Animal fat: the cholesterol moved, the deaths did not follow

The strongest trial evidence on animal fat comes from a trial that took it away. In 9423 institutionalised adults aged 20 to 97 in Minnesota between 1968 and 1973, replacing the saturated fat of animal fats with linoleic acid cut serum cholesterol by 13.8% against 1.0% in controls, P < 0.001. Pooled with four other randomised trials, 10 808 people in all, that swap did not lower deaths from coronary heart disease, 1.13 (0.83 to 1.54), or deaths from any cause, 1.07 (0.90 to 1.27). The participants lived in nursing homes and psychiatric hospitals and were followed for under three years on average, and the control diet was the animal-fat one, so the trial measures the replacement and not the food on its own. WHO still holds saturated fat at 10% of total energy as a strong recommendation, with moderate certainty behind that number, and records that significant reductions in cardiovascular disease appeared only below 9% of energy. Animal fat is one carrier of saturated fat among several, so that ceiling bounds the food indirectly.

The numbers, per 100 g

How much is actually in it

• In sheep and cattle 96.7% of the alpha-linolenic acid fed as oil or animal fat is hydrogenated in the rumen before it can be absorbed, which is why ruminant fat stays saturated whatever the animal is fed. — database of duodenal fatty acid flows in sheep and cattle, no human participants (n = 83 predictive models) Evidence D source
  Ruminal biohydrogenation of c9c12c15-C18:3 96.7% for the oil or animal fat subset against 94.8% for the seed subset
• In dairy cows 83.8% of the oleic acid in milk fat comes from the animal desaturating stearic acid rather than from the feed, so feeding oils moves the fatty acid profile far less than the recipe suggests. — 34 published papers, 50 experiments and 142 treatments in dairy cows, no human participants (n = 142 treatments) Evidence D source
  Desaturation contributes 83.8% (plus or minus 0.75) of milk cis-9 C18:1 and 86.8% (plus or minus 2.8) of cis-9,trans-11 CLA

What your body absorbs

• Eating vegetables at the same time as some fat improves how much phylloquinone the body takes up from them, though the amount absorbed is still lower than from oils. — general adult population, NIH Office of Dietary Supplements review Evidence E source
  Free phylloquinone is absorbed at about 80% while absorption from foods is markedly lower, and the body takes up only 4% to 17% as much phylloquinone from spinach as from a tablet
• Animal fats carry preformed vitamin A as retinol and retinyl esters, which the body uses directly, while plant foods supply provitamin A carotenoids that have to be converted first. — general population, NIH Office of Dietary Supplements review Evidence E source
  Two dietary forms: preformed vitamin A from animal sources against provitamin A carotenoids from plants, converted in the intestine by BCMO1 with genetic variability in conversion rate

What it does to your health

• Across 10 cohort and case-control studies, the highest total fat intake carried a 26% higher risk of non-Hodgkin lymphoma (RR 1.26, 1.12 to 1.42). — 10 studies (2 cohorts, 8 case-control) selected from 221 screened (n = 10 studies) Evidence C source
  Total fat RR 1.26 (1.12 to 1.42); diffuse large B-cell lymphoma 1.41 (1.08 to 1.84); follicular, small lymphocytic and T-cell subtypes not significant
• Among 2459 Iranians screened by angiography, animal fat intake showed no association with premature coronary disease, while liquid non-hydrogenated vegetable oil went with odds of 0.37 (0.29 to 0.46). — 2459 Iranian adults, 1395 with premature coronary artery disease and 1064 controls, mean age 51.5 (n = 2459) Evidence C source
  Non-hydrogenated vegetable oil odds ratio 0.37 (95% CI 0.29 to 0.46), odds rather than risk; no significant association for hydrogenated oil, animal fat or the composite fat index
• A Western eating pattern defined partly by animal fats went with nearly double the risk of inflammatory bowel disease across nine studies (RR 1.92, 1.37 to 2.68). — 9 studies with 1491 cases of inflammatory bowel disease and 53 089 controls, 7 case-control and 2 prospective cohorts (n = 1491 cases, 53089 controls) Evidence C source
  All inflammatory bowel disease RR 1.92 (1.37 to 2.68); Crohn's disease 1.72 (1.01 to 2.93); ulcerative colitis 2.15 (1.38 to 3.34)
• In 200 stroke survivors, a Mediterranean diet limiting animal fats did not beat a low-fat diet on LDL cholesterol after 90 days, 66.5 against 69.9 mg/dL. — 200 adults within a month of an ischemic stroke, 103 Mediterranean diet and 97 low-fat, 90 days, 189 completed (n = 200) Evidence B source
  LDL-C 66.5 mg/dL (59.6 to 73.4) against 69.9 mg/dL (62.6 to 77.2), adjusted difference -3.4 mg/dL, P = 0.50

