What Is a Healthy Amount of Beef That Can Be Consumed by a Women 2019

Research

Association of changes in red meat consumption with total and cause specific mortality among US women and men: two prospective cohort studies

BMJ 2019; 365 doi: https://doi.org/ten.1136/bmj.l2110 (Published 12 June 2019) Cite this every bit: BMJ 2019;365:l2110

Yan Zheng , professor123,
Yanping Li , enquiry scientistiii,
Ambika Satija , research beauthree,
An Pan , professor4,
Mercedes Sotos-Prieto , assistant professor3567,
Eric Rimm , professor389,
Walter C Willett , professor389,
Frank B Hu , professor389

^oneDepartment of Cardiology, Country Key Laboratory of Genetic Engineering science, School of Life Sciences and Zhongshan Infirmary, Fudan University, Shanghai, China
²Ministry building of Instruction Cardinal Laboratory of Public Health Safety, Schoolhouse of Public Health, Fudan University, Shanghai, Communist china
³Department of Nutrition, Harvard T.H. Chan School of Public Wellness, Boston, MA, U.s.
⁴Department of Epidemiology and Biostatistics, and Ministry of Education Central Laboratory of Environment and Wellness, and Land Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong Academy of Science and Technology, Wuhan, Communist china
^fiveDepartment of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, United states
⁶Division of Food Sciences and Nutrition, School of Applied Health Sciences and Wellness, and Diabetes Plant, Ohio University, Athens, OH, USA
⁷Department of Preventive Medicine and Public Wellness, School of Medicine, Universidad Autonoma de Madrid, Madrid, Espana
^eightDepartment of Epidemiology, Harvard T.H. Chan Schoolhouse of Public Health, Boston, MA, USA
⁹Channing Partitioning of Network Medicine, Department of Medicine, Brigham and Women'south Infirmary, Harvard Medical Schoolhouse, Boston, MA, USA

Correspondence to: F B Hu, Department of Nutrition, Harvard T.H. Chan Schoolhouse of Public Health, Boston, MA 02115, United states of america fhu{at}hsph.harvard.edu

Accustomed 25 Apr 2019

Abstract

Objective To evaluate the association of changes in red meat consumption with total and cause specific mortality in women and men.

Design Two prospective cohort studies with repeated measures of diet and lifestyle factors.

Setting Nurses' Health Study and the Health Professionals Follow-upwardly Study, United states of america.

Participants 53 553 women and 27 916 men without cardiovascular disease or cancer at baseline.

Master outcome measure Death confirmed by land vital statistics records, the national death alphabetize, or reported by families and the postal organization.

Results xiv 019 deaths occurred during ane.two 1000000 person years of follow-up. Increases in red meat consumption over eight years were associated with a higher mortality risk in the subsequent eight years amid women and men (both P for tendency<0.05, P for heterogeneity=0.97). An increase in total red meat consumption of at least half a serving per day was associated with a x% higher mortality chance (pooled take a chance ratio 1.10, 95% confidence interval one.04 to 1.17). For candy and unprocessed red meat consumption, an increment of at to the lowest degree half a serving per twenty-four hours was associated with a 13% higher mortality risk (one.13, one.04 to 1.23) and a 9% higher bloodshed run a risk (1.09, 1.02 to 1.17), respectively. A decrease in consumption of candy or unprocessed reddish meat of at least half a serving per day was not associated with bloodshed risk. The clan betwixt increased carmine meat consumption and mortality risk was consistent across subgroups defined by age, concrete activeness, dietary quality, smoking condition, or alcohol consumption.

Decision Increases in red meat consumption, especially candy meat, were associated with higher overall bloodshed rates.

Introduction

A large body of evidence has shown that college red meat consumption, especially processed ruby meat, is associated with an increased risk of blazon 2 diabetes,1 cardiovascular disease,two certain types of cancer, including colorectal cancer,3 and mortality.45 Consumption of processed red meat (eg, salary, hot dogs, and sausages) has been associated with additional wellness outcomes, including chronic obstructive pulmonary disease,6 center failure,seven and hypertension.viii Components of carmine and processed meats such as proatherosclerotic lipids (eg, saturated fatty),9 potential carcinogens (eg, polycyclic aromatic hydrocarbons),ten sodium, and preservatives could contribute to adverse wellness outcomes.

