Beef and lamb: the answer depends on what replaces them

Red meat research mostly answers a question the trials picked, rather than the one you came with. Replacing red meat with plant protein lowered LDL cholesterol by 0.19 mmol/L (95 percent credible interval 0.03 to 0.36) and total cholesterol by 0.14 mmol/L across 36 randomised trials, on evidence the authors themselves graded very low to low. Against other animal protein the same review found no advantage. The number is about the swap, and which comparison a trial picks turns out to matter. Of 44 clinical trials on unprocessed red meat and cardiovascular risk factors, 66 percent had a link to the red meat industry, and those trials were 3.75 times more likely to report a favourable or neutral result (95 percent CI 1.62 to 8.67). Every independent trial in that set reported an unfavourable or neutral outcome and every industry-linked one a favourable or neutral outcome, and the reviewers name comparator choice as the reason. Where beef gets named for a nutrient load, the figures are about how much people eat rather than about the meat. The NIH Office of Dietary Supplements says beef supplies 20 percent of zinc intake from food in the United States because it is commonly eaten, and that oysters hold more zinc per serving than any other food. In more than 215 000 US adults from five ethnic groups, all meat together supplied 19.7 to 40 percent of vitamin B12 intake, 11.1 to 29.3 percent of zinc and only 4.3 to 14.2 percent of iron. That was all meat rather than beef and lamb alone, and poultry contributed more than red meat in every group except Latino men born in Mexico.

How much is actually in it

• The NIH Office of Dietary Supplements states that beef supplies 20 percent of zinc intake from food in the United States, and that zinc absorbed from food ranges from 5 percent to more than 50 percent depending on how much phytate the diet carries. — United States population, agency fact sheet for health professionals Evidence E source
  Beef 20 percent of US dietary zinc, zinc absorption from food 5 percent to more than 50 percent depending on dietary phytate
• In a cohort of more than 215 000 adults from five ethnic groups, all meat together supplied 19.7 to 40 percent of vitamin B12, 11.1 to 29.3 percent of zinc and only 4.3 to 14.2 percent of iron intake. — more than 215 000 African American, Latino, Japanese American, Native Hawaiian and Caucasian adults aged 45 to 75 in Hawaii and Los Angeles (n = more than 215 000) Evidence C source
  Meat contribution 19.7 to 40 percent for vitamin B12, 11.1 to 29.3 percent for zinc, 4.3 to 14.2 percent for iron, varying by ethnic and sex group

What a real portion looks like

• Weighted mean red meat intake, counting beef plus lamb together, was 67.3 g a day for Australian boys and 52.2 g for girls aged 7 to 12, rising to 87.7 g and 54.2 g at ages 12 to 18. — Australian children and adolescents aged 7 to 18 across three dietary surveys, two national and two regional (n = three surveys pooled by weighted mean) Evidence C source
  Beef plus lamb 67.3 g a day in boys and 52.2 g in girls aged 7 to 12, and 87.7 g and 54.2 g at 12 to 18
• Among 319 adults who picked the same portion size for beef, lamb and veal on a food frequency questionnaire, the amounts men actually reported in 24 hour recalls were significantly larger than the amounts women reported. — 319 members of the Hawaii and Los Angeles Multiethnic Cohort aged 56 to 80 who completed three 24 hour recalls and a quantitative food frequency questionnaire (n = 319) Evidence C source
  Significantly higher mean reported portions in men than women for beef, lamb and veal and for seven other food items chosen at the same questionnaire portion size

What your body absorbs

• In a meta-analysis of 13 randomised trials of iron supplements, heme iron raised haemoglobin by 1.06 g/dL more than non-heme iron in children with anaemia or low iron stores (95 percent CI 0.34 to 1.78). Total side effects fell by 38 percent among everyone given heme iron. Most trials gave heme iron in low doses combined with non-heme iron rather than as meat, and certainty was very low. — non-hospitalised people of any age in 13 randomised trials comparing heme with non-heme iron supplements, with the haemoglobin difference coming from the children who had anaemia or low iron stores (n = 13 trials) Evidence A source
  Haemoglobin mean difference 1.06 g/dL, 95 percent CI 0.34 to 1.78, in children with anaemia, and total side effects relative risk 0.62, 95 percent CI 0.40 to 0.96

