Healthy Soils Result in Healthy Crops, Livestock and Production
Duration: 36 mins.
Public Seminar with Professor Carlo Leifert. Southern Cross University, Coffs Harbour Campus. Duration 40 mins.
Professor Carlo Leifert - Coffs Harbour Campus September 2018
Introduction was by Lorraine Gordon
Does organic and low-input production improve the nutritional value of meat and milk?
I will present today the known benefits with regard to nutritional quality that you get when you switch to organic production methods. Lorraine will put the data against it on how that works on the economic front. What I have found in my career, if you work towards the organic principles in organic farming that actually gets you closer to a good profit margin as well. I will explain why that my particularly the case in Australia while I am going through my talk. All the information I am presenting here, except from one area is from data not from Australia. Data from Europe and data from the US primarily. In some areas of Europe and some areas of the US production backgrounds and the production methods are similar to those in Australia. That still tells us something.
Does organic and low-input production improve the nutritional value of meat and milk?
I want to remind you where the differences are between traditional and organic production methods. What we measure in nutritional differences must come from what farmers do, not from getting a certification stamp. That just makes sure farmers do what they should do as organic farmers.
ORGANIC FOCUS: welfare (animal) and on-farm sustainability.
- outside production is prescribed;
- lower stocking density (with any type of livestock);
- no antibiotic growth promoters - ABGPs/hormones used (the same applies to pesticides used as protection against parasites. Certain organically acceptable plant-based extracts can be used for the treatment of animals);
- longer withdrawal periods (in the US the use of veterinary medicines is not permitted, sick animals which cannot be cured are either sent to the slaughter house or a conventional farm). There is a big discussion in the organic world, which is the better approach? If you have stricter rules then your selection of animals is stricter because you need more robust animals and in the long run you end up with better animals from an organic system – which is the benefit of the US system. Europe treats animals on farm but enforces longer withdrawal periods between treatment and sale);
- on-farm feed production (on farm sustainability is the aim of organic production, so there is a large proportion of space dedicated to ruminant production (sheep and cattle) and smaller areas for non-ruminants (pigs and poultry). They need space to reproduce on the farm although there are some deregulations in some areas where this is not possible;
- only mineral & methionine (poultry) supplements used (although in some areas of the world deregulations permit synthetic methionine use in poultry production only);
- ruminants (cattle, sheep, goats) need to be on high grazing intake diets, which is very important for the quality of ruminant products. (Grass-fed systems are prescribed, the amount of conserved forage and the amount of concentrate, the use of cereals and protein crops in ruminant diets is greatly restricted in organic systems).
CONVENTIONAL FOCUS – a comparison: maximum production efficiency
- more “indoor” production (having cattle in feed-lot systems or corals);
- high stocking densities;
- ABGPs/hormones used (in many parts of the world e.g. the US farmers can use antibiotic growth promoters and hormones in production);
- standard withdrawal period (the withdrawal period is one third to half the time of organic farming systems after use of veterinary medicines);
- brought in feed (so not produced on the farm);
- mineral, synthetic amino acid & Vitamin supplements (widely) used;
- feedlot (high grain/conserved forage) systems for ruminants, pigs and poultry are common.
All the differences we find in nutritional qualities we find in our studies are linked to the parameters listed above, but to a different extent.
I will now discuss the methodology particularly of what’s called meta-analysis
- What is nutritionally desirable and undesirable in milk (fat) and meat (fat) – most of the discussion is on the fat component because people haven’t really studied the composition differences for anything else except fat. There may be other differences between organic and conventional with respect to nutritional composition but I can’t tell you about them because people haven’t studied them.
- Then I will go through the results. Are there differences in nutritional quality between organic and conventional crops? – systematic literature review and meta-analysis. This will be complemented with a little bit of data from America which is the first study that SCU was involved in looking at organic food quality. Part of our team did the statistical analysis of data collected in America. Until recently, we didn’t know how organic and conventional milk quality compared in America, this is new information. All the meta-analysis data are mainly from European studies.
