The Healthspan Map · Nutrition (Ch9-10)
Supplement discipline
What this is linked to
| Nutrient or lever | Direction | Strength | Evidence type | What was found | Source |
|---|---|---|---|---|---|
| Supplement discipline | Do this | Moderate | Review / narrative | Appropriate iron/B12/folate supplementation corrects the common nutritional anemias. | Correcting deficiencies via supplements (opens in a new tab) |
| Supplement discipline | Do this | Emerging | RCT / meta-analysis | Sensible vitamin-D dosing (800-1000 IU/day, not intermittent megadoses) matters — high-dose boluses raise fall risk. | Vitamin D & falls network meta-analysis (PMC11064304) (opens in a new tab) |
| Supplement discipline | Do this | Emerging | Review / narrative | Correcting a genuine micronutrient gap (iron, B12, D, magnesium) reduces fatigue; beyond repletion, supplements add little. | Micronutrients for energy/fatigue review (Tardy 2020) (opens in a new tab) |
| Supplement discipline | Do this | Emerging | Established clinical | Excess supplements (magnesium, vitamin C, iron, zinc) commonly cause diarrhoea/nausea; discipline limits this. | NIH Office of Dietary Supplements — Magnesium (opens in a new tab) |
| Supplement discipline | Do this | Emerging | Systematic review | Sensible supplementing matters here: too little B12 or too much B6 both damage nerves, so keep B6 supplements low and check B12. | Vitamin B6 & neuropathy (opens in a new tab) |
| Supplement discipline | Do this | Moderate | Review / narrative | Correcting deficiencies (folate, zinc, vitamin D, omega-3) supports fertility, but antioxidant megadosing can backfire via reductive stress — sensible, food-first dosing matters. | Dietary antioxidants & male infertility – antioxidant paradox (PMC8003818) (opens in a new tab) |
| Supplement discipline | Do this | Moderate | Systematic review | Correcting vitamin D and zinc reduces respiratory-infection risk/duration — but sensible dosing matters, since megadosing vitamin A/E/beta-carotene/iron can backfire. | Micronutrient supplements & respiratory infection meta-analysis (BMJ Glob Health 2021) (opens in a new tab) |
| Supplement discipline | Do this | Emerging | Review / narrative | Supplements help hair/skin mainly when correcting a proven deficiency; megadosing (A, selenium, zinc) can worsen hair loss. | Correcting deficiency vs megadosing (opens in a new tab) |
| Supplement discipline | Do this | Emerging | Review / narrative | Correcting vitamin-D deficiency (common in OSA) is the main evidence-based supplement consideration. | Vitamin D & OSA review (PubMed 38414320) (opens in a new tab) |
| Supplement discipline | Do this | Moderate | Review / narrative | Iodine and selenium both follow a U-shape: repletion within the optimal window helps, but over-supplementation (especially iodine) can precipitate dysfunction — disciplined dosing matters. | Nutrition & thyroid myths/facts review (J Endocrinol Invest 2026) (opens in a new tab) |
| Supplement discipline | Do this | Moderate | RCT / meta-analysis | The AREDS/AREDS2 formula (C, E, zinc, copper, lutein/zeaxanthin) cuts progression to advanced AMD ~25% — but it is for people who already have intermediate AMD, not universal use. | AREDS/AREDS2 review (PMC7015456) (opens in a new tab) |
| Supplement discipline | Do this | Emerging | Review / narrative | Correcting genuine micronutrient gaps restores immune function; indiscriminate megadosing does not boost a healthy system. | Micronutrient repletion (opens in a new tab) |
| Supplement discipline | Do this | Moderate | Established clinical | Megadoses of vitamin A, niacin, iron, vitamin C and vitamin D can injure the liver or kidneys; food-first, sensible dosing protects both organs. | Vitamin A hepatotoxicity (NIH LiverTox) (opens in a new tab) |