It’s the mineral, magnesium, of which dark chocolate (with at least 70% cacao content) contains an abundance.
Why is magnesium so vital for heart health?
Magnesium works synergistically with other important nutrients that support heart health, including B-Complex vitamins, vitamin D3 with K2 and omega 3 fatty acids, but it is often overlooked and underappreciated.
Magnesium is responsible for well over 300 enzyme-activated biochemical reactions in the body. It also helps create energy. As our body’s fourth most abundant mineral, magnesium plays a vital role in regulating blood pressure, heart rate and blood sugar levels, maintaining nerve function and keeping muscles relaxed. Magnesium is also a critical “calming” mineral, potent in its ability to alleviate stress.1
According to Dr. Carolyn Dean, a medical doctor, naturopath and author of The Magnesium Miracle, this mineral plays an important role in heart health because magnesium:
- Prevents muscle spasms of the heart blood vessels, which can lead to a heart attack.
- Prevents muscle spasms of the peripheral blood vessels which can lead to high blood pressure.
- Prevents calcium buildup in cholesterol plaque in arteries, which leads to clogged arteries.2
Studies show that its role in heart health is far-reaching.
A meta-analysis, published in The American Journal of Clinical Nutrition, concluded that “Circulating and dietary magnesium are inversely associated with cardiovascular disease (CVD).” 3 And, researchers found that abnormally low, circulating magnesium, or “hypomagnesemia” (<0.65 mmol/L), is a known risk factor for cardiac arrest.4 This means that the lower your magnesium intake (and the lower the circulating levels of magnesium in your body)—the higher your risk for cardiovascular disease.
Supplementing with magnesium can help reduce arterial stiffness, a marker for heart disease. In a 2016 clinical trial, overweight and obese participants were given 350 mg magnesium citrate per day in 3 divided doses. After six months, participants experienced a significant reduction in arterial stiffness.5
High blood pressure (hypertension) is another risk factor for heart disease. A meta-analysis, published in the journal Hypertension suggests a causal link between low magnesium and high blood pressure. Researchers found that taking 300 mg per day of supplemental magnesium for one month was helpful in significantly reducing blood pressure.6
In addition to heart health, magnesium is a key mineral to our overall health, hormonal balance, energy, mood and vitality. Unfortunately, most of us—some experts estimate up to 80% of Americans—are deficient in magnesium.
Including me. I had low magnesium…
About 10 years ago, I was in what most people would consider peak physical shape. At the time, I was an intense exerciser, working out about two to three hours a day, 5 to 6 days a week. As a runner, I clocked about 35 miles a week (7 miles/5 days a week) and strength-trained most days as well. I looked healthy and fit, yet, I struggled with uncomfortable symptoms that bordered on alarming: muscle cramps and spasms, random muscle twitches, foot pain, chronic tendonitis, a racing heart and heart palpitations that prevented—or disrupted—my sleep. And, though I was in top running form, I had high blood pressure! My blood pressure ranged from 130 to 140 (systolic) / 90 to 99 (diastolic)…and, once as high as 160/100. One nutritionist suspected an electrolyte imbalance, but she focused on potassium and calcium—not magnesium. Drinking potassium-rich V-8 and tomato juice and taking calcium supplements gave me zero relief. At the time, I did not realize that magnesium, which is also an electrolyte, can be quickly depleted by overtraining. It was 3 years before I discovered magnesium and began supplementing with it.
Causes of magnesium loss
Our modern diet and lifestyle easily depletes magnesium. Common reasons why we lose magnesium include:
- Eating processed foods
- Consuming a high sugar diet
- Regular daily consumption of caffeine: coffee, tea, soda
- Eating insufficient amounts of dark, leafy greens
- Chronic stress
- Excessive sweating (from physical exertion)
- Overtraining or over-exercising
- Taking birth control pills
- Lack of sleep
- Alcohol consumption
- Use of prescription drugs, like diuretics, corticosteroids (oral and inhaled), acid blockers, antibiotics, and cholestyramine, a cholesterol-lowering agent7
Foods sources of magnesium
Dark leafy greens and cruciferous vegetables—Swiss chard, kale, spinach, collard greens, romaine, broccoli, Brussels sprouts, bok choy—are excellent sources of magnesium. Other particularly good sources include wild caught salmon, wild rice, seeds (pumpkin, sunflower and sesame) and nuts (cashews, almonds and Brazil nuts), avocado, black-eyed peas, squash and herbs, such as purslane, cilantro, burdock, dandelion and nettles, and dulse, a seaweed.
