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Cited by 2Nutritional Studies and DietFatty Acid Research and HealthLipoproteins and Cardiovascular Health

Saturated Fat Restriction for Cardiovascular Disease Prevention: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Open access
Satoru Yamada, Tomomi Shirai, Sakiko Inaba, Gaku Inoue, Minami Torigoe, Naoto Fukuyama·2025·JMA Journal
DOI 10.31662/jmaj.2024-0324PMC PMC12095860
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Abstract

Background: The recommendation to limit dietary saturated fat intake is primarily drawn from observational studies rather than randomized controlled trials of cardiovascular disease prevention. Thus, we aimed to investigate the efficacy of saturated fat reduction in preventing mortality and cardiovascular diseases. Methods: In this systematic review and meta-analysis of randomized controlled trials, Cochrane CENTRAL, PubMed, and Ichu-shi databases were searched for articles up to April 2023. Randomized controlled trials on saturated fat reduction to prevent cardiovascular diseases were selected. Cardiovascular and all-cause mortality and cardiovascular outcomes were evaluated. Changes in electrocardiography or coronary angiography findings were excluded because they could be evaluated arbitrarily. Two or more reviewers independently extracted and assessed the data. A random-effects meta-analysis was performed. Results: Nine eligible trials with 13,532 participants were identified (2 were primary and 7 were secondary prevention studies). No significant differences in cardiovascular mortality (relative risk [RR] = 0.94, 95% confidence interval [CI]: 0.75-1.19), all-cause mortality (RR = 1.01, 95% CI: 0.89-1.14), myocardial infarction (RR = 0.85, 95% CI: 0.71-1.02), and coronary artery events (RR = 0.85, 95% CI: 0.65-1.11) were observed between the intervention and control groups. However, owing to limited reported cases, the impact of stroke could not be evaluated. Conclusions: The findings indicate that a reduction in saturated fats cannot be recommended at present to prevent cardiovascular diseases and mortality. Clinical trials are needed to evaluate the effects of saturated fat reduction under the best possible medical care, including statin administration. Systematic review registration number: This systematic review and meta-analysis was registered with the International Prospective Register of Systematic Reviews (CRD42023428498).

AI snapshot

Written from the paper’s full text.

TL;DR

This systematic review and meta-analysis of 9 randomized controlled trials found no statistically significant reduction in cardiovascular mortality, all-cause mortality, myocardial infarction, or coronary artery events with saturated fat restriction. The authors conclude that saturated fat reduction cannot currently be recommended for cardiovascular disease prevention and call for trials under contemporary care including statins.

Key findings

  • Across 9 trials with 13,532 participants (2 primary prevention, 7 secondary prevention), saturated fat restriction showed no significant differences for cardiovascular mortality (RR/OR = 0.94, 95% CI: 0.75–1.19), all-cause mortality (RR/OR = 1.01, 95% CI: 0.89–1.14), myocardial infarction (RR/OR = 0.85, 95% CI: 0.71–1.02), or any coronary artery events (RR/OR = 0.85, 95% CI: 0.65–1.11).
  • Stroke and a composite of non-fatal MI, non-fatal stroke, and cardiovascular death could not be meta-analyzed because of limited reported cases; stroke incidence was almost zero in 2 of the 3 stroke-reporting studies.
  • No association was observed between the difference in saturated fat intake and relative or absolute risk reduction for any outcome, and no association was observed between study duration and relative or absolute risk reduction.
  • Risk of bias was not low in any trial: 7 trials had “some concerns” and 2 had high risk of bias; all trials were not pre-registered. Funnel plots showed no publication bias.

Methods

  • Systematic review and random-effects meta-analysis of randomized controlled trials of saturated fat restriction for cardiovascular disease prevention, registered with PROSPERO (CRD42023428498).
  • Searched Cochrane CENTRAL, PubMed, and Ichu-shi from inception to April 2023; included adults, RCT design, saturated fat restriction as intervention, and cardiovascular disease as outcome. Two or more reviewers independently screened, extracted, and assessed data.
  • Primary outcome was cardiovascular mortality; secondary outcomes included all-cause mortality, myocardial infarction, any coronary artery events, stroke, and a composite of non-fatal MI, non-fatal stroke, and cardiovascular death. Risk of bias was assessed with RoB2; heterogeneity was evaluated with I² statistics and publication bias with funnel plots.

