Modern Farmer has an interesting piece on Greek Yogurt’s Dark Side detailing the problem of disposing tens of millions of gallons of acid whey and some of the solutions that are being developed to make use of it. The central problem is that making Greek style yogurt produces more byproduct than traditional yogurt. That is because more liquid is strained in order to concentrate the protein content. You need to concentrate the protein content because you are using less fat and you want that lush texture and mouthfeel that traditional low-fat yogurt lacks.
There is a very simple solution to the problem. Stop eating Greek style yogurt. Stop avoiding dairy fat. Eat whole milk yogurt. It is more nutritious, it tastes better and it probably better for weight management and is not associated with heart disease. Problem solved.
I’m not exactly sure what inspired Allison Aubrey to report on two research papers from last year as breaking news, but I’m glad she did, and glad her story has gained some legs.
New research suggests we may want to look anew.
Consider the findings of two recent studies that conclude the consumption of whole-fat dairy is linked to reduced body fat.
In one paper, published by Swedish researchers in the Scandinavian Journal of Primary Health Care, middle-aged men who consumed high-fat milk, butter and cream were significantly less likely to become obese over a period of 12 years compared with men who never or rarely ate high-fat dairy.
Yep, that’s right. The butter and whole-milk eaters did better at keeping the pounds off.
“I would say it’s counterintuitive,” says Greg Miller, executive vice president of the National Dairy Council.
The second study, published in the European Journal of Nutrition, is a meta-analysis of 16 observational studies. There has been a hypothesis that high-fat dairy foods contribute to obesity and heart disease risk, but the reviewers concluded that the evidence does not support this hypothesis. In fact, the reviewers found that in most of the studies, high-fat dairy was associated with a lower risk of obesity.
The reason I’m glad, is that this goes to a long running pet peeve of mine. All too often, the conventional wisdom in nutrition is unsupported by the data. Sometimes, it’s in direct contradiction.
When I first started becoming interested in nutrition, I came across a study headed by a Harvard study from 2005 that followed a group of 12,829 US children, aged 9 to 14 years from 1996 through 1999. The purpose of the study was to “assess the associations between milk, calcium from foods and beverages, dairy fat, and weight change over time.” Data was collected by surveys returned by mail. After looking at the data, these were their conclusions:
Children who drank the most milk gained more weight, but the added calories appeared responsible. Contrary to our hypotheses, dietary calcium and skim and 1% milk were associated with weight gain, but dairy fat was not. Drinking large amounts of milk may provide excess energy to some children.
At the time, it seemed interesting and counterintuitive and was duly filed away to some empty dendrites I had lying around. Not long after, in 2006, came news that New York City was removing whole milk from the public school cafeterias in order to combat childhood obesity. Low fat chocolate milk would be allowed, but whole milk would be banished. The report also mentioned that Los Angeles had done the same in 2000. It was reported that some states had made the same change or were considering it.
I had to wonder; had the nutritionist for a school system with 1.1 million students have missed the Harvard study? Was there other research that contradicted the 2005 study? Had anyone bothered to collect any data in Los Angeles to measure the impact of the change made in 2000? In 2006, those answers to those questions weren’t as easy to find for an amateur with a short attention span like myself. I was reduced to stewing on the fact that a very large public health intervention had been made in contradiction of the only research I could find on the issue. A huge pet peeve of mine is the willingness, especially in nutrition to undertake public policy interventions in the absence of any evidence that they will achieve the desired outcome. (I’m looking at you restaurant calorie postings.)
The one other thing I found on the issue at the time, was that hog farmers have been using skim to fatten hogs since your grandfather was in short pants. The observation that skim milk was particularly fattening was borne out by the research at the time. From the Station Bulletin, Oregon State Agricultural College – November 1930 [pdf]:
Skim milk. This is not only the very best supplement for growing pigs, but is of almost equal value for fattening purposes. Though very low in dry-matter content, milk furnishes a complete protein, which fact accounts in a large measure for the excellent returns. Milk renders the ration more palatable, inducing greater consumption and consequently greater daily gains. Also milk is a good source of minerals.
Granted, they weren’t comparing it to whole milk, but still … not a promising observation for Hansel and Gretel.
Sometime in 2011, I did finally follow up and gather all the relevant research I could find. The nearly dozen and a half papers I gathered at the time were nearly an exact match to those that the Kratz paper looked at.
METHODS: We have conducted a systematic literature review of observational studies on the relationship between dairy fat and high-fat dairy foods, obesity, and cardiometabolic disease. We have integrated these findings with data from controlled studies showing effects of several minor dairy fatty acids on adiposity and cardiometabolic risk factors, and data on how bovine feeding practices influence the composition of dairy fat.
