Our bodies contain about 25 grams of magnesium, of which about 60% is in our bones, 39% is in our soft tissues, and only a mere 1% is in our blood (National Institutes of Health [NIH], 2018). Put more simply, 99% of our magnesium is intracellular (inside of our cells). Therefore, it is impossible to identify if a magnesium deficiency exists with typical serum blood work (NIH, 2018). Even if your magnesium level was normal in your last workup you could still be deficient within your cells and bones (NIH, 2018). Often when is even more confusing to people is that the deficiency is usually subclinical (which means initially there are no obvious signs). Magnesium is a vital cofactor in more than 300 enzyme systems in the body and it regulates a multitude of processes. Unfortunately, more than half of Americans do not even get the recommended daily amount in their diet.
“Because of chronic diseases, medications, decreases in food crop magnesium contents, and the availability of refined and processed foods, the vast majority of people in modern societies are at risk for magnesium deficiency” – DiNicolantonio et al., Open Heart Journal, 2018
So how can supplementing with magnesium prevent preeclampsia? We will be discussing each of these functions of magnesium and connecting them to preeclampsia.(source of list: NIH, 2018)
- It regulates blood pressure
- It plays a role in the transport of calcium and potassium across cells
- It contributes to the development of bones and teeth
- It is required for protein synthesis
- It is required for production of the antioxidant glutathione
- It is required for the breakdown of glucose
(1) Magnesium regulates blood pressure and (2) plays a role in the transport of calcium and potassium across cells
In my previous post, Preventing Preeclampsia Part I: Connecting the K2 Dots, we briefly discussed how there is a disturbance in calcium metabolism in preeclampsia. Magnesium is vital to proper calcium metabolism because it aids the transport of calcium across cells. According to Rosenoff (2005), healthy blood pressure depends upon a balance of magnesium and calcium at the cellular and whole body levels which means adequate, long-term intakes of nutritional magnesium are required. A total body magnesium deficiency will result in low blood levels of calcium even if you are consuming plenty of calcium.
Remember we already know preeclamptic women (when compared to pregnant women without high blood pressure) have significantly lower serum calcium levels (Devi, 2014). It is likely that low blood calcium levels (but high intracellular calcium levels) found in preeclamptic women are actually due to low magnesium levels, because magnesium is essential for keeping intracellular calcium low. Indeed, there are a number of studies which demonstrate prenatal high blood pressure is directly related to lack of magnesium. We must also take into account the high fetal demands for the very same nutrients a woman needs for herself. If a magnesium deficiency exists, and the baby continues to “take what it needs,” we can reasonably assume that the mother’s deficiency will worsen. DiNicolantonio et al. (2018) corroborate this statement by stating pregnancy can cause magnesium deficiency, and seizures are a sign of severe deficiency.
Some preeclamptic women will progress to eclampsia (preeclampsia becomes eclampsia when the woman develops seizures). And what do we get when there is severe magnesium deficiency? Seizures. And what are those women given intravenously to prevent those seizures and maintain a stable blood pressure when in the hospital setting? Magnesium.
Here are the results of just a few studies and reviews which support the benefits of magnesium supplementation during pregnancy to prevent preeclampsia (and other pregnancy complications):
“Magnesium supplementation during pregnancy likely decreases probability of occurrence of many complications of pregnancy. We believe that using the right dose of magnesium plays a crucial role in the treatment of unwanted pregnancy disorders as well as preventing of preterm birth, low birth weight, and preeclampsia” – Tarjan & Zarean, Advanced Biomedical Research Journal, 2017
“Magnesium is involved in the regulation of blood pressure and that the increase in blood pressure in pregnancy could be due to a lack of magnesium.” – Bullardo et al., Gynecology and Obstetrics Journal, 2013
“In summary, four studies from four different countries demonstrate that the supplementation with magnesium during pregnancy reduces the risk of pregnancy induced high blood pressure.” – Rylander, AIMS Public Health Journal, 2015
Unrelated to preeclampsia specifically, but worth including:
“Oral magnesium supplementation seems to be a valuable therapeutic tool in the treatment of pregnancy-related leg cramps” – Berg et al., American Journal of Obstetrics and Gynecology, 1995
There are many more; but it gets repetitive. Let’s move on.
