Naturopathy vs. Science: Prenatal Vitamins


This is another post in the naturopathy versus science series, where a naturopath’s medical advice is assessed against the scientific evidence. Today’s topic is brought to you by Toronto naturopath Shawna Darou, who recently published her evaluation of prenatal vitamins.

Vitamin supplementation is unnecessary for the vast majority of people. You wouldn’t know this walking through a drug store, where you’ll usually find an entire aisle packed with supplements. Alternative health providers like naturopaths tend to be strong supporters of supplementation, but this advice seems to be based mainly on the belief that “vitamins are magic” rather than good science. The best research hasn’t established a strong evidence base for taking  supplements. We definitely need vitamins in our diet to live. But that’s where we should be getting those vitamins – from our food, instead of from pills. If you eat a reasonable and balanced diet, and have no medical conditions that require special consideration, vitamin supplementation won’t offer meaningful health benefits. In the absence of any deficiency, vitamin supplements seem to be useless at best and harmful at worst.

That doesn’t mean vitamins are always useless or unnecessary. They can also have important science-based roles. Vitamin deficiencies can occur, and sometimes the consequences can be significant. Pregnancy is one example. Pregnant women may not obtain adequate amounts of nutrients like folate in their diet. Deficiencies are linked to major birth abnormalities: neural tube defects (NTDs). It is well-established that folic acid supplementation around the time of conception, and continued through pregnancy, can significantly reduce the risk of NTDs, and may reduce the risk of some other abnormalities as well. There are now widespread recommendations for folic acid supplementation in pregnancy. Because many pregnancies are unplanned, public health strategies have included fortifying food with folic acid, and this approach also seems to reduce birth defects in populations.

Folate is not the only deficiency possible in pregnancy. Pregnant women have higher requirements for calcium and iron. There’s also the need to ensure adequate amounts of vitamins A, the Bs, C, D, E and zinc. While these needs can potentially be met through diet, some guidelines recommend a multivitamin (and not just folic acid) because of the consequences of a deficiency and a lack of any real risks. And supplementation works. The most common maternal multivitamin (at least here in Canada) is Materna, though there are many competitors and lots of generics. Costs can be as low as $4-8 per month. Prenatal vitamins will usually contain 0.4mg to 1mg of folic acid – it’s the most essential ingredient. Most contain slightly higher amounts of calcium and iron than a typical daily multivitamin, along with modest amounts of other micronutrients. This formula helps pregnant women’s diets meet their nutritional requirements, reduces the risk of birth defects, and is a practice aligned with the best evidence.

Choosing a prenatal vitamin is normally a fairly straightforward matter: pick one, and take it daily, starting from when you begin to contemplate having a baby. I could find no guidelines that have established one brand of prenatal vitamin as superior, though some may be better tolerated than others. I usually suggest Materna (as it’s been used in clinical trials) but it’s expensive, so if cost is an issue, a store-brand product should be fine. (In Canada a prescription-only vitamin called PregVit is also popular.) With the exception of occasional reports of nausea and vomiting, most women have no problems finding a product they can tolerate and also afford. Beyond the basic prenatal vitamin brands, you’ll find other brands that are advertised as being superior for you and your baby’s growth. That’s why I read a recent blog post from a naturopath with interest, as she listed her preferred prenatal vitamins, and why.

What do naturopaths think of prenatal vitamins?

I first learned about naturopathy when I was a retail pharmacist in Toronto – Toronto has one of a handful of naturopathy schools in North America, so it’s not uncommon to meet patients that consult with them. I spent some of my time in that pharmacy helping patients source strange supplements, which sometimes cost hundreds of dollars per month. It was good for that pharmacy’s sales, but I was curious how naturopaths could always find conditions like food “intolerance”, pH “imbalances”, adrenal “fatigue”, and hormone “depletion” in their patients. I’d never heard of these conditions, and there was nothing in the medical literature that established they were real. It seemed the likelihood of being diagnosed with a condition like “candida overgrowth” was highly correlated with visiting a naturopath, as nearly every client was taking purgatives and avoiding bread, believing they were fighting some sort of a whole-body colonization of yeast that was widespread yet not detectable by medical science. The treatment, of course, was more supplements, sometimes combined with different forms of “detox” kits and some homeopathy.

