Genome Replication
Supplements
Dietary supplements, often containing vitamins, are used to ensure that
adequate amounts of nutrients are obtained on a daily basis, if optimal amounts
of the nutrients cannot be obtained through a varied diet. Scientific evidence
supporting the benefits of some dietary supplements is well established for
certain health conditions, but others need further study.
Some research has suggested that supplements do not only provide no tangible
health benefits for generally healthy individuals, but may actually increase
mortality.
In the United States, advertising for dietary supplements is
required to include a disclaimer that the product is not intended to treat,
diagnose,
mitigate, prevent, or cure disease, and that any health claims have not been
evaluated by the
Food and Drug Administration.
In some cases, dietary supplements may have unwanted effects, especially if
taken before surgery, with other dietary supplements or medicines, or if the
person taking them has certain health conditions.
Vitamin supplements may also contain levels of vitamins many times higher, and
in different forms, than one may ingest through food.
Intake of excessive quantities can cause
vitamin poisoning, often due to overdose of
Vitamin A
and Vitamin D
(The most common poisoning with multinutrient supplement pills does not involve
a vitamin, but is rather due to the mineral
iron). Due to
toxicity, most common vitamins have recommended upper daily intake amounts.
Governmental regulation of vitamin supplements
Most countries place dietary supplements in a special category under the
general umbrella of foods, not drugs. This necessitates that the
manufacturer, and not the government, be responsible for ensuring that its
dietary supplement products are safe before they are marketed. Unlike drug
products, that must explicitly be proven safe and effective for their intended
use before marketing, there are often no provisions to "approve" dietary
supplements for safety or effectiveness before they reach the consumer. Also
unlike drug products, manufacturers and distributors of dietary supplements are
not generally required to report any claims of injuries or illnesses that may be
related to the use of their products.
Names in current and previous nomenclatures
The reason the set of vitamins seems to skip directly from E to K is that the
vitamins corresponding to "letters" F-J were either reclassified over time,
discarded as false leads, or renamed because of their relationship to "vitamin
B", which became a "complex" of vitamins. The German-speaking scientists who
isolated and described vitamin K (in addition to naming it as such) did so
because the vitamin is intimately involved in the Koagulation of blood
following wounding. At the time, most (but not all) of the letters from F
through J were already designated, so the use of the letter K was considered
quite reasonable.
The following table lists chemicals that had previously been classified as
vitamins, as well as the earlier names of vitamins that later became part of the
B-complex:
| Previous name |
Chemical name |
Reason for name change |
|
Vitamin B4 |
Adenine |
DNA metabolite |
|
Vitamin B8 |
Adenylic acid |
DNA metabolite |
|
Vitamin F |
Essential fatty acids |
Needed in large quantities (does
not fit the definition of a vitamin). |
|
Vitamin G |
Riboflavin |
Reclassified as
Vitamin B2 |
|
Vitamin H |
Biotin |
Reclassified as
Vitamin B7 |
|
Vitamin J |
Catechol,
Flavin |
Protein metabolite |
| Vitamin L1 |
Anthranilic acid |
Protein metabolite |
| Vitamin L2 |
Adenylthiomethylpentose |
RNA metabolite |
|
Vitamin M |
Folic acid |
Reclassified as
Vitamin B9 |
| Vitamin O |
Carnitine |
Protein metabolite |
|
Vitamin P |
Flavonoids |
No longer classified as a vitamin |
|
Vitamin PP |
Niacin |
Reclassified as
Vitamin B3 |
|
Vitamin U |
S-Methylmethionine |
Protein metabolite |
|
