Nutrition Science and Everyday Application - beta v 0.1

OTHER MINERALS IMPORTANT TO BONE HEALTH 511
plants; therefore green leafy vegetables are good dietary sources of magnesium. Magnesium
is also found in high concentrations in nuts, whole grains, legumes, potatoes, dairy products,
fish, and meats. Most foods that are high in fiber are good sources of magnesium, and it is
added to some fortified foods, such as breakfast cereal. Additionally, chocolate, coffee, and
hard water contain a good amount of magnesium.
Figure 9.8. Dietary sources of magnesium. Examples of good sources pictured include almonds,
black beans, brown rice, edamame, and potatoes. Source: NIH Office of Dietary Supplements
Magnesium Deficiency and Toxicity
Most people in the U.S. do not meet the RDA for magnesium, and studies indicate that
consuming adequate magnesium may improve health. For example, people with higher
dietary intakes of magnesium tend to have lower rates of cardiovascular disease, type 2
diabetes, and osteoporosis, leading some researchers to hypothesize that low intake of
magnesium may increase the risk of these chronic diseases. More studies are needed to
determine whether magnesium supplements may help prevent these diseases. However,
since magnesium is present in many healthful whole foods, improving magnesium intake
through diet may bring multiple benefits.
Obvious magnesium deficiency due to low dietary intake is rare in healthy people, because
the kidneys can decrease urinary excretion of this mineral when intake is inadequate. People
at greater risk of magnesium deficiency include those with type 2 diabetes, gastrointestinal
diseases like Crohn’s and celiac, chronic alcoholism, and older adults. A magnesium
deficiency can cause decreased appetite, nausea, vomiting, fatigue, and weakness. If
extreme, it can cause personality changes, muscle cramps, numbness, tingling, seizures, and
an abnormal heart rhythm. 3
Excessive intake of magnesium from foods is not a risk, as the kidneys can effectively