I was recently asked about eating lunch meats – thinly sliced turkey or chicken – and turkey bacon, since these are convenient ways to add protein to salads. This is a very good question indeed, and cannot be simply answered without exploring a number of nutritional issues. Nevertheless, my initial approach would be to apply the evolutionary template which clearly indicates our hunter gatherer ancestors would have never consumed processed, cured or canned meats.1 Their staples were the fresh meats, flesh and organs of wild animals along with gathered wild plant foods.2
Common additives to canned, cured and processed meats include:
Salt, corn syrup, high fructose corn syrup, dextrose (glucose), sucrose (table sugar), modified food starch (made from wheat, corn, potatoes, soy, etc. ) sodium lactate, potassium lactate, calcium sulfate, BHA, BHT, citric acid, propyl gallate, silicon dioxide, vinegar, sodium nitrite, sodium nitrate, potassium nitrite, potassium nitrate, sodium tripolyphosphate, hexametaphosphate, acid pyrophosphate, orthophosphates, erythorbate, vitamin C, vitamin E, oleoresins, spices, monosodium glutamate (MSG), sodium diacetate, bromelin, carrageenan, ficin, gelatin, hydrolyzed proteins (wheat, soy, milk), papain, sodium caseinate, dried whey.
Read the labels of most lunch meats, processed meats, canned meats, sausages, salamis and bacon, and you will invariably find numerous additives listed above.
Clearly refined sugars, salt, soy, dairy and cereals added to processed meats are not “Paleo” ingredients. Many other compounds in this list are added to prevent food borne illnesses, bacterial contamination, and spoilage. Prominent in these functions are added nitrites and nitrates.3 We all know that fresh, raw meats rapidly spoil and can cause illness, gastric distress and diarrhea if left unrefrigerated at room temperatures for long periods. So this fact alone should tip you off to potential health hazards associated with consumption of processed meats, which typically don’t spoil at room temperatures because of their chemical additives. If the chemicals in these meats are “bad” for bacteria, they just might be “bad” for our body’s cells as well. Before I get into nitrite and nitrate health concerns, let’s talk about more wide-ranging nutritional issues involving consumption of processed meats.
Unless you can find a supplier who manufactures their processed meats from wild game or grass-fed animals, any processed meat you consume originates mainly from feed lot animals eating virtually nothing but grains (corn primarily) before they are slaughtered. As my research group and I have previously pointed out,4, 5 this practice produces inferior meat with an unnatural fatty acid balance characterized by high omega 6 fatty acids, low omega 3 fatty acids, a low protein content, a high fat content and many other important nutritional shortcomings.6 So, with almost all processed meats, we’ve got a nutritionally inferior product to start with even before it is transformed into hams, bacon, lunch meats, bologna, hot dogs, salamis, sausages, deli meats, canned spam, Vienna sausages, etc.
Feed lot-produced animals whether cattle, hogs, chickens, or turkeys are invariably exposed to pesticides,7, 8 or are deliberately administered antibiotics,9 and hormones;10-12 all of which may ultimately find their way into our food supply. Virtually all feed lot cattle in the U.S. are implanted with estrogenic hormones in their ears to promote rapid growth and weight gain. Although the jury is still out, exposure to these hormones may compromise our health.10-12 Hence, most processed meats should be avoided on at least one level because they are significant dietary sources of pesticides, antibiotics and hormones which have the potential to disrupt our health. In contrast, grass produced or free ranging animals are not fed cereal grains, thereby potentially reducing pesticide exposure. Further, most grass fed animals are never given hormones to increase their growth rate and rarely are routinely administered antibiotics.
Almost all processed meats typically are cooked for long periods, frequently at high temperatures. Cooking meats in this manner produces at least two cancer causing compounds: 1) heterocyclic amines (HCAs) and 2) polycyclic aromatic hydrocarbons (PAHs).13 Further, consumption of cooked, canned and cured meats causes high levels of advanced glycation end products (AGEs) to accumulate in the bloodstream.14 As AGEs build up in higher and higher concentrations in the blood they increase the risk for heart disease,15 cancer16 and inflammation,17 a process that underlies virtually all chronic disease. If these events weren’t enough to make you shy away from eating these adulterated meats, they are also concentrated sources of oxidized cholesterol,18 a potent compound known to promote artery clogging or atherosclerosis.19
One of the original reasons scientists advised us to limit consumption of processed meats was because of their high concentration of nitrites and nitrates. These chemicals are added to salami, lunch meats, bacon, sausages and other processed meats because they inhibit bacteria which cause food borne illnesses while also enhancing the color and flavor of processed meats.20 Many early scientific studies examining dietary nitrites and nitrates suggested that the metabolism of these compounds in our bodies produced potent cancer causing chemical called nitrosamines. Hence, consumers were advised not to eat processed meats containing nitrites or nitrates.20 This viewpoint has been challenged in the past decade by a number of researchers who suggest that dietary nitrites and nitrates are actually protective against cancer, heart disease and other illnesses.20-23 In the body, these compounds are metabolized to nitric oxide, a chemical which promotes cardiovascular health and has many other therapeutic effects.21-23
In the U.S. diet, nitrates and nitrites are not only found as additives in processed meats, but rather their greatest dietary source comes from fresh fruits and vegetables 20, 22 which are protective for cardiovascular disease, cancer and other illnesses. Hence, the available evidence suggests that the cancer causing effects of processed meats stems not from their nitrite or nitrate additives, but rather from HCA, PAH or other chemicals added to them during processing.
