Minerals — Iron, Zinc, Magnesium, Calcium, Selenium

Core topics

Lessons in this module

Learning objectives

By the end of this module you will be able to

Lesson summary ↓Graded claims ↓Self-check ↓Vignettes ↓Glossary ↓

L01
Diagnose iron deficiency with ferritin + transferrin saturation, knowing inflammation confounds.
L02
Compare oral iron strategies — daily, alternate-day, salt forms — per Moretti and Stoffel data.
L03
Counsel on calcium supplementation in postmenopausal women with respect to WHI CV signal.
L04
Identify clinical scenarios for zinc and selenium supplementation vs dietary correction.

Expected takeaways

What you should walk away believing

→Ferritin <30 ng/mL = iron deficiency in most adults; <100 if inflammation present.
→Alternate-day oral iron may match daily-dosing efficacy with fewer GI side effects.
→Routine calcium supplementation beyond dietary adequacy does not reduce fractures and may marginally increase CV risk.
→Zinc lozenges (>75 mg/d) shorten cold duration modestly but cause taste disturbance.

Lesson · Core emphasis

What this means for you

Patient summary

If your iron is low, treating it makes a big difference. Magnesium can help some kinds of migraines and constipation. Most adults don't need extra calcium pills if they eat dairy or fortified foods — and high doses haven't reduced fractures in studies.

Clinician summary

Iron: oral first (alternate day if intolerant); IV for malabsorption, intolerance, CKD, ongoing loss. Calcium: food-first; supplement to reach 1000–1200 mg/d total only when dietary inadequate. Magnesium glycinate or citrate for migraine prophylaxis (400 mg/d) — modest evidence.

Advanced note

Hepcidin rises after a single iron dose, blocking absorption for 24 h — biological basis for alternate-day dosing (Stoffel, Lancet Haematology 2017).

Evidence framework

Where this module sits on the device evidence map

Minerals: clear deficiency-rescue benefit; population supplementation often null or harmful.

Tier map →Tier 1 →Tier 2 →Tier 3 →

Myth-buster

Everyone over 50 needs a calcium pill.

Reality

WHI and meta-analyses (Bolland 2010) suggest no fracture benefit and possible CV signal; dietary calcium preferred.

Evidence-graded claims

What the data says

B

Oral iron alternate-day matches daily for repletion with better tolerance

Stoffel/Moretti 2017.

D

Calcium supplementation reduces fractures in community-dwelling adults

WHI and meta-analyses largely null.

B

Magnesium 400–600 mg/d reduces migraine frequency

AAN/AHS Level B.

F

Selenium supplementation prevents cancer in selenium-replete populations

SELECT negative.

Objective self-check

Test the learning objectives

Score0 / 1(0 answered)

Q1L01 — IDA ferritin cutoff?

Case vignettes

Apply it: real-world counseling scenarios

Short patient encounters that test your judgment, not your recall. Pick the most defensible response, then reveal the rationale and a sample coaching script you could actually say at the bedside.

Vignette proficiency

In progress · 0/1 submitted

Correct0/1 (0%)Pitfalls avoided0/0 (0%)Composite0

Composite weighting

Accuracy 60%Pitfalls 40%

← all pitfallsbalancedall accuracy →

Composite = 60% answer accuracy + 40% pitfalls avoided. Your weighting is saved for this module.

Order · randomized[1]

Vignette 1 of 1· source #1

Calcium for everyone?

Objective · Calcium counseling.

A 62-year-old asks if she should take a 1200 mg calcium pill daily 'for her bones.' She drinks 2 cups of milk and eats yogurt daily.

Best advice?

Quick check

Test yourself

Q1Best oral iron dosing strategy per Moretti?

Q2WHI calcium + vit D primary endpoint?

Flashcards · Spaced repetition

Lock it in — review what's due

Due2Total2

FrontNew

2 in queue

Magnesium form least likely to cause diarrhea?

Click to reveal answer

Glossary

Key terms & abbreviations

Hepcidin: Hepatic peptide hormone — master regulator of iron absorption; rises with inflammation and after iron dose.
Iron deficiency anemiaIDA: Microcytic anemia from depleted iron stores; defined by low ferritin / transferrin saturation.

Optional deeper dive

Alternate-day iron — Stoffel et al. — Lancet Haematol 2017↗
WHI calcium/vit D — NEJM 2006↗