Magnesium, the fourth most abundant mineral in the body, is a cofactor for hundreds of metabolic reactions. A cofactor is a substance that helps enzymes do their job. Magnesium helps make proteins, muscle and nerve function, blood sugar balance, blood pressure regulation, and energy production (Al Alawi, 2018). But one of magnesium's most important jobs is to help the body build and maintain healthy bones.
Around 50 to 60 percent of the magnesium in your body is found in the bones (de Baaij, 2015). Low magnesium levels are linked to decreased bone mineral density (BMD) and an increased risk of osteoporosis. Understanding why magnesium is so important for your bones and where to find magnesium in food can help ensure you're getting enough of this essential nutrient.
Magnesium for your bones
Magnesium is essential for bones, but because it's needed for many other functions, the body tightly regulates how much is in the blood. If intake is low, magnesium will be pulled from the bones to compensate (Castiglioni, 2013).
Research suggests eating more magnesium supports bone mineral density (BMD) (Groenendijk, 2022). Magnesium deficiency could interfere with bone formation and contribute to fracture risk from brittle bones because of its role in bone mineralization (Uwitonze, 2018).
But magnesium doesn't work alone. Since it's a cofactor, it works with other nutrients—especially calcium and vitamin D—to support your bones. All three of these nutrients are essential for strong bones.
How does magnesium work with calcium and vitamin D?
Think of magnesium, calcium, and vitamin D as teammates. They all support and need each other to do their jobs well. Even supplementing with only one of the three isn't always beneficial if the other nutrients are low (Reddy, 2019). In other words, you need enough magnesium to help your body absorb and use calcium and vitamin D for bone health and vice versa.
Magnesium helps convert vitamin D to its active form and even improves intestinal absorption of vitamin D. Since vitamin D helps with calcium regulation and absorption, low magnesium can impact the ability of all three nutrients to maintain healthy bones. Research suggests that most enzymes needed to metabolize vitamin D need magnesium to function correctly (Uwitonze, 2018).
Sources of magnesium
Magnesium can be found in many foods that you eat every day. Leafy greens, nuts, seeds, whole grains, meat, poultry, and fish all contain magnesium. Examples of foods higher in magnesium include (USDA):
- Pumpkin seeds
- Chia seeds
- Black beans
- Peanut butter
- Brown rice
Best form of magnesium for bone health
Getting your magnesium from food first is always best. Food also provides other vitamins and minerals that work together to support your bones and overall health.
Supplements can be an option to add more magnesium when there are gaps in your diet. There are multiple forms of magnesium, but research often focuses on magnesium citrate, carbonate, and oxide—and all appear to support bone mineral density and reduce fracture risk (Rondanelli, 2021).
The best form of magnesium for bone health is the one you'll consume regularly. Personalizing your preferences and lifestyle can help you get the magnesium your body needs.
How much magnesium do you need?
Recommendations for daily amounts of magnesium vary based on age. All women over 30 (except if pregnant or breastfeeding) need 320 mg daily (NIH, 2022). To compare that amount to food, one cup of raw spinach contains 28 mg of magnesium, and one cup of cooked brown rice contains 86 mg (USDA).
It's also helpful to remember that these are baseline amounts. If you are deficient in other nutrients that need magnesium for absorption, like vitamin D or need more magnesium due to a health condition, your healthcare practitioner may recommend a higher dose. If you're unsure, talk to your healthcare provider about the best amount for you.
How common is a magnesium deficiency?
Even though magnesium is found in many foods, intake has decreased over the past few decades as processed foods have replaced fresh foods. It's estimated that 45 percent of Americans are deficient, and 60 percent don't meet recommendations (Workinger, 2018).
Low magnesium and osteoporosis
Multiple studies link low magnesium status with osteoporosis risk (Rondanelli, 2021). One study found women with osteoporosis had significantly lower magnesium levels than those without (Mederle, 2018). Another study found a link between low serum magnesium and osteoporosis of the spine (Okyay, 2013).
The good news is that research suggests that higher intakes of magnesium-rich foods or supplements are linked to increased BMD for postmenopausal women (Orchard, 2014). A systematic review of 12 studies found that higher magnesium intakes from any source (supplement or food) were linked to increased hip and femoral neck bone mineral density (Farsinejad-Marj, 2016).
The bottom line on magnesium for bone health
Magnesium supports strong bones, directly influencing other critical bone-building nutrients like vitamin D and calcium. While many other factors are also crucial for bone health, including exercise and calcium intake, magnesium may be an additional way to support your bone health and reduce your risk of osteoporosis.
With a well-planned diet, you can get enough magnesium from food sources. Still, people often take magnesium supplements to meet recommendations. If you aren't sure you're getting enough, ask your doctor or a registered dietitian to examine your daily intake and help determine if a supplement is right for you.