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New Zealand cows fed Palm Kernel Expeller, producing a new type of trans fat in milk. Is it safe?


Some of you may be aware that our cows are no longer totally grass fed. New Zealand has been importing increasing amounts of palm kernel expeller – the leftovers from when kernel oil is pressed out from the nut in the palm fruit – to supplement dairy cows’ largely grass diet.

In 2004, palm kernel cake imports were just 95,920 tonnes. In 2008 they swelled to just over a million tonnes, falling back to 665,382 tonnes in 2009. The other controversy is that palm plantations are causing the felling of rain forests. Our Destructive Ways

Palm kernels take cows a little getting used to – but they do digest them. I’ve been wondering for some time what happens further down the track – does it affect the fatty acid composition of the milk fat, does it change the fatty acid composition of meat fat? And if it does – how does this affect the health of the humans consuming the milk, butter or meat of these cows.

The answer to the milk fat question appeared in an article in today’s New Zealand Herald.

The fat of the land

New Zealanders don’t eat a lot of harmful trans fats and food manufacturers have reduced trans fat levels in the food made in New Zealand.

Now the not so good. Unlike the rest of the world, most of the trans fats we eat come from dairy foods and red meat and that’s related to what we feed our sheep and cows – lush pasture with clover, with palm kernel expeller supplement for our cows.

Here’s the kicker. Two naturally occurring trans fatty acids in our milk and meat have just been shown to be associated with polyvascular disease and stroke in high risk patients.

The startling finding comes from an observational study led by Dr Jocelyne Benatar at the Cardiovascular Research Unit of Auckland City Hospital, now published in the peer-reviewed European Journal of Cardiovascular Prevention and Rehabilitation.

“It came out of left field. It was a study looking at lots of other things,” says Benatar who is quick to point out it is not a causal finding. “You can’t overplay this study. It’s just the first time we’ve shown it.”

Fair enough – more studies are needed. But the hypothesis generated by this study has the potential to change how we farm and what we eat.

The startling aspect of the research, which Benatar presented to the Cardiac Society of Australia and New Zealand’s June annual scientific meeting, is the presence of palmitelaidic acid, a trans fat derived from palm kernel.

The fact that it turns up in the analysis of blood samples taken from 390 patients with severe coronary disease is evidence that what we’re feeding our cows wends its way through the food chain to us. We are what we eat.

Benatar’s research shows the palm kernel-based trans fat does not originate from processed food.

“In New Zealand the palmitelaidic acid comes from our dairy foods which means what our cows are being fed is coming up through the food chain,” she says. “The ruminant bacteria in the cows’ stomachs are making it into trans fat and that’s the trans fat we get.”

It’s long been known that naturally occurring trans fats are present in the milk and the meat of ruminant animals such as sheep and cows, the most common being vaccenic acid.

What most probably don’t know is that grazing cows produce more of it than grain-fed cows. So it wasn’t terribly surprising that vaccenic trans fat showed up in the lipid analysis of the patients’ blood, along with other trans fats found in processed foods.

But the presence of the palmitelaidic trans fat hadn’t been seen before.

“I wondered how it was getting into our cows.” It was only when Benatar noticed a news item on Greenpeace concerns about the amount of palm kernel animal feed imported into New Zealand that she made the connection. The use of palm kernel expeller – the leftovers from when kernel oil is pressed out from the nut in the palm fruit – to supplement dairy cows’ largely grass diet is increasing in New Zealand.

In 2004 when the study began, palm kernel cake imports were just 95,920 tonnes. In 2008 they swelled to just over a million tonnes, falling back to 665,382 tonnes in 2009. Greenpeace’s concern was the destructive effect that the palm oil industry was having on the last remaining rainforests in Indonesia.

Trans fat intake is very low in New Zealand – around half a per cent of total dietary energy compared to between 2-4 per cent for other Western countries. New Zealanders’ intake of trans fats is predominantly from dairy sources (60-75 per cent), whereas in most Western countries the trans fats ingested come from processed foods (about 85 per cent).

All of which seems to indicate New Zealanders are less at risk from the health hazards of too much trans fat consumption, especially the adverse effect on cardiovascular health.

Studies all tended to show that artificially produced trans fats are the problem, rather than the naturally occurring trans fats in our milk and meat. Until now.

