Protocol
Regular blood donation (iron reduction)
Giving a unit of whole blood removes iron with it.
Grade D, tested: a human randomized trial looked for a benefit on the endpoint The outcome a trial measures to decide whether the treatment worked, such as heart attacks, blood pressure or a symptom score. graded and did not find one. How to read a grade →
At a glance
Giving blood takes iron out of the body. Some people think less iron protects the heart. Early studies found blood donors had fewer heart attacks. But only healthy people are allowed to give blood, so donors start out healthier. When studies allowed for this, the gap went away. One trial took blood every 6 months from people with blocked leg arteries. It did not clearly lower deaths, heart attacks or strokes. Giving blood often can leave people low in iron.
Heart attack, stroke and cardiovascular death (D): scheduled blood removal was tested in a randomized trial and did not significantly reduce them. No randomized trial has enrolled healthy blood donors.
Why this letter
Why this gradeGrade D, tested, no benefit. The reasoning, and what the grade does not cover.
Grade D on Route 2 Human randomized trials have been run and did not show benefit on the stated outcome. One of the two routes to the lowest letter on EBL's scale.: tested, no benefit. FeAST randomized 1,277 adults with symptomatic peripheral artery disease to blood removal at 6-month intervals or none. All-cause death was 20 against 23 percent (hazard ratio How often an event happened in the treated group compared with the control group over the same period. A ratio of 0.80 means 20 percent fewer events. 0.85, 95% CI 0.67 to 1.08) and death, nonfatal heart attack or stroke 28 against 32 percent (hazard ratio 0.88, 0.72 to 1.07), neither significant (Zacharski et al., 2007; PMID PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed. 17299195). Secondary analyses of the same trial found benefit in the youngest quarter of patients (PMID 22093213) and in smokers (PMID 23518844); subgroups of a trial that missed its endpoints are not a replicated The same finding reproduced by a separate research group. A result seen once can be chance or bias; a replicated one is harder to explain away. finding, and no second trial has tested them. No randomized trial has been run in healthy blood donors. The closest substitute compared donors permanently deferred by a false-positive screening test, which falls essentially at random, with donors who kept giving, and found the same rate of coronary heart disease (rate ratio 1.02, 0.92 to 1.13; Germain et al., 2013; PMID 23320537). Observational Research that watches what people already do rather than assigning a treatment. It can show that two things travel together, not that one causes the other. data inform this context but never carry a grade.
WHY NOT Cthe only randomized trial on the stated endpoint did not show benefit, and the positive signals in it are post hoc subgroups.
WHAT THIS GRADE DOES NOT COVERdonation as a gift of blood to patients, which this site does not grade; therapeutic phlebotomy for hereditary hemochromatosis or polycythemia vera, a medical treatment for iron or red cell overload; and blood pressure. One small randomized trial in 64 adults with metabolic syndrome found systolic pressure 16.6 mmHg lower after two phlebotomies (PMID 22647517); it has not been repeated, and it measured a marker, not heart attacks or deaths.
A grade describes the human evidence for a named use. It is not advice, and it is not a judgment on any individual prescription. How the letters are decided →
Trials report an average. This box says whether any trial on this record looked at who the result applies to, and what it found.
For this record's Grade D · Subgroup tested, effect differedFeAST was null overall, but two later analyses of the same trial found benefit in some patients: the youngest quarter of patients (death, heart attack or stroke, hazard ratio 0.34; Zacharski et al., Am Heart J, 2011; PMID 22093213) and smokers (hazard ratio 0.64; DePalma et al., Vascular, 2013; PMID 23518844). Both were in people with peripheral artery disease, and no second trial has tested either group. A subgroup result shows who the effect appeared in within these trials. It does not change the letter. This subgroup was identified after the results were in and has not been confirmed in a trial designed to test it.
Evidence notes: randomized trial
Endpoint graded: All-cause death; death, nonfatal heart attack or stroke (hard)
Last reviewed: October 2026
The trial that would change this grade.
A positive trial of this shape would move this entry to C.
Why the current trials fall short
No randomized trial has enrolled healthy donors. A positive trial of this kind would lift the letter to C; a replicated one, to A. Blood services already randomize donation intervals (INTERVAL, PMID 28941948), so a trial of this design is feasible.
Why people believe itOne human source; no published case reports of benefit; three reports of harm.
The case for regular blood donation is the iron hypothesis, proposed in 1981: stored iron feeds oxidation in artery walls, so removing iron should protect the heart, which would also explain why women before menopause have less heart disease. Early donor studies found fewer heart attacks among donors.
What supporters point to, and what each source actually shows. None of it is enough to move this letter higher; the trial described above under Evidence wanted is what would.
