13.9: Summary
- Page ID
- 57731
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Throughout history, food has often been described as having magical powers. Then, when vitamin extracts were thought to have cured diseases, it led people to believe that vitamins were the answer to many health problems.
Vitamins are substances which are essential to our diet in very small amounts, can’t be made by our bodies, and have a variety of functions. The Recommended Dietary Allowances (RDAs) are calculated to provide the amounts needed by over 95% of the population, and take into account variations found among healthy people.
The public often thinks of vitamins as a “natural” type of medicine but, in reality, vitamins can only “heal” by curing a pre-existing vitamin deficiency. When huge doses of vitamins are given, vitamins work as drugs, not as nutrients. Like drugs, vitamins given in huge doses have side effects, which can be unhealthy, even dangerous. Also, self-medication can delay getting a true diagnosis.
It’s easy to be misled into thinking we have a nutrient deficiency. First, most symptoms are very general and easily confused. Second, we may latch onto one particular symptom, when in reality, a true nutrient deficiency has an array of symptoms.
What are reasonable tests of a diagnosis of deficiency? If there is but one symptom, it’s important to consider whether it’s due to something other than a vitamin deficiency. Checking to see whether one’s diet is supplying less than the RDA for that nutrient is also helpful. But it must be remembered that the RDAs include safety margins, and take into account normal life stresses.
Real deficiencies take a long time to develop —months, not days. The deficiency will affect the whole body, not just one specific area, though signs usually appear in some areas earlier than others, as the body tries to protect vital organs at the expense of “lesser” organs like the skin.
To be labeled as a vitamin, the ultimate test is whether a substance functions as a vitamin in the body. Synthetic vitamins function just like “natural” vitamins, and thus have the same bodily functions. In reality, the working form of the vitamin is the same no matter what the source. In fact, the best way to get “extras” and the “most natural” vitamins is to eat a variety of healthful foods, rather than take supplements.
Many of us are convinced by advertising that we should take dietary supplements to be sure we are getting enough. Many foods in the U.S. have nutrients added to them. Getting a vitamin from fortified foods or a vitamin pill is advised for certain people (e.g., folate for women of child-bearing age, B12 for people over age 50). But, still, the overall aim for all of us is to get our nutrients from a variety of healthful foods.