Limitations

  • The paper states that dietary intervention trials cannot be completely blinded, all included trials were not pre-registered, most trials did not involve statin administration, most did not include female participants, most were conducted in Western countries, and many replaced animal fats with vegetable fats without analyzing individual saturated fatty acids of different chain lengths.
  • The paper also states that only 1 trial included participants receiving statins, and only 2 trials included female participants, so effects under current best medical care and in women remain scarcely investigated.
  • Evident from the text: the abstract reports relative risks (RR) while the Methods and Results report odds ratios (OR) for the same pooled estimates; heterogeneity I² values are mentioned as planned but not reported in the provided text.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.31662/jmaj.2024-0324

Cites

38 of 38 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

40 of 89 cited sources checked · 21 supported · 5 flagged · accuracy not yet measured

  • Interpretationcitation

    The cardiovascular mortality result in the Cochrane Systematic Review by Hooper et al. (RR = 0.96; 95% CI: 0.90-1.03) is similar to that of our present study (OR = 0.94; 95% CI: 0.75-1.19).

    “Regarding the Cochrane Systematic Review by Hooper et al. (28), the results of cardiovascular (relative risk [RR] = 0.96; 95% CI: 0.90-1.03) and all-cause mortalities (RR = 0.94; 95% CI: 0.78-1.13) are similar to those of our present study (OR = 0.94; 95% CI: 0.75-1.19 for cardiovascular mortality and OR = 1.01; 95% CI: 0.89-1.14 for all-cause mortality).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [28] Hooper L, Martin N, Jimoh OF, et al. Reduction in saturated fat intake for cardiovascular disease. Cochrane Database Syst Rev. 2020; 5(5): CD011737. 32428300 PMC7388853 source

      The review assigns RR 0.96 (95% CI 0.90–1.03) to all-cause mortality, not cardiovascular mortality (Primary outcomes; Participants’ level of risk). It assigns RR 0.94 (95% CI 0.78–1.13) to cardiovascular mortality (Cardiovascular mortality; Participants’ level of risk). The citing sentence reverses the two outcomes. (LLM, conf=0.94)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
  • Interpretationcitation

    The all-cause mortality result in the Cochrane Systematic Review by Hooper et al. (RR = 0.94; 95% CI: 0.78-1.13) is similar to that of our present study (OR = 1.01; 95% CI: 0.89-1.14).

    “Regarding the Cochrane Systematic Review by Hooper et al. (28), the results of cardiovascular (relative risk [RR] = 0.96; 95% CI: 0.90-1.03) and all-cause mortalities (RR = 0.94; 95% CI: 0.78-1.13) are similar to those of our present study (OR = 0.94; 95% CI: 0.75-1.19 for cardiovascular mortality and OR = 1.01; 95% CI: 0.89-1.14 for all-cause mortality).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [28] Hooper L, Martin N, Jimoh OF, et al. Reduction in saturated fat intake for cardiovascular disease. Cochrane Database Syst Rev. 2020; 5(5): CD011737. 32428300 PMC7388853 source

      The Participants’ level of risk section assigns RR 0.96 (95% CI 0.90–1.03) to total mortality and RR 0.94 (95% CI 0.78–1.13) to cardiovascular mortality. The citing sentence reverses those outcome labels. The review’s Primary outcomes and Cardiovascular mortality sections confirm the respective assignments. (LLM, conf=0.90)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
  • Interpretationcitation

    Such small changes in LDL-C levels do not seem to affect cardiovascular outcomes with statin administration.

    “Such small changes in LDL-C levels do not seem to affect cardiovascular outcomes and serum lipid profiles with statin administration, which can reduce the LDL-C level by approximately 50 mg/dL (40).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [40] Cannon CP, Steinberg BA, Murphy SA, et al. Meta-analysis of cardiovascular outcomes trials comparing intensive versus moderate statin therapy. J Am Coll Cardiol. 2006; 48(3): 438-45. 16875966 source

      The Results report that a 26 mg/dL difference in LDL-C between statin treatment groups accompanied a significant 16% reduction in coronary death or myocardial infarction. The Discussion likewise says that this LDL-C difference would be expected to reduce cardiovascular events by about 14%, and that the observed reduction was 16%. This is contrary to the claim that such changes do not seem to affect cardiovascular outcomes. (LLM, conf=0.91)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
  • Premisenone given

    The recommendation to limit dietary saturated fat intake is primarily drawn from observational studies rather than randomized controlled trials of cardiovascular disease prevention.

    “The recommendation to limit dietary saturated fat intake is primarily drawn from observational studies rather than randomized controlled trials of cardiovascular disease prevention.”
    Quote in the paperSubstantial claim3 of 3 sources checked
    • cites [1] Mozaffarian D, Rosenberg I, Uauy R. History of modern nutrition science-implications for current research, dietary guidelines, and food policy. BMJ. 2018; 361: k2392. 29899124 PMC5998735 source

      The ‘1950s to 1970s’ and ‘1970s to 1990s’ sections (page unavailable) say that ecological studies helped shape advice to limit fat and that the 1980 guidelines included saturated fat. But they also identify short-term interventions and experiments using surrogate outcomes as sources of that advice. The paper does not establish that saturated-fat recommendations were primarily drawn from observational studies rather than randomized trials of cardiovascular disease prevention. (LLM, conf=0.83)

