What would count as evidence for a supplement?
Connect deficiency, performance, disease prevention, formulation and interactions before turning a promising ingredient into a shopping decision.
8 source recordsRead the lesson
A LEARNING PATH
Evidence before the bottle
For whom, for which outcome, compared with what?
Understand ingredients, deficiency, trial populations and uncertainty without a shopping stack.
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STAGE 01 · 2 QUESTIONS
Start with the whole label
After reading, try this: Distinguish an ingredient, a serving, a product claim and an interaction question.
- 01Audit a supplement stack by ingredient, serving and unit
Audit a supplement stack by ingredient, serving and unit
Three different bottles can contain the same nutrient. Work through invented vitamin D and magnesium labels to separate arithmetic, reference values and the decision about whether a product is useful.
Free lesson 5 min · full lesson - 02Supplement interactions: absorption, drug effects and laboratory tests
Supplement interactions: absorption, drug effects and laboratory tests
Use vitamin K, magnesium, St. John’s wort and biotin to distinguish several mechanisms. Learn what information makes a pharmacist’s review possible without turning the examples into a self-directed medicine schedule.
Free lesson 4 min · full lesson
STAGE 02 · 5 QUESTIONS
Match nutrients to context
After reading, try this: Explain why correcting a deficiency and preventing disease are different questions.
- 03Vitamin D for stronger bones: why did a large fracture trial find no benefit?
Vitamin D for stronger bones: why did a large fracture trial find no benefit?
Vitamin D is necessary for bone mineralization, but necessity does not mean that adding more prevents fractures in every population.
Free lesson 2 min · full lesson - 04Does vitamin D prevent cancer or heart disease in generally healthy adults?
Does vitamin D prevent cancer or heart disease in generally healthy adults?
Compare vitamin D biology, blood measurements and disease prevention without treating them as interchangeable outcomes.
Free lesson 2 min · full lesson - 05Calcium from food or a supplement: what actually changes?
Calcium from food or a supplement: what actually changes?
Calcium adequacy, absorption, bone density and fracture prevention are connected questions with different evidence requirements.
Free lesson 3 min · full lesson - 06Can iron help fatigue even when hemoglobin is normal?
Can iron help fatigue even when hemoglobin is normal?
Iron stores, anemia and fatigue are related but nonidentical concepts; testing the cause matters more than choosing an energy supplement.
Free lesson 2 min · full lesson - 07Why can vitamin B12 be low despite an apparently healthy diet?
Why can vitamin B12 be low despite an apparently healthy diet?
B12 needs both a reliable source and a functioning absorption pathway. Plant-based diets, stomach changes and some medicines affect different parts of that pathway.
Free lesson 3 min · full lesson
STAGE 03 · 4 QUESTIONS
Read performance and sleep claims
After reading, try this: Keep the training conditions, study population and intended outcome together.
- 08What does creatine actually add to strength training?
What does creatine actually add to strength training?
Understand the short-burst energy system before comparing creatine with protein powders, stimulants or endurance fuel.
Free lesson 3 min · full lesson - 09Can creatine compensate for a night of lost sleep?
Can creatine compensate for a night of lost sleep?
A small laboratory experiment raises an interesting brain-energy question without establishing a sleep-replacement strategy.
Free lesson 2 min · full lesson - 10How much extra muscle does protein supplementation add to training?
How much extra muscle does protein supplementation add to training?
The useful comparison is training with versus without additional protein, while accounting for the protein already supplied by food.
Free lesson 2 min · full lesson - 11Magnesium for sleep: established aid or promising small-study signal?
Magnesium for sleep: established aid or promising small-study signal?
Separate magnesium’s essential biology from the limited clinical evidence for insomnia and claims about premium supplement forms.
Free lesson 2 min · full lesson
STAGE 04 · 5 QUESTIONS
Preserve formulation and outcome
After reading, try this: Explain why evidence for one formulation or strain does not transfer automatically.
- 12Do ordinary fish-oil capsules prevent a first cardiovascular event?
Do ordinary fish-oil capsules prevent a first cardiovascular event?
Learn why omega-3 biology, eating fish and taking a capsule are related but distinct questions.
Free lesson 2 min · full lesson - 13Why can prescription EPA help when a fish-oil trial does not?
Why can prescription EPA help when a fish-oil trial does not?
The formulation, enrolled risk group and background treatment define the intervention more precisely than the phrase omega-3.
Free lesson 2 min · full lesson - 14Why do probiotic results depend on the strain and the problem?
Why do probiotic results depend on the strain and the problem?
A probiotic is not one uniform ingredient. Learn to identify the organism, formulation and clinical purpose.
Free lesson 2 min · full lesson - 15Can probiotics prevent antibiotic-associated diarrhea in children?
Can probiotics prevent antibiotic-associated diarrhea in children?
This is a specific prevention question with stronger evidence than a general promise to improve the microbiome.
Free lesson 2 min · full lesson - 16Do multivitamins make an older brain two years younger?
Do multivitamins make an older brain two years younger?
COSMOS reported small cognitive-test benefits; the age-equivalent headline is a model translation, not a measured reversal of aging.
Free lesson 2 min · full lesson
Explore topic figures and further reading
ONE STUDY, IN CONTEXT
Vitamin D: an estimate and its uncertainty
25,871 midlife and older adults; median follow-up 5.3 years; not selected for deficiency, low bone mass or osteoporosis.
Total-fracture hazard ratio and 95% confidence interval
Vitamin D vs placebo
HR 0.98 · 95% CI 0.89–1.08
0.80.91.01.11.2
1.0 = no between-group difference
Participants with fracture: 769/12,927 versus 782/12,944. No significant reduction in total fractures.
The interval crosses 1.0. This does not answer whether treating diagnosed deficiency helps, and the hazard ratio is not the raw event-count ratio.
LeBoff et al. · NEJM · 2022 · 2026-09-21Original editorial redraw · Professional review pending
Read the numbers, study scope and original source
25,871 midlife and older adults; median follow-up 5.3 years; not selected for deficiency, low bone mass or osteoporosis.
Total-fracture hazard ratio and 95% confidence interval
- Vitamin D vs placebo
- 0.98 · HR 0.98 · 95% CI 0.89–1.08
Participants with fracture: 769/12,927 versus 782/12,944. No significant reduction in total fractures.
The interval crosses 1.0. This does not answer whether treating diagnosed deficiency helps, and the hazard ratio is not the raw event-count ratio.
Original-paper abstract/results via search index; direct page returned no body.
LeBoff et al. · NEJM · 2022Connect the questions
Keep watching & listening
Explore creators’ ideas in their original context. These media links are not the scientific evidence for this course.
Developing a Rational Approach to Supplementation for Health & Performance
Original episode and transcript; distinguishes behavior, nutrition and supplementation.
FoundMyFitness #100 — Darren Candow, PhD
2025-03-31 interview. Attribute specialist explanations to Candow, not automatically to Patrick.