A newly published article in JAMA Internal Medicine has investigated the relationship between (animal vs. plant) protein sources and mortality risk from almost 30 years of follow-up from the Nurses’ Health Study and Health Professionals Follow-up Study, which together included over 170,000 participants.
Interesting findings came out of one particular question the researchers asked: What would happen if the participants replaced some of their animal protein with plant protein?
They analyzed the data to estimate how participants’ risk of death from all causes over the follow-up period would change if some of the animal protein sources (equivalent to 3 percent of total daily calories) were replaced with plant protein sources:
- Replace processed red meat: 34 percent decrease in risk
- Replace unprocessed red meat: 12 percent decrease in risk
- Replace poultry: 6 percent decrease in risk
- Replace fish: 6 percent decrease in risk
- Replace eggs: 19 percent decrease in risk
- Replace dairy: 8 percent decrease in risk1
What’s wrong with animal protein sources?
- Animal protein elevates IGF-1, which is linked to increased cancer risk.2-4
- Carnitine and choline from meat and eggs are converted by gut bacteria to TMAO — a pro-inflammatory compound that promotes cardiovascular disease.5,6
- Heme iron in excess is an oxidant that contributes to cardiovascular disease and Alzheimer’s disease.7Arachidonic acid promotes inflammation, which may increase cancer risk.8
- Carcinogenic compounds: Heterocyclic amines, polycyclic aromatic hydrocarbons, and N-nitroso compounds (mostly processed meats).9 Higher animal protein intake promotes weight gain. 10,11 In fact, a recent study compared meat availability, sugar availability, and obesity rates in different countries, and found that sugar and meat had similar correlations to obesity rates. This result suggests that availability of meat contributes to obesity just as much as availability of sugar.12
This is the latest of many studies to link greater meat consumption to a greater risk of death.13-15 In contrast, plant protein sources are associated with better health: for example, seeds and nuts reduce the risk of cardiovascular disease and are linked to longevity, and micronutrient and fiber-rich beans are linked to improved blood pressure, LDL cholesterol, body weight, insulin sensitivity and enhanced lifespan.16-20
- Song M, Fung TT, Hu FB, et al: Association of Animal and Plant Protein Intake With All-Cause and Cause-Specific Mortality. JAMA Intern Med 2016.
- Levine ME, Suarez JA, Brandhorst S, et al: Low Protein Intake Is Associated with a Major Reduction in IGF-1, Cancer, and Overall Mortality in the 65 and Younger but Not Older Population. Cell Metab 2014;19:407-417.
- Key TJ, Appleby PN, Reeves GK, et al: Insulin-like growth factor 1 (IGF1), IGF binding protein 3 (IGFBP3), and breast cancer risk: pooled individual data analysis of 17 prospective studies. The lancet oncology 2010;11:530-542.
- Rowlands MA, Gunnell D, Harris R, et al: Circulating insulin-like growth factor peptides and prostate cancer risk: a systematic review and meta-analysis. Int J Cancer 2009;124:2416-2429.
- Koeth RA, Wang Z, Levison BS, et al: Intestinal microbiota metabolism of l-carnitine, a nutrient in red meat, promotes atherosclerosis. Nat Med 2013.
- Tang WH, Wang Z, Levison BS, et al: Intestinal microbial metabolism of phosphatidylcholine and cardiovascular risk. N Engl J Med 2013;368:1575-1584.
- Brewer GJ: Iron and copper toxicity in diseases of aging, particularly atherosclerosis and Alzheimer's disease. Exp Biol Med 2007;232:323-335.
- de Lorgeril M, Salen P: New insights into the health effects of dietary saturated and omega-6 and omega-3 polyunsaturated fatty acids. BMC Med 2012;10:50.
- National Cancer Institute. Chemicals in Meat Cooked at High Temperatures and Cancer Risk.http://www.cancer.gov/cancertopics/factsheet/Risk/cooked-meats. Accessed July 1, 2014.
- Bujnowski D, Xun P, Daviglus ML, et al: Longitudinal Association between Animal and Vegetable Protein Intake and Obesity among Men in the United States: The Chicago Western Electric Study. J Am Diet Assoc 2011;111:1150-1155 e1151.
- Rosell M, Appleby P, Spencer E, et al: Weight gain over 5 years in 21,966 meat-eating, fish-eating, vegetarian, and vegan men and women in EPIC-Oxford. Int J Obes (Lond) 2006;30:1389-1396.
- You W, Henneberg M: Meat in Modern Diet, Just as Bad as Sugar, Correlates with Worldwide Obesity: An Ecological Analysis. Journal of Nutrition & Food Sciences 2016;6.
- Wang X, Lin X, Ouyang YY, et al: Red and processed meat consumption and mortality: dose-response meta-analysis of prospective cohort studies. Public Health Nutr 2016;19:893-905.
- Pan A, Sun Q, Bernstein AM, et al: Red Meat Consumption and Mortality: Results From 2 Prospective Cohort Studies.Arch Intern Med 2012.
- Sinha R, Cross AJ, Graubard BI, et al: Meat intake and mortality: a prospective study of over half a million people.Arch Intern Med 2009;169:562-571.
- Grosso G, Yang J, Marventano S, et al: Nut consumption on all-cause, cardiovascular, and cancer mortality risk: a systematic review and meta-analysis of epidemiologic studies. Am J Clin Nutr 2015;101:783-793.
- Jenkins DJ, Kendall CW, Augustin LS, et al: Effect of legumes as part of a low glycemic index diet on glycemic control and cardiovascular risk factors in type 2 diabetes mellitus: a randomized controlled trial. Arch Intern Med2012;172:1653-1660.
- Bazzano LA, Thompson AM, Tees MT, et al: Non-soy legume consumption lowers cholesterol levels: a meta-analysis of randomized controlled trials. Nutrition, metabolism, and cardiovascular diseases : NMCD 2011;21:94-103.
- Papanikolaou Y, Fulgoni VL, 3rd: Bean consumption is associated with greater nutrient intake, reduced systolic blood pressure, lower body weight, and a smaller waist circumference in adults: results from the National Health and Nutrition Examination Survey 1999-2002. J Am Coll Nutr 2008;27:569-576.
- Darmadi-Blackberry I, Wahlqvist ML, Kouris-Blazos A, et al: Legumes: the most important dietary predictor of survival in older people of different ethnicities. Asia Pac J Clin Nutr 2004;13:217-220.