Not all meat is created equal. The way food is grown has a significant impact on its nutritional quality--fruits, vegetables, and animal products alike. When it comes to meat, eggs and dairy, the difference really comes down to what the animal ate. It just so happens that raising livestock on pasture, a more natural habitat than a barn or a feedlot, results in healthier food for humans. (Our animal welfare standards don't dictate outdoor access for every species, but we do believe providing access to lush pasture affords the highest level of animal welfare.) Pasture-raised foods tend to be leaner (thanks to the animal's healthier diet and freedom to exercise), but they also have many other nutritional advantages.
Chickens and Eggs
Like humans, chickens are omnivorous; their natural diet consists of animal and plant foods. (The "vegetarian-fed" label often found on egg cartons isn't necessarily a good thing.) Chickens raised in CAFOs (concentrated animal feeding operations) may receive an omnivorous diet in the form of animal by-products (such as feather meal, bone meal, and processed animal waste), but it's hardly the ideal dietary regimen for a bird. Raising chickens on pasture enables them to supplement their standard grain ration with foods that are better suited to their biology: vegetation, insects and worms to name a few. It is these enhancements that make pasture-raised chicken and eggs so much more nutrient-dense.
Egg-laying hens at Burns Heritage Farm
Compared to conventional, meat from pastured chickens has twice the omega-3 fatty acids, four times as much vitamin E, and seven times as much vitamin D3 (1). Eggs from pastured chickens have 38% more vitamin A, twice the vitamin E, and ten times as much omega-3 fatty acids as eggs from conventional chickens (2)(3).
Omega-3 fatty acids are essential, meaning the body cannot synthesize them and must acquire them from external sources. Foods containing essential fatty acids are often measured by their ratio of omega-6's (which are associated with inflammation) to omega-3's (which are prized for their anti-inflammatory properties). We should aim for the lowest possible ratio (1:1) in our diet, in order to prevent inflammation and subsequent chronic disease, but unfortunately, the Western diet exhibits a ratio of 15:1 (4).
Vitamin D3 is the preferred form of vitamin D (crucial for absorption of calcium and phosphorous) because it is more efficacious than D2, the form commonly found in vegetarian vitamin supplements. Vitamin D is also fat-soluble, meaning its absorption rate is optimized when consumed with fat, making pastured eggs and whole milk perfect vehicles for this nutrient.
Vitamin E (the anti-aging and heart-healthy nutrient) is not usually associated with animal foods, despite the fact that they provide a naturally higher absorption rate than many plant sources. This is because vitamin E is fat-soluble, and is best absorbed in the form of eggs, whole milk, and other animal fats.
Beef & Dairy Cattle
Unlike chickens and pigs, cattle do perfectly well without additional feed; in fact, their digestive systems are specifically meant for grass. A cow's four-part stomach includes a rumen, in which resides an entire ecosystem of bacteria that keep the animal healthy. But the bacteria depend on the cellulose in grass to thrive, and the cow depends on the bacteria to thrive. Thus, a cow that survives on grains, animal by-products, and commercial food processing waste (common feeds in cattle CAFOs, especially in industrial dairies) is not in optimal health. A diet of fresh grass, as is achieved by regularly moving the herd to a rested plot of pasture, creates the healthiest cattle, and thus the most nutritious beef and milk.
Grass-fed dairy cattle at Lone Oak Farm
Cattle raised on robustly growing pasture can produce meat that has three times as much CLA (conjugated linoleic acid), seven times as much vitamin A, and five times as much omega-3's as conventionally raised cattle (5). In fact, local farm Ron Gargasz Organic Farm submitted their beef to Pennsylvania State University for nutritional testing and found their beef had ten times the omega-3's of the conventional sample (6).
Milk from pasture-raised, grass-fed cows contains 50% more vitamin E, 62% more omega-3's, 65% more vitamin A, and five times as much CLA as milk from conventionally raised cows (7)(8)(9).
Vitamin A is an antioxidant most closely associated with orange vegetables (carrots, sweet potatoes, winter squash), although plant sources actually contain the precursor to vitamin A: beta-carotene, which must be converted by our bodies. Unfortunately, the conversion rate of beta-carotene to vitamin A ranges from 3.6:1 to 28:1 (10). Crucial for healthy bones, eyes, and immune systems (among many other things), vitamin A is another fat-soluble vitamin, best absorbed in animal foods, where the conversion is already complete.
