Guest post: 6 Prenatal Nutrition Misconceptions That Need to Stop by Lily Nichols, RDN, CDE, CLT

Real-Food-for-GD-Cover-250x377Today’s post is a guest post my Real food dietitian Lily Nichols, an expert on the topic of gestational (pregnancy) diabetes. Unfortunately, the current guidelines to manage gestational diabetes still include the consumption of too many carbs and don’t focus on food quality during this crucial period for baby.  

If you’re interested in learning more about this topic, I highly recommend her book which I had the pleasure to read before its publication. It has EVERYTHING women with gestational diabetes need to know about how to eat the right way to ensure both mom and baby stay healthy.

Here’s her post!

6 Prenatal Nutrition Misconceptions That Need to Stop

If you’ve just found out that you’re pregnant, some of the first questions that come to mind are:

“What am I supposed to eat?”

–       and   –

“What foods do I need to avoid?”

Understandably, there’s a lot to think about and no mother wants to do anything that might risk the health of her future child. Sadly, there’s a lot of prenatal nutrition misconceptions out there, maybe even a few that you were given to you by your doctor or nutritionist that should be retired. Here are some of the worst offenders.

1. Don’t Eat Liver

If we rewind the clock a hundred years, doctors actually encouraged mothers to consume liver throughout pregnancy. Although there’s more support for consuming liver within the Paleo/Primal and Real Food community, conventional doctors and nutritionists still advise against it. Why? Because liver is high in vitamin A. Studies on synthetic vitamin A (from supplements) show that too much can lead to birth defects. So, following that simple logic, liver should be avoided.

But, food-sourced vitamin A does not have the same toxicity, especially when it’s consumed with adequate vitamin D and vitamin K, both of which happen to be found in liver.[1]

Don’t take my word for it, though:

“Liver and supplements are not of equivalent teratogenic potential [risk of causing birth defects]. Advice to pregnant women on the consumption of liver based on the reported teratogenicity of vitamin A supplements should be reconsidered.”[2]

Plus, at least one third of pregnant women don’t consume enough vitamin A, so liver would serve as a fantastic source of this nutrient.[3] Liver is also rich in choline, which is necessary for normal brain and eye development and the prevention of neural tube defects. In addition, liver boasts high levels of folate, all the B vitamins, iron, zinc, and more. It’s quite literally like eating a multivitamin!

2. Limit Your Fat Intake

The whole idea of eating a low-fat diet, pregnant or not, is not founded on solid scientific evidence. First of all, real food fat provides vitamins A, D, E, and K and the omega-3, DHA, that are needed in higher amounts during pregnancy. Restricting fat limits your access to these nutrients.

Plus, fat usually accompanies other essential nutrients, especially protein. For example, the classic advice to “eat lean meat” ends up limiting the quantity of glycine in the diet, an amino acid that becomes essential to obtain from the diet during pregnancy. Glycine is critical for normal cardiovascular and tissue development in a growing baby.[4] The primary sources of glycine in the diet are the skin, bones, and connective tissue of meat, poultry, and fish. So, enjoy the crisp skin on your chicken, relish some yummy pulled pork, and don’t trim the fat off your steak.

3. You Can’t Eat Fish

With increased awareness about mercury and other contaminants in fish, some women have been told not to consume fish while pregnant. Now, certain fish are very high in mercury that I believe should be avoided, including tuna, swordfish, tilefish, king mackerel, and shark. But, many other types of fish are perfectly safe to eat while pregnant, even if they contain a small amount of mercury, and here’s why. Most fish also contains high amounts of selenium, a mineral that readily binds with mercury, thereby preventing it from exerting toxic effects in the body.[5]

Now that the mercury confusion is cleared up, we can focus on the good stuff. Fish is an excellent source of protein, iodine (a mineral that impacts brain development), zinc, and vitamin D. Of course, we can’t forget that fatty, cold-water fish are the best food source of DHA an omega-3 fat that’s, again, needed for brain development. Some of the best fish to consume are wild-caught salmon, herring, and sardines, due to their high DHA content and low concentrations of mercury and other contaminants.

4. You Can Get All of your Omega-3s from Plants

It’s no secret that omega-3 fats aid fetal brain development, but there’s confusion on the best food sources. Some are eating additional flax seeds or chia seeds to get their omega-3 and while these are healthy for other reasons, they are not going to boost your baby’s brain development.

