Nutrition Science and Everyday Application - beta v 0.1

510 ALICE CALLAHAN, PHD, HEATHER LEONARD, MED, RDN, AND TAMBERLY POWELL, MS, RDN
Figure 9.7. Food sources of phosphorus. Examples of good sources pictured include yogurt,
salmon, potatoes, and chili (made with ground beef and kidney beans). Source: NIH Office of
Dietary Supplements
Phosphorus Deficiency and Toxicity
Both deficiency and toxicity of phosphorus are rare. The average intake of phosphorus in
U.S. adults ranges between 1,000 and 1,500 milligrams per day, well above the RDA of 700
milligrams per day. The UL set for phosphorus is 4,000 milligrams per day for adults and
3,000 milligrams per day for people over age 70. Very high doses of phosphorus taken in
supplement form can interfere with calcium regulation and cause calcification, or hardening,
of soft tissues, especially the kidneys. 2
MAGNESIUM
Approximately 60% of magnesium in the human body is stored in the skeleton, making
up about 1% of mineralized bone tissue. In addition to contributing to bone maintenance,
magnesium has several other functions in the body. It is required in every reaction involving
ATP, amounting to more than three hundred enzymatic reactions. Magnesium plays a role
in the synthesis of DNA and RNA, carbohydrates, and lipids, and it’s essential for nerve
conduction, muscle contraction, and normal heart rhythm.
Dietary Sources of Magnesium
Magnesium is part of the green pigment, chlorophyll, which is vital for photosynthesis in