What it does to your health

• Across 36 randomised trials, replacing red meat with plant protein sources lowered LDL cholesterol by 0.19 mmol/L (95 percent credible interval 0.03 to 0.36) and total cholesterol by 0.14 mmol/L, while the certainty of evidence was rated very low to low. — adults in 36 randomised controlled trials comparing red meat diets with diets replacing red meat (n = 36 trials) Evidence A source
  LDL cholesterol mean difference -0.19 mmol/L, 95 percent CrI -0.36 to -0.03, and total cholesterol -0.14 mmol/L, 95 percent CrI -0.28 to -0.001
• In a crossover trial, 27 healthy men ate matched burrito meals on four occasions. Grain-fed beef and lamb produced a lower plasma triglyceride response than a plant-based burger (grain beef -0.346, lamb -0.458). — 27 healthy males, standardised burrito-style meals matched for protein and carbohydrate, blood sampled hourly for 4 hours, washout at least 1 week (n = 27) Evidence B source
  Postprandial plasma triglyceride difference -0.346 for grain-fed beef and -0.458 for lamb against the plant-based meat alternative
• Pooling 31 observational studies, red meat intake went with a 13 percent higher risk of colorectal adenomas (RR 1.13, 95 percent CI 1.05 to 1.21), while unprocessed red meat on its own showed no significant association. — participants of 31 observational studies of meat intake and precancerous colorectal lesions, published to December 2024 (n = 31 studies) Evidence C source
  Colorectal adenomas relative risk 1.13, 95 percent CI 1.05 to 1.21, colorectal polyps 1.73, 95 percent CI 1.02 to 2.94, processed meat and adenomas not significant at 1.14, 95 percent CI 0.93 to 1.41

Safety, limits and interactions

• An umbrella review of 34 articles and 54 meta-analyses put 50 g a day of processed meat at 72 percent higher gastric cancer risk, 17 percent higher colorectal cancer risk and 4 percent higher prostate cancer risk, all on low to very low certainty evidence. — participants of 54 meta-analyses of processed meat intake and health outcomes, searched to May 2025 (n = 34 articles and 54 meta-analyses) Evidence C source
  Per 50 g a day: gastric cancer 72 percent higher risk, colorectal cancer 17 percent, prostate cancer 4 percent, COPD 8 percent
• In 276 retail meat samples from southern Mexico, Toxoplasma gondii DNA was found in 10.9 percent overall, in 1.4 percent of lamb and in no beef sample, while pork reached 28.0 percent. — 276 meat samples of pork, chicken, beef, lamb and horse meat from butcher shops, markets and supermarkets in Veracruz, Mexico, February to July 2024 (n = 276 samples) Evidence C source
  Overall positivity 10.9 percent, pork 28.0 percent, lamb 1.4 percent, beef 0 percent, butcher shops adjusted odds ratio 22.50 against supermarkets

What people believe that the data does not support

• Of 44 clinical trials on unprocessed red meat and cardiovascular risk, 66 percent had a link to the red meat industry, and those trials were 3.75 times more likely to report a favourable or neutral result (95 percent CI 1.62 to 8.67). — 44 clinical trials of unprocessed red meat and cardiovascular risk factors, classified by industry link (n = 44 trials) Evidence B source
  Odds ratio 3.75, 95 percent CI 1.62 to 8.67, for reporting a favourable or neutral outcome when the authors had a red meat industry link
• WHO reports that pooled data from 10 studies put the colorectal cancer risk increase at about 18 percent for every 50 g of processed meat eaten daily, and at 17 percent per 100 g of red meat if that association proved causal. — general population, WHO question and answer document on the IARC evaluation (n = 10 studies) Evidence E source
  About 18 percent higher colorectal cancer risk per 50 g processed meat a day, and a conditional 17 percent per 100 g red meat a day

