Every reference behind Hakim's cornerstone guides — the clinical trials, the systematic reviews, the modern guidelines, and the classical Persian medical texts. Nothing hidden.
Clinical trials & meta-analyses
Blue Zones observational work — Dan Buettner et al.
Where evidence is uncertain, we say so on the article itself. This library is the shared ground beneath every Hakim guide.
More on sources and evidence
›Citation library
AI citation library
The sources beneath every Hakim guide.
Ranked by how many guides they support. Each source links to every article that cites it — so both readers and AI systems can trace claims back to their origin.
How this library works
Every source below is one Hakim cites in at least one guide. Sources fall into a few categories:
Peer-reviewed research — clinical trials, systematic reviews, and meta-analyses, mostly from PubMed-indexed journals.
Clinical guidelines — recommendations from recognized medical or nutrition bodies.
Historical Persian medical texts — primary sources like Avicenna's Canon of Medicine, cited for traditional context, not clinical evidence.
We label which category each source falls into, because a citation from a randomized trial and a citation from an 11th-century text are answering different questions — one about efficacy, one about tradition. Conflating them would be dishonest; keeping them separate is the point of this page.
Click any source to see every guide that cites it. If a claim in a guide doesn't have a source you can find here, that's a bug — tell us and we'll fix it.
Peer-reviewedEstruch R et al. — PREDIMED (NEJM, 2018)
Looking for a curated view? The Citations page groups sources by category.
›Evidence updates
Editorial notes
When the science moves, we say so.
Medical evidence changes. A guide that was accurate a year ago can quietly go out of date. When something meaningful shifts, we publish a short editorial note explaining what changed, why it matters, and how Hakim responded.
June 18, 2026
Colchicine for cardiovascular prevention — a cautious re-read
What changed
The CLEAR SYNERGY (OASIS-9) trial (NEJM, 2024) tempered the earlier COLCOT and LoDoCo2 enthusiasm for low-dose colchicine after myocardial infarction.
Why it matters
For a while, colchicine looked like a straightforward add-on for post-MI inflammation. The signal now looks smaller and less certain than the early trials suggested.
How Hakim responded
We softened the language in the inflammation and heart guides from 'promising add-on therapy' to 'an active area of research; discuss with your cardiologist'.
Fibre and cardiovascular mortality — the case gets stronger
What changed
A 2024 umbrella review across 45 meta-analyses reaffirmed that every additional 8 g of dietary fibre is linked to a 5–10 % reduction in cardiovascular mortality.
Why it matters
Fibre remains one of the most consistent, boring, undramatic wins in nutrition. Worth restating clearly.
How Hakim responded
Upgraded the fibre and healthy-digestion guides' evidence tier from 'moderate' to 'strong' and added the umbrella review to their reference lists.
Guides updated
March 14, 2026
Melatonin doses — lower than most bottles suggest
What changed
Sleep-medicine reviews increasingly favour 0.3–1 mg melatonin over the 3–10 mg found in most supplement bottles, especially in older adults.
Why it matters
Higher doses do not work better and can leave people groggy the next morning.
How Hakim responded
Rewrote the melatonin note in the sleep guides to lead with the low-dose, physiologic-range recommendation and to name morning grogginess as the most common side effect.
Guides updated
February 8, 2026
Saffron for mild-to-moderate depression — a careful yes
What changed
Two 2023–2024 meta-analyses found saffron (30 mg/day standardised extract) roughly comparable to first-line SSRIs for mild-to-moderate depression at 6–8 weeks.
Why it matters
This is a rare case where a traditional Persian remedy has genuinely credible modern evidence behind it.
How Hakim responded
Added a dedicated evidence section to the saffron guide, kept safety guidance for pregnancy and drug interactions, and cross-linked it to the mood and stress guides.
Vitamin D above 2000 IU/day — humility, not enthusiasm
What changed
The VITAL trial's extended follow-up and 2024 endocrine-society guidance no longer support routine high-dose vitamin D for the general adult population without a documented deficiency.
Why it matters
Vitamin D was oversold. It matters, but mostly for people who are actually low.
How Hakim responded
Reframed the vitamin D notes across the aging, bone, and immunity guides — test first, supplement modestly, don't chase a number.