Red meat is a major component of dietary patterns in Western populations. The boilerplate consumption of red meat in the United States has decreased in contempo decades, only information technology remains more than twice the global average.11 Several epidemiological studies have analyzed the relation between cherry meat consumption and mortality risk. In this written report, we examined whether changes in red meat intake are associated with subsequent gamble of total and crusade specific mortality.

We analyzed the association of changes in red meat consumption over eight years with mortality hazard during the subsequent eight years. Participants were US women from the Nurses' Health Study and US men from the Health Professionals Follow-up Study. The Dietary Guidelines for Americans 2015-2020 include the recommendation: "Strategies to increase the variety of protein foods include incorporating seafood as the poly peptide foods selection in meals . . . and using legumes or nuts and seeds in mixed dishes instead of some meat or poultry."12 Therefore, we used statistical models to estimate the effects of replacing crimson meat with equivalent amounts of other protein sources, such as nuts, poultry, fish, dairy, eggs, and legumes, and whole grains and vegetables.

Methods

Study population

The Nurses' Health Study is a prospective cohort report of 121 700 US registered female nurses aged 30-55 at enrollment. The study started in 1976 and nurses completed a baseline questionnaire near demographic factors, diet habits, lifestyle, and medical history. The Wellness Professionals Follow-up Study was established in 1986 when 51 529 U.s. male wellness professionals anile 40-75 returned a baseline questionnaire about detailed medical history, lifestyle, and usual diet. In both cohorts, questionnaires were completed biennially after baseline to collect and update information on lifestyle and occurrence of new onset diseases. The follow-upwards rates were approximately 90% for both cohorts. Detailed descriptions of the cohorts have been published elsewhere.1314

The baseline of the current analysis was ready as 1994, which is viii years subsequently 1986 when detailed information on diet, concrete activity, and other lifestyle factors was nerveless for both cohorts. The terminate of follow-up was 2010. We excluded participants who had a history of heart disease, stroke or cancer, missing data on diet and lifestyle covariates, farthermost free energy intake (men: <800 or >4200 kcal/day; women: <500 or >3500 kcal/solar day; 1 kcal=four.18 kJ=0.00418 MJ), or those who died before baseline (that is, 1994). The final analysis included 53 553 women and 27 916 men.

Dietary cess

The ii cohorts completed a validated semiquantitative food frequency questionnaire in 1986 and every iv years thereafter. Participants were asked how often, on average, they consumed a standard portion of each food in the past year. Frequency response categories ranged from never or less than once a calendar month, to six or more than times each twenty-four hours. Questionnaire items on unprocessed cerise meat (one serving, 85 g) included beef, pork, and lamb every bit a main dish; hamburger; and beef, pork, or lamb equally a sandwich or mixed dish. Items on processed blood-red meat included bacon (one serving, ii slices, 13 grand), hot dogs (ane serving, one hot dog, 45 g), and sausage, salami, bologna, and other processed red meats (one serving, ane slice, 28 k). Total red meat included unprocessed and candy red meat. The reproducibility and validity of the nutrient frequency questionnaire take been described elsewhere151617 and evidence good correlations with several weeks of food records.16 For the Health Professionals Follow-up Study, the corrected correlation coefficients between the food frequency questionnaire and multiple dietary records were 0.59 for unprocessed red meat and 0.52 for processed red meat18; we observed like correlations for the Nurses' Health Written report.xvi In a subcohort of the Nurses' Health Study (n=3690), higher ruby-red meat consumption was associated with unfavorable plasma concentrations of inflammatory and glucose metabolic biomarkers.19 In the electric current study, we calculated a modified diet score of the alternative healthy eating index to assess overall nutrition quality after removing the cerise meat components.17

Ascertainment of mortality

Expiry from any cause was the primary outcome of this analysis. We identified deaths by using the state vital statistics records, the national death index, reports by families, and the postal system.xx Using these methods, we ascertained 98% of deaths in each cohort.xx We sought death certificates for all deaths, and when appropriate, requested permission from the next of kin to review medical records. A physician reviewed decease certificates and medical records and determined the underlying cause of expiry according to the ICD-8 and ICD-nine (international classification of diseases, eighth and ninth revisions). We grouped causes of death into 6 major categories (supplementary table 1).