Naturopaths consider themselves to be primary care providers comparable to medical doctors. Toronto naturopath Shawna Darou’s bio notes she “graduated from the Canadian College of Naturopathic Medicine ( ) at the top of her class and was the recipient of the prestigious Governor’s Medal of Excellence”, so presumably she’s an example of the advice you’d get from a typical Toronto naturopath. Her services advertised include women’s health and prenatal care, so I’d expect her to know what she’s talking about if she’s going to make recommendations about nutrition in pregnancy. There is a well-established evidence base to rely on, alongside dozens of guidelines and advice from groups like the Cochrane Collaboration.

The naturopath’s advice

Darou opens her post:

Choosing prenatal vitamins can be complicated, as the world of supplements is difficult to navigate. The two most popular prenatal vitamins are “Materna” and “Preg vit”, but I would like to show you why professional brands of supplements are far superior in both nutrient levels, and absorption. My current favourite prenatal vitamin is NFH brand “Prenatal SAP”, as they have integrated the most current research into their prenatal vitamin formula. Other great brands are Thorne Research, Douglas laboratories and Pure Encapsulations.

Perhaps not surprisingly, Darou’s website sells NFH Prenatal SAP. The same company also sells products to fight candida overgrowth and adrenal fatigue (both common naturopath-diagnosed conditions), which sends a signal about the credibility of the company, since candida overgrowth (as defined by naturopaths) and adrenal fatigue are both fake diseases.

Darou says she had four criteria for her selection:

  1. Nutrient levels – how much of each individual vitamin and mineral is in a daily dose?
  2. Absorbability of nutrients – are the vitamins and minerals found in their most absorbable form?
  3. Form of folate – folic acid or methylated folate? This is essential if you carry a defect in the MTHFR gene.
  4. Fillers and other additives. It’s amazing what you find when you read the fine print!

Darou has designed her own chart that compares the different brands.

Nutrient levels

Not surprisingly, more is better to Darou:

In a careful comparison between seven prenatal vitamins, I found that there is an enormous difference in the amount of basic nutrients, with the biggest discrepancy in B-vitamin levels. For example, vitamin B-5 levels range from 5 mg per day in PregVit to 100 mg per day in NFH’s Prenatal SAP. Overall, the professional lines (Pure Encapsulations, Douglas labs, Thorne Research and NFH) contained significantly higher levels of essential nutrients.

The most important nutrient in a prenatal vitamin is folic acid. Optimal levels of the others are not known, as there’s no evidence to suggest that additional amounts of the other B-vitamins or other ingredients offers any benefits at improving perinatal health. They’re unlikely to be harmful, however.


Darou criticizes three ingredients in multivitamins as being “cheap” (and presumably, inferior):

Calcium carbonate vs. calcium citrate: Darou prefers the citrate version, stating it is “more easily broken down and absorbed’. When given as single supplements, calcium citrate may cause less stomach upset than the carbonate version, but at the expense of larger tablets (citrate versions contain less elemental calcium). However, the amounts in multivitamins are all low, and when prenatal vitamins are taken with food, the choice of carbonate or citrate should not result in any meaningful differences.

Oxide forms of minerals vs. citrate forms (magnesium, zinc, copper): Darou states the oxide versions of minerals “have lower absorption, and can be irritating to the digestive tract, while the citrate forms have much better absorbability.” Even if correct, it doesn’t mean no absorption or that there are clinically meaningful differences. Again, this is a trivial difference without any meaningful impact on perinatal health.

Vitamin B12: cyanocobalamin vs. methylcobalamin: Darou states:

Cyanocobalamin is a synthetic form of vitamin B12 that does not exist in nature. When absorbed, it releases a cyanide molecule which is toxic and must be processed by the body. It is added to most multivitamins as it is significantly cheaper than the higher absorbed, more bioavailable form called methylcobalamin. All of the naturopathic lines of prenatal vitamins contain methylcobalamin.