(3) Magnesium contributes to the development of bones and teeth (4) and is required for protein synthesis
Magnesium is vital to the development of bones and teeth. Calcium, phosphorus, vitamin D3, K2, and A also play a role (as we discussed in Part I of this series), but here our focus is magnesium.
Preeclampsia usually begins at 20 weeks gestation. So what is the fetus doing at around 20 weeks gestation? Building the bones and the proteins that comprise their bodies.
Using amino acids (the building blocks of life) that are delivered to the fetus via the placenta and umbilical cord, the fetus is building itself out of proteins at an incredibly rapid rate. “To meet the needs of rapid fetal protein synthesis, particularly in skeletal muscle, liver, and gut, amino acids must be supplied at a rate estimated to be between 10 and 60 grams per day per kg fetus” (Powell et al., 2017). So if the fetus is 6 pounds (2.72 kg), there could be a requirement of 163 grams of amino acids per day. One egg has less than 20 total grams of amino acids (note: grams of amino acids are not the same as grams of protein). And lets not forget that the mother still must also supply herself with what her own body needs.
The next article in this series will go into amino acid-preeclampsia connection in depth, but for now we simply need to understand that magnesium is required for protein synthesis. Therefore, a magnesium deficiency can result in a disruption of this process. The fetus will take what it needs even if deficiency exists in the mother, but if deficiency is severe enough, the fetus will be deficient too. Depletion of maternal magnesium increases her chances of developing preeclampsia or other pregnancy complications.
During fetal development the placenta actively transports calcium, phosphorus, and magnesium (Kovacs, 2011). Fetal calcium levels suggest that ionized calcium is transferred from the mother to the fetus at a rate of 50 mg per day at 20 weeks of gestation to a maximum of 330 mg per day at 35 weeks of gestation (Institute of Medicine, 1990). We can assume there is a correlating demand for magnesium since magnesium is required for bone formation. Preeclampsia presents around the same time (20 weeks) that fetal demands for calcium and magnesium increase. Often, the blood pressure continues to rise as the pregnancy progresses (as fetal demands increase) and the woman needs to be admitted to the hospital for intravenous magnesium therapy. The connection is obvious.
(5) Magnesium is required for production of the antioxidant glutathione and reduces inflammation
Oxidative stress and inflammation of the blood vessels plays a significant role in preeclampsia.
Glutathione is the most powerful antioxidant (antioxidants counteract oxidative stress) and detoxifier in our body. The body makes glutathione using amino acids (from proteins that we eat) aided by magnesium. I will be writing a different post specifically about glutathione, but for our purposes know this: studies show that preeclamptic women have low glutathione levels (Chu et al., 2016). Magnesium deficiency will result in lower than normal glutathione levels, because our bodies need magnesium to make it.
Considering magnesium’s actions on calcium, the widespread inadequate intakes of magnesium, and the large number of reports associating magnesium deficiency with inflammatory and oxidative stress, the role of magnesium as an anti-inflammatory is far reaching (Neilson, 2018).
(6) Magnesium is required for the breakdown of glucose
Recall that one of the risk factors for preeclampsia is diabetes (type 2) or insulin resistance. In patients who are at risk for diabetes and patients who already have diabetes, magnesium supplementation has been proven to improve insulin sensitivity (Barbagallo et al., 2016). Perhaps magnesium deficiency plays a role in insulin resistance making insulin resistance a risk factor for preeclampsia when in fact magnesium deficiency is at the root of the issue.
Also, recall from Part I of this series that inflammation and vascular damage play a role in preeclampsia. Hyperglycemia (high blood glucose) is a major cause of vascular damage. Magnesium helps to prevent high blood sugar levels, and also helps to prevent inflammation. By doing this, it reduces risk factors for developing preeclampsia.
How much magnesium should you take?
Chart Source: (NIH, 2018).
There is no upper limit established for the magnesium obtained from foods. However there is an established upper limit for magnesium that is obtained from supplements:
Chart Source: (NIH, 2018)
Most studies on oral magnesium supplementation for pregnant women safely used doses in the range of 100 mg per day to 300 mg per day.
