Dietary supplements: what do you need to know about them?

The 1994 Supplementary Food Supplement (DSHEA) Act defines dietary supplements as any product (other than tobacco) - in the form of a pill, capsule, tablet or liquid containing a vitamin, mineral, herb, amino acid or other recognized dietary substance that is intended to be an attachment to the usual diet.

The act requires that the product label identify the product as a dietary supplement and notify the consumer that the declared properties of the additive did not pass the evaluation of the Food and Drug Administration; The label should also offer a list of each component with its name, quantity and total weight and identify the plant parts from which these components are derived (see DSHEA at www.fda.gov). Manufacturers are permitted to provide information on the composition of the product and its functions (eg, the benefit to the healthy functioning of the urinary tract), but it is not permitted to make or imply statements that the drug can be used as a medicine or therapeutic agent (eg, treats urinary tract infection).

Dietary supplements are most often used from all complementary and alternative therapies, primarily because they are widely available and can be bought without consulting a professional health professional. Most patients who use dietary supplements consider that they are useful for health in general, safe and effective for the treatment of certain conditions, or combine all of these properties, and it is also believed that these supplements are natural (ie derived from plants or animals) and some of them have been used for centuries in traditional medicine. However, the Committee for the Control of Food and Drug Administration treats dietary supplements differently from drugs. The Food and Drug Administration regulates only quality control and the production process, but does not guarantee the standardization of active ingredients. However, although slowly, some steps have already been taken in this direction. Also, the Food and Drug Administration does not require a manufacturer of dietary supplements a certificate of safety or efficacy (although additives should have a reputation for being safe). Most additives have not been strictly studied. For most, the evidence of safety or effectiveness is the very tradition of using them, laboratory experiments, some recorded cases of using and studying the actions of additives in animals. However, it has been proven that some of the additives (eg, fish oil, chondroitin / glucosamine, palm sereno) are now a safe and useful addition to standard medicines. The number of evidence for the safety and effectiveness of dietary supplements is growing rapidly as more and more clinical studies are conducted. Information on such studies can be found on the National Institutes of Health website of the National Center for Complementary and Alternative Medicine (NCCAM) (www.nccam.nih.gov).

Lack of regulation and government monitoring also means that supplements are not checked to ensure that they contain the same components or the same amount of active ingredient that is incorporated into the additive description by the manufacturer of the drug. The additive may contain unregistered components that may be inert or harmful, or may contain a varying amount of active ingredients, especially depending on whether the herbs or extracts thereof are included. Consumers risk receiving less, more or, in some cases, no active ingredient at all, even if the active ingredient is known. Most herbal supplements are mixtures of several substances, while which of the components is the most active, is not always known. Some additives have been standardized and may have a standardization certificate on the label.

An additional object of concern is the use of dietary supplements in place of real medicines, the stability of additives (especially herbal preparations) manufactured some time ago, the toxicity of supplements for children and the elderly, and the interaction of supplements and medications. Most of the information about such problems stems from sporadic individual reports on the interaction of supplements and drugs and some cases.

Despite these additive-related problems, many patients still blindly believe in the usefulness of supplements and continue to use them with or without a doctor's recommendation. Patients may not admit to taking supplements, or may wish to hide the fact of using dietary supplements. For this reason, the history of the outpatient should periodically record direct questions about past and present use of complementary and alternative therapies, including dietary supplements. Many doctors include the use of certain supplements in their medical practice; the reason for this can be the proven utility of the supplement, the desire to guarantee the safe use of supplements by patients who will use supplements anyway, and the doctor's confidence that the supplements are safe and effective. Data that could allow us to give competent recommendations on the use of safe supplements is not enough at the moment, but some experts believe that the total number of problems associated with dietary supplements is small compared to the total number of doses taken and that a qualitatively manufactured drug, safe. As a result, experts advise you to buy supplements of well-known manufacturers, and it is often recommended to give preference to additives manufactured in Germany, where they are treated as medicines and, therefore, control over their manufacture is more stringent than in the US.

