An estimated 50,000 mice worldwide are charting new territories of chubbiness as they chow down on the infamous, lard-based, high-fat rodent diet, “D12492.” As I reported a few days ago over at The Daily Lipid, it turns out these mice are chowing down on twice the amount of polyunsaturated fatty acids (PUFAs) as Research Diets, the producer of D12492, has heretofore been reporting. In this post I’ll address a few questions that came up in the comments, like which fatty acids the PUFAs had displaced, and what we can expect from higher-quality, pastured lard.
Here’s a graph showing the difference between the new and old estimates (1):
The graph shows the difference between the actual fatty acid profile as determined by direct analysis of the lard and the previously reported fatty acid profile, which had been estimated using the USDA database. We can see that the actual fatty acid profile is much higher in PUFAs, at the expense of both saturated and monounsaturated fats. In fact, the company had originally estimated the diet to provide 17 percent of its fat as PUFA, but now estimates it to provide a whopping 32 percent!
The particular fatty acids that are decreased the most are palmitic, stearic, palmitoleic, and oleic acids. These are the primary fatty acids that pigs, humans, and other animals produce when we make fat from carbohydrate. This suggests that the pigs are consuming seed oils, which would increase their intake of PUFAs at the expense of the carbohydrates found in grains and legumes.
The ratio of omega-6 linoleic acid to omega-3 linolenic acid is almost double what had been estimated based on the USDA database, suggesting that the oils the pigs are consuming are particularly rich in omega-6 fatty acids.
Raising pigs on pasture isn’t in itself a very effective way to reduce the PUFA content of lard. In one study (2), lard from pigs fed pasture and acorns was 8.7 percent PUFA while lard from pigs fed barley, wheat bran, soy meal, lard, and nutritional supplements was 6.9 percent PUFA. Grass has many benefits, but including it doesn’t lower the PUFA content of lard beyond what could be accomplished simply by banishing vegetable oils from these poor piggies’ diets.
The most effective way to minimize the PUFA content of lard that I’m aware of is to feed the pigs a traditional Pacific Island diet rich in coconut. Here is the fatty acid profile of lard from the island of Tokelau (3):
The lard is only 3.1 percent PUFA — more than ten times lower in PUFA than that darned chubby-mouse diet — and the ratio of omega-6 linoleic acid to omega-3 linolenic acid is 3.3. At least this was the case when it was measured back in 1981. Even the chicken fat on this island was only 3.2 percent PUFA.
The islanders reserved meat for special feasts. Day by day they subsisted mostly on coconut, fish, and various starches. As a result, they obtained about half their calories from saturated fat, but only two percent of calories from PUFA, most of which came from fish.
In the grand scheme of things, then, we can say that the lard used in Research Diets D12492 is incredibly high in PUFA, and the diet itself, which also contains a small amount of soybean oil, is a very high-PUFA diet. We can probably expect at least one new high-profile study using this diet to hit the press every couple of months. Will they continue to blame the effects on “saturated” fat? Only time will tell.
Read more about the author, Chris Masterjohn, PhD, here.
1. Dr. Matthew Ricci, Vice-President and Science Director of Research Diets. Personal communication. November 18, 2011.
2. Timon ML, Martin L, Petron MJ, Jurado A Garcia C. Composition of subcutaneous fat from dry-cured Iberian hams as influenced by pig feeding. J Sci Food Agric. 2002;82(2):186-91.
3. Prior IA, Davidson F, Salmond CE, Czochanska Z. Cholesterol, coconuts, and diet on Polynesian atolls: a natural experiment: the Pukapuka and Tokelau island studies. Am J Clin Nutr. 1981;34(8):1552-61.🖨️ Print post
“Raising pigs on pasture isn’t in itself a very effective way to reduce the PUFA content of lard. In one study (2), lard from pigs fed pasture and acorns was 8.7 percent PUFA while lard from pigs fed barley, wheat bran, soy meal, lard, and nutritional supplements was 6.9 percent PUFA. ”
Doesn’t it seem the pigs were fed on pasture AND acorns (the latter high in omega 6’s)? Also, its not just the total PUFA’s that is important, it is the ratio of omega-3/omega-6’s?