Covariates measurement

Information on potential confounders was assessed and updated biennially. These confounders included age, race, family unit history of myocardial infarction, diabetes or cancer, weight, smoking status, aspirin use, multivitamin use, menopausal status and postmenopausal hormone therapy use for women, physical action, and doc diagnosed hypertension, diabetes, or hypercholesterolemia. Alcohol consumption was assessed and updated from the food frequency questionnaire every four years. Tiptop and weight were used to calculate body mass index. Detailed descriptions of the validity and reproducibility of self reported body weight, concrete activity, and alcohol consumption have been published elsewhere.212223

Statistical assay

We calculated the follow-up person years from the date of returning the 1994 questionnaire to the date of death or the stop of follow-up, whichever came starting time. Updated eight yr change in red meat consumption was used as the time varying exposure. Nosotros used time dependent Cox proportional hazards regression to gauge the run a risk ratios and 95% confidence intervals of total and cause specific mortality in the subsequent eight years; that is, changes in red meat consumption between 1986 and 1994 predicted mortality in 1994-2002, and changes in red meat consumption between 1994 and 2002 predicted mortality in 2002-ten. Nosotros divided participants into v categories based on their changes in red meat consumption: 2 increment categories (increase of >0.5 serving per mean solar day or 3.5 servings per week; increase of 0.15-0.5 serving per day or ane-3.5 servings per week); two decrease categories (decrease of >0.five serving per day or iii.5 servings per calendar week; decrease of 0.15-0.five serving per day or one-three.5 servings per week), and 1 reference category (increase or subtract of <0.15 serving per day or <1 serving per week). We also calculated hazard ratios and the corresponding 95% confidence intervals for changes in ruddy meat consumption.

We adjusted multivariable models for initial age, calendar yr as the underlying fourth dimension scale, race (white 5 other), family history of myocardial infarction, diabetes, or cancer (yes v no), initial aspirin use (yep v no), and initial multivitamin employ (yes v no). Nosotros besides adjusted for initial consumption of cherry-red meat (in fifths); torso mass index categories (<23, 23-24.9, 25-29.9, xxx-34.9, and ≥35); menopausal condition and hormone therapy use in women (premenopausal, postmenopausal and hormone therapy never user, postmenopausal and hormone therapy current user, postmenopausal and hormone therapy past user, or missing indicator); simultaneous changes in smoking status (never to never, never to electric current, former to former, former to current, current to former, current to current, or missing indicator); initial and simultaneous changes in physical activity, alcohol consumption, total energy intake, and other primary food groups, including vegetables, fruits, whole grains, and saccharide-sweetened beverages (all in fifths). In an additional model, we farther adjusted for initial history of hypertension, hypercholesterolemia, or diabetes (all yep five no), and simultaneous weight alter (in fifths), which were potential mediators of the association betwixt cerise meat changes and mortality. Unprocessed and processed red meat changes were also estimated separately. Stratified analyses were performed a priori by treating total cerise meat change as a continuous variable according to initial age, body mass index, smoking condition, physical activeness, alcohol consumption, and modified alternative healthy eating alphabetize. The significance of the interaction terms was tested past including cross product terms for each category and change in red meat consumption in the multivariable models.

We also examined the risk of death associated with a decrease in reddish meat by i serving per day and a simultaneous increment of 1 serving per 24-hour interval of poultry (no pare), fish, dairy products, eggs, legumes, nuts, whole grains, or vegetables (no legumes). We included concurrent changes in all these nutrient sources, in addition to crimson meat, in the same multivariable model. The difference in the β coefficients for change in scarlet meat and change in the alternative food was used to guess the gamble ratio; the corresponding variances and covariance were used to estimate 95% confidence intervals.24

In secondary analyses, we estimated short term (4 yr) and long term (12 year) changes in red meat consumption for associations with full mortality (iv yr change in red meat consumption predicted 4 yr follow-up, and 12 yr change in red meat consumption predicted 12 twelvemonth follow-up). Nosotros also modeled associations of a decrease of one serving per day of red meat substituted with an alternative food over four years with total mortality in the subsequent four years, and the aforementioned exchange over 12 years with total mortality in the subsequent 12 years.

We calculated gamble ratios and 95% conviction intervals from the unlike models separately for each cohort, and and then we pooled the results by using an inverse variance weighted meta-analysis with the fixed effects model. Analyses were performed with SAS version ix.4 for UNIX (SAS Institute, Cary, NC). Statistical tests were two sided and a P value less than 0.05 was considered statistically pregnant.

Patient and public involvement

No patients were involved in setting the inquiry question or the consequence measures, nor were they involved in the design and implementation of the report. No plans exist to involve patients in broadcasting.