That’s because plant-sourced omega-3s (with the exception of certain algae), come in a form called “ALA” and the type our brain and eyes need is “DHA.” As much as people like to argue that our body can make DHA from these plant sources, these claims don’t stand up to science. It turns out the conversion of ALA to DHA in humans is incredibly poor, at most 3.8%. Plus, if your diet is high in omega-6 (which happen to be concentrated in seeds, nuts, and vegetable oils), this conversion rate drops to 1.9%.[6] A diet high in saturated fat improves this conversion rate, but the truth is: no matter what, you cannot provide enough DHA for your growing baby if you do not eat DHA directly. The best source of DHA, by far, is fish as described above. If you do not eat fish, you can take fish oil, cod liver oil, or algae oil to obtain DHA. You’ll also find smaller amounts of DHA in eggs from pastured chickens and meat from pasture-raised or grass-fed animals (but only if you eat the yolks and fattier cuts of meat).

5. You Must Eat Plenty of Whole Grains

Virtually all beneficial nutrients in whole grains are easily found in other foods, and with far less detrimental side effects. For example, B-vitamins are readily found in meat (especially organ meats), fish, eggs, nuts, seeds, and a variety of vegetables. Plenty of foods can provide fiber (with far fewer carbohydrates) – avocados, shredded coconut, almonds, chia seeds, berries, and vegetables.

If you are not already careful with your grain intake, it may actually be wise to reduce it during pregnancy. Grains are rich in high-glycemic carbohydrates, which when eaten in excess, can lead to elevated blood sugar, elevated blood pressure, and excessive weight gain during pregnancy. Women with gestational diabetes have a 50% lower risk of requiring insulin when they eat a low-glycemic index diet.[7] If you feel better without grains in your diet, leave them out!

6. Always Take Folic Acid

This causes a lot of controversy. On one hand, supplementing with folic acid has, at a population level, reduced the number of neural tube defects. However, folic acid is a synthetic form of the B-vitamin, folate. And due to genetics, an estimated 40-60% of the population are unable to use “folic acid.”[8] These folks require the type of folate found in whole foods, like liver, meat, green leafy vegetables, nuts and eggs (just to name a few) or the appropriate form called L-methylfolate or L-5-methyltetrahydrofolate. If you happen to have this common genetic mutation (which researchers refer to as “MTHFR”), supplementing with synthetic folic acid won’t do you any good. It’s also best to avoid refined grain products, since these are commonly fortified with folic acid.

 

Summary

As you can see, there are a variety of commonly promoted prenatal nutrition myths that are not evidence-based. The best way to “build” a healthy baby is to focus on nutrient-dense, real foods. That includes a variety of animal-based and plant foods as outlined above.

Real-Food-for-GD-Cover-250x377About Lily:

Lily Nichols, RDN, CDE, CLT is one of the country’s most sought after ‘real food for pregnancy’ experts whose approach to nutrition embraces real food, integrative medicine, and mindful eating. You can learn more about Lily by visiting her popular blog, www.PilatesNutritionist.com and get her book, Real Food for Gestational Diabetes: An Alternative to the Conventional Nutrition Approach (and snag an exclusive FREE guide on managing gestational diabetes), at www.realfoodforGD.com.

Références

[1] Masterjohn, Christopher. “Vitamin D toxicity redefined: vitamin K and the molecular mechanism.” Medical hypotheses 68.5 (2007): 1026-1034.
[2] Buss, NE et al. “The teratogenic metabolites of vitamin A in women following supplements and liver.” Human & experimental toxicology 13.1 (1994): 33-43.
[3] Strobel, Manuela, Jana Tinz, and Hans-Konrad Biesalski. “The importance of β-carotene as a source of vitamin A with special regard to pregnant and breastfeeding women.” European journal of nutrition 46.9 (2007): 1-20.
[4] Persaud, Chandarika et al. “The excretion of 5‐oxoproline in urine, as an index of glycine status, during normal pregnancy.” BJOG: An International Journal of Obstetrics & Gynaecology 96.4 (1989): 440-444.
[5] Ralston, Nicholas VC, and Laura J Raymond. “Dietary selenium’s protective effects against methylmercury toxicity.” Toxicology 278.1 (2010): 112-123.
[6] Gerster, H. “Can adults adequately convert alpha-linolenic acid (18: 3n-3) to eicosapentaenoic acid (20: 5n-3) and docosahexaenoic acid (22: 6n-3)?.” International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin-und Ernahrungsforschung. Journal international de vitaminologie et de nutrition 68.3 (1997): 159-173.
[7] Moses, Robert G et al. “Can a low–glycemic index diet reduce the need for insulin in gestational diabetes mellitus? A randomized trial.” Diabetes Care 32.6 (2009): 996-1000.
[8] Greenberg, James A, and Stacey J Bell. “Multivitamin supplementation during pregnancy: emphasis on folic acid and l-methylfolate.” Reviews in Obstetrics and Gynecology 4.3-4 (2011): 126.