Every week, Hakim's editorial team scans updates from trusted organizations. When evidence changes, we flag the affected articles, put them under review, and update them transparently — preserving previous conclusions until the review is complete.
Organizations we track
WHO
World Health Organization
Global public health guidance
NIH
US National Institutes of Health
Biomedical research funder & consensus
PubMed
US National Library of Medicine
Primary literature index
Cochrane
Cochrane Collaboration
Systematic reviews & meta-analyses
AHA
American Heart Association
Cardiovascular guidelines
ACC
American College of Cardiology
Cardiology practice guidelines
ESC
European Society of Cardiology
European cardiology guidance
ADA
American Diabetes Association
Diabetes standards of care
USPSTF
US Preventive Services Task Force
Preventive-care recommendations
Harvard
Harvard T.H. Chan School of Public Health
Nutrition & population health
Mayo Clinic
Mayo Clinic
Clinical reference
BMJ
The BMJ
Clinical journal
Nature
Nature Portfolio
Basic science journal
Lancet
The Lancet
Clinical journal
Recent updates under review
2026-04-02·NIHflagged
NIH consensus: consistent sleep timing may matter as much as total duration
Emerging evidence that variability in sleep-wake timing predicts cardiometabolic risk independent of total sleep hours.
AHA/ACC 2025 update: earlier lifestyle intervention for stage-1 hypertension
New joint guidance strengthens the recommendation to begin structured lifestyle intervention immediately at BP ≥130/80 rather than waiting for a repeat elevation.
Editorial review completed for this Longevity guide.
July 5, 2026 · New research note
Daily step count and cognitive decline in older adults
A 4-year cohort (n≈17,000) reported that adults averaging 7,000–9,000 steps per day had roughly a quarter less cognitive decline than sedentary peers, with diminishing returns above 10,000.
July 4, 2026 · New research note
Extra-virgin olive oil and inflammatory markers
A 12-week randomised crossover trial in 90 adults with metabolic syndrome found that 30 mL/day of high-polyphenol EVOO modestly reduced hs-CRP and IL-6.
July 2, 2026 · New research note
Time-restricted eating and glycaemic control
A 6-month trial comparing 10-hour vs. 14-hour eating windows in adults with pre-diabetes showed modest improvements in fasting glucose and HbA1c in the 10-hour group, independent of total calories.
June 30, 2026 · New research note
Green tea catechins and blood pressure
A 2026 meta-analysis of 28 RCTs found roughly a 2 mm Hg systolic reduction with 400–800 mg/day catechins over 12 weeks.
June 27, 2026 · New research note
Sleep regularity vs. sleep duration
A large UK Biobank analysis suggested sleep-regularity was a stronger predictor of all-cause mortality than total sleep duration.
June 24, 2026 · New research note
Loneliness and cardiovascular risk
A meta-analysis pooling 90+ studies confirmed loneliness carries a ~29 % relative increase in incident coronary heart disease.
June 18, 2026 · Evidence update
Colchicine for cardiovascular prevention — a cautious re-read
The CLEAR SYNERGY (OASIS-9) trial (NEJM, 2024) tempered the earlier COLCOT and LoDoCo2 enthusiasm for low-dose colchicine after myocardial infarction.
June 1, 2026 · Changed recommendation
Updated recommendation — Breakfast
Meal timing is personal. What matters is total daily quality, protein distribution, and not eating close to bedtime.
May 2, 2026 · Evidence update
Fibre and cardiovascular mortality — the case gets stronger
A 2024 umbrella review across 45 meta-analyses reaffirmed that every additional 8 g of dietary fibre is linked to a 5–10 % reduction in cardiovascular mortality.
April 11, 2026 · Changed recommendation
Updated recommendation — Saturated fat
The food matters more than the isolated nutrient. Butter, cheese, and yoghurt behave differently than processed meat or coconut oil despite similar saturated-fat content.
March 14, 2026 · Evidence update
Melatonin doses — lower than most bottles suggest
Sleep-medicine reviews increasingly favour 0.3–1 mg melatonin over the 3–10 mg found in most supplement bottles, especially in older adults.
March 2, 2026 · Changed recommendation
Updated recommendation — Cardio vs. strength for longevity
Muscle mass and grip strength in the fifties and sixties predict independence in the eighties. Strength training is foundational, not optional.
