Important Factors to Consider With Dietary Supplement
Usage
1) Drug-Nutrient
Interaction
- Approximately 80%
of adults older than 50 years take at least 1 prescription medication, and more
than 20% take 5 or more prescription medications.
- Among prescription
medication users, >50% concurrently use dietary supplements
- Among CAM users,
77% concurrently use 1 or more prescription medications
- The potential for clinically
significant interactions between medications and dietary supplements has
been reported to range between 21% and 46%, of which approximately 30%
of the interactions are clinically significant
- Drug-herb
interaction can be pharmacokinetic, where the absorption and metabolism are
affected, or pharmacodynamic, where
the effect is additive or antagonistic.
(Example: St John’s wort and Garlic may
decrease while Kava and Valerian may increase the effect of simvastatin,
verapamil, amlodipine, diazepam, and others; St John’s wort may decrease the
effect while Kava and Ginkgo biloba may increase the effect of glipizide,
ibuprofen, carvedilol, celecoxib, and others;
Ginger, garlic, G biloba and glucosamine may increase risk of bleeding in
patients concurrently taking warfarin, while Co-Q10, St John’s wort and vitamin
K may decrease the effectiveness of warfarin)
2) Nutrient-Nutrient
Interactions
- Too much of any
one nutrient can have toxic effects; while nutrients may also compete for
receptor sites and cause an imbalance of other nutrients.
- Dietary Reference Intakes
(DRIs) for age and gender should be consulted as reference values to plan and
assess dietary food and supplement intake
- Vitamin and
mineral supplementation may be recommended for specific vulnerable populations,
including the supplementation of folate for women of childbearing age, vitamin
D for breastfed infants, or formula fortified with vitamin D for bottle-fed
infants in the first year of life.
- At the same time,
it is also important to be aware that nutrient excesses can also pose a health threat. (Example: Excess folic acid intake may mask a vitamin B 12
deficiency, and high doses of iron supplements can decrease zinc absorption)
3) Safety
- It is a common
misperception to assume that dietary supplements are safe because they come
from natural sources. (Eg: Kava is a natural product, but was reported to
cause liver damage)
- Unlike
medications, dietary supplements are not
approved by the government for safety and effectiveness before they are
made available to consumers.
- Dietary
supplements are only reviewed by the FDA if they contain new ingredients that
were not readily available to consumers prior to 1994, and a product must be
proven unsafe by the FDA before it can legally be removed from the market
- It is also
possible for natural products to be contaminated during growth and processing.
(For example, some reported noncommon
side effects of ginseng, including breast tenderness, menstrual irregularities,
and high blood pressure, have been proposed to be linked to nonpure
preparations of the herb)
- It is best to
purchase dietary supplements from well-known, reputable manufacturers.
The Role of Healthcare Professional
- The umbrella term dietary
supplements includes vitamin/mineral supplements as well as
nonvitamin/mineral supplements. Healthcare professionals should understand the
differences between these 2 categories of supplements and address both types of
dietary supplements as appropriate.
- According to
the Academy of Nutrition and Dietetics (AND), the best way for the general population to meet their nutrition needs is
through a variety of foods
- However, the AND
does recognize that dietary intake may not always be sufficient, especially
for select vitamins or minerals and in specific populations, at which time
dietary supplements may be beneficial to ensure that individuals meet all of
their nutrient needs for optimal health.
- Therefore,
dietetic professionals play an important role to recommend dietary supplement
to appropriate selected population while empowering their ability to
consume a healthy and balanced diet. (ZYL)
Practical Advice of Healthcare professional
- Four basic roles: communication,
education, evaluation, and documentation
1) Communication:
- non-judgmental
when discussing dietary supplement use, ask pertinent questions and encourage
and open dialogue
- explain to the
patient why your knowledge of his or her dietary supplement use is important to
you as
[Example of questions: WHAT are you currently
taking? (dietary supplement, brand,
dose); WHY did you start taking it?; WHEN did
you start taking it? WHEN in the day do you take it?; WHO recommended the
product or WHERE did you learn about the product?; HOW is it working?]
2) Education
- You need to have
some knowledge of and familiarity with the popular dietary supplements
- Important to not
only pay attention to the ads that the consumer sees but also know where to go
to find scientifically sound research and resources to educate yourself
3) Evaluation
- You should weigh
the risks against the benefits of supplementation
- Remember to take
into account dietary intake, costs of supplementation, any potential safety
issues, and drug-nutrient interactions and to weigh these issues against any
potential benefits of supplementation for health promotion and disease
prevention or management
- Also consider the
patient’s or client’s personal beliefs on dietary supplementation, allopathic
treatment, and complementary and alternative therapies in your evaluation and
in framing your individual recommendations.
4) Documentation
- To monitor patient
progress and to document and report any adverse effects.
- Report to MedWatch
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