Who this works differently for

• Among 482 women aged 20 to 50 in Tehran, those in the highest quartile of red meat intake had 2.51 times the odds of depressive symptoms (95 percent CI 1.32 to 4.76) against the lowest quartile, and these are odds rather than risks. — 482 women aged 20 to 50 attending health centres of Tehran University of Medical Sciences in 2018 (n = 482) Evidence C source
  Depressive symptoms odds ratio 2.51, 95 percent CI 1.32 to 4.76, anxiety 1.82, 95 percent CI 1.00 to 3.29, stress 3.47, 95 percent CI 1.88 to 6.42

What is still unknown

• Across 13 randomised trials with 553 people and a median of 28 days, higher red meat intake raised TMAO in 6 diet comparisons, changed nothing in 7, and lowered it in 2 where the comparison diet contained seafood. — generally healthy adults or adults with stable chronic disease in 13 randomised trials of at least 7 days (n = 553) Evidence A source
  6 of 15 comparisons showed higher circulating or urinary TMAO at 71 to 420 g red meat a day, 7 showed no difference at 60 to 156 g a day, 2 showed lower TMAO

The bottom line

The cancer numbers here belong mostly to processed meat, and their wording keeps getting lost. WHO says pooled data from 10 studies put colorectal cancer risk about 18 percent higher for every 50 g of processed meat eaten daily, and 17 percent higher per 100 g of red meat only if that association were proven causal. Both are relative increases on a lifetime baseline rather than absolute risk. An umbrella review of 34 articles and 54 meta-analyses put 50 g a day of processed meat at 72 percent higher gastric cancer risk, 17 percent higher colorectal cancer risk and 4 percent higher prostate cancer risk. Every one of those dose-response figures was graded low to very low certainty, and that review re-analysed nothing. Pooling 31 observational studies, red meat as a category was associated with a 13 percent higher risk of colorectal adenomas (RR 1.13, 95 percent CI 1.05 to 1.21), while unprocessed red meat on its own showed no significant association. Pooling observational studies does not turn them into experiments. A real portion sits nowhere near the 100 g those figures are keyed to. Australian boys aged 12 to 18 averaged 87.7 g of beef plus lamb a day and girls 54.2 g, and at ages 7 to 12 it was 67.3 g and 52.2 g, from surveys some of which date to 1985 and 1995. Portion size is measured badly as well. Among 319 adults aged 56 to 80 who picked the same portion size for beef, lamb and veal on a questionnaire, the amounts men reported in 24 hour recalls were significantly larger than the amounts women reported. Iron is where the claims are loudest and the evidence thinnest. In 13 randomised trials heme iron raised haemoglobin by 1.06 g/dL more than non-heme iron in children with anaemia or low iron stores (95 percent CI 0.34 to 1.78), on GRADE certainty rated very low. Total side effects fell 38 percent (RR 0.62, 95 percent CI 0.40 to 0.96), most of those trials gave low dose heme iron combined with non-heme iron rather than a portion of meat, and no other age group showed a difference. For zinc the NIH Office of Dietary Supplements says beef contributes 20 percent of US zinc intake because it is commonly eaten, while oysters hold more per serving. Absorption of zinc from food runs from 5 percent to more than 50 percent depending on how much phytate the whole diet carries, which is a range for diets and not for a steak. Who should be careful: the only contamination numbers we have describe the meat counter. In 276 retail meat samples from Veracruz, Mexico, Toxoplasma gondii DNA turned up in 10.9 percent overall, in 1.4 percent of lamb and in no beef sample, against 28.0 percent of pork. PCR finds DNA rather than a living parasite, which those authors state plainly. Samples from butcher shops had 22.50 times the adjusted odds of testing positive against supermarkets, which is a fact about where meat was sold. This is one region of Mexico, and zero positives in its beef does not mean beef never carries it. We found no card on pregnancy and none on cooking, so this page can tell a pregnant reader neither what that detection means for her nor what heat does to the parasite. Two more findings get quoted loosely. Among 482 women aged 20 to 50 at Tehran clinics, the highest quartile of red meat intake carried 2.51 times the odds of depressive symptoms against the lowest quartile (95 percent CI 1.32 to 4.76). Those are odds rather than risks, diet and mood were measured at the same moment, and that red meat category included liver, kidney and heart. On TMAO, 13 randomised trials in 553 people over a median of 28 days went three ways. Six comparisons showed more TMAO at 71 to 420 g of red meat a day, seven showed no difference at 60 to 156 g, and two showed less where the comparison diet held seafood. Nothing could be pooled, and whether a TMAO shift of that size changes anything a person would notice is unknown. One meal test in 27 healthy men found grain-fed beef and lamb gave a lower plasma triglyceride response over four hours than one plant-based burger, by 0.346 and 0.458 on a scale the abstract leaves without units, a difference those authors call subtle. We have no USDA composition record for this pair, which is why the table above is empty, and we found no trial in kidney disease and nothing that separates beef from lamb on any of the cancer figures.