Results

In the Nurses' Health Study, nosotros identified 8426 deaths during the follow-up (804 685 person years): 1774 deaths from cardiovascular affliction, 3138 from cancer, 939 from neurodegenerative diseases, 751 from respiratory diseases, and 1824 from other causes. In the Wellness Professionals Follow-up Study, nosotros identified 5593 deaths during follow-up (409 073 person years): 1754 deaths from cardiovascular disease, 1754 from cancer, 434 from respiratory diseases, 375 from neurodegenerative diseases, and 1276 from other causes.

Tabular array 1 shows scarlet meat consumption from 1986 to 2006. Full cherry meat consumption (mean serving per day) decreased from 1.05 to 0.74 in women, and from 1.14 to 1.03 in men. Processed meat consumption decreased from 0.thirty to 0.21 (from approximately 9 to six thou/day) in women, and remained at about 0.35 (approximately x g/day) in men. Unprocessed meat consumption decreased from 0.76 to 0.53 (from approximately 65 to 44 one thousand/mean solar day) in women, and from 0.78 to 0.69 (from approximately 66 to 59 g/day) in men.

Table 1

Consumption of carmine meat in Nurses' Wellness Study and Wellness Professionals Follow-up Study (1986-2006). Data are hateful (standard deviation) serving/day

Table ii shows distributions of lifestyle characteristics in 1994 based on 8 year (1986-1994) changes in total crimson meat consumption. During this period, more women and men decreased red meat consumption than participants who increased consumption. Compared with the participants with a relatively stable consumption of red meat, those who increased or decreased consumption were more probable to have started with a less good for you nutrition consisting of a higher intake of energy and booze; they were besides more likely to be less physically active, have a higher body mass alphabetize, and exist electric current smokers. Participants who decreased their consumption of red meat were more than probable to have hypercholesterolemia. Nosotros found that consumption of red meat changed in the aforementioned management every bit changes in daily energy intake, and in the reverse direction to changes in dietary quality score.

Table 2

Age adapted characteristics based on eight year changes (1986-1994) in total red meat consumption in Nurses' Health Study and Wellness Professionals Follow-up Study. Values are ways (standard deviations) unless stated otherwise

Table 3 shows associations of changes in cerise meat consumption with total mortality across categories of total cerise meat, processed meat, and unprocessed meat. In the age adjusted model of pooled women and men, an increase in carmine meat consumption was associated with a higher run a risk of expiry, while a decrease in blood-red meat consumption was related to a lower risk of death. Farther adjustment of initial traditional run a risk factors, initial and concurrent changes in lifestyle, calorie intake, and other food consumption did non substantially change the results for increased consumption (when consumption was increased by more than half a serving per day, pooled chance ratio 1.x, 95% confidence interval ane.04 to i.17). Still, the initially observed association for decreased consumption was no longer axiomatic after multivariable adjustment (when consumption was decreased past more than half a serving per 24-hour interval, pooled hazard ratio 0.97, 95% confidence interval 0.91 to 1.03). The magnitudes of associations were consistent among women and men (P for heterogeneity=0.97).

Tabular array three

Overall eight twelvemonth hazard ratios (95% conviction intervals) for mortality risk according to updated 8 year change in total reddish meat consumption in Nurses' Health Study and Health Professionals Follow-up Study (1986-2010)

Changes in candy meat and unprocessed meat were significantly associated with mortality (both pooled P for tendency<0.05), and such associations were mainly driven past the increased consumption (tabular array 3). Nosotros found that changes in processed meat consumption had a stronger association with mortality than changes in unprocessed meat consumption (table three). Further adjustment for hypertension, diabetes, and hypercholesterolemia, and concurrent weight modify did non substantially modify the results (supplementary table 2). When nosotros adapted the model for socioeconomic condition represented past the educational attainment of the nurses and their husbands, the results in the Nurses' Health Study did non change (data non shown).

Associations of four yr and 12 yr changes in consumption of total cherry-red meat, candy meat, and unprocessed meat with total mortality (four year and 12 year chance of expiry, respectively) were in full general similar to the results from the viii year analysis (supplementary tables iii and 4, respectively). In the pooled results for women and men, an increase of more than half a serving per solar day of cerise meat over four years was associated with a 20% higher bloodshed risk in the subsequent four years (pooled hazard ratio 1.20, 95% confidence interval 1.13 to 1.27); and an increase of more than than half a serving per day of red meat over 12 years was associated with a 12% higher mortality risk in the subsequent 12 years (1.12, one.03 to 1.22). However, a subtract in cherry-red meat consumption was non associated with bloodshed in whatsoever of the analyses.