RESULTS: In 11 of 16 studies, high-fat dairy intake was inversely associated with measures of adiposity. Studies examining the relationship between high-fat dairy consumption and metabolic health reported either an inverse or no association. Studies investigating the connection between high-fat dairy intake and diabetes or cardiovascular disease incidence were inconsistent. We discuss factors that may have contributed to the variability between studies, including differences in the potential for residual confounding; the types of high-fat dairy foods consumed; and bovine feeding practices (pasture- vs. grain-based) known to influence the composition of dairy fat.
CONCLUSIONS: The observational evidence does not support the hypothesis that dairy fat or high-fat dairy foods contribute to obesity or cardiometabolic risk, and suggests that high-fat dairy consumption within typical dietary patterns is inversely associated with obesity risk. Although not conclusive, these findings may provide a rationale for future research into the bioactive properties of dairy fat and the impact of bovine feeding practices on the health effects of dairy fat.
The literature gathered was from 1999 to 2011. As to my earlier question about what research had been available at the time the New York school district was making the decision to eliminate whole milk from their cafeterias, seven of the studies considered were available at the time. None of them supported the idea that removing whole milk from students diets would be helpful in combatting obesity. The clear majority suggested the opposite.
I had drawn the same conclusions looking at the same literature as Kratz and company did. But, I also wondered about the studies that did show a correlation between dairy fat consumption, adiposity and metabolic health. The paper’s authors noticed the same geographic pattern that I had.
Examining Table 1, it is clear that location has a major inﬂuence on the studies’ outcomes. Of the nine studies that were conducted in Europe, eight found that dairy fat intake
is inversely associated with adiposity. Of the seven that were conducted in the United States, three found an inverse association, while four did not. Three factors stand out as possible explanations for this discrepancy.
The ﬁrst is the high potential for residual and unmeasured confounding in US cohorts. Since the 1980s, there has been a public health campaign in the United States to lower the consumption of SFA-rich foods such as animal fats. As a result, dairy fat is perceived as unhealthy in the United States, and one would expect its consumption to be associated with other behaviors that are perceived as unhealthy. Indeed, Liu et al. reported that US women in the highest quintile of high-fat dairy intake were 62 % more likely to be current smokers than women in the lowest quintile, whereas women in the highest quintile of low-fat dairy intake were 62 % less likely to smoke than the lowest quintile.
Similarly, dietary ﬁber intake was 21 % lower in the highest quintile of high-fat dairy intake compared to the lowest. Comparable trends were reported by Margolis et al., including substantially higher physical activity and income level in the top quintile of low-fat dairy intake, and substantially lower physical activity and income level in the top quintile of high-fat dairy intake . This demonstrates the cultural stigma attached to dairy fat consumption in the United States, and casts doubt upon the ability of observational studies to fully adjust for the unhealthy lifestyle patterns that associate with dairy fat consumption in this environment.
Or as I would put it: Pizza and Cheeseburgers.
So it was unsurprising, when I learned later that week that, “that an astonishing 13% of the U.S. population consumed pizza on any given day”. More disturbing:
For this large population — more than 1 out of 8 Americans — who consumed pizza in a particular day:
- Pizza accounted for 25% (among kids) and 29% (among adults) of daily food energy intake. More than a quarter of all calorie intake was pizza.
- Pizza accounted for 33% (among kids) and 39% (among adults) of daily saturated fat intake. Compared with foods in general, pizza is much heavier in saturated fat.
- Pizza accounted for 33% (among kids) and 38% (among adults) of sodium intake. Compared with foods in general, pizza is much heavier in sodium.
In recent years, USDA’s dairy checkoff program has spent many millions of dollars to increase pizza consumption among U.S. children and adults. Using the federal government’s taxation powers, the checkoff program collects a mandatory assessment of 15 cents on every hundredweight of milk that is sold for use as fluid milk or dairy products. The total mandatory assessment in 2011 was $104 million for fluid milk and $98 million for other dairy products, according to the most recent annual USDA Report to Congress. These expenditures are many times greater than federal spending on promoting fruits and vegetables, whole grains, or any of the other foods for which the Dietary Guidelines recommend increased consumption.
I love it when a plan comes together. But, not always.
The Full-Fat Paradox: Whole Milk May Keep Us Lean
Allison Aubrey | The Salt/NPR | 12 February 2014
High dairy fat intake related to less central obesity: a male cohort study with 12 years’ follow-up.
Holmberg S, Thelin A. | Scandinavian Journal of Primary Heathcare | June 2013
The relationship between high-fat dairy consumption and obesity, cardiovascular, and metabolic disease.
M Kratz, T Baars, S Guyenet | The European Journal of Nutrition | February 2013 | [pdf]
Milk, dairy fat, dietary calcium, and weight gain: a longitudinal study of adolescents.