Sources

1. bflm-r2-09 · fact sheet
   Oysters contain more zinc per serving than any other food, but beef contributes 20% of zinc intakes from food in the United States because it is commonly consumed [7]. ... The amount of zinc absorbed from food ranges from 5% to more than 50%, depending on the amount of plant-based foods (and thus of phytate) in the diet [3]. The absorption of zinc from mixed meals or diets containing a combination of animal-based and plant-based foods is lower than from diets or meals containing animal-based foods only [10].
   NIH Office of Dietary Supplements, Zinc fact sheet for health professionals · checked 2026-09-24
2. bflm-r2-12 · cohort study
   The contribution of meat was most substantial for zinc (11.1-29.3%) and vitamin B₁₂ (19.7-40%) and, to a lesser extent, for iron (4.3-14.2%).
   J Hum Nutr Diet, 2013 · checked 2026-09-24
3. bflm-r2-11 · review of survey data
   Weighted mean intakes of red meat (beef plus lamb) across the three most recent studies were 67.3 and 52.2 g/d, respectively, for males and females aged between 7 and 12 years and 87.7 and 54.2 g/d, respectively, for males and females aged 12-18 years.
   Br J Nutr, 2009 · checked 2026-09-24
4. bflm-r2-13 · cross-sectional study
   Although they chose the same portion size on the QFFQ, mean intake amounts from 24HDRs were significantly higher for men than for women for "beef/lamb/veal," "white rice," "brown/wild rice," "lettuce/tossed salad," "eggs cooked/raw," "whole wheat/rye bread," "buns/rolls," and "mayonnaise in sandwiches."
   J Acad Nutr Diet, 2018 · checked 2026-09-24
5. bflm-r2-03 · meta-analysis
   After screening 3097 articles, 13 studies were included. Most of the interventions used HI in low doses combined with NHI. The meta-analysis showed higher hemoglobin increases in children with anemia or low iron stores receiving HI (MD 1.06 g/dL; 95% CI: 0.34; 1.78; CoE: very low). ... Participants receiving HI had a 38% relative risk reduction of total side effects compared to NHI (RR 0.62; 95% CI 0.40; 0.96; CoE: very low).
   Eur J Nutr, 2024 · checked 2026-09-24
6. bflm-r2-01 · network meta-analysis
   Thirty-six RCTs were included in the analysis. Consuming plant proteins resulted in a greater reduction in total cholesterol (TC) levels (mean difference (MD) = -0.14; 95 % credible interval (CrI): -0.28 to -0.001, p < 0.05) and low-density lipoprotein cholesterol (LDL-C) levels (MD = -0.19; 95 % CrI: -0.36 to -0.03, p < 0.05) compared to red meat interventions.
   Clin Nutr, 2025 · checked 2026-09-24
7. bflm-r2-05 · randomised controlled trial
   We conducted a randomized crossover trial where healthy males (n = 27) consumed a standardized burrito-style meal containing meat or an alternative matched for protein and carbohydrate content on 4 separate occasions, with a minimum washout period of 1-wk. ... The grain beef and lamb showed a significantly lower triglyceride response in plasma compared to PBMA (grain: -0.346; 95% CI: -0.692, -0.0004; lamb: -0.458; 95% CI: -0.880, -0.034).
   Am J Clin Nutr, 2025 · checked 2026-09-24
8. bflm-r2-06 · meta-analysis of observational studies
   The results positively linked red meat intake to the risk of colorectal adenomas (RR: 1.13; 95% CI: 1.05, 1.21), colorectal polyps (1.73; 1.02, 2.94), and distal colon adenomas (1.19; 1.02, 1.40). Processed meat consumption was correlated with increased colorectal polyp risk (1.65; 1.05, 2.61) but not colorectal adenoma risk (1.14; 0.93, 1.41). ... Pooled RRs and 95% CIs suggest that the intake of total meat, charred meat, and unprocessed red meat had no significant associations with precancerous lesions of CRC.