- Population study, not a trialIn 2,862 Finnish men, 1 of 153 recent blood donors had a heart attack, against 316 of 2,529 non-donors. Donors are screened for good health, which an observational study cannot fully remove. PMID 9737556
A case report describes what happened to one or a few patients. It cannot show the treatment caused the change, and reports of success are published more often than reports of failure.
A PubMed search in October 2026 found no published case report of benefit for this use.
- A healthy 19-year-old soldier who gave blood five times in 12 weeks was found to have iron deficiency anemia. PMID 19920443
- Three donors developed a deep vein clot in the arm within hours to 3 days of giving whole blood; all needed blood thinners. PMID 25712335
- A 39-year-old man had a heart attack with open coronary arteries after giving blood. PMID 39675934
Searched PubMed, October 2026: 38 case report record(s) returned. 12 describe harm to donors, including fainting, arm clots, vessel injuries, a heart attack and iron deficiency from too-frequent donation; three are listed. 26 concern donor screening, infections or antibodies passed to recipients, or donor programs. None describes heart benefit.
Dose, form and timing
Measured outcome in the trial: death, heart attack and stroke over years, not a marker that can be checked at home. Ferritin and hemoglobin are what donation moves: in REDS-II RISE, 27 percent of returning female frequent donors and 18 percent of male had absent iron stores (ferritin below 12 ng/mL) by their final visit (PMID 22023513), and in INTERVAL shorter intervals between donations lowered hemoglobin and ferritin (PMID 28941948).
As studiedDose, form, population and duration for every use.
A grade describes the intervention that was tested. Where the product on the shelf differs from it, this says so.
Safety
Frequent donation depletes iron. In INTERVAL, 45,263 donors randomized to shorter intervals between donations reported more tiredness, breathlessness, dizziness and restless legs and had lower hemoglobin and ferritin (PMID 28941948). Iron depletion A fall in a nutrient's level caused by a medication, for example through reduced absorption or increased loss. is most common in young women and in frequent donors (PMID 22023513). Blood services set their own eligibility rules and minimum intervals.
Grade history
How this letter has changedLatest: October 2026 · First graded.
Regular blood donation is widely repeated as a way to lower heart attack risk by lowering iron stores. It now has a graded record. The one randomized trial on hard outcomes removed blood every 6 months in 1,277 veterans with peripheral artery disease and did not significantly reduce death (hazard ratio 0.85) or death, heart attack and stroke (hazard ratio 0.88) (Zacharski et al., JAMA, 2007; PMID 17299195): Grade D on Route 2. In healthy donors, donors deferred essentially at random by a false-positive screening test had the same coronary heart disease rate as donors who kept giving (Germain et al., Transfusion, 2013; PMID 23320537), and a systematic review A review that searches for every study on a question using a method set in advance, then assesses them together. of 44 studies found the question unresolved, with positive studies likely reflecting the healthy donor effect (Quee et al., Transfus Med Rev, 2022; PMID 35606245). One small randomized trial in metabolic syndrome found lower systolic blood pressure; it has not been repeated.PMID 17299195 PMID 23320537 PMID 35606245
Every change to a letter on this site is dated and published. The full evidence log →
Sources
The evidence, in full23 papers, each linked to its PubMed record.
Randomized, hard endpoints An outcome that matters directly to a person and is counted without judgment, such as death, heart attack, stroke or fracture.: Zacharski et al. (JAMA, 2007; PMID 17299195), FeAST, VA Cooperative Study 410: 1,277 adults with symptomatic peripheral artery disease randomized to phlebotomy at 6-month intervals, volumes set to lower ferritin without causing iron deficiency, or to no phlebotomy; all-cause death 20 against 23 percent (hazard ratio 0.85, 95% CI 0.67 to 1.08); death, nonfatal myocardial infarction or stroke 28 against 32 percent (hazard ratio 0.88, 0.72 to 1.07); neither significant. Secondary analyses of the same trial: Zacharski et al. (Am Heart J, 2011; PMID 22093213), benefit in the youngest age quartile (all-cause death hazard ratio 0.44, 0.21 to 0.92; death, myocardial infarction or stroke 0.34, 0.19 to 0.61); DePalma et al. (Vascular, 2013; PMID 23518844), benefit in smokers (0.66, 0.45 to 0.97) and not in non-smokers. Natural experiment in healthy donors: Germain et al. (Transfusion, 2013; PMID 23320537), 12,357 Quebec donors permanently deferred by a false-positive infection screening test against 50,889 who stayed eligible; coronary heart disease 3.60 