Note the naturalistic fallacy – cyanocobalamin is not only unnatural, it releases cyanide! Vitamin B12 is a group of related compounds containing cobalt as the central ion. Cyanocobalamin is a version of B12 with a cyanide group. Darou doesn’t mention the fact that the amount of cyanide released from cyanocobalamin is insignificant to the body (and besides, cyanide is natural). She also doesn’t mention that cyanocobalamin is the version of B12 that is the most studied. There’s no published evidence that shows methylcobalamin is superior to cyanocobalamin as a prenatal supplement. B12 is widely believed to be some sort of energy panacea, but the science doesn’t support this claim. In your prenatal supplement, there’s no evidence demonstrating cyanocobalamin is inferior.

Forms of folate

Darou says:

…..up to 65% of women contain a defect in an enzyme called MTHFR which is essential in the absorption of folate. What this means is that ‘folic acid’, found in most prenatal vitamins may not be absorbed well for many women. I highly recommend folate supplements in the ‘methylated’ version which bypasses this step of absorption. Folate in the form of 5-MTHF (5-methyl tetra hydrofolate) is best.

The MTHFR deficiency has no effect on folic acid absorption (contrary to what Darou says) but rather its metabolism. Daroun recommends 5-methyl tetra hydrofolate another version of folic acid. While there is some preliminary evidence suggesting that MTHFR deficiency in the mother may increase the risk of NTDs, there isn’t any published evidence suggesting 5-methyl tetra hydrofolate is superior to folic acid in the prevention of NTDs. All of the large trials establishing the benefits of folate supplementation have used folic acid, so folic acid remains the preferred, evidence-based version of folate that should be used for the prevention of NTDs.

Tablet fillers and other additives: Not a bug, but a feature

Darou doesn’t like other ingredients in her supplements:

It is shocking to find the fillers and additives found in pharmacy brands of prenatal vitamins. For example Materna contains: BHT, corn starch, FD&C red #40, gelatin, lactose, mineral oil, polysorbate 80, sodium lauryl sulfate, soybean oil, titanium dioxide among others! Note that there are three key allergens here (corn, soy and lactose), and several toxic chemicals! PregVit vitamins are even worse in the fillers, containing ammonium hydroxide, D&C Red #27, FD&C Blue #1, FD&C Blue #2, FD&C Red #40, FD&C Yellow #6, PEG 3350, polyvinyl alcohol, propylene glycol, shellac glaze, sodium lauryl sulfate, talc and titanium dioxide!!

These ingredients are included in pharmaceuticals and vitamin supplements for one reason: to ensure the finished product is of high quality. A high quality product has a long shelf life, doesn’t smell bad, has consistent ingredient quality, is easy to swallow and then dissolves quickly and thoroughly, with the ingredients being absorbed quickly. A tablet manufactured without any excipients would likely disintegrate in the bottle or in a worst case scenario, fail to dissolve at all. Excipients are not harmful and actually improve the quality of the product, rather than weaken it. She doesn’t seem to understand that “the dose makes the poison” and the amounts in any product are deliberately there to ensure the final product is of high quality. In the absence of allergy, there are no harms, real or expected, from the excipients in supplements.


Darou paints a negative picture of conventional multivitamins using weak, and sometimes erroneous arguments, while subtly promoting a product and brand of vitamin that she happens to sells on her website. If you want a textbook example of a conflict of interest in health, here it is. Her recommendations are largely consistent with what I’ve seen from naturopaths before – limited scientific literacy that is filtered through a belief system, generating advice that can sometimes be reasonable but more often than not is inconsistent with the best medical evidence. The product Darou recommends is actually supported by weaker evidence that the products she recommends against. While the risks of these alternative (and much more expensive) multivitamins are relatively low, claims that they are superior to conventional (and more popular) multivitamins are not supported by good evidence. Women that need nutritional advice would be better advised to speak with health professionals that practice according to scientific standards, such as registered dieticians. You’ll be more likely to get reliable and most importantly, unbiased advice. The stakes are too high in pregnancy to rely on the advice of alternative medicine providers.

Photo from flickr user Thomas van Ardenne used under a CC licence.

Posted in: Naturopathy

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