Safety, limits and interactions

• WHO's 2023 guideline holds saturated fat at 10% of total energy intake as a strong recommendation, with moderate certainty behind that number and significant risk reduction seen only below 9%. — adults and children, population-level guidance Evidence E source
  Ceiling of 10% of total energy from saturated fatty acids, strong recommendation, moderate certainty; risk reductions for cardiovascular disease and its mortality appeared below 9% of energy
• Across 21 prospective cohorts of pregnant women, the highest animal fat intake carried a 56% higher risk of gestational diabetes (RR 1.56, 1.34 to 1.89), the largest of any fat examined. — 21 prospective cohort studies of pregnant women, searched to August 2023 (n = 21 cohorts) Evidence C source
  Animal fat RR 1.56 (95% CI 1.34 to 1.89) for gestational diabetes against total fat 1.08 (1.02 to 1.14) and vegetable fat 1.23 (1.05 to 1.45); no association with preeclampsia

What people believe that the data does not support

• Replacing the saturated fat of animal fats with linoleic acid cut serum cholesterol by 13.8% in a 9423-person trial, and across five randomised trials it did not lower deaths from heart disease (1.13, 0.83 to 1.54). — 9423 institutionalised adults aged 20 to 97 in Minnesota, 1968 to 1973, plus five randomised trials totalling 10 808 people (n = 9423 randomised, 10808 in the meta-analysis) Evidence A source
  Serum cholesterol -13.8% against -1.0% in controls, P < 0.001; coronary mortality 1.13 (0.83 to 1.54) and all-cause mortality 1.07 (0.90 to 1.27), neither significant
• Pooling 24 prospective cohort studies found no association between animal fat intake and breast cancer risk, and the weak signal for total fat disappeared once the usual risk factors were adjusted for. — 24 prospective cohort studies on dietary fat, 7 on serum fatty acids, searched to September 2015 (n = 24 studies) Evidence C source
  No association for animal fat, vegetable fat or any fatty acid class; total fat highest against lowest RR 1.10 (1.02 to 1.19), absent after adjustment
• A dose-response meta-analysis of 23 studies found no link between total fat intake and type 2 diabetes, and saturated fat above roughly 17 g a day tracked slightly lower risk (0.95, 0.90 to 1.00). — 23 studies from 19 prospective cohorts of adults, searched to October 2019 (n = 23 studies, 19 cohorts) Evidence C source
  Saturated fatty acids above about 17 g/d SRR 0.95 (0.90 to 1.00), p nonlinearity 0.028, n = 11; vegetable fat up to 13 g/d 0.81 (0.76 to 0.88); no association for total fat

Who this works differently for

• Reviewing 24 observational studies of adolescents, diets high in sodium, animal fat and refined carbohydrate went with higher blood pressure and more body fat, though only 14 of the 24 found any significant association. — 24 observational studies of adolescents, searched July 2020 (n = 24 studies) Evidence C source
  Direction only: positive association of such patterns with blood pressure and adiposity markers, significant in 14 of 24 studies

What is still unknown

• The FDA's own health claim rule on dietary lipids and cancer states that neither human nor animal studies agree on which cancer sites fat intake is linked to. — United States regulatory text, 21 CFR 101.73 Evidence E source
  Regulator records inconsistency across studies on site-specific effects of dietary fat