- Why are there composition differences? Which agronomic practices do these differences result from? This information is taken from farmer-participatory surveys and field experiments, carried out in Europe and America across different regions to get an idea about the interaction between different climatic zones and differences in quality.
So what is a systematic literature review and meta-analysis?
*Literature search using scientific data-bases
In short, you go a scientific data base or several scientific data bases and extract all the publications that report the nutritional differences between organic and conventional meat or dairy products.
*Extract all accessible data and convert them into percentage differences between organic and conventional crops
*Statistical synthesis (“averaging”) of results. In simple terms you use a mathematical model to average the composition differences data.
*Both weighted and unweighted meta-analyses were done. Only weighted meta-analyses are considered scientifically sound from a mathematical point of view and is presented here.
A weighted meta-analysis looks at many samples across many parts of the world, thus it has a bigger weight than for instance a small study that might have looked at two milk samples. This is a more complicated mathematical algorithms and you need data on the statistical variation within the study. You can’t include data from studies which haven’t reported their variation. Even in peer-reviewed journals, this is sometimes the case in this particular space of science. This is why we also did an un-weighted meta-analysis, because that allows you to include all those studies which haven’t reported their variation, which gives you a little bit of a sensitivity analysis, on whether your weighted analysis, for which you have fewer data for, is actually sound.
We published the data on milk in 2016, and you can see that it’s a big group of people that were involved.
Średnicka-Tober, D., Barański, M., Seal, C., Sanderson, R., Benbrook, C., Steinmamn, H., Gromadzka-Ostrowska, J., Rembiałkowska, E., Skwarło-Santo, K., Eyre, M., Cozzi, G., Krogh Larsen, M., Jordon, T., Niggli, U., Sakowski, T., Calder, P.C., Burdge, G.C., Sotaraki, S., Stefanakis, A., Stergiadis, S., Yolcu, H., Chatzidimitriou, E., Butler, G., Steward, G., and Leifert, C. (2016)
Higher PUFA, and n-3 PUFA, conjugated linoleic acid, α-tocopherol and iron, but lower iodine and selenium concentrations in organic milk: a systematic literature review and meta-analysis. British Journal of Nutrition 115, 1045-1060: 2016
For more information see:
We had to find information from all sorts of different countries and a lot of the information in this particular space of science comes from data which is not published in English, so we needed to translate quite a bit from Germany and also from Poland. At the beginning of 2018 we published a big gap in the milk data which is what’s happening in the US.
Benbrook, C.M., Davis, D.R., Heins, B.J., Latif, M.A., Leifert, C., Peterman, L., Butler, G., Faergerman, O., Abel-caines, S., Baranski, M. Enhancing the fatty acid profile of (organic) milk through forage-based rations, with nutrition modelling of diet outcomes, Food Science and Nutrition 6, 681-700: 2018
For more information see:
This study allowed us to look at two different types of organic production: standard organic and grass-fed organic. This is possible in the US because they now have a market for a sub-division of organic product which is grass-fed organic milk products. This allows us to learn a little bit more about the potential is for improving organic farming. This is why I am showing you data from that study as well. The data set that we have for milk and dairy products is very solid, it’s based on 170 papers on cow’s milk alone. There’s a few on sheep as well which show the same results. I am showing you the cow’s milk data.
Średnicka-Tober, D., Barański, M., Seal, C., Sanderson, R., Benbrook, C., Steinmamn, H., Gromadzka-Ostrowska, J., Rembiałkowska, E., Skwarło-Santo, K., Eyre, M., Cozzi, G., Krogh Larsen, M., Jordon, T., Niggli, U., Sakowski, T., Calder, P.C., Burdge, G.C., Sotaraki, S., Stefanakis, A., Stergiadis, S., Yolcu, H., Chatzidimitriou, E., Butler, G., Steward, G., and Leifert, C. (2016) Composition differences between organic and conventional meat: a systematic literature review and meta-analysis. British Journal of Nutrition 115, 994-10111: 2016
For more information see:
We also published in 2016. We had 67 papers on meat, which is a lot less. This sounds impressive at first but when you dig down a little bit and look at the individual meat commodities, it’s relatively little. Sixteen reviews on beef, they are not all reporting on the same nutritional composition components and this is not a lot. On meat we know a lot less than milk. The good thing is, the quality of milk is linked to the same agronomic parameters as the quality of meat with respect to fat at least. We can only talk about fat because we only have composition difference data.