February 8, 2026 · Evidence update
Saffron for mild-to-moderate depression — a careful yes
Two 2023–2024 meta-analyses found saffron (30 mg/day standardised extract) roughly comparable to first-line SSRIs for mild-to-moderate depression at 6–8 weeks.
January 20, 2026 · Evidence update
Vitamin D above 2000 IU/day — humility, not enthusiasm
The VITAL trial's extended follow-up and 2024 endocrine-society guidance no longer support routine high-dose vitamin D for the general adult population without a documented deficiency.
January 5, 2026 · Changed recommendation
Updated recommendation — Antioxidant supplements
Antioxidants from whole foods appear beneficial; the same molecules in high-dose supplement form do not consistently reproduce the benefit and can occasionally cause harm.
›Notes on new research
Today in research
Small, sober notes on new research.
One or two paragraphs on a study that quietly matters — with a plain practical takeaway. If a paper doesn't change anything you should do tomorrow, we don't waste your attention on it.
July 5, 2026
Daily step count and cognitive decline in older adults
A 4-year cohort (n≈17,000) reported that adults averaging 7,000–9,000 steps per day had roughly a quarter less cognitive decline than sedentary peers, with diminishing returns above 10,000.
The practical target for most older adults is between 7,000 and 9,000 steps — not the folklore 10,000.
July 4, 2026
Extra-virgin olive oil and inflammatory markers
A 12-week randomised crossover trial in 90 adults with metabolic syndrome found that 30 mL/day of high-polyphenol EVOO modestly reduced hs-CRP and IL-6.
Real EVOO, at a real culinary dose, still measurably calms low-grade inflammation.
July 2, 2026
Time-restricted eating and glycaemic control
A 6-month trial comparing 10-hour vs. 14-hour eating windows in adults with pre-diabetes showed modest improvements in fasting glucose and HbA1c in the 10-hour group, independent of total calories.
Compressing the eating window — not shrinking it dramatically — is the version most people can actually sustain.
June 30, 2026
Green tea catechins and blood pressure
A 2026 meta-analysis of 28 RCTs found roughly a 2 mm Hg systolic reduction with 400–800 mg/day catechins over 12 weeks.
A useful nudge, not a treatment. Two cups a day is a reasonable culinary target.
June 27, 2026
Sleep regularity vs. sleep duration
A large UK Biobank analysis suggested sleep-regularity was a stronger predictor of all-cause mortality than total sleep duration.
Same bedtime, same wake time — even more than 'more hours' — is the durable habit.
June 24, 2026
Loneliness and cardiovascular risk
A meta-analysis pooling 90+ studies confirmed loneliness carries a ~29 % relative increase in incident coronary heart disease.
Social connection is not a soft factor. It sits alongside blood pressure and lipids.
›What we know and don't know
Honest uncertainty
What we know — and what we don't.
Nutrition science evolves. Traditional medicine contains wisdom that modern research is still catching up to. Modern medicine keeps learning what it thought it already knew. Hakim respects all three — and distinguishes clearly between them.
Where evidence is strong
Strong Human Research
Regular movement extends healthspan. Mediterranean-style eating patterns reduce cardiovascular risk. Sleep matters — deeply. Excessive alcohol harms nearly every system. Tobacco kills. These are not opinions; they are reproducibly demonstrated across decades of research.
Where evidence is moderate
Moderate Research
Specific herbs, spices, and dietary patterns show meaningful effects in trials, but effect sizes vary by person and dose. Hakim reports the range honestly rather than a single reassuring number.
Where evidence is emerging
Emerging Evidence
Personalized nutrition, gut microbiome interventions, time-restricted eating, and some longevity supplements are actively being studied. Interesting — but not settled. We say so.
Where tradition leads and science follows
Traditional Persian Knowledge
Persian medicine's emphasis on constitution (mizaj), seasonal eating, gentle warming foods, and mindful daily routines predates modern research by a millennium. Some of it is now confirmed. Some is not yet studied. We tell you which is which.
Where we simply don't know
Limited Research
Nutrition studies at the individual level are hard. Long-term effects of many supplements have never been rigorously tested. When we don't know, we say so — and we don't recommend based on hope.
Certainty sold as fact is the oldest trick in wellness. We refuse it.