      Experimental — accuracy not yet measured
    • cites [5] Wang DD, Li Y, Chiuve SE, et al. Association of specific dietary fats with total and cause-specific mortality. JAMA Intern Med. 2016; 176(8): 1134-45. 27379574 PMC5123772 source

      The Introduction says replacing saturated fat with unsaturated fat is widely recommended, and the Discussion identifies this study as observational. Neither passage says the recommendation is drawn primarily from observational studies rather than randomized cardiovascular-prevention trials; the Discussion also notes consistency with randomized trials on diet and CVD-related outcomes. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [7] Arnett DK, Blumenthal RS, Albert MA, et al. 2019 ACC/AHA guideline on the primary prevention of cardiovascular disease: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2019; 140(11): e596-646. 30879355 PMC7734661 source
  • Premisecitation

    The American College of Cardiology/American Heart Association guideline recommended SFA restriction on the basis of 2 observational studies.

    “On the basis of 2 observational studies (5), (6), the American College of Cardiology/American Heart Association (AHA) guideline (7) recommended SFA restriction.”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites [5] Wang DD, Li Y, Chiuve SE, et al. Association of specific dietary fats with total and cause-specific mortality. JAMA Intern Med. 2016; 176(8): 1134-45. 27379574 PMC5123772 source

      The Discussion supports replacing saturated fats with unsaturated fats as a dietary recommendation, but it does not discuss the American College of Cardiology/American Heart Association guideline or what evidence that guideline relied on. Searches for the guideline and for a basis of two observational studies found no passage addressing the claim. (LLM, conf=0.74)

      Experimental — accuracy not yet measured
    • cites [6] Dehghan M, Mente A, Zhang X, et al. Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): a prospective cohort study. Lancet. 2017; 390(10107): 2050-62. 28864332 source
    • cites [7] Arnett DK, Blumenthal RS, Albert MA, et al. 2019 ACC/AHA guideline on the primary prevention of cardiovascular disease: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2019; 140(11): e596-646. 30879355 PMC7734661 source
  • Classified as probably not a substantial claim. 32
  • May combine two claims. 22
  • The quote only partly states this claim. 1

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    The literature search strategy was not described in the study by Mozaffarian et al. (26).

    “In the presidential advisory of the AHA by Sacks et al. (27), the literature search strategy was not described, similarly to the study by Mozaffarian et al. (26)”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [26] Mozaffarian D, Micha R, Wallace S. Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials. PLoS Med. 2010; 7(3): e1000252. 20351774 PMC2843598 source

      The Methods section has a subsection titled “Search Strategy.” It names the databases searched, gives the search period and MEDLINE terms, and points to a full list of terms for all databases in the protocol. The paper therefore describes a literature search strategy, contrary to the claim. (LLM, conf=0.95)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingcitation

    In the only study in which all participants received statins, no significant difference was observed in CVD events (2.0% of participants experienced non-fatal MI and 0 experienced stroke and cardiovascular death in both groups).

    “In the only study in which all participants received statins, no significant difference was observed in CVD events (2.0% of participants experienced non-fatal MI and 0 experienced stroke and cardiovascular death in both groups) or LDL-C level (89.6 ± 28.9 mg/dL in intervention and 91.0 ± 21.8 mg/dL in control groups) (25).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [25] Vijayakumar M, Vasudevan DM, Sundaram KR, et al. A randomized study of coconut oil versus sunflower oil on cardiovascular risk factors in patients with stable coronary heart disease. Indian Heart J. 2016; 68(4): 498-506. 27543472 PMC4990731 source

      The Results say all participants were taking statins, and the paper reports no significant difference in cardiovascular events between groups. But the Discussion states that there was no myocardial infarction in either group; the 2% figure refers to repeat revascularization in each group, not non-fatal MI. No page number is available in our copy. (LLM, conf=0.90)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Several previous meta-analyses have investigated the role of SFA restriction for CVD prevention, and these have been cited as evidence supporting the recommendation of SFA restriction by the European Society of Cardiology/European Atherosclerosis Society.

    “Several previous meta-analysis have investigated the role of SFA restriction for CVD prevention (26), (27), (28), and these have been cited as evidence supporting the recommendation of SFA restriction by the European Society of Cardiology/European Atherosclerosis Society (29).”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites [26] Mozaffarian D, Micha R, Wallace S. Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials. PLoS Med. 2010; 7(3): e1000252. 20351774 PMC2843598 source
    • cites [27] Sacks FM, Lichtenstein AH, Wu JHY, et al. Dietary fats and cardiovascular disease: a Presidential Advisory from the American Heart Association. Circulation. 2017; 136(3): e1-23. 28620111 source

      Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured
    • cites [29] Mach F, Baigent C, Catapano AL, et al. 2019 ESC/EAS Guidelines for the management of dyslipidaemias: lipid modification to reduce cardiovascular risk. Eur Heart J. 2020; 41(1): 111-88. 31504418 source

      Split into 2 atoms — 0 confirmed, 0 partially supported, 0 disputed, 0 misattributed, 2 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingown data

    Only 3 included studies were on stroke, and the incidence of stroke was almost zero in 2 of those studies.