Some Possible Consequences of Interaction of Dietary Supplements and Drugs

Dietary Supplements	Drugs that are influenced by supplements	Interaction
Chamomile	Barbiturates and other sedatives	May enhance or prolong the effect of sedatives, because its volatile oils have additional effects
	Additives containing iron	Can reduce the absorption of iron through plant tannins
	Warfarin	May increase the risk of bleeding, because chamomile contains phytocoumarins, which may have additional effects
Echinacea	Drugs metabolized by cytochrome P450 enzymes (eg, amiodarone, anabolic steroids, ketoconazole, methotrexate)	When taken together these drugs may increase the risk of hepatotoxicity by slowing their metabolism
	Immunosuppressants (eg, corticosteroids, cyclosporine)	Can reduce immunosuppressive effects through T cell stimulation
Pyrethrum	Medications against migraine (eg, ergotamine, metisergide)	May increase heart rate and blood pressure, because they have additional vasoconstrictive effects; can enhance the effects of metisergide
	Antiplatelet drugs	May increase the risk of bleeding, because pyrethrum inhibits platelet aggregation (have additional effects)
	Additives containing iron	Can reduce the absorption of iron through plant tannins
	Non-steroidal anti-inflammatory drugs	The effectiveness of pyrethrum for preventing and eliminating headaches with migraine is reduced by nonsteroidal anti-inflammatory drugs.
	Warfarin	May increase the risk of bleeding, since warfarin may have additional effects
Garlic	Antihypertensive drugs	May increase the antihypertensive effect
	Antiplatelet drugs	May increase the risk of bleeding, since these drugs deny the inhibition of garlic clots of platelet and fibrinolytic effects
	Protease inhibitors (eg saquinavir)	The blood level of protease inhibitors is reduced by garlic
	Warfarin	May increase the risk of bleeding by increasing the effects of anticoagulant warfarin.
Ginkgo	Anticonvulsants (eg, phenytoin)	Can reduce the effectiveness of anticonvulsants, since impurities in ginkgo compounds can reduce the effects of anticonvulsant
	Aspirin and other non-steroidal anti-inflammatory drugs	May increase risk of bleeding by increasing inhibition of antiplatelet aggregation
	Warfarin	May increase the risk of bleeding by enhancing the effects of warfarin anticoagulant
Ginseng	Antihypoglycemic drugs (eg, glipizide)	May enhance the effects of these drugs, causing hypoglycemia
	Aspirin and other non-steroidal anti-inflammatory drugs	May increase risk of bleeding by increasing inhibition of antiplatelet aggregation
	Corticosteroids	Can enhance the adverse effects of corticosteroids, since ginseng has anti inflammatory effects
	Estrogens	May increase the level of digoxin May enhance the adverse effects of estrogen
	Monoamine oxidase inhibitors (eg tranylcypromine)	May cause headache, concussion and bouts of insanity
	Warfarin	May increase the risk of bleeding by enhancing the anticoagulant effects of warfarin
Hydrastis	Warfarin and heparin	Can withstand the effects of warfarin and heparin, increasing the risk of thromboembolism
Marjin thistle	Antihypoglycemic drugs	May enhance the effects of these drugs, causing hypoglycemia
	Indinavir	Can interfere with the work of enzymes of digestion, lowering the level of indinavir in the blood
Palma Serenoi	Estrogens (for example, oral contraceptives)	May increase the effects of these drugs
St. John's Wort	Cyclosporin	Can reduce the level of cyclosporine in the blood, increasing the risk of rejection during organ transplantation Can reduce the level of digoxin in the blood, making it less effective, with potentially dangerous results
	Iron supplements	Can reduce iron absorption
	Monoamine oxidase inhibitors	May increase the effects of monoamine oxidase inhibitors, causing very high blood pressure, which may require emergency treatment
	The irreversibly acting transcriptase inhibitors	Increases the metabolism of these drugs, reducing their effectiveness
	Oral contraceptives	Increases the metabolism of these drugs, reducing their effectiveness
Ginger	Antiplatelet drugs	May increase the risk of bleeding by increasing the inhibition of platelet aggregation
	Warfarin	May increase the risk of bleeding by increasing the effects of anticoagulant warfarin.
Valerian	Barbiturates	Can enhance the effects of barbiturates, causing excessive sedation

When dietary supplements are used, special care is required because these products are not standardized and therefore vary considerably and because information about their use is continuously changing. The theoretical status of a large amount of material on interactions does not eliminate the need for careful use of them. Before prescribing any drug, health practices should be asked from patients, they take dietary supplements and, if so, which ones. Practitioners should identify any potential adverse interactions between medications and supplements taken by the patient, and then determine the appropriate medications and dosages.

[1], [2], [3], [4], [5], [6], [7]