Women requiring higher doses of folate should not take multiple prenatal vitamins. Multiple prenatal vitamins will give toxic levels of other vitamins and nutrients. Instead, find folate supplements and take these in addition to your regular prenatal vitamin.
Folate and folic acid are similar but not the same.
Folic acid needs to be converted into the active form, folate by the liver to be used in your body. Not everyone converts folic acid into folate with the same efficiency. Some people have what is called a MTHFR mutation. To find out more about this mutation and how to know if you have, it checkout my article on the MTHFR mutation. I recommend finding a prenatal supplement that contains folate instead of folic acid. By taking folate you don’t need to worry about the conversion of folic acid to folate.
Iron is important in pregnancy. The growing fetus requires iron and therefore diminishes the maternal iron stores. Many women are anemic before pregnancy and the problem only worsen during pregnancy. It is estimated that 19% of pregnant women are anemic.
The recommendation is to take at least 30mg of supplemental iron. If you are already anemic prior to ttc you should definitely consider additional supplementation. You could take as much as 120mg of iron per day without any concern for toxicity. Iron is so important that for women who continue to be deficient despite supplementation, doctors will further prescribe IV iron infusions
Some women have difficulty tolerating additional iron supplements. The most common side effects are stomach ache and constipation. For that reason some prenatal vitamins don’t contain iron. If you choose a vitamin without iron I strongly recommend you calculate the iron you consume in your diet, or take another iron supplement. If you are experiencing unpleasant side effects, try Floradix. Floradix is easier to digest. However, it is more expensive and it does need to be refrigerated.
#3 Vitamin D
Vitamin D has been a topic of discussion recently. Some recent studies have stated that vitamin D deficiency has been linked to poor birth outcomes. Although the causation is not clear, the recommendation is to take atleast 400 units of vitamin D daily.
Not all vitamin D is created equal. Vitamin D supplementation comes in 2 forms. It can either be D2 (ergocalciferol) or D3 (cholecalciferol). D3 is better absorbed in the body and is the form of vitamin D most commonly found in prescription prenatal vitamins. D2 is often found in commercial prenatal vitamins. However, there are definitely over the counter prenatal vitamins out there with D3. You just have to check the label.
If you get limited sun exposure you may want to consider looking for D3 and possibly increasing your supplementation to 600 or 1000 units, especially in the colder months. Vitamin D supplementation is safe and there is a very low risk of any complications from getting too much vitamin D. However, to be safe try to avoid supplements with more than 4000 units per day. Remember- when you are in the sun getting lots of Vitamin D, apply safe sunscreen regularly to prevent damage from the sun.
Calcium along with vitamin D is required for fetal bone development. Women should consume 1000mg of calcium per day. I searched through the labels of many prenatal vitamins and discovered most prenatal vitamins have far less than 1000mg of calcium.
The good news is that many foods do contain calcium. For example, 1 cup of cow’s milk contains 300mg of calcium. To find out the calcium composition of your common foods, checkout the USDA’s Food Composition Database.
If you can get your required calcium from your diet, then kudos to you! If not you can check out which prenatal vitamins I recommend that are higher in calcium or you can take an additional calcium supplement. Make sure to check the label of the calcium supplement! Many calcium supplements also contain Vitamin D3, which aids in calcium absorption. You don’t want to accidentally be taking too much of any vitamin.
Iodine is essential for adequate thyroid function. Women ttc or women who are pregnant should take 220 mcg -250 mcg of iodine per day. One study in the United States estimated that 56% of pregnant women had iodine deficiencies.
The American Thyroid Association recommends that women who are ttc or who are pregnant supplement their diet with150 mcg of iodine per day in the form of potassium iodide. Many prenatal vitamins, including prescription vitamins, don’t contain any iodine. It is important to check your labels. I found many prenatal vitamins that do contain the recommended 150 mcg of iodine.
However, it is also important to know that you can take too much supplemental iodine. Excessive iodine intake has been shown to cause fetal goiter in a very small number of women. This has been found primarily in Japanese women consuming a very large quantity of seaweed. These women are estimated to consume over 3mg of iodine daily, which is more than 10 times the daily-recommended intake (source).
Choline is important for the development of the fetal nervous system. Deficiencies of choline have been linked to lower cognitive function in children. In 1998 the Institute of Medicine recommended that pregnant women consume 450mg/day of choline.
Most prenatal vitamins have very little to no choline.
In fact, in June of 2017 the American Medical Association (AMA) recommended that prenatal vitamins increase their supplementation of choline to help women reach the recommendation of 450mg per day. I was only able to find one prenatal vitamin that had the recommended intake of choline.