The bottom line

Where the numbers get bigger, the design gets weaker. Across 21 prospective cohorts of pregnant women, the highest animal fat intake went with a 56% higher risk of gestational diabetes, RR 1.56 (1.34 to 1.89), the largest figure for any fat in that review. Intake came from food frequency questionnaires, so whatever else those diets held travels with the result. The same review found no association with preeclampsia. In pregnancy that is an association measured by food frequency questionnaire and not a demonstrated effect, and it is the largest number on this page for animal fat as its own exposure. Beyond the population ceiling and that pregnancy signal, this page has little to put under limits. We found no study of what heating or reusing lard or tallow does, and nothing on a drug interaction under this name. For the diseases people worry about most, animal fat as its own exposure keeps coming up empty. Pooling 24 prospective cohorts found no association with breast cancer, and the weak signal for total fat, RR 1.10 (1.02 to 1.19), was absent after adjustment for the usual risk factors. Among 2459 Iranian adults screened by angiography, 1395 of them with premature coronary disease, animal fat showed no significant association. Liquid non-hydrogenated vegetable oil in the same study went with odds of 0.37 (0.29 to 0.46), odds rather than risk, in a case-control design where recall runs with the outcome, so the null for animal fat is weak evidence of absence. In 200 adults randomised within a month of an ischemic stroke, a Mediterranean diet limiting animal fats gave LDL cholesterol of 66.5 mg/dL against 69.9 mg/dL on a low-fat diet after 90 days, P = 0.50. Both arms restricted animal fat and most participants were on statins. Two associations do point upward, and both are about patterns rather than about fat from an animal. Total fat intake, which is what the pooled estimate actually measured, carried a 26% higher risk of non-Hodgkin lymphoma across 10 studies, RR 1.26 (1.12 to 1.42), eight of them case-control. A Western eating pattern defined partly by animal fats went with RR 1.92 (1.37 to 2.68) for inflammatory bowel disease across nine studies with 1491 cases. A pattern needed only some of its features to count, so animal fat is one ingredient of that signal. A dose-response meta-analysis of 23 studies found no link between total fat and type 2 diabetes and an apparently protective curve for saturated fat above about 17 g a day, 0.95 (0.90 to 1.00). The authors rate their own certainty very low to moderate and name high unexplained inconsistency, so read that curve as unresolved rather than as permission. In 24 observational studies of adolescents, diets high in sodium, animal fat and refined carbohydrate went with higher blood pressure and more body fat, with a significant association in only 14 of the 24 and no pooling done. Fat on the plate does do one plain job. Eating vegetables at the same time as some fat improves how much phylloquinone the body takes up from them, though the amount absorbed is still lower than from oils, and the body takes up only 4 to 17% as much phylloquinone from spinach as from a tablet. Animal fats also carry vitamin A already formed, as retinol and retinyl esters, while plant foods supply carotenoids that the intestine has to convert first. Neither point ranks animal fat against oils, and both come from a reviewing body rather than from a trial. As for why ruminant fat stays saturated whatever the animal eats, sheep and cattle hydrogenate 96.7% of the alpha-linolenic acid fed as oil or animal fat before it can be absorbed. Dairy cows make 83.8% of the oleic acid in milk fat themselves out of stearic acid. Those are numbers about ruminant digestion and not about yours. On the big question, the health claim rule of the FDA on dietary lipids and cancer says plainly that neither human nor animal studies are consistent about which cancer sites fat intake is linked to.