The association of changes in red meat consumption with mortality was consequent across participants, irrespective of age, physical activity level, dietary quality, smoking condition, or booze consumption (fig ane). Among normal weight participants, an increment in one serving per day of red meat over eight years was associated with a thirteen% higher chance of death (pooled hazard ratio 1.13, 95% conviction interval one.06 to ane.20). All the same, among participants who were overweight or obese, the respective increased risk was lower (i.06, one.01 to i.13, pooled P for interaction=0.02; fig 1). This interaction was significant in women only (P for interaction=0.03; fig ane).

Fig 1

Fig i

Gamble ratios (95% confidence intervals) for all cause mortality associated with an increase in red meat consumption of one serving per day over 8 years according to characteristics of participants. Cox proportional hazards models were adjusted for initial historic period (years); race (white v other); family history of myocardial infarction, diabetes, or cancer (aye v no); initial aspirin use (yeah five no) and multivitamin apply (yes v no); initial consumption of red meat (in fifths); body mass index categories (<23, 23-24.9, 25-29.9, 30-34.9, and ≥35); menopausal status and hormone therapy use in women (premenopausal, postmenopausal and hormone therapy never user, postmenopausal and hormone therapy current user, postmenopausal and hormone therapy past user, or missing indicator); simultaneous changes in smoking status (never to never, never to current, former to former, former to electric current, current to sometime, electric current to current, or missing indicator); initial and simultaneous changes in physical activity, booze intake, total energy intake, and other main food groups, including vegetables, fruits, whole grains, and sugar-sweetened beverages (all in fifths). P for interaction was calculated using the likelihood ratio test. The cutting-off point of physical activity was defined equally 150 min/week at a moderate level or at to the lowest degree 75 min/week at a vigorous level (equivalent to at to the lowest degree nine MET hours/week) as recommended.25 Moderate alcohol consumption was defined as equivalent to fourteen yard/day in women and 28 g/solar day in men; alternative healthy eating index college or equal to versus lower than median in each cohort. MET=metabolic equivalent of job

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In multivariable analyses, an eight year alter in red meat consumption as a continuous variable showed a trend of direct associations with the subsequent viii yr adventure of full mortality and most causes of decease amid women and men (supplementary fig 1). In the pooled meta-analysis of women and men, an increase of one serving per solar day of total red meat was associated with a 9% college risk of all crusade mortality (pooled hazard ratio 1.09, 95% confidence interval 1.04 to i.13); an increase of one serving per day of processed meat and unprocessed meat was associated with a 17% and five% higher take chances of all crusade death, respectively (processed meat: pooled hazard ratio ane.17, 95% confidence interval ane.08 to i.26; unprocessed meat: 1.05, 1.00 to 1.eleven). We observed significant positive associations of changes in red meat with deaths from cardiovascular illness and respiratory disease. In particular, an increase of i serving per 24-hour interval of processed meat over eight years was associated with a 19% college risk of expiry from cardiovascular disease (i.19, one.03 to one.38) and a 57% college risk of death from neurodegenerative disease (ane.57, i.21 to 2.03) in the subsequent eight years. Associations of changes in unprocessed meat consumption with death from specific causes were weaker and non-significant in general (except for death from respiratory disease or other disease) compared with changes in processed meat consumption.

Table 4 shows the eight year all cause mortality associated with a decrease of one serving per day of red meat consumption and a simultaneous increase of one serving per twenty-four hour period of another major dietary protein source, whole grains, or vegetables over the previous viii years. Overall, we constitute a decrease in red meat and an increment in whole grains, vegetables, or other protein sources was associated with a lower take a chance of expiry among women and men. The pooled results showed a substantially lower mortality risk with a decrease in cerise meat consumption and a simultaneous increase in the consumption of nuts (pooled risk ratio 0.81, 95% CI 0.79 to 0.84); fish (0.83, 0.76 to 0.91); whole grains (0.88, 0.83 to 0.94); poultry without skin (0.ninety, 0.86 to 0.95); vegetables without legumes (0.90, 0.87 to 0.93); dairy (0.92, 0.86 to 0.99); eggs (0.92, 0.89 to 0.96); or legumes (0.94, 0.90 to 0.99). A subtract in processed meat and a simultaneous increase in whole grains, vegetables, or other protein sources was fifty-fifty more strongly associated with lower total bloodshed, with the largest reductions in run a risk seen with increases in nuts (0.74, 0.70 to 0.79) and fish (0.75, 0.68 to 0.84). We found that a subtract in unprocessed ruddy meat and a simultaneous increase in other protein sources except for legumes, whole grains, vegetables, or dairy was as well associated with a substantially lower take a chance of expiry. Supplementary tabular array v shows the associations of changes in all the above food groups including red meat with eight year mortality in the replacement modeling analyses. Nosotros found similar results with changes over 4 and 12 years (supplementary tables 6 and 7).