The good news is that many foods contain choline. One egg contains 150mg of choline. Choline is also found in meat, fish and milk. However, 90% of women still aren’t getting enough choline. The toxic limit of choline intake is 3500mg, so you would need to consume a lot of choline to be concerned about toxicity. If you aren’t getting enough choline in your diet you may want to consider adding an additional choline supplement to your diet.
To find out which prenatal choline supplements I recommend, read my article “Best Prenatal Choline Supplements“.
Zinc is important for fetal growth. Studies have found an increase in growth-restricted babies born to women who were deficient in zinc. However, zinc deficiency is relatively uncommon in the US. Vegetarians, especially those who don’t consume beans, are at a higher risk of zinc deficiency. Women who are pregnant or trying to become pregnant should consume 11mg of zinc per day in food or supplement form. Fun fact: Oysters contain more 10 times more zinc than any other food. However the majority of zinc in our diet comes from meat and beans. Lobster and crab also contain a large amount of zinc. Some breakfast cereals are fortified with zinc.
Zinc can reach toxic levels. Too much zinc can interact with the absorption of other vitamins and minerals. Additionally, toxic levels of zinc can impair your immune system, making you more susceptible to other illnesses. The National Institute of Health (NIH) recommends consuming no more than 40mg of zinc per day. You may have noticed that one helping of oysters would put you past the upper limit of zinc intake. Occasionally eating oysters is harmless, but I wouldn’t make them a part of your regular diet.
#8 Vitamin A
Vitamin A is on this last for a different reason. In the US vitamin A toxicity is more common that vitamin A deficiency. The recommended daily intake of vitamin A is 770 mcg/day. It is very unlikely to consume too much vitamin A from your diet.
Most vitamin A toxicity is caused by supplements. Avoid supplements with over 5000 international units or 1500mcg of Vitamin A. Excessive vitamin A intake can cause liver damage, nausea, vomiting, headaches, skin irritation and more. Even more surprisingly- excessive supplemental vitamin A intake has been linked to congenital birth defects. Excessive vitamin A intake is commonly caused by taking multiple vitamins and supplements all with varying amounts of vitamin A.
Not all vitamin A is the same. Vitamin A comes in 2 forms. Plant-based vitamin A is beta-carotene. A high consumption of beta-carotene does not cause birth defects. Animal sources of vitamin A are retinol. Retinol is the active form of vitamin A and therefore can cause toxicity. However, consumption of vitamin A from the diet is unlikely to reach toxic levels. Some sources still recommend pregnant women avoid a high consumption of liver because liver is very high in retinol. Retinol can cause birth defects.
DHA is often not found in prenatal vitamins, but must be taken separately. DHA is a type of omega-3 essential fatty acid that is essential for the brain development of your baby. The recommendation is to consume 200-300mg of DHA per day.
It is best to consume DHA from fish sources, but it is important to consume fish low in mercury. Some fish that are high in DHA and low in mercury include mussels, oysters, farmed and wild salmon, sardines, snapper, and trout. DHA is often added to some fortified foods such as orange juice, milk and eggs.
Studies looking at women who consumed supplemental DHA found that supplemental DHA did not have the same effects as dietary DHA. However, if you find it difficult to consume enough DHA from dietary sources I recommend looking for a supplement with at least 300mg of DHA.
My recommendation for you:
Try to include as many of these nutrients in your diet as possible. Typically vitamins and minerals are better absorbed when consumed in the dietary form as opposed to the supplemental form. However, just to be safe, I recommend taking a prenatal vitamin that contains as many of your required nutrients as possible without going above the safe limit.
If you want to consume more of any individual vitamin do not consume multiple daily multi-vitamins (such as a prenatal vitamin). Instead, find a vitamin supplement that just contains that one vitamin (such as Calcium). Taking multiple prenatal vitamins can expose you to toxic levels of other vitamins, especially vitamin A.
I’ve summarized my recommendations below for you. You can use this as a guide to help you purchase a prenatal vitamin that meets your dietary needs.
|Recommended Level||Upper Limit|
|Folate (Not Folic Acid)||400-1000mcg (1mg)*|
|Vitamin D||400 units||4000 units|
|Vitamin A||770mcg||1500mcg (5000 IU)|
*Women with increased risk of ONTD should consume 4mg of folic acid per day for the first 12 weeks of pregnancy.
Personally, I’d recommend taking a balanced prenatal vitamin and then taking calcium, choline, iron and/or DHA separately depending on your nutritional needs and based on what your prenatal vitamin is lacking. Stay tuned for my next article where I review prenatal vitamins and recommend which to take and which ones to avoid.