However, Carolyn Dean, MD/ND and author of the excellent book The Magnesium Miracle disagrees with those recommendations and limits. She explains that magnesium is very safe so long as there is no medical history that would create a contraindication including kidney failure, myasthenia gravis, bowel obstruction, or an excessively slow heart rate. She states that if magnesium deficiency exists (as it does for most of us) much higher doses are required (sometimes triple the recommendation). I personally took 1 gram of magnesium glycinate for about 8 weeks before lowering my dose to a maintenance dose of 200 mg per day, which I still take now. There are many forms of magnesium. Magnesium glycinate does not cause any gastrointestinal symptoms and is highly bioavailable, so that is my personal preference.
In my opinion . . .
All pregnant women or women who are planning for pregnancy should be supplementing with magnesium, vitamin D3, vitamin A (from cod liver oil), and vitamin K2. If you are at risk for preeclampsia, or if you have preeclampsia, supplementing these is even more crucial. These nutrients will improve your pregnancy outcomes, improve your overall health, and dramatically reduce the chances of developing cardiovascular disease in the future. Unless you eat organ meats on the regular basis, you are likely not getting enough Vitamin A. Unless you get at least 20 minutes of sunshine on your totally naked body sans sunscreen (and then do not shower or jump in the pool right afterward), you are likely not getting enough vitamin D. Unless you eat natto (a disgusting Japanese food with the texture of boogers) or strictly eat only grass fed meat and butter, you are likely not getting enough K2. And even if you are eating lots of dark leafy greens, the magnesium content of our soil is so depleted that you still may not be getting enough magnesium to support your pregnancy. Eating organic is ideal, but let’s be honest: eating organic is expensive and most of us simply cannot afford it.
The brands I trust for magnesium glycinate are Pure Encapsulations or Dr’s. Best. The Pure Encapsulations brand pills are easier to swallow. For my children I use Kal’s Chewable Magnesium Glycinate. They are orange flavored and my kids love them. There are many other brands available, but be sure to check into where they are made, if they are tested for purity, or if they contain too many fillers.
This post will be updated as I learn new information.
Go ahead and subscribe to stay updated and follow this series, and to get notified of any new articles. Next we will discuss the supporting evidence for either Vitamin D or amino acid therapy for preeclampsia prevention and treatment. I haven’t decided which one yet, so it will be a surprise!
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Berg., G., Dahle, L., Hammer, M., Hurtig, M., & Larsson, L. (1995). The effect of oral magnesium substitution on pregnancy-induced leg cramps. Retrieved from https://www.ajog.org/article/0002-9378(95)90186-8/pdf
Bullardo, M., Kolisek, M., Nestler, A., Nielsen, T., Odman, N., Rylander, R., & Vormann, J. (2013). Magnesium supplementation to prevent high blood pressure in pregnancy: a randomised placebo control trial. Retrieved from https://link.springer.com/article/10.1007%2Fs00404-013-2900-2
Chu, K., Huang, Z., Jia, X., Jing, Z., Li, J., Li, X. . . . Wang, J. (2016). Evaluation of glutathione peroxidase 4 role in preeclampsia. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5027559/
DiNicolantonio, J., O’Keefe, J., & Wilson, W. (2018). Subclinical magnesium deficiency: a principal driver of cardiovascular disease and a public health crisis. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5786912/
Institute of Medicine. (1990). Nutrition During Pregnancy: Part I Weight Gain: Part II Nutrient Supplements. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK235246/
Kovacs, C. Bone development in the fetus and neonate: role of the calciotropic hormones. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/21904825
National Institutes of Health. (2018). Magnesium. Retrieved from https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/
Nielsen, F. (2018). Magnesium deficiency and increased inflammation: current perspectives. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5783146/
Powell, T., Jansson, T., Vaughan, O., Rosario, F. (2017). Chapter Eight – Regulation of Placental Amino Acid Transport and Fetal Growth. Retrieved from https://www.sciencedirect.com/science/article/pii/S1877117316301132
Tarjan, A., Zarean, E. (2017). Effect of Magnesium Supplement on Pregnancy Outcomes: A Randomized Control Trial. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5590399/
Rosenoff, A. (2005). Magnesium and hypertension. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/15692166
Rylander, (2015). Treatment with Magnesium in Pregnancy. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5690444/