The skeptical cardiologist first mentioned magnesium in a post on the treatment of premature ventricular contractions (PVCs). I wrote that some individuals find relief from this troubling arrhythmia with the use of magnesium supplements.
I noted then that:
Most of the internet’s top quacks, however, greedily market and glowingly swear by magnesium for all manner of common ailments. A Google search for magnesium cardiovascular disease yields 833,000 entries and the first page is a Who’s Who of quackery, including Dr Mercola (strong candidate for America’s greatest quack), Dr. Sinatra (see here), NaturalNews and Life Extension (see here).
This Weston Price Foundation blurb on magnesium is typical of the inaccurate and dangerous misinformation found widely on the internet:
(M agnesium) deficiency is related to atherosclerosis, hypertension, strokes and heart attacks. But magnesium shines brightest in cardiovascular health. It alone can fulfill the role of many common cardiac medications: magnesium inhibits blood clots (like aspirin), thins the blood (like Coumadin), blocks calcium uptake (like calcium channel-blocking durgs such as Procardia) and relaxes blood vessels (like ACE inhibitors such as Vasotec)Weston Price Foundation
Today the Google search for magnesium cardiovascular yields 27,220,000 entries. The potential cures for magnesium supplementation according to many pseudoscientific websites are legion and extend well beyond PVCs and cardiovascular disease.
You can be assured that a sales pitch accompanies these claims and that the magnesium-containing snake oil being promoted has not been proven effective or safe. Because symptomatic PVCs like most benign, common and troubling conditions (lower back pain, fatigue, insomnia and nonspecific GI troubles come to mind), are closely related to mood and wax and wain spontaneously; the placebo effect proves powerful. In such conditions, snake oil and charlatans thrive.
To be clear, magnesium plays a crucial role in multiple crucial enzymatic processes in the body. Magnesium levels are very important to monitor in hospitalized and critically ill patients, especially those receiving diuretics and medications that can affect cardiac electrical activity.
However, the evidence that magnesium supplementation is beneficial for the majority of the population who suffer from common chronic diseases is lacking.
Although observational studies have shown a weak association of low magnesium levels (hypomagnesemia) with cardiovascular disease, magnesium supplementation has not been proven beneficial for the prevention or treatment of any chronic cardiovascular disease.
The Best Magnesium Supplement: The Candidates are Legion
Those who promote and sell magnesium supplements for all manner of ailments have to promote the idea that hypomagnesemia is rampant, causing widespread symptoms and underdiagnosed by the medical profession.
Once establishing this concept they then will try to distinguish their product from the magnesium that doctors typically prescribe (magnesium oxide) and those supplements which are cheaper and available through other sources. This aggressive marketing of useless supplements is, of course, the #1 red flag of quackery.
Thus if we look at the bestselling magnesium supplements on Amazon we see in addition to magnesium oxide, an inorganic salt, multiple organic magnesium salts:
- Magnesium glycinate lysinate
- Magnesium L-threonate
- Magnesium citrate
- Magnesium malate
Depending on the marketing goals of the supplement maker, differing magnesium preparations are promoted to “support bone and muscle health”, or “support stress relief, sleep, heart health, nerves, muscles” with no scientific basis for the claims.
In fact, magnesium pushers have invented specific niches for different magnesium preparations with absolutely no solid scientific support.
An article in Healthline.com entitled “10 Interesting Types of Magnesium (and What to Use Each For)” helps propagate this magnesium propaganda. Despite its appearance as a reliable and referenced source of nutritional information, the article aids supplement manufacturers by suggesting these products “may” have benefits for varying conditions.
Healthline’s article starts with Magnesium citrate, which doctors have traditionally used to treat constipation and induce diarrhea in order to clean out colons prior to procedures:
it’s occasionally marketed as a calming agent to help relieve symptoms associated with depression and anxiety, but more research is needed on these uses
The Healthline article also mentions multiple times that these alternative forms of magnesium when available as a salt with an organic compound are better absorbed or more bioavailable. The implication here and in multiple magnesium snake oil sites across the internet is that you are far better off buying a more expensive niche brand of magnesium than the cheaper magnesium oxide your physician might recommend.
Intestinal Absorption and Bioavailability of Different Magnesium Salts
Those who promote and sell magnesium supplements for all manner of ailments have to promote the idea that hypomagnesemia is rampant, causing widespread symptoms and underdiagnosed by the medical profession..