Tabular array 4

Statistical model based hazard ratios (95% conviction intervals) for viii yr all cause bloodshed associated with subtract of ane serving per solar day of cherry meat and simultaneous increase of one serving per day of another major dietary protein source, whole grains, or vegetables over an eight year follow-up in Nurses' Wellness Study and Health Professionals Follow-upwardly Study

Discussion

In two large prospective cohorts of United states of america women and men, we found an increase in red meat consumption over viii years was directly associated with risk of death during the subsequent eight years, and was contained of initial red meat intake and concurrent changes in lifestyle factors. This clan with mortality was observed with increased consumption of processed and unprocessed meat, but was stronger for candy meat. A decrease in total red meat consumption and a simultaneous increase in the consumption of nuts, fish, poultry without peel, dairy, eggs, whole grains, or vegetables over 8 years was associated with a lower gamble of death in the subsequent eight years. These findings suggest that a change in protein source or eating salubrious plant based foods such as vegetables or whole grains tin can improve longevity. We also observed the same associations with bloodshed and replacement foods in shorter term (four yr) and longer term (12 yr) studies.

Strengths and weaknesses in relation to other studies

Systematic reviews and meta-analyses of prospective cohort studies accept indicated an adverse association of consumption of cherry-red meat, in particular processed meat, with mortality.2627 For example, a recent meta-analysis that summarized 17 prospective cohorts suggested that full red meat consumption was statistically significantly associated with increased risk of expiry, and this take chances was by and large because of processed meat.27 One serving of processed meat per day was associated with a 15% higher take a chance of all crusade mortality (hazard ratio 1.15, 95% confidence interval i.11 to i.19), a 15% higher take a chance of cardiovascular expiry (1.xv, 1.07 to 1.24), and an 8% college gamble of cancer death (one.08, i.06 to 1.11); like results were shown for total cherry meat consumption. Unprocessed meat consumption was only associated with mortality in the US populations, simply non in European or Asian populations.27 A contempo Japanese report did not find any strong association between red meat consumption and cardiovascular illness death.28 Still, the consumption level was much lower in the Japanese population than in our cohorts. Also, the Japanese written report did not examine changes in cherry-red meat intake and subsequent mortality take a chance. Our previous analysis in the same cohorts indicated that a higher consumption of red meat was associated with an increased risk of all cause, cardiovascular, and cancer mortality.29 However, none of these studies considered changes in consumption of red meat. Because people's eating behaviors change over time, it is of import to examine whether changes in cherry meat intake influence subsequent wellness outcomes. Our current findings are consistent with previous evidence and extend the results. We have shown that short, medium, and long term changes in consumption of ruby meat, processed meat, and unprocessed meat were all directly associated with mortality, irrespective of the initial consumption level. Our observation of an interaction betwixt initial body mass index and mortality is consistent with a previous report of an interaction betwixt initial torso mass index and take chances of blazon 2 diabetes.30 The pre-existing higher risk of death among people who are overweight or obese could partially account for the relatively small-scale increased risk later on higher red meat consumption compared with that for people of normal weight. Even so, the subgroup analysis results demand to exist interpreted with caution because these findings might be due to chance.

Within a relatively fixed daily calorie intake, changes of cerise meat consumption will be accompanied by changes in other foods, typically protein sources. Previous modeling analyses in our cohorts institute that intake of fish, poultry, basics, legumes, or depression fat dairy was associated with a lower risk of total mortality compared with consumption of red meat.29 In the current data based modeling investigation, we establish that a decrease in cerise meat consumption at the population level and a simultaneous increase in other protein sources, whole grains, or vegetables was statistically significantly associated with a lower bloodshed risk. For example, we observed that a subtract of one serving per mean solar day of reddish meat and an increment of ane serving per twenty-four hours of fish over eight years was related to a 17% lower risk of decease in the subsequent eight years. In exercise, crimson meat tin exist replaced by a mixture of healthier protein sources and establish foods with less protein, such every bit vegetables and whole grains.