While Benatar’s research isn’t conclusive, it does raise some intriguing questions. The statistical association between the “natural” trans fats and vascular disease including stroke, like the presence of palmitelaidic acid, is something not seen before.

Polyvascular disease involves atherosclerosis, the thickening of artery walls through a build-up of fatty materials such as cholesterol. The possibility that natural trans fats may play a part in that disease is something Benatar wants to investigate further.

While the World Health Organisation recommends people should consume no more than 1 per cent of their daily kilojoules from trans fatty acids, the Auckland hospital study indicates for high risk patients the safe threshold may be much lower.

“The study is saying if you are a high risk patient, 1 per cent is probably not safe,” say Benatar.

“Maybe having a lot of trans fats, regardless of where they come from, affects atherosclerosis throughout your body and not just heart disease on its own.”

For at risk patients with cardiovascular disease the conventional wisdom is to reduce the dietary intake of saturated fats – hence no butter, limited red meat and so on.

But Benatar’s research indicates a more complex interrelation may be at play, with naturally occurring tans fats – even at very low levels – having a larger role than previously thought. “It may be the combination of trans fats as well as the saturated fats in red meat and dairy that affect the disease.”

So does this mean at risk coronary patients should stop drinking milk? Not all says Benatar. If the naturally occurring trans fats are found to be a key factor in cardiovascular disease, rather than the problematic business of trying to alter dietary habits, it should be possible to correct the problem at the source.

First stop feeding cows palm kernel and then investigate how changing our pasture grasses might reduce trans fat production. “You could also look at the bacteria in the gut of cows and see whether changing that has an effect on vaccenic acid in the milk.” As Benatar points out, dairy product are not inherently bad. “Things like yoghurt and milk are very good for you.”

The huge opportunity for New Zealand, she says, is that we are one of the few countries where researchers can look at dairy trans fats without being overwhelmed by industrial trans fats.

Benatar is about to begin a new a dietary intervention study with subjects who will either increase their dairy intake, reduce it, or leave it the same for a month – because it takes three weeks for trans fats to wash out of a person’s system.

“That will prove where these trans fats are coming from.” If her research proves correct, it could write a new chapter in the book on cardiovascular disease.

Here is a PDF Presentation of  the study, which contains graphs and graphics


New Zealand has a reputation in the Paleo arena of having high quality purely grass fed meat and dairy. Palm Kernel Expeller (PKE) can make up to a third of cows feed in times of grass shortage such as a drought. I believe the affect of this new type of trans fat on our health needs further investigation.There is probably no way of knowing whether the milk or butter you eat is free of it. Recently with our high rainfall and abundant grass, there is likely to have been little supplemental PKE feed used.

What about sheep? – due to the high copper content of PKE, sheep cannot consume it, so they are still predominantly grass fed.


  1. Nice spotting Julianne… and definitely one to watch and follow up. I stand to be corrected, but I believe that PKE is only used in the dairy herds and is imported by Fonterra to prop up the dairy output of its herds (seeing as Fonterra insists on exporting dairy protein to the world). I do not think it is used in our beef cattle and as you say, isn’t used in our sheep herds. As a dairy-free Paleo, it shouldn’t impact on me from a nutritional standpoint, but it is certainly an issue I am concerned about from both an environmental and animal health standpoint.


    • Jamie,
      From the info in the link above to PKE they state:
      Most palm kernel meal imported into New Zealand is used on dairy farms, particularly in the North Island. It is used primarily as a supplement for milking cows to increase production or make up shortfalls in pasture.
      Use of PKE for fattening beef cattle or as a supplement for beef cows when pasture is limiting is increasing.”

      Which is a concern, as I assumed beef cattle were fully grass fed.

    • Thanks, I’d be interested to hear what his view is.
      I’ll do a bit more research too on palmitelaidic acid as it looks like it is also made via vegetable oil hydrogenation, that makes it different from the vaccenic trans fat, which is only made naturally through ruminant digestion.

      • Keith is interested. Then again, so should most Kiwis be. If palm kernel-based trans fats are derived from NZ dairy/meat then we’re now the subjects in a rather large, uncontrolled experiment…

  2. Well that sucks… perhaps time to emphasise lamb over beef a bit more. The annoying thing is, any stats regarding CHD risk that comes through locally will inevitably be attributed to saturated fat and not to this sort of thing occuring. I wonder how much this already occurs overseas?