Enjoy your scholarship!
Chris Masterjohn says
Yes it does mean that, but it is not possible to raise a pig on grass alone. But besides that, grass is extremely high in PUFA as a percentage of its fatty acids. It happens that grass is an excellent source of omega-3. So by including grass and acorns, the grass helps balance the omega-3 and omega-6 values, but of the two of them it is probably the acorns and not the grass that is keeping total PUFA to a moderate value.
Great article Chris. It’s mind blowing how much incorrect information we get from the scientific community.
Chris Masterjohn says
Excellent post. How many studies have erroneous conclusions and results based on this rodent diet? The devil is in the details!
1. Are mice even supposed to eat lard? I was under the impression they were mostly plant eaters, and certainly wouldn’t go around chewing on pig carcasses. Rats, on the other hand…
So I wouldn’t expect good outcomes on normal mice even with good lard in their diet, and I do not even care about transgenic mice, since I am not a transgenic *person.*
2. European pigs would not naturally run across coconut to add to their daily diets. Yet Europeans eating their traditional diets including traditionally fed pork tend to be healthy and long-lived.
I’m not sure it’s as cut-and-dried (ha, I almost wrote “fried”) as PUFA content. I do think saturated fat is healthier, but *no* animal fat is purely one thing or another. Butterfat might come closest and even it is not purely saturated.
I think in the end it’ll come out that we’re better off eating more animals rather than more plants, and that those animals need to have eaten their natural diets in life. And that may in the end be all we need to know. Could be that even in animals with more PUFA naturally occurring in their fat, there may be some other factor protecting against the worst effects of the PUFA, perhaps a factor not present in seed oils. No idea.
Chris Masterjohn says
It could be like that, I’m not sure, but even if it is like that, I don’t think pigs even in Europe eat added oils as their natural diet.
Great Question! Most of the studies on flax in food look at the lhteah benefits to the consumer, i.e. does the person eating muffins with flax actually see an increase in omega-3 fats in the body. The answer is yes if there is a lot of flax in each muffin. I did find one study where they put ground flax into a processed pasta product and found that the ALA omega-3 fat was unchanged during both processing and cooking. A separate study looked at flax in muffins and the effect on the lignan content. The lignan was unchanged in the baking process. However, omega-3 fats are delicate fats, easily oxidized. So I suggest adding them to foods just before consumption when possible, especially for foods that you will be reheating at high temperatures. For example, items like chili should be reheated to 165 degrees Fahrenheit for food safety reasons and this temperature may compromise the omega-3 fats. Hope this information is helpful. Thanks so much for writing and for asking your questions.
Er, forget what I said about transgenic mice… not applicable here. I think I got distracted by that weird mouse-feed name. I don’t think I have had enough caffeine yet today. >_<
awesome article! too bad more stores don’t sell pork that was raised on coconuts
Chris Masterjohn says
Seth Roberts says
I wonder how much that measurement varies from lab to lab and month to month. Maybe a lot. Maybe the new measurement is a mistake.
Chris Masterjohn says
It could be, but there was no “old” measurement at all. This is the only measurement. As I said, I’ve heard from people who have measured the fatty acids by GC privately and found similar results, only a little higher in omega-6. I agree there’s likely variation in lot to lot, but these values are so high in PUFA compared to pigs who are not eating added oils that I think the production method is a factor.
Simon Primal says
Very interesting reading, and definitely a good reason to ensure your pork comes from a reputable source.
One question, though I’m sure coconut may be the dream food for pastured pigs, do you have a more realistic suggestion for pastured pigs being farmed in the UK?
I don’t think it would be practical to attempt to source large quantities of coconut to feed to pastured pigs in the UK – It’s already hard enough as it is to make it profitable without such an added cost.
Would simply keep the pigs diet as “piggy paleo” as possible – I.e. free from processed foods, grains and seeds etc/high in real food?
Chris Masterjohn says
Yes I think that’s the best option. Just avoid the high omega-6 foods and don’t add any fat to the diet whatsoever (unless you want to try coconut oil I suppose).