   Nutr Rev, 2026 · checked 2026-09-24
9. bflm-r2-07 · umbrella review
   Dose-response analysis revealed that an increase in PM consumption of 50 g/day was associated with a 72% higher risk of gastric cancer, 17% higher risk of colorectal cancer, 4% higher risk of prostate cancer, and an 8% higher risk of chronic obstructive pulmonary disease (COPD). All the above dose-response associations are based on low to very low certainty evidence as assessed by the GRADE system.
   Front Public Health, 2026 · checked 2026-09-24
10. bflm-r2-10 · cross-sectional prevalence survey
    Between February and July 2024, a total of 276 meat samples (pork, chicken, beef, lamb, and horse meat) were collected from butcher shops, local markets, and supermarkets in Veracruz, Mexico. ... T. gondii DNA was detected in 30 samples (10.9%). Pork showed the highest positivity rate (28.0%), whereas chicken (3.1%), lamb (1.4%), and horse meat (25.0%) exhibited lower detection frequencies; no beef samples tested positive.
    Acta Parasitol, 2026 · checked 2026-09-24
11. bflm-r2-02 · systematic review
    A total of 44 studies were included, of which 66% had a link to the red meat industry. All independent studies reported either unfavorable (73.3%) or neutral (26.7%) cardiovascular outcomes when consuming unprocessed red meat. Conversely, all studies related to the red meat industry reported either favorable (20.7%) or neutral (79.3%) cardiovascular outcomes for red meat intake. ... Studies with conflicts of interest were nearly 4 times more likely to report "Favorable/Neutral" outcomes compared with independent studies (odds ratio 3.75, 95% confidence interval: 1.62, 8.67).
    Am J Clin Nutr, 2025 · checked 2026-09-24
12. bflm-r2-08 · agency question and answer
    An analysis of data from 10 studies estimated that every 50 gram portion of processed meat eaten daily increases the risk of colorectal cancer by about 18%. ... However, if the association of red meat and colorectal cancer were proven to be causal, data from the same studies suggest that the risk of colorectal cancer could increase by 17% for every 100 gram portion of red meat eaten daily.
    WHO, Cancer: carcinogenicity of the consumption of red meat and processed meat, questions and answers · checked 2026-09-24
13. bflm-r2-14 · cross-sectional study
    The red meat category was defined as the sum of red meats (beef, lamb), and organ meats (beef liver, kidney, and heart, ruminant meat). ... After controlling for potential confounders, women in the highest quartile of red meat had a highest prevalence of depressive symptoms (OR: 2.51; 95% CI: 1.32-4.76; p = 0.002), anxiety (OR: 1.82; 95% CI: 1.00-3.29; p = 0.034) and stress (OR: 3.47; 95% CI: 1.88-6.42; p < 0.001) compared with those in the lowest quartile.
    Complement Ther Med, 2021 · checked 2026-09-24
14. bflm-r2-04 · systematic review
    Fifteen publications reporting the results of 13 RCTs (n = 553; median duration 28 d), including 15 diet comparisons, were eligible. ... In 7 comparisons, no differences in serum/plasma TMAO concentrations were observed with higher red meat-containing diets ... Two comparisons showed that consuming higher red meat diets lowered TMAO concentrations after 28 d compared with lower red meat diets containing seafood.
    Adv Nutr, 2025 · checked 2026-09-24