Possible explanations and implications

An agin effect of reddish meat consumption on run a risk of death could be attributable to a combination of factors that promote cardiometabolic disturbances. Saturated fat, cholesterol, and heme iron in red meat could accelerate atherosclerotic processes and affect the incidence and prognosis of hypertension, hypercholesterolemia, endothelial dysfunction, insulin resistance, and type 2 diabetes.3132 Because of its high content of saturated fat and cholesterol, randomized controlled trials have shown that consumption of ruddy meat increases low density lipoprotein cholesterol compared with plant sources of protein, such as nuts, soy foods, and other legumes.33 Besides, the high content of sodium in processed meat is a strong adventure factor for hypertension and vascular stiffness, which might increment bloodshed caused by stroke, myocardial infarction, arterial stiffening, heart failure, and renal insufficiency.34 Recent studies have suggested that L carnitine and phosphatidylcholine in cerise meat and gut microbiota derived metabolite trimethylamine N oxide might promote atherosclerosis.3536 Additionally, cooked red meat is a source of carcinogens, such every bit polycyclic aromatic hydrocarbons and heterocyclic amines, which may contribute to cancer take chances.ten Processed meat appears to be more carcinogenic than unprocessed meat, peradventure owing to the abundance of strong nitrosyl heme molecules that course North nitroso compounds.ten In our written report, the lack of a stiff association between the changes in blood-red meat consumption and cancer decease could partially exist explained by the long latency of tumorigenesis and the heterogeneity of different types of cancer.

The observed association of increased crimson meat consumption with higher mortality from respiratory disease is consistent with previous reports,37 and the formation of reactive nitrogen species could exist 1 major correspondent.38 In our cohorts, the leading causes of neurodegenerative deaths were dementia (more common in women) and Parkinson's illness (more common in men because female hormones might exist neuroprotective against dopamine loss while male hormones are not39). Processed red meat might be associated with a higher hazard of dementia because of the high content of saturated and trans fatty acids and the low content of unsaturated fat acids, which could lead to claret brain barrier dysfunction and an increase in amyloid β aggregation.4041 Processed red meat is also reported to be inversely associated with Parkinson's disease risk through niacin, a vitamin related to nicotinamide metabolism.4243 These mechanisms could partially explicate the association between increased processed meat consumption and higher mortality from neurodegenerative disease in women (722 deaths from dementia and 122 from Parkinson's disease), but not in men (153 deaths from dementia and 172 from Parkinson's illness). Our results on neurodegenerative mortality warrant farther investigations because of the express statistical ability.

Strengths and weaknesses of this study

In the current study, we used observational data to investigate associations with bloodshed, and thus causality cannot be necessarily assumed. Nevertheless, the advantage of long term follow-upward periods and private food changes over several years owing to repeated dietary measures means that our "change to risk" analytical arroyo partly mimics an interventional trial; in an interventional trial, investigators allocate groups to increase, subtract, or keep stable crimson meat consumption. Moreover, our "change replace change" substitution analysis imitates flexible intervention arms, and therefore nosotros are able to provide practical recommendations on optimizing nutrient sources to the general public. The results of this change analysis can help to strengthen the causal inference compared with the traditional "baseline to risk" analysis because this type of analysis at to the lowest degree partially accounts for the innate characteristics of participants. The results of our short term (four years), medium term (eight years), and long term (12 years) analyses provide a applied message to the general public of how dynamic changes in cerise meat consumption are associated with health. Other strengths include big report populations, loftier rates of long term follow-upwards, repeated assessment of diet and lifestyle factors, and consistency of the results between the two cohorts.

Our analysis has several limitations. Because of the observational nature of the study, we cannot automatically assume the causality of the observed relations. In particular, residual misreckoning cannot be completely excluded, although nosotros controlled detailed assessments of demographic and lifestyle factors in the current analyses. Nosotros did non appraise the reasons for changes in scarlet meat consumption and this could confound the observed associations. For example, the development of latent or active diseases during the corresponding years when the alter of ruby meat occurred would bias the favorable association of a decrease in consumption of red meat with mortality towards the nothing or fifty-fifty an adverse association. Nevertheless, our results showed a consistent trend of favorable associations of a subtract in consumption of ruby-red meat in women and men.