The scientific data showing that consumption of processed meats has multiple adverse health effects is persuasive, unambiguous and overwhelming.24, 25 These facts are not surprising when considered in the evolutionary light. Our hunter gatherer ancestors had practically no evolutionary experience with these Johnnie come lately foods, and consequently our physiological and metabolic systems have had virtually no time to overcome these food borne toxins with genetic adaptations. I believe that consumption of fresh, grass produced meats under the context of a diet high in fruits and veggies (i.e. The Paleo Diet) will reduce your risk for all chronic diseases that plague western societies.
- Sebranek JG, Bacus JN. Cured meat products without direct addition of nitrate or nitrite: what are the issues? Meat Sci. 2007 Sep;77(1):136-47
- Cordain L. Nutritional Differences between Grass- and Grain-Fed Beef: Health Implications.
- Corrigan PJ, Seneviratna P. Pesticide residues in Australian meat. Vet Rec. 1989 Aug 19;125(8):180-1.
- Schafer KS, Kegley SE. Persistent toxic chemicals in the US food supply. J Epidemiol Community Health. 2002 Nov;56(11):813-7.
- Marshall BM, Levy SB. Food animals and antimicrobials: impacts on human health. Clin Microbiol Rev. 2011 Oct;24(4):718-33.
- Andersson AM, Skakkebaek NE. Exposure to exogenous estrogens in food: possible impact on human development and health. Endocrinol. 1999 Jun;140(6):477-85.
- Stephany RW. Hormonal growth promoting agents in food producing animals. Handb Exp Pharmacol. 2010;(195):355-67.
- Serratosa J, Blass A, Rigau B, Mongrell B, Rigau T, Tortadès M, Tolosa E, Aguilar C, Ribó O, Balagué J. Residues from veterinary medicinal products, growth promoters and performance enhancers in food-producing animals: a European Union perspective. Rev Sci Tech. 2006 Aug;25(2):637-53.
- Cross AJ, Sinha R. Meat-related mutagens/carcinogens in the etiology of colorectal cancer. Environ Mol Mutagen. 2004;44(1):44-55
- Uribarri J, Woodruff S, Goodman S, Cai W, Chen X, Pyzik R, Yong A, Striker GE, Vlassara H. Advanced glycation end products in foods and a practical guide to their reduction in the diet. J Am Diet Assoc. 2010 Jun;110(6):911-16
- Nin JW, Jorsal A, Ferreira I, Schalkwijk CG, Prins MH, Parving HH, Tarnow L, Rossing P, Stehouwer CD. Higher plasma levels of advanced glycation end products are associated with incident cardiovascular disease and all-cause mortality in type 1 diabetes: a 12-year follow-up study. Diabetes Care. 2011 Feb;34(2):442-7.
- Abe R, Yamagishi S. AGE-RAGE system and carcinogenesis. Curr Pharm Des. 2008;14(10):940-5
- Bengmark S. Advanced glycation and lipoxidation end products–amplifiers of inflammation: the role of food. JPEN J Parenter Enteral Nutr. 2007 Sep-Oct;31(5):430-40.
- Savage GP, Dutta PC, Rodriguez-Estrada MT. Cholesterol oxides: their occurrence and methods to prevent their generation in foods. Asia Pac J Clin Nutr. 2002;11(1):72-8.
- Staprans I, Pan XM, Rapp JH, Feingold KR. The role of dietary oxidized cholesterol and oxidized fatty acids in the development of atherosclerosis. Mol Nutr Food Res. 2005 Nov;49(11):1075-82.
- Sindelar JJ, Milkowski AL. Human safety controversies surrounding nitrate and nitrite in the diet. Nitric Oxide. 2012 May 15;26(4):259-66.
- Hord NG. Dietary nitrates, nitrites, and cardiovascular disease. Curr Atheroscler Rep. 2011 Dec;13(6):484-92
- Hord NG, Tang Y, Bryan NS. Food sources of nitrates and nitrites: the physiologic context for potential health benefits. Am J Clin Nutr. 2009 Jul;90(1):1-10
- Machha A, Schechter AN. Dietary nitrite and nitrate: a review of potential mechanisms of cardiovascular benefits. Eur J Nutr. 2011 Aug;50(5):293-303
- Micha R, Wallace SK, Mozaffarian D. Red and processed meat consumption and risk of incident coronary heart disease, stroke, and diabetes mellitus: a systematic review and meta-analysis. Circulation. 2010 Jun 1;121(21):2271-83.
- Larsson SC, Orsini N, Wolk A. Processed meat consumption and stomach cancer risk: a meta-analysis. J Natl Cancer Inst. 2006 Aug 2;98(15):1078-87.