    “Only 3 studies were on stroke (20), (23), (25), and the incidence of stroke was almost zero in 2 of those studies (23), (25).”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [20] Dayton S, Pearce ML, Hashimoto S, et al. A controlled clinical trial of a diet high in unsaturated fat in preventing complications of atherosclerosis. Circulation. 1969; 40(1s2): II-1-63. source
    • cites [23] Watts GF, Lewis B, Brunt JN, et al. Effects on coronary artery disease of lipid-lowering diet, or diet plus cholestyramine, in the St Thomas’ Atherosclerosis Regression Study (STARS). Lancet. 1992; 339(8793): 563-9. 1347091 source
    • cites [25] Vijayakumar M, Vasudevan DM, Sundaram KR, et al. A randomized study of coconut oil versus sunflower oil on cardiovascular risk factors in patients with stable coronary heart disease. Indian Heart J. 2016; 68(4): 498-506. 27543472 PMC4990731 source

      The Discussion (page unavailable) identifies stroke as an important endpoint, but does not report how many strokes occurred. The Results report revascularizations and deaths, not stroke incidence. Searches for stroke incidence and Table 10 did not establish the claimed near-zero rate; this trial also cannot establish how many studies the citing document included. (LLM, conf=0.72)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingown data

    Only 2 included studies were primary prevention trials from the USA; the remaining 7 were secondary prevention trials.

    “Only 2 studies were primary prevention trials from the USA (20), (22); the remaining 7 were secondary prevention trials.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [20] Dayton S, Pearce ML, Hashimoto S, et al. A controlled clinical trial of a diet high in unsaturated fat in preventing complications of atherosclerosis. Circulation. 1969; 40(1s2): II-1-63. source
    • cites [22] Frantz Jr ID, Dawson EA, Ashman PL, et al. Test of effect of lipid lowering by diet on cardiovascular risk. The Minnesota coronary survey. Arteriosclerosis. 1989; 9(1): 129-35. 2643423 source

  • May combine two claims.

    Findingcitation

    Only 2 included studies included female participants, showing no differences in cardiovascular outcomes between the intervention and control groups.

    “Only 2 studies included female participants, showing no differences in cardiovascular outcomes between the intervention and control groups (22), (25).”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [22] Frantz Jr ID, Dawson EA, Ashman PL, et al. Test of effect of lipid lowering by diet on cardiovascular risk. The Minnesota coronary survey. Arteriosclerosis. 1989; 9(1): 129-35. 2643423 source
    • cites [25] Vijayakumar M, Vasudevan DM, Sundaram KR, et al. A randomized study of coconut oil versus sunflower oil on cardiovascular risk factors in patients with stable coronary heart disease. Indian Heart J. 2016; 68(4): 498-506. 27543472 PMC4990731 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    Five included studies were conducted in European countries, 2 in the USA, 1 in Australia, and 1 in India.

    “Five studies were conducted in European countries (15), (18), (19), (21), (23), 2 in the USA (20), (22), 1 in Australia (24), and 1 in India (25).”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites [15] Controlled trial of soya-bean oil in myocardial infarction. Lancet. 1968; 2(7570): 693-9. 4175085 source
    • cites [20] Dayton S, Pearce ML, Hashimoto S, et al. A controlled clinical trial of a diet high in unsaturated fat in preventing complications of atherosclerosis. Circulation. 1969; 40(1s2): II-1-63. source
    • cites [25] Vijayakumar M, Vasudevan DM, Sundaram KR, et al. A randomized study of coconut oil versus sunflower oil on cardiovascular risk factors in patients with stable coronary heart disease. Indian Heart J. 2016; 68(4): 498-506. 27543472 PMC4990731 source

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Restriction of SFA intake reduced the large buoyant LDL-C level but not the small dense LDL-C level.

    “According to the lipoprotein subfraction analysis by Bergeron et al. (10), restriction of SFA intake reduced the large buoyant LDL-C level but not the small dense LDL-C level, which are the most atherogenic lipoproteins.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [10] Bergeron N, Chiu S, Williams PT, et al. Effects of red meat, white meat, and nonmeat protein sources on atherogenic lipoprotein measures in the context of low compared with high saturated fat intake: a randomized controlled trial. Am J Clin Nutr. 2019; 110(1): 24-33. 31161217 PMC6599736 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    Risk of bias was assessed using the updated Cochrane Collaboration's risk of bias tool (RoB2).