That is a limited evidence base, too limited to even detect differences for some of the components people have measured. So sometimes we have 60% differences still not being statistically significant because of the variations on top of these studies. There are probably additional composition differences which will be detected once we have more information.
That’s a long introduction. There is more to include in the introduction because fat composition differences need a little bit of information on why they are actually nutritionally desirable or undesirable. I am concentrating on the main areas of where we currently know about the differences between organic and conventional foods.
Nutritionally desirable compounds in milk and meat fat are the polyunsaturated fatty acids (PUFA), in particular:
- Omega 3 (Ω-3 fatty acids)
- Conjugated linoleic acid (CLA)
Alpha linolenic acid (shortest chain omega-3 fatty acid) - (ALA), EPA, DPA, DHA are desirable because they are:
Linked to a reduced risk of diabetes and heart/cardiovascular diseases;
Additional benefits linked specifically to increased long chain Ω-3 (EPA, DPA, DHA) intake include (a) improved fetal brain development, (b) delayed decline in cognitive function in elderly men and (c) reduced risk of dementia. This is probably the only food component that the food standard agencies around the world believe and agree on, you should have more of in your diet.
*EPSA recommends that dietary intakes of long chain Ω-3 fatty acids (EPA, DPA, DHA) are
increased by 100%, especially during pregnancy.
The other component that some people believe is good for you is:
*Linked to a reduced risk of heart disease, obesity and cancer; improved immune function
*Most evidence if from in vitro and animal studies
The latest meta-analysis of human dietary intervention studies where people have been given synthetic CLA, suggest there is a trend to reduced weight-gain. That’s all we can say from the human studies. We have to take the benefits of CLA with a ‘pinch of salt’, many people believe in the benefits and buy CLA supplements. There is no EPSA recommendation to increase our intake but there is some scientific evidence that it may have some benefits, that’s why people are buying supplements.
Nutritionally undesirable fatty acids:
Polyunsaturated fatty acids are overall undesirable and yet essential.
Omega 6 (Ω-6) fatty acids (are essential fatty acids, but we are adding too much to our typical Western diet.)
Linoleic acid (LA)
- Ω-6 intakes in Western diets are thought to be too high
- increased consumption over 100 years, of plant oils with high Ω-6 content
- g. corn and soybean oil have Ω-6:Ω-3 ratios of 50:1
- Ω-6:Ω-3 ratios in average Western diets: 15:1
- Ω-6:Ω-3 ratios during most of human evolution 1:1
- high Ω-6 intakes and/or dietary Ω-6/ Ω-3 ratios were linked to an increased risk of cardiovascular and other chronic diseases (Benbrook et al. 2018)
Most people agree that anything we can do to reduce dietary Ω-6 is a good thing.
Saturated fatty acids (are not all bad, but the three listed below have been linked to negative impacts upon health).
Lauric (C12:0), myristic acid (C14:0), palmitic acid (C16:0)
- linked to an increased risk of cardiovascular diseases, obesity and cancer, (the omega-6 fatty acids have a negative impact upon what the omega 3 fatty acids have a positive impact upon).
Myristic acid is the worst, a 14-carbon fatty acid. This is where we find the difference between organic and conventional meat and I will come back to this later.
