Keep your Vitamin D blood levels high for 5 years
and reduce your risk of many illnesses by 20 to 70%
This is a simple list of the top 10 illnesses or conditions, where maintaining your blood Vitamin D levels higher over more than 5 years is associated with reduced risk or incidence.
You need to achieve blood Vitamin D levels of 25(OH)D at around 100-150 nmol/L or 40-60 ng/ml
Based on studies compiled by GrassRootsHealth and VitaminDwiki using observational cohort data, pooled analyses, and participant studies, the list prioritizes the highest reported percentage risk reductions first, drawn primarily from pooled data emphasizing benefits at these higher levels-vs-deficiency or lower levels.
These are approximate percentages from observational/long-term data rather than only large Randomised Control Trials RCTs.
(They recommend ≥100nmol/L compared to 20-30 nmol/L which is more typical of the general public),
These apply to both sexes unless specified.
- Breast Cancer — Primarily female — Around 71% reduction
From GrassrootsHealth analyses of participant data and pooled studies.
- Invasive Cancer (any, excluding skin) — Both sexes (stronger in women) — Up to 70% reduction
From pooled analyses and charts cited on GrassrootsHealth.
- Colorectal Cancer — Both sexes — often in the 50-65% range
From global/ecological and cohort data referenced in some sources.
- Prostate Cancer — Males only — Around 30-60% reduction in incidence or risk.
Supportive observational/ecological data link higher lifetime/sustained levels to lower incidence. GrassrootsHealth notes potential 25-80% cancer risk reductions by type, with prostate highlighted positively in some analyses for prevention, plus slower progression at optimal high levels.
- Type 2 Diabetes — Both sexes — Around 60% lower incidence
- Autoimmune Diseases — Both sexes — Around 22-40% reduction
Long-term follow-up data from the VITAL study and GrassrootsHealth emphasise higher levels for prevention.
- Multiple Sclerosis — Both sexes (some stronger in women) — Significant reduction
Observational data on VitaminDWiki and other sources link sustained high levels to markedly lower risk
- Cardiovascular Disease/Events — Both sexes — 13-25% reduction in major events
From trials and expert summaries on GrassrootsHealth.
- Influenza or Respiratory Infections — Both sexes — 40-50%+ in some contexts
From studies compiled on VitaminDWiki.
- All-cause Mortality — Both sexes — Up to 18-25% reduction
Estimated by raising Vitamin D to optimal high levels, from some analyses.
These figures reflect advocacy-focused sources promoting 100-150 nmol/L for prevention, rather than for treatment
Examples come from GrassRootsHealth and VitaminDwiki where data show large benefits for certain cancers at ≥100nmol/L (40 ng/ml), and pooled observational evidence).
Prostate cancer inclusion places it mid-list due to supportive but less consistently high percentages compared to breast or general invasive cancer in these sources—often framed as reduced incidence/progression rather than the top-tier reductions seen elsewhere.
Evidence is stronger for some cancers than others, and mainstream views often note inconsistencies or limited RCT support for very high blood level targets targets in prevention.
Test your levels, consult a doctor (especially for men with prostate concerns/PSA), and personalize your Vitamin D supplementation.
How much Vitamin D should you start with ?
The NHS suggests 400IU per day for everyone, whether you are a baby, or small or large
This is probably way too little for an adult, as the government is very cautious
The European Food Safety Agency allows any adult to take 4,000IU per day, and up to 10,000IU per day under medical advice
Vitamin D lasts in your body for 30-60 days so you could take 20,000IU once a week, which is equivalent to nearly 3,000IU per day
As long as you don’t have sarcoidosis, you could consider taking 4,000IU each day for a few months, and then ask your doctor for a blood test
Look for a source of Vitamin D3 that is easy to swallow or dissolve in water, and is hypo-allergenic
Supplement-Search is not a doctor, so you must do your own research on this !