    “We used the updated Cochrane Collaboration’s risk of bias tool to assess the risk of bias (RoB2) (17).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [17] Sterne JAC, Savovic J, Page MJ, et al. RoB 2: a revised tool for assessing risk of bias in randomised trials. BMJ. 2019; 366: l4898. 31462531 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    One observational study showed a positive correlation between SFA intake and all-cause mortality.

    “One study showed a positive correlation between SFA intake and all-cause mortality (5), but the other did not reveal such an association (6).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [5] Wang DD, Li Y, Chiuve SE, et al. Association of specific dietary fats with total and cause-specific mortality. JAMA Intern Med. 2016; 176(8): 1134-45. 27379574 PMC5123772 source

  • May combine two claims.

    Findingcitation

    Only 1 included study included participants who received statins, and it showed no difference in CVD events between the intervention and control groups.

    “Only 1 study included participants who received statins, and it showed no difference in CVD events between the intervention and control groups (25).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [25] Vijayakumar M, Vasudevan DM, Sundaram KR, et al. A randomized study of coconut oil versus sunflower oil on cardiovascular risk factors in patients with stable coronary heart disease. Indian Heart J. 2016; 68(4): 498-506. 27543472 PMC4990731 source

  • Classified as probably not a substantial claim.

    Premisecitation

    Mozaffarian et al. reported a significant reduction in CVD events with SFA restriction.

    “Mozaffarian et al. (26) reported a significant reduction in CVD events with SFA restriction.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [26] Mozaffarian D, Micha R, Wallace S. Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials. PLoS Med. 2010; 7(3): e1000252. 20351774 PMC2843598 source

      The Discussion reports a significant reduction in CHD events when PUFA replaced SFA. It also states that the findings cannot establish a benefit from decreasing SFA when it is replaced by any other nutrient. The claim omits that essential replacement condition and describes the outcome more broadly as CVD events. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    The primary strengths of our study lie in its rigorous inclusion criteria and the specification of its literature search strategy.

    “Compared with those of previous meta-analyses (26), (27), (28), the primary strengths of our study lie in its rigorous inclusion criteria and the specification of its literature search strategy.”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites [26] Mozaffarian D, Micha R, Wallace S. Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials. PLoS Med. 2010; 7(3): e1000252. 20351774 PMC2843598 source
    • cites [27] Sacks FM, Lichtenstein AH, Wu JHY, et al. Dietary fats and cardiovascular disease: a Presidential Advisory from the American Heart Association. Circulation. 2017; 136(3): e1-23. 28620111 source
    • cites [28] Hooper L, Martin N, Jimoh OF, et al. Reduction in saturated fat intake for cardiovascular disease. Cochrane Database Syst Rev. 2020; 5(5): CD011737. 32428300 PMC7388853 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    The literature search strategy was not described in the AHA presidential advisory by Sacks et al. (27).

    “In the presidential advisory of the AHA by Sacks et al. (27), the literature search strategy was not described”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [27] Sacks FM, Lichtenstein AH, Wu JHY, et al. Dietary fats and cardiovascular disease: a Presidential Advisory from the American Heart Association. Circulation. 2017; 136(3): e1-23. 28620111 source

      The “CVD Outcomes: Prospective Observational Studies” section identifies the reviews and kinds of studies considered, but the retrieved passages do not describe a database or keyword search strategy. Searches for “search strategy,” databases, and search terms found no decisive passage; under the supplied rubric, that absence alone cannot verify the claim. (LLM, conf=0.65)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Hooper et al. reported a statistically significant reduction (p = 0.03) in combined cardiovascular events with SFA reduction (RR = 0.83, 95% CI: 0.70-0.98).

    “However, Hooper et al. reported a statistically significant reduction (p = 0.03) in combined cardiovascular events with SFA reduction (RR = 0.83, 95% CI: 0.70-0.98) (28)”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [28] Hooper L, Martin N, Jimoh OF, et al. Reduction in saturated fat intake for cardiovascular disease. Cochrane Database Syst Rev. 2020; 5(5): CD011737. 32428300 PMC7388853 source

      The Combined cardiovascular events section (page unavailable) reports a reduction with SFA reduction, and its 95% CI excludes 1. However, it gives RR 0.79 (95% CI 0.66–0.93), not the cited RR 0.83 (0.70–0.98); the cited p = 0.03 is not supported by the retrieved passages. (LLM, conf=0.90)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The sample sizes in the included studies ranged from 50 to 9,057.

    “The sample sizes in these studies ranged from 50 to 9,057.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Of the nine included trials, 2 were primary prevention and 7 were secondary prevention studies.

    “Nine eligible trials with 13,532 participants were identified (2 were primary and 7 were secondary prevention studies).”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Findingown data

    A total of 7,419 articles were identified during the search; 52 were assessed for eligibility; 9 studies were included.

