There are a few issues with grass-fed meat and dairy. Know what you are consuming.

“Grass-fed”, “grass-finished”, and “organic” are sought after terms in association with meat, dairy products and eggs. Pasture-grazing animals have a more natural diet and consume a greater diversity of foods than conventionally-fed animals. That is a good thing. It’s good for their health and for consumers of their meat, milk, and eggs. However, there are a few nutrients that are found at reduced levels in grass-fed compared to conventionally raised meat.

Perhaps the most concerning nutritional difference with grass-fed meat is the oleic acid content. Oleic acid, which is a monounsaturated fatty acid and one of the substances conferring health benefits to olive oil, is found at lower concentration in grass-fed meat than in the conventionally-fed counterpart.

Whereas higher oleic acid is desirable, less of the saturated palmitic acid is probably a good thing. There are a number of physiological effects that result from the ratio of these fatty acids. Grass-fed meat does have less palmitic acid than conventional-meat but it has even less oleic acid. Therefore, the ratio of palmitic to oleic acid in grass-fed meat is higher. There are many negative effects that have been associated with higher palmitic, lower oleic acid in the body. Of course, this concern can be ameliorated by also eating high-oleic acid foods, such as olive oil, avocados, and nuts.

Another potential area of concern with pasture-raised meat, poultry, eggs and dairy is toxicity. A number of studies have found free ranging animals not only consume a greater diversity of nutrients, they also may consume a greater number of toxins!

I was certainly surprised to learn that grass-fed and organic foods could contain more of certain toxic chemicals than conventionally produced food. While organic and grass-fed are expected to have lower levels of pesticides, antibiotics, and added hormones, there are toxins from other sources that are a concern.

Dioxins and PCBs are human-produced chemicals contaminating air, soil, and water to varying degrees throughout the world. Polychlorinated biphenyls (PCBs) and Polybrominated biphenyls (PBBs) were once widely used for a variety of industrial purposes. Although banned years ago, because of their high stability, PCBs and PBBs persist in the environment. Dioxins result from waste incineration and various industrial activities, including the chlorine bleaching of paper pulp and metal smelting. Dioxins also are formed from wildfires. These toxins accumulate in the food chain, being found at low level in plant foods. The primary sources of human exposure are through the consumption of meat, dairy products, and seafood. Meat is by far the leading source of intake, followed by dairy. These persistent toxins build up in soil and pasture-grazing animals consume these contaminants when eating plants and worms. These substances get stored in fatty tissues. Consistent with this fact, high-fat cuts of beef, bacon, frankfurters, full-fat cheeses, fatty fish (e.g., salmon), and butter are high in dioxins. Tallow and lard would likewise be expected to have high concentrations. Skim milk has less dioxins than does whole milk. Dioxins and PCBs are among the perisistent organic pollutants – environmental chemicals that get stored in human fatty tissues. Body fat mass and age are two factors influencing levels of these toxins in humans. Research conducted on pasture-grazing animals across various countries has frequently revealed that grass-fed, free-ranging animals tend to have elevated levels of these toxins in their meat, milk, and eggs compared to conventionally-fed animals. Livers of grass-fed animals have been found to be particularly high in these chemicals. One study, testing conventional and grass-fed versions of a number of foods, found organic yogurt to be especially high in PCDD/Fs and dioxin-like-PCBs.

Dioxin toxicity is linked to various health issues, such as hypertension, atherosclerosis, type 2 diabetes, cancer, and disorders affecting the immune, reproductive, developmental, dermatologic, endocrine, and nervous systems. Whether an individual will suffer adverse health effects from the levels of these chemicals found in food is a matter of some controversy. Because of genetic and many individual factors, each person may be extremely different in his/her tolerance for these pollutants. (see Do You Need to Detoxify?)

In humans, dioxins increase the hepatic production of a damaging bacterial co-metabolite called TMAO. L-carnitine and perhaps phosphatidylcholine, betaine, and choline from animal products ultimately get converted to TMAO. From my reading of many studies, L-carnitine from meat seems to be the primary raw material that intestinal bacteria convert to trimethylamine, which gets absorbed then converted to trimethlyamine N-oxide (TMAO). Dioxin has been found to increase the activity of the liver enzyme that converts TMA to TMAO. I have not seen TMAO studies that specified the use of grass-fed beef. I have, however, observed a trend of increased incidence of TMAO elevation in patients eating a lot of grass-fed beef. TMAO is probably best known for being a cardiovascular risk factor but it is damaging to many different organs. There are nutritional strategies, in addition to eliminating meat, that may lower TMAO and also reduce its toxic effects.

Commercial labs can measure PCBs from a blood specimen.  Dioxin testing is not routinely available but I am looking for labs that offer this test.