A Look at Magnesium and its Role in Bone Health and Osteoporosis

Magnesium is an important mineral (metallic element – Mg) that has many  important structural and functional roles in the body. It is especially important for bone health, and more than sixty percent of the body’s magnesium is contained in the skeleton.

Regarding bone strength it is noteworthy that the presence of the active form of vitamin D increases absorption of magnesium into the skeleton but this absorption is not dependent on vitamin D. One of the other main minerals found in the bone, calcium, does not appear to have much impact on magnesium levels.

As magnesium represents approximately one percent of bone tissue it is no surprise that it plays vital roles regarding bone health. It is a key component of the bone matrix, and deficiencies of the mineral can lead to brittleness of bones, which in turn can dramatically increase the risk of bone fragility fractures. This is largely due to mineral crystals becoming bigger in the bone when magnesium is deficient, this in turn leads to an increase in brittleness.

In addition to an important role in the structure of bones, magnesium is also involved in the metabolism of bone minerals. Although calcium levels do not appear to have much affect on magnesium levels the reverse is not true, and low levels of magnesium in the serum levels of calcium, and on the beneficial bone building roles of vitamin D. Therefore it is essential to get an adequate amount of magnesium in order to prevent loss of bone.

Magnesium Recommended Daily Allowances

The RDA of magnesium given below are based on those provided by the FNB at the IOM and the LPI. It is noteworthy that these RDA’s are aimed at preventing deficiency of the mineral, and do not wholly relate to the amount of the mineral that is required to prevent conditions. That is to say that the amount of magnesium required to prevent osteoporosis/osteopenia is likely to be higher  than the amounts recommended by the FNBIM

AgeFemale: milligrams (mg) per dayMale: milligrams (mg) per day
Up to six months (Adequate Intake)3030
Six months to one year (Adequate Intake)7575
One to three8080
Four to eight130130
Nine to thirteen 240240
Fourteen to eighteen360410
Adults (up to 30)310400
Adults (above to 30)320420
Pregnant/Lactating women - Teens400 / 360
Pregnant/Lactating women - Adults (up to 30)350 / 310
Pregnant/Lactating women - Adults (above 30)360 / 320

Magnesium Rich Foods

The inclusion of magnesium rich foods should be an important part of any diet aimed at the prevention of osteoporosis. Unfortunately many people do not get adequate amounts of the magnesium mineral through diet alone (men typically consume ~80% of the RDA, and women just ~65%!).

chocolate osteoporosis
Chocolate is a delicious source of magnesium and can therefore be included in your diet to prevent osteopenia and osteoporosis. Photograph by John Loo.

Therefore the best way for many people to get adequate amounts of the nutrient is through the consumption of magnesium supplements; this is is a shame as magnesium is relatively easy to include in ones diet. Some rich sources of the nutrient include leafy vegetables, such as cabbage and kale, chocolate,  fruits such as bananas, nuts such as almonds, and grains (though it is probably best to limit grains in the diet, as the consensus is that grains are not as healthy for you as once thought).

Magnesium Rich Foods List

This table of foods that are rich in magnesium is extrapolated from the USDA lists.

Food Source
Size of Serving 100 g (3.5 oz)
Magnesium content in milligrams (mg)
Banana (raw)27
Beans: White - canned51
Beans: Black - boiled70
Beans: Lima - immature/cooked56
Beef - Sirloin24
Beet greens68
Broccoli - boiled/fresh21 / 20
Carrots - raw12
Celery - raw11
Cereals: All Bran363
Cheese: Cheddar28
Cheese: Ricotta15
Cheese: Swiss38
Chicken breast24
Chocolate (semi-sweet)114
Cereals: Oats (cooked)27
Fish: Haddock26
Fish: Halibut28
Fish: Pollock81
Fish: Salmon36
Fish: Tuna (fresh - cooked)42
Flour: Buckwheat250
Flour: Wheat136
Milk (2%)11
Noodles - egg24
Nuts: Almonds268
Nuts: Brazil377
Nuts: Cashew271
Nuts: Macadamia116
Nuts: Pinenuts250
Nuts: Walnuts159
Peas: Blackeye52
Pineapple (Fresh)12
Potato (baked)29
Rice: Brown (cooked)43
Rice: white (cooked)27
Seeds: Pumpkin550
Seeds: Sunflower128
Strawberries - raw13
Soybean (boiled)82
Spinach (fresh/frozen)82
Squash: Summer23
Squash: Winter13
Sweet potato27
Tomato puree42
Turkey - whole25
Yoghurt - plain17

Magnesium Supplements

Although it is relatively easy to include magnesium as part of a healthy diet, unfortunately not every one follows one. The fact that neither the average man and woman does not gain enough of the mineral through their diet makes it necessary for people to take magnesium supplements to prevent themselves from having a marginal magnesium deficiency; which can lead to a loss of bone minerals and a change in bone tissue structure, which in turn will lead to bone weakness/brittleness and an increased risk of osteoporotic related fractures.

The commonest forms of supplement include magnesium oxide, magnesium citrate salt, magnesium gluconate and magnesium chloride. These are often combined with calcium and vitamin D. It is noteworthy that many companies make a big issue about the importance ratio of calcium to magnesium in their products; this can be dismissed as marketing and their is no scientific proof that the ratio of calcium to magnesium in a supplement impacts absorption levels. It is more important that you get adequate supplies of both minerals in to your body as opposed to the ratios that you consume them at, visit this page for in-depth Calcium RDA/Calcium Rich Foods List.