    “A total of 7,419 articles were identified during our search; 52 were assessed for their eligibility for inclusion (Figure 1). Finally, 9 studies were included in the systematic review and meta-analysis (15), (18), (19), (20), (21), (22), (23), (24), (25).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The results for MI and any coronary artery events did not reach statistical significance in our present meta-analysis.

    “In fact, although the results for MI and any coronary artery events (Figure 4 and 5) did not reach statistical significance in our present meta-analysis, our findings suggest a trend toward effectiveness.”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Findingown data

    Regarding statin administration, only 1 RCT showed no significant difference in LDL-C levels between the intervention and control groups.

    “Specifically, regarding statin administration, only 1 RCT showed no significant difference in CVD events and LDL-C levels between the intervention and control groups.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Data from eligible studies were extracted by two authors.

    “The following information from the eligible studies was extracted by 2 authors (SY and NF): authors, publication year, country, sample characteristics, sample size, length of follow-up, cardiovascular outcomes, SFA energy percentage (if available), and lipid profile (if available).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Two or more reviewers independently extracted and assessed the data.

    “Two or more reviewers independently extracted and assessed the data.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    Full-text screening was done by two authors with consensus, and disagreements were resolved by discussion with a third author.

    “In the next stage of full-text screening, the authors (SY and TS) reached a consensus on which studies should be included or excluded. Disagreements regarding the results of the screened studies were resolved by discussion with a third author (NF).”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    Replacing SFA with monounsaturated fatty acids, polyunsaturated fatty acids, and carbohydrates reduces serum total cholesterol and low-density lipoprotein cholesterol levels.

    “A recent World Health Organization (WHO) report by Mensink stated that replacing SFA with monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), and carbohydrates reduces serum total cholesterol and low-density lipoprotein cholesterol (LDL-C) levels (4).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [4] Mensink RP. Effects of saturated fatty acids on serum lipids and lipoproteins: a systematic review and regression analysis [Internet]. World Health Organization; 2016 [cited 2022 Oct 30]. Available from: https://iris.who.int/bitstream/handle/10665/246104/9789241565349-eng.pdf

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    All trials were not pre-registered in a clinical trial registry such as Clinical Trials Gov and UMIN.

    “All trials were not pre-registered in a clinical trial registry such as Clinical Trials Gov and UMIN.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The study was approved by the Kitasato Institute Hospital Research Ethics Committee (number 22057).

    “This study was approved by the Kitasato Institute Hospital Research Ethics Committee (number 22057).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Another observational study did not reveal an association between SFA intake and all-cause mortality.

    “One study showed a positive correlation between SFA intake and all-cause mortality (5), but the other did not reveal such an association (6).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [6] Dehghan M, Mente A, Zhang X, et al. Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): a prospective cohort study. Lancet. 2017; 390(10107): 2050-62. 28864332 source

  • May combine two claims.

    Study design and conductown data

    Funnel plots for cardiovascular mortality and all-cause mortality, and any other outcomes, showed no publication bias.

    “Funnel plots for cardiovascular mortality and all-cause mortality, and any other outcomes, showed no publication bias (Figure 9 and 10).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    The systematic review and meta-analysis used a predefined protocol and was registered with PROSPERO (CRD42023428498) in accordance with PRISMA guidelines.

    “This systematic review and meta-analysis used a predefined protocol and was registered with the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42023428498) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Two investigators independently screened titles and abstracts according to the inclusion criteria.

    “Two investigators (SY and TS) independently screened the titles and abstracts of articles according to the inclusion criteria.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    Seven trials exhibited some concerns on RoB2, and 2 trials exhibited a high risk of bias.

    “Seven trials exhibited some concerns (15), (19), (20), (21), (22), (24), (25), and 2 trials exhibited a high risk of bias (18), (23).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [15] Controlled trial of soya-bean oil in myocardial infarction. Lancet. 1968; 2(7570): 693-9. 4175085 source
    • cites [18] Rose GA, Thomson WB, Williams RT. Corn oil in treatment of ischaemic heart disease. Br Med J. 1965; 1(5449): 1531-3. 14288105 PMC2166702 source
    • cites [23] Watts GF, Lewis B, Brunt JN, et al. Effects on coronary artery disease of lipid-lowering diet, or diet plus cholestyramine, in the St Thomas’ Atherosclerosis Regression Study (STARS). Lancet. 1992; 339(8793): 563-9. 1347091 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    The definition or criteria for cardiac ischemia were not provided in Houtsmuller et al. (34), (35).

    “Although other reports in the analysis by Houtsmuller et al.(34), (35) have reported cardiovascular outcomes, the definition or criteria for cardiac ischemia were not provided.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [34] Houtsmuller AJ, van Hal-Ferwerda J, Zahn KJ, et al. Favourable influences of linoleic acid on the progression of diabetic micro- and macroangiopathy. Nutr Metab. 1980; 24(suppl 1): 105-18. 7454128 source
    • cites [35] Houtsmuller AJ, van Hal-Ferwerda J, Zahn KJ, et al. Influence of different diets on the progression of diabetic retinopathy. Prog Food Nutr Sci. 1980; 4(5): 41-6. 7005962 source

  • May combine two claims.