  3. Just read through the presentation – thanks for putting that up. Probably not a great deal of concern at this stage, but certainly from the environmental & animal welfare side of things, this should be looked at more closely.

    From the DairyNZ website:
    Palm kernel extract (PKE) is a by-product of the palm oil industry in South East Asia. It is derived from the nut of the palm fruit after the oil is mechanically extracted. This feed is a dry gritty meal with a soapy smell and has low palatability. However, PKE has reasonable levels of energy (ME) and protein, and is relatively easy to introduce to cows over a range of farm systems. The profitability of PKE is dependent on the price of PKE relative to payout and the utilisation of PKE and pasture.



    From the presentation, the message that should be reinforced is that what an animal eats can affect us. Therefore, not only are we what we eat, but what it ate. For example, I have a coeliac friend who can eat all the gluten free Freedom Farms bacon in the world, but reacts to non-GF, non-free range bacon.

    There are a multitude of reasons why I dislike the dairy industry (I don’t like seeing the Canterbury rivers get sucked dry for a start). This adds to it.

    • Thanks for the comments and links.

      It’s interesting that gluten appears to be found intact in pork. That is scary.
      I try to strictly avoid gluten due to Hashimotos, and don’t have any noticeable reaction if I eat a small amount. So I could be eating it incidentally and not know it if I eat normal pork! I’ll be sticking to the Freedom Farms pork in future.

      Does your friend also react to grain fed poultry – or is the gluten digested fully in poultry due to their digestive system?

  4. I suspect birds might be able to break it down a bit more readily. She doesn’t react to poultry as far as we have been able to see and we have to keep in mind that it might be something else in bacon that she is reacting to. Though, the Freedom Farms bacon is still cured in much the same way. It might also be that it isn’t intact gluten but perhaps antibodies that the animal has produced to gluten that are passing through a leaky gut intact and causing issues. Just very interesting that the only real difference as far as we can tell is the fact that FF bacon is gluten free & free range and the regular bacon isn’t.

  5. As a kiwi living abroad I’m a bit upset to hear about this. Is this the encroaching industrialisation of farming entering NZ? People here in the UK are sold NZ butter with adverts claiming it is pure and produced by cows living a natural life and eating grass. They won’t be buying it if they hear that it contains transfats. The dairy industry needs to be very careful if it wants to maintain exports to markets like the UK and Europe.

  6. Hi,

    We came across your article by accident whilst researching on paleolithic lifestyles and what concerned me was does this also occur to ‘free-range’ or organic beef?

  7. Hi Julianne: I did see an article the other day probably on the farming page of the Press where they mentioned plans to increase supplementary feeding (grains?, PKE?) for beef cattle which would be kept on rolling, less productive high country land. I’m not sure if it would be the totally grim CAFO (contained animal feeding operation) or just akin to letting the animals have access to supplementary food. Definitely a bad business. The presence of palmitelaidic adid in NZ’s dairy milk needs to be publicised so I’ll share the original article on FB.

    As a side issue, I’m very interested in your dietary and other approaches to managing Hashimoto’s Disease as I have that too. Not sure how raised the anti-thyroid antibodies are at the moment but my TSH is down from 10 to 3 and the T4 and T3 are improved but not in the upper third of the normal range. I’ve been taking 3 brazil nuts a day, a couple of tbs of coconut oil, magnesium supplements and am generally gluten free though I do cheat a bit but not with bread! Any advice would be very appreciated. I’ve heard from one source that I should avoid iodine supplements until the thyroid a/bs have gone.

    I’ve been watching a series of videos from this naturopathic physician:

    I’d be grateful if you could dispense any of your wisdom on Hashi’s. Regards, Honora

    • Thanks for the link – looks like an interesting site – I haven’t seen this before.
      When I tried iodine it was a disaster, but I didn’t obviously do it the right way. Getting the thyroid nutrients optimised first.
      Is this what you did?

      Some say to introduce iodine – but very slowly, increasing dose just once month.

      I’ll take a look at the protocol in these videos. I’ve been going by Dr Kharrazian’s advice so far and info on Chris Kressers blog.