Conjugated Linoleic Acid (CLA) is a potent anti-carcinogen found almost exclusively in the meat and dairy of ruminants (cows, goats, sheep, deer), especially ruminants eating exclusively fresh grass. Some forms of CLA have the additional benefit of aiding in weight loss. Early research also suggests that CLA may help control diabetes and boost the immune system (11).
Pigs are another omnivorous farm animal, but they are unique in the many variables that effect the nutritional profile of their meat: breed, habitat, and many feed options. The extent to which the pigs rely on grain feed is perhaps the biggest factor. Depending on the land and the time of year, some pigs have access to a wide variety of wild foods, like apples and nuts. There is also the issue of how often pigs are moved, as they can turn a grassy pen into a muddy one within a week. While there is a degree of variance in the nutritional differences between pastured and conventional, pastured pork has the potential for a significant nutritional advantage.
Pastured pigs at Blackberry Meadows Farm
When pigs are raised on pasture, they can produce pork with three times as much iron, four times as much vitamin E, and ten times as much omega-3 fatty acids (12)(13).
Coupled with the fact that hormones and sub-therapeutic antibiotics are virtually unheard of on pasture-based farms, there's really no contest when it comes to the health benefits of pasture-raised meats. And the best source of these foods isn't far from your home. To find an ethical farm serving Southwestern PA, download Pittsburgh's Guide to Ethical Farms.
2: Vitamins A & E: Karsten, H.D., Patterson, P.H., Stout, R. and Crews, G. (2010) ‘Vitamins A, E and fatty acid composition of the eggs of caged hens and pastured hens’, Renewable Agriculture and Food Systems, 25(1), pp. 45–54. doi: 10.1017/S1742170509990214. https://doi.org/10.1017/S1742170509990214
3: Simopoulos, A.P. and N. Salem, Jr. (1989). "n-3 fatty acids in eggs from range-fed Greek chickens." N Engl J Med 321(20): 1412. https://www.jstage.jst.go.jp/article/jnsv1973/37/6/37_6_545/_pdf
4: Simopoulos, A. P. (2006). Evolutionary aspects of diet, the omega-6/omega-3 ratio and genetic variation: nutritional implications for chronic diseases. Biomedicine & pharmacotherapy, 60(9), 502-507.
5: Daley, C. A., Abbott, A., Doyle, P. S., Nader, G. A., & Larson, S. (2010). A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef. Nutrition journal, 9(1), 10.
7: Searles, S. K., & Armstrong, J. G. (1970). Vitamin E, vitamin A, and carotene contents of Alberta butter. Journal of dairy science, 53(2), 150-154.
8: Benbrook, C. M., Butler, G., Latif, M. A., Leifert, C., & Davis, D. R. (2013). Organic production enhances milk nutritional quality by shifting fatty acid composition: a United States–wide, 18-month study. PLoS One, 8(12), e82429. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0082429
9: Dhiman, T. R., Anand, G. R., Satter, L. D., & Pariza, M. W. (1999). Conjugated Linoleic Acid Content of Milk from Cows Fed Different Diets1. Journal of Dairy Science, 82(10), 2146-2156.
10: Tang, G. (2010). Bioconversion of dietary provitamin A carotenoids to vitamin A in humans–. The American journal of clinical nutrition, 91(5), 1468S-1473S.
11: McGuire, M. A., & McGuire, M. K. (2000). Conjugated linoleic acid (CLA): A ruminant fatty acid with beneficial effects on human health. Journal of Animal Science, 77(E-Suppl), 1-8.
12: Daza, A., Rey, A. I., Ruiz, J., & Lopez-Bote, C. J. (2005). Effects of feeding in free-range conditions or in confinement with different dietary MUFA/PUFA ratios and α-tocopheryl acetate, on antioxidants accumulation and oxidative stability in Iberian pigs. Meat Science, 69(1), 151-163.
13: Hoffman, L. C., Styger, E., Muller, M., & Brand, T. S. (2003). The growth and carcass and meat characteristics of pigs raised in a free-range or conventional housing system. South African Journal of Animal Science, 33(3), 166-175.