Sources

1. anfa-daily-r1-08 · animal meta-analysis
   The c9c12c15-C18:3 RBH was higher for oil/fat than seed (96.7% v. 94.8%) and a protective effect of Leguminosae v. Gramineae against RBH for that FA appeared in the forage subset.
   Animal, 2019 · checked 2026-09-24
2. anfa-daily-r1-09 · animal meta-analysis
   Models of amounts desaturated from C18:0 into cis-9 C18:1 and trans-11 C18:1 into cis-9,trans-11 CLA indicated that the contribution of C18:0 and trans-11 C18:1 desaturation to respective cis-9 C18:1 and cis-9,trans-11 CLA yields in milk fat was 83.8% (±0.75) and 86.8% (±2.8).
   J Dairy Sci, 2019 · checked 2026-09-24
3. anfa-daily-r1-10 · fact sheet
   Consuming vegetables at the same time as some fat improves phylloquinone absorption from the vegetables, but the amount absorbed is still lower than that from oils.
   NIH ODS Vitamin K Fact Sheet for Health Professionals · checked 2026-09-24
4. anfa-daily-r1-11 · fact sheet
   The human diet contains two sources for vitamin A: preformed vitamin A (retinol and retinyl esters) and provitamin A carotenoids [1,5]. Preformed vitamin A is found in foods from animal sources, including dairy products, eggs, fish, and organ meats [1,2].
   NIH ODS Vitamin A and Carotenoids Fact Sheet for Health Professionals · checked 2026-09-24
5. anfa-daily-r1-06 · meta-analysis of observational studies
   There was a significant association between total fat consumption and increased risk of NHL (RR = 1.26; 95% CI: 1.12-1.42); in addition, subgroup analysis showed a significant correlation with diffuse large B-cell lymphoma (RR = 1.41; 95% CI: 1.08-1.84) but not with follicular lymphoma (RR = 1.21; 95% CI: 0.97-1.52), small lymphocytic lymphoma/chronic lymphocytic leukemia (RR = 0.91; 95% CI: 0.68-1.23), nor with T cell lymphoma (RR = 1.12; 95% CI: 0.60-2.09).
   Nutr Cancer, 2017 · checked 2026-09-24
6. anfa-daily-r1-07 · case-control study
   A higher non-HVO intake was associated with a lower risk of PCAD in the fully adjusted model (odds ratio [OR]: 0.37; 95 % confidence interval [CI]: 0.29, 0.46)...No significant associations were observed between HVO, animal fat, or FCI.
   Nutr Metab Cardiovasc Dis, 2026 · checked 2026-09-24
7. anfa-daily-r1-14 · meta-analysis of observational studies
   A Western dietary pattern was associated with a risk of all IBD (relative risk [RR] 1.92, 95% CI 1.37-2.68) and separately with Crohn's disease (CD) (RR 1.72, 95% CI 1.01-2.93) and ulcerative colitis (UC) (RR 2.15, 95% CI 1.38-3.34).
   J Dig Dis, 2020 · checked 2026-09-24
8. anfa-daily-r1-15 · randomised controlled trial
   There were no significant differences in LDL-C levels between the MeDi group and the low-fat group at 90 days: 66.5 mg/dL (95% confidence interval [CI] 59.6, 73.4) in the MeDi group and 69.9 mg/dL (62.6, 77.2) in the low-fat group at the end of follow-up.
   Lipids Health Dis, 2025 · checked 2026-09-24
9. anfa-daily-r1-02 · guideline
   WHO recommends that adults and children reduce saturated fatty acid intake to 10% of total energy intake (strong recommendation).
   WHO guideline: Saturated fatty acid and trans-fatty acid intake for adults and children, 2023 · checked 2026-09-24
10. anfa-daily-r1-03 · meta-analysis of cohorts
    Findings indicated that higher intakes of total fat (relative risk [RR], 1.08; 95% confidence interval [CI], 1.02-1.14), animal fat (RR, 1.56; 95%CI, 1.34-1.89), vegetable fat (RR, 1.23; 95%CI, 1.05-1.45), dietary cholesterol (RR, 1.48; 95%CI, 1.10-2.00), and omega-3 fatty acid (RR, 1.11; 95%CI, 1.02-1.20) are associated with a greater risk of GDM.
    Nutr Rev, 2025 · checked 2026-09-24
11. anfa-daily-r1-01 · meta-analysis of RCTs
    The intervention group had significant reduction in serum cholesterol compared with controls (mean change from baseline -13.8%v-1.0%; P<0.001)...In meta-analyses, these cholesterol lowering interventions showed no evidence of benefit on mortality from coronary heart disease (1.13, 0.83 to 1.54) or all cause mortality (1.07, 0.90 to 1.27).
    BMJ, 2016 · checked 2026-09-24
12. anfa-daily-r1-04 · meta-analysis of cohorts
    No association was observed between animal fat, vegetable fat, saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), n-3 PUFA, n-6 PUFA, eicosapentaenoic acid, docosahexaenoic acid, alpha-linolenic acid, oleic acid, linoleic acid and arachidonic acid and risk of breast cancer.
    Int J Cancer, 2016 · checked 2026-09-24
13. anfa-daily-r1-05 · meta-analysis of cohorts
    Saturated fatty acids showed an apparent protective association above intakes around 17 g/d with T2D (SRR [95% CI]: 0.95 [0.90; 1.00], pnonlinearity = 0.028, n = 11)...There was no association between total fat intake and the incidence of T2D.
    PLoS Med, 2020 · checked 2026-09-24
14. anfa-daily-r1-13 · systematic review of cohorts and cross-sectional studies
    There was a positive association of dietary patterns - characterized by the consumption of foods rich in sodium, animal fat, refined carbohydrates, and low in fiber - with increased blood pressure and body adiposity.
    Eur J Clin Nutr, 2021 · checked 2026-09-24
15. anfa-daily-r1-12 · regulation
    A question that has been the subject of considerable research is whether the effect of fat on cancer is site-specific. Neither human nor animal studies are consistent in the association of fat intake with specific cancer sites.
    21 CFR 101.73, health claims: dietary lipids and cancer · checked 2026-09-24