Let’s look at the composition differences that we found in the meta-analysis and the farm surveys. Primary assessment SLIDE HERE The meta-analysis showed that both milk and meat have between 50% and 60% higher concentrations of omega-3 fatty acids. The evidence base is quite solid for both organic milk n=12, P<0.001 and meat n=21, P=0.026, one of the few parameters where we have fairly solid evidence for meat as well as for milk. Looking at America allowed us to look at both standard organic systems where farmers on average include about 20% - 30% grain in the diet, some use more. some use none at all, the data is based on averages. You can see that going from standard organic to grass-fed organic you get a massive additional boost of omega-3 fatty acids. You may have 50% more with standard organic but you have 100% more with grass-fed organic. An area of organic farming if it wanted to quality focused still has massive reserves. Remember, the nutritional experts tell us we need more omega-3 in our diet. If we look at the omega-6/omega-3 ratio in our meta-analysis, we showed that going to organic dairy production we can reduce that by about 2/3. The omega-6 content in milk remains the same. The omega-3 content goes up when we go to standard organic. We have a reduction in the ratio of omega-6 to omega-3 ratio when we go to standard organic and this is in line with dietary recommendations (I REPHRASED THIS A LITTLE).SLIDE HERE If we go to grass-fed organic, the information is only available from the US farm survey, (where less grain is fed in organic farming systems than in Europe), the ratio is reduced to 1:1, which is where it was before evolution. So organic grass-fed milk and the same is true for beef, it would dilute the high omega 6/omega 3 ratio that we get in our diet from the plant fats.
Now I am coming to some of the other composition differences that we detected from milk in the meta-analysis. There were also significantly higher but only a small increase for total polyunsaturates. There was 40% more CLA, and if academics eventually find that CLA is definitely good for us then this is good news as well. SLIDE HERE. There were slightly higher concentrations of Vitamin E, but it tended to much higher concentrations of the natural Vitamin E. This is because organic farmers are not allowed to use Vitamin E supplements. So despite conventional farmers all using synthetic Vitamin E supplements in the milk, the production system that was based on grazing, still had higher Vitamin E content, and all of it is natural Vitamin E. That’s quite impressive if you consider how much synthetic Vitamin E is added for the health of the cow in conventional farming.
Iodine concentrations were significantly lower. SLIDE HERE We expected that, because iodine is mainly supplied by a mineral supplement via grain to organic cows. This can be positive or negative, depending on the iodine supplementation strategy of your country. We had slightly higher concentrations of iron, slightly lower concentrations of selenium. That is relatively irrelevant for human nutrition because we don’t get much of our iron and selenium from milk and dairy products. But in some countries we do get a lot of our iodine from milk.
Let me tell you a little bit about iodine because it’s a complex story. As I said, it can be a good message and it can be a bad message.
Iodine SLIDE HERE
Essential mineral for thyroid function and brain development (especially in pregnancy and early life). So you need omega-3 and iodine for brain development of the child.
-Recommendations for iodine intakes are higher for pregnant women (iodine supplements are often used for pregnant women when iodine is difficult to access from the diet)
Most foods (terrestrial) are low in iodine, because our soils have been exploited for iodine over a long period of time.
-Fish, seaweed and dairy products are high iodine (for different reasons, fish and seaweed because there is lots of iodine in the sea. Dairy products are high in iodine because we use a lot of iodine fortification in milk. Iodine supplements are added to the grain that we feed cattle).
Iodine fortification is widely used for:
-Table salt (WHO recommendation). In *Australian I note that you fortify table salt, so I assume that like the Chinese you have a general rule that you fortify table salt (*CHECK THIS FOR CARLO). In the UK this is not the rule, it is difficult to obtain fortified table salt.
-Milk (supplementation of concentrate feed, UK)
Optimum iodine intake levels are relatively close to excessive (unhealthy) intake. The symptoms you get are pretty much the same ?, so that is the problem with getting iodine intake right. Especially if you have parts of the population which stop drinking milk, then they get too little iodine. The bad thing in the UK, girls between 12 and 20 stop drinking milk because they think it makes them fat, then you get too little iodine and if you get pregnant you have problems. In circumstances like the UK where people have less iodine in organic milk, this situation is not a good thing. If they don’t drink any milk it doesn’t matter if it’s organic or conventional.
Generally in Europe we have a problem with high iodine levels found in milk because:
-iodine teat-disinfection and mineral supplementation in livestock production can result in excessive dietary iodine intakes in humans.