      • Really chuffed to get your response. Thanks for that. The iodine thing can be a contentious issue in the blogosphere. I’ve certainly started including iodised salt in the diet after avoiding it for decades. Ridiculous considering my BP is usually 100/60…Good news. My anti-TPO has plummetted from 800 something down to 63 which is weakly positive! Just read something on Chris Kressers’s blog about amaganthra (sp!?) being beneficial for thyroids and will do some research on that.

  8. oops. Didn’t answer your question: >Getting the thyroid nutrients optimised first.
    Is this what you did?

    Yes, I’ve done that but was put on iodine at the standard daily Japanese intake dose (15mg I think). I took one bottle of it and actually must look at my results for that time to see what effect it had. I queried it with the chiropracter and he was surprised to hear that some people thought it would be an issue so I took it. I’ll get back on this as it’s 11pm.

  9. hi i,m a dairy farmer we feed our cows 1-2kg of pke a day i’ve also been instructed to feed it to our calves which are 2 months of age weighing in 110kg plus growing at 1.1kg a day over the last 20 day period and it is true i have heard of beef cattle getting upto 4-6kg of pke a day over winter in a feed lot environment my concern is and this is a question to you scientists out there does feeding pke to calves under 8 months of age have the potential to shrink their ovaries ?????

  10. I am a dairyfarm in Hamilton,I have notice a big swing to feeding parm Kernal Expeller by farmers in our area all year round,we are one of a few who do not feed it in our area.I have notice when I drink the milk that I buy from the shop’s I get alot of acid in my stomach and my daughter has same problem.But when We drink milk from our vat the symptoms seem to disapair is this because we are all grass fed system ???

  11. I was talking to a rumen feed expert today. He says PKE is banned as a food for goats in New Zealand as “it rips their guts up”. Specifically he means it causes intestinal permeablity i.e. leaky gut.

    Mentioned this to a dairy farmer and he said he avoids the stuff as it’s full of some nasty foreign bodies e.g. tires and dead bits of monkey. PKE is traditionally a waste product. It lands here having cost the importer $17 a tonne to ship and is on-sold to the dairy farmer for $260/tonne. Clearly big money for the middle merchants.

  12. Just adding.. Im on a sheep farm and this winter we are feeding sheep nuts, I see on the ingredients PKE is included in the list amongst a load of other ingredients I wouldnt feed myself. This is their first year on them, im interested to see how the lambing percentage is this coming spring to see if the owners will open their eyes to feeding their stock this stuff.

      • Sorry. But no they are being fed “supplement” feed since recently. the ingredients in sheep nuts are .

        Barley, Wheat, Palm Kernel Meal, Wheat By-products,
        Grass seed meal, Soyabean meal, Canola, Linseed, Maize,
        Oats, Peas, Molasses, Sodium Bentonite, Minerals, Vitamins,
        Trace elements

        On another farm we were on last year fed out straight grain or barley, we had very hyper crazy sheep!!

  13. I have regular contact with a rumen nutrition specialist who informs me that PKE causes intestinal permeability i.e. leaky gut. He describes it as ripping their guts up. I wonder if there is a non-PKE source of sheep nuts.

  14. what do you think of this list of sheep nut feed?

    Wheat, Barley, Grain By-Products,
    Peas, Soyabean Meal, Canola, Cottonseed
    Meal, Copra Meal, Vegetable Oils or Fats,
    Molasses, Limestone, Bentonite, Dicalcium
    Phosphate, Salt, Vitamins and Trace
    Minerals, Flavouring.

    • Hey, I know even less than you do but selenium is missing. I talked to my contact about the sheep nuts and what you could do. He said the nuts are overpriced and just to give them barley with a monthly squirt (pinned down to 5 or 10 mls of selenium in the feed as per the usual dose). He said wheat is more easily absorbed due to not having a hull unlike barley hence the frisky animals. He said wheat is usually fed to pregnant stock not pre-mating stock. I’ll pick his brains some more when I see him regarding the latter list of ingredients. It sounds pretty yummy to me.

      He also said animals are more tolerant of selenium dosing than humans who now and again experience selenium poisoning when they start self-dosing with the animal stuff. I’ve actually met someone – a farmer’s wife, so to speak, who overdosed on a single slug of selenium and became very unwell.

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