Kit Davidson says
Tim Boyd suggested you might help me find a supplement or pill to raise repeat RAISE cholesterol levels. Mine are a very strong risk factor for hemorrhagic stroke. Eggs are the obvious, but a new study reveals a very serious problem with prostate cancer. All help appreciated. (800 460-1842)
Chris Masterjohn says
Low cholesterol levels are only a risk factor for hemorrhagic stroke if you have high blood pressure. Normalizing blood pressure is likely to be a much more effective way of preventing any type of stroke than modifying cholesterol levels, regardless of whether your cholesterol levels are high or low. If you want to raise your cholesterol levels, I would try eating more eggs and coconut oil. That said, I would instead look at your hormones and digestion. If your sex hormones are in good shape and you have no problem digesting fats, then I doubt you need to worry about your cholesterol levels. Cholesterol can be low because you aren’t making enough or because you’re efficiently converting it to other things. The former is bad but the latter is good.
Elizabeth,I am a Personal Trainer that is starting to zpmhasiee more good nutrition choices as well as exercise to my clients. That’s why I’m following your articles so I can learn as much as I can from you. I have a similar meal replacement drink recipe as yours that I give my clients. I borrowed 2 of your ingredients of cinnamon and coco, along with Whey and some kind of greens powder & ground flax. However, I add a teaspoon of extra virgin olive oil to my recipe to add some more fat and follow a Mediterranean diet. My question is, am I doing my clients a disfavor by adding the omega 6 olive oil? I still zpmhasiee eating fish, or fish oil, fibrous vegetables and whole grains. One more thing, I never realized that straight coco tastes that bad (what do I know I’m a man). Any suggestions? Thanks,Jim
carlos nunes says
The answer is not for me but with all the respect for everybody i want to help with my experience since I discovered Dr Weston Price.
The pinnacle of all good foods for cardio vascular problems and health in general is the 100% Acorn feed Iberico Ham ( 36 or better 48 month dry cured. Depending of the region, the MUFA could reach 85 % of all fat beyond all goods ingredients that the maturation process create .
You dont need to invented the wheel .
Your life will never be the same .
Mike Ellwood says
Traditionally in England (where I live), pigs were fed “pig swill”, which may have contained fruit, but I believe they were often given fruit anyway (a good way to dispose of rotting fruit). I think the swill would have been pretty high in carbs, so the result was almost certainly, quite nicely saturated (or rather: sat+mono) in the pig (and in the lard).
Traditionally, they would also have been free to graze and nose around for whatever they fancied.
A disadvantage of pigs seems to be that, not being ruminants, their fat reflects their diet more closely than cows, sheep, and goats, who can, to some extent, “detoxify” what they eat. So, a well-fed (traditionally-fed) pig is safe to eat. An “industrially” fed pig may not be.
We raise our own freezer pigs mainly on cooked turnips, turnip greens, and potatoes grown for the purpose in our veg patch, supplemented with kitchen scraps – including fish offal, and the odd meat bone, which they love. We’d love to know what we’re getting in our home rendered lard.
Just wondering if you know of a simple, at-home, “kitchen lab” type assay that would give us a rough idea of the fat profile of our lard. Don’t need high-tech precision, but some way of determining rough PUFA, MUFA and SFA percentages would be fascinating.
I was scouring the net trying to find the answer to that question. I raise Berkshires on alfalfa, coconuts, squash, greens and some grain and dairy. (Wow, yum!) I would love the ability to get a profile of my lard too and test it from time to time against varying diets. Can anyone answer this question? Funny, I’m shooting for lard with HIGHER sat fat, while most pork is marketed as the lean, other white meat (gag)
Kyle Mamounis says
I’m reading a paper right now that used Research Diets Rodent Chow #D12451 HFD, do you know if that’s a similar formulation? And the sequitur to this blog post would be a simple experiment putting mice on this high PUFA HFD vs. a different ratio (probably low PUFA/high SFA or mixed SFA/MUFA) to measure the different in weight gain from the different fat sources.
I am interested in finding nutritional information on pastured lard. I am hoping to use the nutritional information in a magazine article featuring a menu that uses less store bought staples and more items created in the kitchen such as in processing vegetables, bread, cheese and of course lard for the fat.
I’m glad to have stumbled upon your post, would you be able to show me a way to additional information on nutrition and possibly culinary benefits?