    Premisecitation

    The dietary intervention in the study by Ley et al. focused on a reduction in total fat but not in SFA.

    “Moreover, the dietary intervention in this study focused on a reduction in total fat but not in SFA (36).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [36] Ley SJ, Metcalf PA, Scragg RKR, et al. Long-term effects of a reduced fat diet intervention on cardiovascular disease risk factors in individuals with glucose intolerance. Diabetes Res Clin Pract. 2004; 63(2): 103-12. 14739050 source

  • Probably not a substantial claim: may not pass S4 (based).

    Premisereasoning

    Cross-over trials are inappropriate for cardiovascular outcome studies owing to potential carry-over effects, referred to as a metabolic memory or legacy effect.

    “In addition to being a non-randomized trial, we believe that cross-over trials are inappropriate for cardiovascular outcome studies owing to potential carry-over effects, referred to as a metabolic memory or legacy effect (Table 2).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The dietary intervention in Black et al. focused on a reduction in total fat but not in SFA.

    “Furthermore, dietary intervention focused on a reduction in total fat but not in SFA.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Most of the Finnish Mental Hospital Studies were non-randomized and did not follow a cross-over design.

    “Most of these studies were non-randomized and did not follow a cross-over design (30), (31).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [30] Turpeinen O, Karvonen MJ, Pekkarinen M, et al. Dietary prevention of coronary heart disease: the Finnish Mental Hospital Study. Int J Epidemiol. 1979; 8(2): 99-118. 393644 source
    • cites [31] Miettinen M, Turpeinen O, Karvonen MJ, et al. Dietary prevention of coronary heart disease in women: the Finnish mental hospital study. Int J Epidemiol. 1983; 12(1): 17-25. 6840954 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Other reports in the analysis by Houtsmuller et al. (34), (35) have reported cardiovascular outcomes.

    “Although other reports in the analysis by Houtsmuller et al.(34), (35) have reported cardiovascular outcomes, the definition or criteria for cardiac ischemia were not provided.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [34] Houtsmuller AJ, van Hal-Ferwerda J, Zahn KJ, et al. Favourable influences of linoleic acid on the progression of diabetic micro- and macroangiopathy. Nutr Metab. 1980; 24(suppl 1): 105-18. 7454128 source
    • cites [35] Houtsmuller AJ, van Hal-Ferwerda J, Zahn KJ, et al. Influence of different diets on the progression of diabetic retinopathy. Prog Food Nutr Sci. 1980; 4(5): 41-6. 7005962 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given

    The statistically significant difference in glucose levels observed only among female patients could not be explained in terms of causality.

    “However, this phenomenon could not be explained in terms of causality.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationcitation

    Differences in patient characteristics and treatment policies other than diet, and in the interventional and conventional diets between the 2 mental hospitals, may have influenced the results.

    “In addition, differences in patient characteristics and treatment policies other than diet, and in the interventional and conventional diets between the 2 mental hospitals, may have influenced the results (30), (31).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [30] Turpeinen O, Karvonen MJ, Pekkarinen M, et al. Dietary prevention of coronary heart disease: the Finnish Mental Hospital Study. Int J Epidemiol. 1979; 8(2): 99-118. 393644 source
    • cites [31] Miettinen M, Turpeinen O, Karvonen MJ, et al. Dietary prevention of coronary heart disease in women: the Finnish mental hospital study. Int J Epidemiol. 1983; 12(1): 17-25. 6840954 source

  • May combine two claims.

    Premisenone given

    Sacks et al. and Mozaffarian et al. included the Finnish Mental Hospital Studies (30), (31), which are non-randomized cross-over trials.

    “Moreover, those authors included the Finnish Mental Hospital Studies (30), (31), which are non-randomized cross-over trials.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [30] Turpeinen O, Karvonen MJ, Pekkarinen M, et al. Dietary prevention of coronary heart disease: the Finnish Mental Hospital Study. Int J Epidemiol. 1979; 8(2): 99-118. 393644 source
    • cites [31] Miettinen M, Turpeinen O, Karvonen MJ, et al. Dietary prevention of coronary heart disease in women: the Finnish mental hospital study. Int J Epidemiol. 1983; 12(1): 17-25. 6840954 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A statistically significant difference in glucose levels was observed between the 2 groups only among female patients (34).

    “Furthermore, a statistically significant difference in glucose levels was observed between the 2 groups only among female patients (34).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [34] Houtsmuller AJ, van Hal-Ferwerda J, Zahn KJ, et al. Favourable influences of linoleic acid on the progression of diabetic micro- and macroangiopathy. Nutr Metab. 1980; 24(suppl 1): 105-18. 7454128 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The inability to completely blind RCTs on dietary interventions is a common limitation in studies on dietary interventions.