Our study participants mainly consisted of white registered nurses and health professionals. The relative homogeneity of socioeconomic condition tin help to reduce confounding by socioeconomic status, merely it might limit the generalizability of the results to other populations. Nonetheless, previous studies have shown a direct association of cerise meat and processed meat intake with bloodshed take a chance in other populations.4445 The replacement analysis is a statistical modeling strategy that used information beyond the whole population, without identifying people in the cohort population who actually replaced ruby-red meat with the other food groups. Therefore, our results from replacement assay should exist interpreted with caution in the context of statistical modeling, especially when making individualized recommendations.

Conclusion

Increases in red meat consumption, peculiarly processed meat, over viii years were associated with a higher risk of death in the subsequent eight years in US women and men. Increased consumption of healthier animal or found foods was associated with a lower risk of death compared with crimson meat consumption. Our analysis provides further bear witness to back up the replacement of scarlet and processed meat consumption with healthy alternative nutrient choices.

What is already known on this topic

College consumption of crimson meat has been associated with an increased risk of chronic diseases and premature expiry
Show is lacking about how changes in red meat consumption over time influence bloodshed, or what kind of culling nutrient choices would benefit wellness

What this study adds

Increases in ruddy meat consumption, specially candy meat, were associated with a higher risk of decease
Decreases in red meat consumption and simultaneous increases in healthy alternative food choices over fourth dimension were associated with a lower mortality run a risk
Further evidence supports the health benefits of replacing cerise and candy meat consumption with good for you protein sources, whole grains, or vegetables

Acknowledgments

We thank the participants and staff of the Nurses' Wellness Report and the Health Professionals Follow-upwards Written report for their valuable contributions, and several state cancer registries for their assistance: AL, AZ, AR, CA, CO, CT, DE, FL, GA, ID, IL, IN, IA, KY, LA, ME, MD, MA, MI, NE, NH, NJ, NY, NC, ND, OH, OK, OR, PA, RI, SC, TN, TX, VA, WA, WY. The authors assume full responsibility for analyses and interpretation of these information.

Footnotes

Contributors: YZ and FBH had the idea for the study. YZ did the data analysis. YL, AP, MSP, and FBH provided statistical expertise. YZ wrote the first typhoon of the paper. WCW, ER, and FBH obtained funding. All authors contributed to the interpretation of the results and critical revision of the manuscript for important intellectual content, and approved the final version of the manuscript. YZ and FBH are the guarantors. The corresponding author attests that all listed authors run into authorship criteria and that no others meeting the criteria have been omitted.
Funding: The cohorts were supported by grants UM1 CA186107 and UM1 CA167552 from the National Institutes of Health. The current study was supported by grants from the National Heart, Lung, and Blood Found (HL071981, HL034594, HL60712, HL126024), the National Institute of Diabetes and Digestive and Kidney Diseases (DK091718, DK100383, DK112940, DK078616), the Boston Obesity Nutrition Research Center (DK46200). The sources of funding had no role in the design, deport, analysis, or reporting of this study. YZ was supported by a fellowship from the American Diabetes Clan (seven-12-MN-34) and the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning. The funding sources did non participate in the blueprint or bear of the report; drove, management, analysis or interpretation of the data; or preparation, review, or approval of the manuscript.
Competing interests: All authors have completed the ICMJE compatible disclosure form at www.icmje.org/coi_disclosure.pdf and declare: support from the National Institutes of Wellness; National Heart, Lung, and Blood Institute; National Institute of Diabetes and Digestive and Kidney Diseases; and the Boston Obesity Nutrition Enquiry Center for the submitted work; support from the FBH reported being supported past grants HL60712, HL118264, and DK112940 from the National Institutes of Health, and reported receiving research support from the California Walnut Commission and honorariums for lectures from Metagenics and Standard Process and honorariums from Diet Quality Photo Navigation, outside the submitted piece of work.
Ethical approval: The Nurses' Wellness Study and the Wellness Professionals Follow-up Written report were approved by the institutional review boards at Brigham and Women'south Hospital and Harvard T H Chan School of Public Wellness. The render of the completed self administered questionnaire was considered to imply informed consent.
Data sharing: No additional data available.
Transparency: The lead writer (YZ) affirms that the manuscript is an honest, authentic, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study every bit planned have been explained.

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Source: https://www.bmj.com/content/365/bmj.l2110