Two Food Nutrition scientists from the Institute of Food Science and Human Nutrition, Leibniz University in Hannover, Germany surveyed what is known about magnesium absorption and bioavailability in 2017.
They noted that multiple factors influence magnesium (Mg2+) absorption and that “the bioavailability of Mg2+ varies within a broad range, depending on the dose, the food matrix, and enhancing and inhibiting factors.”
Dietary factors play a huge role with some impairing magnesium up-take including “high doses of other minerals, partly fermentable fibres (e.g., hemicellulose), non-fermentable fibres (e.g., cellulose, lignin), phytate and oxalate.”
And some dietary factors enhancing magnesium uptake including proteins, medium-chain-triglycerides, and low- or indigestible carbohydrates (e.g., resistant starch, oligosaccharides, inulin, mannitol and lactulose)
They also noted that there is no widely accepted, standardized method of assessing magnesium bioavailability therefore it is not clear which form of magnesium supplement has the highest bioavailability.
Although animal studies have suggested a slightly higher bioavailability of organic Mg2+ compounds it is not clear that this finding is relevant to any human condition.
Due to the lack of standardized tests to assess Mg2+ status and intestinal absorption, it remains unclear which Mg2+ binding form shows the highest bioavailability.
Animal studies showed that organic and inorganic Mg2+ salts were equally efficient at restoring depleted Mg2+ levels in plasma and red blood cells, despite a slightly higher bioavailability of organic Mg2+ compounds.
Despite what nutraceutical and supplement marketing hype claims and what seemingly reliable health websites like Healthline parrot there is no evidence to support taking one magnesium supplement over another for any particular condition.
Therefore, if you want to try magnesium for PVCs (or insomnia, muscle cramps, depression, etc.) you should choose the cheapest preparation that you are able to tolerate without side effects.
Magnesium Dietary Sources
Rather than focusing on taking a magnesium supplement and thereby adding to the coffers of the nutraceutical industry, I advise following a healthy, balanced diet.
The NIH summarizes magnesium food sources as follows:
Magnesium is widely distributed in plant and animal foods and in beverages. Green leafy vegetables, such as spinach, legumes, nuts, seeds, and whole grains, are good sources. In general, foods containing dietary fiber provide magnesium. Magnesium is also added to some breakfast cereals and other fortified foods. Some types of food processing, such as refining grains in ways that remove the nutrient-rich germ and bran, lower magnesium content substantially. Tap, mineral, and bottled waters can also be sources of magnesium, but the amount of magnesium in water varies by source and brand (ranging from 1 mg/L to more than 120 mg/L) Approximately 30% to 40% of the dietary magnesium consumed is typically absorbed by the body [2,9].
N.B. Mg2+ sources from the NIH
|Pumpkin seeds, roasted, 1 ounce||156||37|
|Chia seeds, 1 ounce||111||26|
|Almonds, dry roasted, 1 ounce||80||19|
|Spinach, boiled, ½ cup||78||19|
|Cashews, dry roasted, 1 ounce||74||18|
|Peanuts, oil roasted, ¼ cup||63||15|
|Cereal, shredded wheat, 2 large biscuits||61||15|
|Soymilk, plain or vanilla, 1 cup||61||15|
|Black beans, cooked, ½ cup||60||14|
|Edamame, shelled, cooked, ½ cup||50||12|
|Peanut butter, smooth, 2 tablespoons||49||12|
|Potato, baked with skin, 3.5 ounces||43||10|
|Rice, brown, cooked, ½ cup||42||10|
|Yogurt, plain, low fat, 8 ounces||42||10|
|Breakfast cereals, fortified with 10% of the DV for magnesium, 1 serving||42||10|
|Oatmeal, instant, 1 packet||36||9|
|Kidney beans, canned, ½ cup||35||8|
|Banana, 1 medium||32||8|
|Salmon, Atlantic, farmed, cooked, 3 ounces||26||6|
|Milk, 1 cup||24–27||6|
|Halibut, cooked, 3 ounces||24||6|
|Raisins, ½ cup||23||5|
|Bread, whole wheat, 1 slice||23||5|
|Avocado, cubed, ½ cup||22||5|
|Chicken breast, roasted, 3 ounces||22||5|
|Beef, ground, 90% lean, pan broiled, 3 ounces||20||5|
|Broccoli, chopped and cooked, ½ cup||12||3|
|Rice, white, cooked, ½ cup||10||2|
|Apple, 1 medium||9||2|
|Carrot, raw, 1 medium||7||2|