Chocolate is often touted as being high in magnesium, and it is—in its raw, unsweetened form, as in raw cacao nibs, raw cacao powder or unsweetened cocoa powder.
It is challenging, however, to get enough magnesium from food alone. Modern farming practices, such as the use of commercial fertilizers, depleted our soil of nutrients; this was noted in a U.S. Senate document as far back as 1936.8 Most of us also lead fast-paced, stressful lives that include processed foods, caffeine, sugar, alcohol and too little sleep, which conspire to keep magnesium levels low.
In my own health journey, I find it necessary to supplement with several forms of magnesium—even though I eat mostly organic foods, filter my water and cook most nights. I have hypothyroidism and adrenal dysfunction, which makes me more sensitive and susceptible to stress of all kinds. Magnesium is key for hormonal balance.
Testing your magnesium level
Magnesium is found mostly in your bones and soft tissues; less than 1% of your body’s total magnesium can be measured in the blood. This is why, instead of a serum (blood) magnesium test, you’ll want to ask your doctor for a magnesium RBC (Red Blood Cell) test, which measures intracellular levels of magnesium. The higher end of the lab reference range is optimal. According to Dean: “The optimal level is 6.5 — within a range of 4.2 to 6.8. Below 6.0, you are magnesium deficient.”
Six easy ways to get more magnesium
1. Eat magnesium-rich foods: leafy greens, nuts, seeds and herbs (nettles and burdock root) and other foods mentioned above.
2. Enjoy dark chocolate (at least 80% cacao) in moderation. Better yet, add raw cacao nibs, organic cacao powder or organic unsweetened cocoa powder to smoothies, shakes or raw treats. The less sugar, the more magnesium!
3. Snack on pumpkin seeds and sunflower seeds.
4. Reduce “magnesium-suckers”: smoking, processed foods, sugar, high alcohol consumption, exposure to environmental toxins and stress.
5. Soak for 20-30 minutes in magnesium salts. You can soak in a tub—or do a foot soak—using Epsom salts (1 cup for a food soak; 2 cups for a bath soak) or these high-quality magnesium bath flakes (1-3 cups for a bath or foot soak).
6. Supplement with magnesium.
Two out of three Americans fail to consume the recommended daily allowance (RDA) for magnesium: 320 mg for women and 420 mg for men. Dean also points out in her book: at best, your body is actually only absorbing about half of what is taken in.
Supplementing with magnesium is fairly safe. In The Magnesium Miracle, Dean notes that, even when taken at high doses, an oral magnesium, like magnesium citrate, has no side effects, except loose stools. This laxative-like effect is the body’s way of releasing excess magnesium that it does not need. It is also a sign to either reduce the overall dosage, or take it in smaller amounts in divided doses. For those who have kidney failure, myasthenia gravis, excessively slow heart rate or bowel obstruction, it is best to avoid magnesium supplementation
There are different types of magnesium. Magnesium citrate powder is a popular form. Personally, I favor magnesium glycinate and transdermal magnesium oil, which is highly absorbable and beneficial for increasing intracellular levels of magnesium.
1, 2, 8 The Magnesium Miracle. Ballantine Books, 2003
3, 4 The American Journal of Clinical Nutrition. 2013 Jul; 98(1): 160–173
5 The American Journal of Clinical Nutrition. Volume 103, Issue 5, 1 May 2016,
6 Hypertension. 2016 Aug; 68(2):324-33
7 Suzy Cohen, R. Ph. Feb. 3, 2015