    “However, this is a common limitation in studies on dietary interventions.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Many studies have been conducted on interventions that replaced animal fats with vegetable fats.

    “Finally, many studies have been conducted on interventions that replaced animal fats with vegetable fats and did not analyze the impact of individual SFAs with different chain lengths.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Most studies failed to examine racial or ethnic differences.

    “Fifth, most studies were conducted in Western countries and failed to examine racial or ethnic differences.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    We could not examine the consistency between the prespecified analysis plan and actual analysis conducted, further increasing the risk of bias.

    “Thus, we could not examine the consistency between the prespecified analysis plan and actual analysis conducted, further increasing the risk of bias.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    According to the WHO report by Mensink, the replacement of 1% energy from SFA with PUFA reduced the LDL-C level by 0.055 mmol/L (2.1 mg/dL), whereas MUFA and carbohydrates reduced the LDL-C level by 0.042 mmol/L (1.6 mg/dL) and 0.033 mmol/L (1.3 mg/dL), respectively.

    “According to the WHO report by Mensink, the replacement of 1% energy from SFA with PUFA reduced the LDL-C level by 0.055 mmol/L (2.1 mg/dL), whereas MUFA and carbohydrates reduced the LDL-C level by 0.042 mmol/L (1.6 mg/dL) and 0.033 mmol/L (1.3 mg/dL), respectively (4).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [4] Mensink RP. Effects of saturated fatty acids on serum lipids and lipoproteins: a systematic review and regression analysis [Internet]. World Health Organization; 2016 [cited 2022 Oct 30]. Available from: https://iris.who.int/bitstream/handle/10665/246104/9789241565349-eng.pdf

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    RCTs on dietary interventions cannot be completely blinded, which introduces a proportional risk of bias.

    “First, RCTs on dietary interventions cannot be completely blinded, which introduces a proportional risk of bias.”
    Quote in the paperNot a substantial claim
47 of 47

  • The paper relies on this without support.

    The effect of saturated fat restriction on cardiovascular outcomes is not materially different in populations receiving statins compared with populations not receiving statins.

    “Only 1 study included participants who received statins, and it showed no difference in CVD events between the intervention and control groups (25). In the other 8 studies, none of the participants used statins. Thus, we did not perform a sub-analysis of statin use.”

  • The paper relies on this without support.

    The risk of bias in the included trials (some concerns or high risk) does not materially alter the pooled null results.

    “The RoB2 tool revealed that none of 9 trials included in our meta-analysis exhibited a low risk of bias. Seven trials exhibited some concerns (15), (19), (20), (21), (22), (24), (25), and 2 trials exhibited a high risk of bias (18), (23).”
2 of 2

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Pooled estimates are labelled both relative risks and odds ratios

    Minor

    The abstract labels the pooled cardiovascular mortality estimate a relative risk, while the results label the same estimate and confidence interval an odds ratio. The paper does not consistently identify which measure was pooled.

  • Figure caption conflicts with the number of included studies

    Minor

    The results state that nine studies were included, whereas the Figure 1 caption says 9,987 studies were included. The latter may refer to search records, but it is labelled as included studies.

2 of 2

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. [35]Houtsmuller AJ, van Hal-Ferwerda J, Zahn KJ, et al. Influence of different diets on the progression of diabetic retinopathy. Prog Food Nutr Sci. 1980; 4(5): 41-6. 7005962

Cited by

Sorted by citations

Related

Authors
Yamada, S., Shirai, T., Inaba, S., Inoue, G., Torigoe, M., & Fukuyama, N.
Affiliations
  • Kitasato Institute Hospital (JP)
  • Tokyo University of Agriculture (JP)
ORCID
Venue
JMA Journal
Publisher
Japan Medical Association
Published
2025
Volume
8
Issue
2
Pages
395-407
ISSN
  • 2433-328X (ISSN-L)
  • 2433-3298
DOI
10.31662/jmaj.2024-0324
PMC
PMC12095860
OpenAlex
W4409125186
Semantic Scholar
2ebf2ddcf89284fdc07331acae890235a9c324b9
Cited by
2
References
2
Citations by year
2026: 2
FWCI
0.59
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • JMA Journal (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • PubMed Central (submittedVersion, cc-by)
Topics
  • Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Nutritional Studies and Diet
  • Health Sciences › Nursing › Nutrition and Dietetics › Fatty Acid Research and Health
  • Health Sciences › Medicine › Surgery › Lipoproteins and Cardiovascular Health
Keywords
dietary saturated fat, cardiovascular disease prevention, cardiovascular mortality, all-cause mortality, myocardial infarction, stroke, statin therapy, primary and secondary prevention

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-19.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-19.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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