16.5: Phosphorus
- Page ID
- 58179
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Phosphorus—the second most abundant body mineral—is found mainly in teeth and bones, and is closely associated with calcium in the building of these tough structures. About 85% of the body’s phosphorus is in bone. The rest can be found throughout the body in phospholipids (recall that phospholipids make up cell membranes), and in such important molecules as DNA, RNA, and ATP (see Fig. 16-6).
| Maintenance | Loss |
| Normal menses | Lack of menses |
| Estrogen replacement | Early menopause |
| Black race | Alcoholism |
| Physical activity | Cigarette smoking |
| Dietary calcium | Slender figure |
| Heavy body weight | Bed rest (months) Anorexia nervosa |
Table 16-2: Factors Associated with Bone Maintenance vs. Bone Loss.
The recommended intake for phosphorus is less than for calcium, but our diets tend to be much richer in phosphorus. Phosphorus is widespread in foods. Meat, milk, fish, grains, and nuts are rich sources.
A phosphorus deficiency is unlikely under ordinary circumstances. In a general way, almost every good source of calcium is also a good source of phosphorus. However, many calcium-poor foods are phosphorus-rich—for example, meat and cereal. Even diet soft drinks can contain a fair amount. As a component of many food additives, generous amounts of phosphorus can also be found in many processed foods.
Phosphorus deficiency has been found in premature infants fed only breast milk. Breast milk has enough phosphorus for a full-term infant, but not enough for a premature infant. Thus, supplemental phosphorus may be needed for these infants to prevent inadequate mineralization of bone (rickets).
Phosphorus deficiencies have also resulted from the prolonged use of aluminum hydroxide as an antacid. Aluminum hydroxide can combine with dietary phosphorus and prevent its absorption from the intestine. A phosphorus deficiency can result in bone loss, weakness, and pain.
Phosphorus intakes can be high when people drink large amounts of phosphorus-containing soft drinks, like colas. Excessive amounts of phosphorus reduces calcium absorption from the diet. Of special concern are youngsters with diets that are both high in phosphorus and low in calcium. Studies with young animals show that such a diet promotes bone loss.
Figure 16-6: Phosphorus is found in bones, teeth, phospholipids, DNA, RNA and ATP.