-EFSA recommendation is to reduce permitted levels of iodine supplementation of livestock concentrate feed, especially in areas where people drink a lot of milk like Holland and Finland, thus it’s a very complex issue. My feeling that is in Australia you are in a similar situation to many European countries, where you have iodine added to table salt, and fish is cheap to buy so you probably have a high fish intake. So for Australians, it is probably a good thing if iodine is slightly lower in organic products. In the UK, the organic farmers have now increased the iodine concentrations in their mineral supplements to get higher concentrations of iodine into their cows via the little bit of concentrate they feed. They are now running UK milk at a slightly higher iodine level than conventional. So they have reacted and in the UK that was essential to do for both marketing and human health reasons.
Any questions about iodine, I know it’s a complex issue.
Let’s get back to meat. In meat, the only other things we can talk about with respect to nutritional differences are total PUFA (polyunsaturated fat). There is a much bigger difference in total polyunsaturated fat (which is generally seen as a positive thing having more of that as opposed to saturated fat), so the difference is bigger than in milk than in meat. But the more interesting thing is, there is also a 20% lower concentration of myristic acid, which is the saturated fatty acid that has been most strongly linked to an increased risk of heart disease. Palmitic acid similarly but less so than myristic acid, has been linked to an increase risk of heart disease, is also slightly but still significantly lower.
That brings us to ‘why’? SLIDE HERE Why does organic milk and meat contain higher levels of omega-3 fatty acids CLA and Vitamin E? There are three factors which influence the concentrations of the above: the most important and significant factor is, diet. An old biodynamic friend of mine in Germany once said when I presented this data to him, “Carlo, you are telling us cows need to eat grass, we knew that”. There is so much more omega-3 available in milk when switching from 70%-80% grass to 100% grass, the most important time is during the lactation period. If you have dry cows on a bit of concentrate, that’s not a bad thing, but during the lactation period that’s when you want to push milk quality.
Evidence form the UK/EU milk and meat quality surveys and experimental studies. SLIDE HERE
The same is true for meat. We have this information not from organic versus conventional comparisons but simply from comparing concentrate, grain and grass-fed systems. These experiments were done 20 to 30 years ago and we just have to look at them. There is a really good study done in Australia that shows that only grass-fed systems can push the omega-3 levels to levels where your food standard agency said that you can sell that meat as an omega-3 rich food. SLIDE HERE This is also true for lamb on grass-based diets, EPA, DPA and DHA concentrations more than double. (Based on data from Nuernberg et al. 2005 and Fisher et al. 2000). The trouble for beef is that eating lamb meat is pretty good on omega-3s, so eating sheep is better than eating cow. Goats are similar to lamb.
So diet is the main driver. But there are a few other areas that can influence your omega-3 and other fatty acids components. SLIDE HERE. This looks a bit confusing doesn’t it, but I have to put it in because it’s the ultimate analysis you can do to get an idea of what affects what. So this diagram shows the output of a redundancy analysis. It is simple in what it tells, the red arrows are the things that you know will drive milk quality, such as the feed components, such as fresh-forage (grass), grass silage, hay, maize silage, mixed hay and concentrate. If you use fresh forage or grass silage your effect on the omega-3s is roughly the same because they both push the omega-3s up. The things that push omega-3 concentrations in milk down, but omega-6 concentrations up are maize silage and maize concentrate which in Europe is widely used in dairy production. SLIDE HERE
How you manage your grass-land is also important, and I want to emphasise that point via some data from Wales. In Wales we have standard conventional production but high grass intake. So this would be, probably, similar to average organic in terms of grass intake, because grass grows very well in Wales. So the studies show standard conventional, organic grass-fed (so nobody in the organic world in southern Wales would buy any concentrate, it is economically not-interesting the grass grows all day, they are all on spring-calving all-year round grazing systems and that makes economic sense in that area). Butler et al. 2008.You also have conventional grass-fed because that also makes economic sense, increasing economic sense, because concentrate prices have gone up since about 15 years ago. Yet still, even though they do exactly the same, they both have grass-clover overlays???, they both graze all year, they have the same type of cattle genotypes, they do exactly the same except for the conventional guys putting a little bit of nitrogen, not even a lot, 50/60 k of nitrogen early in spring to get the grass growing. That changes your grass/clover ratio and the grass/clover/herb ratio in the grassland. You pick that up with a significant difference in omega-3 content. SLIDE HERE The trend we are getting here is a species rich grassland, legumes and herbs coming into the grass land, gives you additional benefit with respect to your overall milk fat quality. SLIDE HERE. The best milk we produce is on herb-rich, legume-rich pastures in the Alpine areas where nitrogen has never been added. I suspect if we look at natural pastures in Australia, we would find the same effect compared to managed and improved pasture land.