against 3.52 per 1,000 person-years (rate ratio 1.02, 0.92 to 1.13). Cohorts: Salonen et al. (Am J Epidemiol, 1998; PMID 9737556), Kuopio, 2,862 Finnish men; 1 heart attack among 153 recent donors against 316 among 2,529 non-donors (relative hazard 0.12, 0.02 to 0.86). Meyers et al. (Heart, 1997; PMID 9326996), Nebraska, 655 donors and 3,200 non-donors; benefit confined to non-smoking men (odds ratio 0.67, 0.45 to 0.99). Meyers et al. (Transfusion, 2002; PMID 12430669), 1,508 frequent against 1,508 casual donors; events 6.3 against 10.5 percent. Ascherio et al. (Circulation, 2001; PMID 11136685), Health Professionals Follow-up Study, 38,244 men; 30 or more lifetime donations against none, myocardial infarction relative risk The risk in one group expressed as a share of the risk in another. It can make a small absolute difference look large. 1.2 (0.8 to 1.8). Peffer et al. (Heart, 2019; PMID 30872386), 159,934 Dutch donors; high-frequency donation and cardiovascular disease hazard ratio 0.91 (0.85 to 0.98) in women, 1.00 (0.95 to 1.05) in men. Karki et al. (Transfusion, 2023; PMID 37057641), Australian 45 and Up Study; regular high-frequency donors hazard ratio 0.93 (0.68 to 1.29) in men and 0.79 (0.49 to 1.28) in women. Mortality, healthy donor effect: Ullum et al. (Transfusion, 2015; PMID 26098293), 1,182,495 Scandinavian donors; 18.6 percent lower mortality per additional annual donation, 7.5 percent after adjustment for the healthy donor effect, which the authors say is not conclusive evidence of benefit. Rahman et al. (Transfusion, 2024; PMID 39494482), no mortality difference with high-frequency donation (relative risk 0.98, 0.68 to 1.28). Rahman et al. (Vox Sang, 2025; PMID 41088737), target trial emulation in 121,967 people; mortality hazard ratio 0.57 crude, 1.0 (0.73 to 1.35) fully adjusted. Systematic review: Quee et al. (Transfus Med Rev, 2022; PMID 35606245), 44 studies; whether donation protects against cardiovascular disease remains unclear, and positive studies may not have dealt with the healthy donor effect. Blood pressure: Houschyar et al. (BMC Med, 2012; PMID 22647517), 64 adults with metabolic syndrome, single-blind, waiting-list control; systolic pressure 16.6 mmHg lower after two phlebotomies over 6 weeks (95% CI 12.5 to 20.7), insulin resistance unchanged. Kamhieh-Milz et al. (Transfusion, 2016; PMID 26643612), 292 donors observed, systolic pressure fell in hypertensive donors; France et al. (Transfusion, 2017; PMID 28083954), donor blood pressure data showing the apparent fall is explained by regression to the mean. Vascular function: Zheng et al. (Arterioscler Thromb Vasc Biol, 2005; PMID 15961703), cross-sectional, greater flow-mediated dilation in high-frequency donors; Jelani et al. (Cardiovasc Ther, 2018; PMID 30341986), 84 adults randomized double-blind Neither the participants nor the people assessing them know who received the real treatment until the trial ends. to four phlebotomies or sham A fake version of a procedure or device used as the comparison, so participants cannot tell which one they received. over 6 months, endothelial function unchanged. Iron and coronary disease: Danesh and Appleby (Circulation, 1999; PMID 10027804), 12 prospective studies, ferritin 200 micrograms/L or more against less, risk ratio 1.0 (0.8 to 1.3). Donor safety: Di Angelantonio et al. (Lancet, 2017; PMID 28941948), INTERVAL, 45,263 donors randomized to shorter intervals between donations; more tiredness, breathlessness, dizziness and restless legs, lower hemoglobin and ferritin. Cable et al. (Transfusion, 2012; PMID 22023513), REDS-II RISE, 2,425 donors; absent iron stores in 27 percent of returning female frequent donors and 18 percent of male. Toss et al. (Transfusion, 2021; PMID 33982278), 963,311 Swedish donors; short-term risks after donation small, mostly fainting.
How EBL searched for the trials (1 search)
The search that was run, what it returned, and what was left out and why, so the absence of evidence can be checked as well as its presence.
("blood donation"[tiab] OR "blood donors"[tiab] OR "blood donor"[tiab] OR "iron reduction"[tiab] OR "reduction of iron stores"[tiab] OR phlebotomy[tiab]) AND ("myocardial infarction"[tiab] OR "coronary heart disease"[tiab] OR "cardiovascular disease"[tiab] OR "cardiovascular events"[tiab] OR "cardiovascular outcomes"[tiab] OR "cardiac events"[tiab] OR "cardiovascular risk"[tiab]) AND humans[mh]Disclosure
Educational use only · Not medical advice · EBL grades published human evidence and does not recommend treatment. Stopping a prescription is a decision for your physician.
Evidence Based Longevity, Inc. is owner-operated and edited by Arnold Sandlow, D.C., a California-licensed chiropractor. Evidence Based Longevity publishes in English only · Machine translations are not produced or reviewed by EBL for accuracy
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