I hope you all had happy holidays and are off to a great start this year. I thought I’d share a few thoughts that have been bouncing around my head lately, stimulated most recently by two articles written by fellow health bloggers.
Don Matesz over at Primal Wisdom wrote a thought-provoking piece on the hormone composition of grass-fed and factory-farmed meat. In it he argues (convincingly, I might add) that meat from CAFO (confined animal feeding operations) does not have dangerously high levels of hormones, in spite of claims to the contrary made by advocates of eating grass-fed meat.
I recommend reading the entire article, I’ll summarize it briefly here. Before CAFO came into being, humans predominantly ate bulls, since eating female animals (cows) was taboo. The taboo made perfect sense in a hunter-gatherer culture, since killing the female could eliminate potential offspring, while killing a few bulls would have no effect on the fecundity of the herd.
Today, CAFO use steer, which are neutered bulls. One reason for this is that steer are a lot easier to manage than bulls. Why? Because hormone levels in bulls (with intact sex organs) are significantly higher than in steer. In fact, bull meat has between 34 and 105 times more testosterone than steer meat. No wonder bulls are harder to manage!
Even when hormones are added to steer in CAFO, the levels are nowhere close to what they are in intact bulls. In fact, studies have found no significant difference in hormone levels between meat from hormone-treated and untreated animals.
This means that Paleo Pete was eating meat with a lot more hormones in it a million years ago than American Andy is when he gets a cheeseburger at McDonalds today.
Hormones in meat are bad – if you eat 200 pounds of meat a day
Studies have also shown that the hormones ingested from food, including CAFO meat, have a negligible effect on human health. From Don’s article:
For example, a prepubertal boy, most vulnerable to adverse effects of excess dietary estrogens, produces about 100 micrograms of estrogen daily. Beef muscle meat contains less than 0.02 micrograms of estrogens per kilogram. To get from beef an intake of estrogens equal to just one percent of his endogenous estrogen production, i.e. 1 microgram, he would have to consume 50 kilograms–110 pounds– of beef in a day!
Another common claim is that adding hormones to meat has increased the rates of cancer and other modern, degenerative diseases. But if that were true, we would have seen these diseases in hunter-gatherer populations that were eating large amounts of bull meat, which has on average 50 times more hormones than the CAFO steer meat eaten today.
So it would seem that there isn’t much difference between grass-fed and CAFO meat when it comes to hormones. So should we all just save some money and eat conventional meat?
It’s not all about hormones. Don’t forget omega-3s!
Not so fast. Mark Sisson published an article earlier this week reporting on a study comparing the effects of eating grass-fed and CAFO meat on omega-3 and omega-6 concentration in human plasma and platelets.
Turns out those that ate the grass-fed meat had significantly higher levels of omega-3 in their plasma and platelets than those that ate CAFO meat, despite the fact that the amount of omega-3 fatty acids in the two types of meat were not hugely different.
The folks consuming grass-finished meat ate, on average, 65 mg/d of long chain omega-3s, while those eating concentrate-finished meat ate about 44 mg/d of long chain omega-6s, yet the lab results – the big improvements in plasma and platelet fatty acid numbers – were lopsided.
What’s happening here? I suspect the answer lies with the difference in omega-6 content in the diets of both groups. Those who ate the CAFO meat had an average intake of 8.5g/d of omega-6 fats, while those that ate grass-fed meat had an average intake of 5.5g/d. In a previous article about how too much omega-6 is making us sick, I explained that omega-6 and omega-3 fatty acids compete for the same conversion enzymes.
Several studies have shown that the biological availability and activity of n-6 fatty acids are inversely related to the concentration of of n-3 fatty acids in tissue. Studies have also shown that greater composition of EPA & DHA in membranes reduces the availability of AA for eicosanoid production.
This works the other way, too. The more omega-6 is consumed, the less omega-3 is available to the tissues. So if two people eat a diet identical in omega-3 content, but one person’s diet is high in omega-6, and the other person’s is low, guess who will end up with more omega-3 in their tissues? That’s right – the one with a low omega-6 intake. This is why I constantly tell people that the most important step they can take in normalizing their omega-3:omega-6 ratio is not boosting omega-3 intake, but reducing omega-6. And this is likely what explains the higher levels of omega-3 in the grass-fed meat eaters in the study, even though grass-fed meat doesn’t have a lot more omega-3 than CAFO meat.
This is important, because the ratio of omega-3 to omega-6 in our tissue is crucial to health. Too much omega-6 in relation to omega-3 has been shown to be a factor in everything from depression and arthritis to heart disease and diabetes. There isn’t a modern disease out there that isn’t influenced by this ratio.
Black, white & shades of grey
So here we have one study suggesting there isn’t much difference between CAFO and grass-fed meat, and another suggesting the opposite. What do we make of this?
As much as we’d all like things to be simple when it comes to food and health, they often aren’t. We have to use our brains to sift through the available information and make intelligent choices based on several different factors.
In the case of grass-fed vs. CAFO meat, there’s a lot more to consider than hormones and fatty acids. There’s also antibiotic use in CAFO cattle and the increased risk of foodborne illness in CAFO meat, and there are several economic and social issues as well. Grass-fed animals are generally treated in a more humane way than CAFO animals. If you’ve ever visited a CAFO you will know what I mean. It’s shocking and disgusting. I personally prefer to support local farmers that use traditional methods of animal husbandry, that pay attention to how the animals are treated and slaughtered, and who care about every phase of the process. I like the money I spend on food to stay in my local community whenever possible.
Clearly this is not a black and white issue, and there’s a lot to take into account when choosing between grass-fed and CAFO meat. As usual, I’d love to hear your thoughts.
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