Effect of grazing and cattle genotype on omega-3 (n-3) concentrations in milk. Grassland management also makes a difference to concentrations of omega-3 in milk and so does breed. Organic principles suggest you should go for traditional robust breeds and that will have a benefit. It doesn’t specify the benefit, it just says it will have a benefit. There are assumptions about where the benefits come from but with respect to the omega-3 fatty acids, and some other fat components we found that is true. In a big study in Switzerland, involving about 1,000 dairy cows, we looked at the individual milk quality components over a year. We compared Traditional Braunvieh cattle (Swiss cattle which never left Switzerland, they were always raised on pasture, not selected for yield on maize-rich diets, so they remained the same relatively small cattle. We could compare this in Switzerland to genetics that were based primarily on US Brown Swiss. These cattle are Traditional Braunvieh which the Swiss emigrants took to the United States about 200 years ago when Switzerland was still poor. The cattle were strongly selected for yield for 150 years and the animals became bigger, they became better at converting maize into higher milk yields. But when they brought them back to Switzerland in the 1960s to increase milk yield, there was a small window where that was done, they are still around in the low-land areas of Switzerland where they grow maize.
If you put these cattle back onto pasture they don’t have the capacity anymore to convert pasture into high omega-3 content milk. These are cattle which were put onto 25% to 50% dry matter intake for grazing, there is no difference between the Traditional and the US Brown Swiss. But the US Brown Swiss on maize-rich diets produce a high milk yield. If you put them onto high forage, (grass-fed diets), the traditional cattle produce twice as much omega-3 fatty acids in their milk and they have the same milk yield. So breed is also important, it’s just a very difficult thing to study. This was an extremely expensive study because it has to be based on about a 1,000 dairy cows from a large-enough number of farms so that your statistician is happy. I don’t think we will ever be able to repeat this again, but it was done and it showed the effect breed can have. SLIDE HERE It gives us a clear hint that if we want to go for quality based marketing, and possibly less costs from the veterinarian, we need to go for cattle that are more robust rather than yield-selected cattle, you need to use traditional breeds. So breed selection will also be important.
In summary, it is really quite easy when it comes to quality of milk and meat from the results that we have had. SLIDE HERE. If you choose outdoor grazing systems and if you have an indoor period or a period where you haven’t got the grass growing you go for conserved forages, during that period and if you use traditional breeds, that is the secret to getting high omega-3s, CLA, total polyunsaturates, Vitamin E and some studies also show carotenoids into your milk and meat. We know that diverse natural pastures may give you an additional ‘kick’, but this is something that is under-investigated, so I don’t have too many data on that. Whereas if you use maize and cereals as a main component of your diet, feedlot systems, then your omega-6, but also your myristic acid and your palmitic acid in meat go up. All of this research was supported by the European Union which has a very forward research program and has funded us, me and my research group for the last 30 years, so I am very grateful to them. Thank you very much. (42:59) Slide of NorthumberlandJ
We gratefully acknowledge funding form the European Community financial participation under the Sixth Framework Programme for Research, Technological Development and Demonstration Activities, for the Integrated Project QUALITYLOWINPUTFOOD, FP6-FOOD-CT-2003-506358
Professor Carlo Leifert, director of the newly-established Centre for Organics Research, gives the first of a series of lectures in organic farming. Duration 30 mins.
Not available at this time.