Overview
This ESPEN guideline summarizes evidence and provides practical recommendations on the assessment, monitoring, and prescription of micronutrients (trace elements and vitamins) in adult clinical nutrition, covering both enteral and parenteral nutrition.
Purpose and Approach
- Micronutrients (MNs) are vital for metabolism, and deficiencies can worsen clinical outcomes.
- The guideline addresses assessment, monitoring, and prescription of 26 key MNs in clinical nutrition.
- Terminology is standardized to reduce confusion (e.g., deficiency vs. depletion).
- Recommendations are based on literature review, expert consensus, and existing SOPs.
Key General Recommendations
- Adequate amounts of all essential trace elements and vitamins should be provided to all patients receiving medical nutrition support.
- Supplements should be given orally or enterally if possible; parenteral route for poor absorption or rapid correction.
- C-reactive protein (CRP) should be measured to interpret micronutrient levels, as inflammation affects blood concentrations.
Assessment and Definitions
- Status: Adequate = within reference range and absence of clinical symptoms.
- Depletion: Reduced blood levels without symptoms.
- Deficiency: Low blood levels with clinical symptoms or metabolic effects.
- Overdose and toxicity: Elevated blood levels, often with symptoms or in specific risk groups (e.g., renal/liver disease).
- Laboratory reference ranges vary; interpret alongside clinical context and inflammation markers.
Requirements and Dosage Concepts
- EAR, AI, RDA, UL, and DRI are standard terms for determining needs.
- Enteral nutrition products should meet DRI requirements for all MNs with typical intake (e.g., 1500 kcal/day).
- Parenteral nutrition has lower requirements for many MNs (due to bypassing the gut), but must balance deficiency and toxicity, especially in organ dysfunction.
Disease and Therapy-Specific Risks
- Certain diseases (e.g., burns, renal failure, malabsorption, liver disease, bariatric surgery) increase the risk of MN deficiencies.
- Specific therapies (e.g., diuretics, renal replacement, some drugs) can cause or worsen deficiencies.
Monitoring and Special Considerations
- Monitor at-risk patients regularly, especially on long-term nutrition support.
- Inflammation and acute illness affect blood MN levels; always interpret MN results with CRP and albumin.
Example: Enteral/Parenteral Nutrition Doses (per 1500 kcal)
- Iron: EN 18–30 mg, PN ≥1 mg.
- Zinc: EN ≥10 mg, PN 3–5 mg.
- Selenium: EN 50–150 μg, PN 60–100 μg.
- Vitamin D: EN ≥1000 IU, PN ≥200 IU.
- Vitamin C: EN ≥100 mg, PN 100–200 mg.
Key Terms & Definitions
- Micronutrient (MN) — Essential trace elements and vitamins required in small amounts.
- Deficiency — Low blood/plasma MN plus clinical signs or symptoms.
- Depletion — Low blood/plasma MN without symptoms.
- RDA/DRI/AI/UL — Reference values for dietary intake and safety.
- CRP — Blood marker of inflammation needed for correct MN interpretation.
- Enteral Nutrition (EN) — Nutrition delivered via the gastrointestinal tract.
- Parenteral Nutrition (PN) — Nutrition delivered intravenously.
Action Items / Next Steps
- Clinicians: Assess risk, monitor and supplement MNs per guideline recommendations, especially in high-risk patients.
- Students: Review and understand terminology, disease risks, recommended dosages, and interpretation strategies.
- Read full guideline for specific recommendations on each micronutrient.