How minerals may play a role in managing muscle cramps, and why magnesium may be the missing link in your diet
Minerals are naturally occurring substances derived from the earth that are important for a healthy body. Some minerals—specifically, calcium, magnesium, potassium, and sodium, are also electrolytes. Electrolytes are charged particles, and are key for regulating fluid balance, muscle contraction, and nerve conduction.
Substantial amounts of Americans do not get the recommended amounts of calcium, magnesium, and potassium in their diet, according to recent survey data. Athletes are especially prone to dietary deficiencies, but also losses through sweating.
What causes muscle cramps?
The jury is still out on exactly what causes muscle cramps, but there are three leading theories the scientific community acknowledges:
- Dehydration. Not consuming enough fluids and/or sweating excessively may reduce body levels of minerals like potassium, salt, calcium or magnesium.
- Electrolyte imbalance. Low levels of electrolytes mean less ability to contract muscles properly or regulate fluid balance.
- Fatigued muscles. There may be an imbalance between nerve signals that excite and nerve cells that inhibit muscle contractions. Think of it as “muscle system overload.” The whole system that initiates muscles to contract becomes hyper-excited, and the system that inhibits contractions is reduced.
Consider a focus on magnesium
Magnesium–after sodium, potassium, and calcium—is the fourth most abundant mineral in the body. Half is in our bones while the other half is in our muscles and other tissues. It helps the muscle relax, whereas calcium helps the muscle contract. If there is little magnesium yet too much calcium in the body, nerve cells can become over-activated and will contract. Since magnesium can be lost through sweat and many do not consume enough magnesium in the diet, muscle cramping may be more likely to occur if you’re not getting enough dietary magnesium.
Magnesium’s other benefits
If you’ve decided to focus on consuming more magnesium-rich foods, you may be surprised to know magnesium offers other benefits to maintain a healthy body:
Most people don’t realize that magnesium is key for both calcium and vitamin D to be absorbed in our body, which is critical for bone formation and strength.
Blood sugar and insulin
In addition to maintaining bone, muscle, and nerve function, magnesium metabolism also influences the release and activity of insulin. People with low serum magnesium levels have a higher risk of developing diabetes and are 6-7 times more likely to have metabolic syndrome than people with normal magnesium levels. Studies have shown adults with high levels from diet and supplements have about a 30% lower risk of developing metabolic syndrome.
For those already living with Type 2 diabetes, magnesium deficiency is common. That’s because with Type 2 diabetes, cells have a hard time recognizing and using insulin. Thus, the need for magnesium is even higher in order to raise intracellular levels, so magnesium can then support insulin’s function.
Blood pressure and heart health
Studies have demonstrated that dietary magnesium acts as a natural calcium channel blocker, increases nitric oxide, may lower blood pressure and improve endothelial function and vasodilation, and may reduce the risk of stroke.
How much magnesium do I need?
The RDA for most teenagers and adults is roughly 300 mg for women and 400 mg for men. There is no Upper Limit for magnesium from food, however there are Upper Intake levels (set by the U.S.’s Institute of Medicine) for dietary supplements is 350 mg/day for those aged 9 and up. Food sources include beans, dark leafy greens (like spinach), halibut, nuts (especially pumpkin seeds, almonds, and cashews), wheat bran, raisin bran cereal, and oatmeal.
What about salt?
Salt can be very important for athletes. Sure, most of the general American public gets too much salt in their diet, but for athletes, salt is key. Like the other electrolytes, salt can be lost through excess sweat and will need to be replaced before, during, and/or after competition. It’s important to note that too much water consumption without salt replacement can lead to a dangerous, and even fatal condition called hyponatremia.
The bottom line: Muscle cramps remain a medical mystery, however hydration, nutrition status, and muscle fatigue appear to play a key role. Since it’s easiest to control your fluid and food intake, focus on eating a healthy diet rich in minerals such as magnesium, potassium and calcium—or supplementing if not able to consume enough through diet. Athletes should pay special attention to these, plus proper sodium intakes, especially during times of excess sweating.
Erin Kelley, MS, RD is a registered dietitian and member of the Academy of Nutrition and Dietetics.