Berkey CS, Rockett HR, Willett WC, Colditz GA. | Archives of Pediatrics and Adolescent Medicine | June 2005
In New York Schools, Whole Milk Is Cast From the Menu
David Herszenhorn | The New York Times | 2 February 2006
Fattening Pigs for Market [pdf]
Agricultural Experiment Station | Oregon State Agricultural College | Station Bulletin | November 1930
USDA reports on pizza consumption and on dairy checkoff program initiatives to increase pizza demand
Parke Wilde | US Food Policy | 7 February 2014
Ed Yong has a fascinating post about a new evolutionary biology study on cow milk and the differences for male and female offspring. If you are interested in animal husbandry and/or evolutionary biology it’s an interesting read especially if you follow through with the links, especially this one.
For the purposes of this blog, I’d like to underline something that Ed’s post alludes to but doesn’t call out specifically.
For decades, the dairy industry has used data to supercharge the humble black-and-white Holstein cow into a milk-producing machine. Across the US, thousands of dairy farmers keep assiduous records about how much milk their cows produce, and the volume and composition of that milk. All of this information feeds into mathematical models that predict the total amount of milk a cow makes over its lifetime. Farmers use this information every day to decide how to care for and breed their animals. As a result, cows today make four times more milk than they did in the 1940s.
. . . Either way, Hinde’s results have implications for the dairy industry. If they wanted to, dairy managers could ensure that most of the calves they breed are females, but they’d need to separate semen by sex to do so. In the past, some people have argued that this isn’t cost-effective, but it might be worth it if it leads to a 2.7 percent bump in milk production.
I think a lot of the conversation around food in this country (and around the world) is hamstrung by the naive, sentimental and sometimes schizophrenic vision many people have of agriculture.
Ed Yong’s post alludes to two things.
First. Modern selective breeding is much more specific and sophisticated than most people realize. In the last hundred plus years, selective breeding has produced much more substantial changes in domesticated animals and crops than people realize. Many amateur ‘critics’ of contemporary agriculture believe that selective breeding means farmers are just mating their healthiest males with their healthiest females in a parallel to survival of the fittest in nature. In their objection to genetic engineering they say that we should stick with our food the way it is, as nature intended. They seem to be completely unaware of how drastically we have engineered the genetics of domesticated plants and animals without recombinant DNA technology. They seem to be unaware that the market for bull semen goes back decades. They seem to be unaware that contemporary plant breeders use tissue cultures and genetic marker assisted breeding in their work. Selective breeding hasn’t been about capitalizing on serendipity for a long time. It works toward very clear, pre-defined goals.
Allow me to risk setting up a strawman argument. You can sometimes hear from the same quarters a pair of schizophrenic claims. In one context, people might say our health problems began 10,000 years ago with the introduction of agriculture and selective breeding. The claim is that humans haven’t been able to co-evolve to thrive on domesticated grains/wheat, as fast as we’ve been able to breed the grains for yield. The same has been said about cow’s milk. (The evidence though seems to go the other way on that count. Europeans actually evolved lactose tolerance very quickly.) In another context, the issue becomes that the (supposed) increase in chronic disease (allergies, autism, insert health problem du jour) in the last three decades must be caused by the rapid changes to agriculture in the last three decades. Our problems are either being caused by the Sumerians or Monsanto.
Where things can get really schizophrenic is when goalposts start getting moved as misinformation and misunderstanding is addressed. It’s about nutrition. No it’s about animal welfare. No it’s about food access and affordability. No, it’s about family farms. No it’s about the environment. I would argue that this stems from the fact that the pastoral sentimentality that drives so much of the current food conversation is really an aesthetic proposition. The arguments to defend that proposition shift as each is found wanting.
The second thing that Yong’s piece touches on is the positive environmental impact of contemporary breeding. I’ll let the Alexis Madrigal piece that he links to in his introduction make the case.
Dairy breeding is perfect for quantitative analysis. Pedigree records have been assiduously kept; relatively easy artificial insemination has helped centralized genetic information in a small number of key bulls since the 1960s; there are a relatively small and easily measurable number of traits — milk production, fat in the milk, protein in the milk, longevity, udder quality — that breeders want to optimize; each cow works for three or four years, which means that farmers invest thousands of dollars into each animal, so it’s worth it to get the best semen money can buy. The economics push breeders to use the genetics.
The bull market (heh) can be reduced to one key statistic, lifetime net merit, though there are many nuances that the single number cannot capture. Net merit denotes the likely additive value of a bull’s genetics. The number is actually denominated in dollars because it is an estimate of how much a bull’s genetic material will likely improve the revenue from a given cow. A very complicated equation weights all of the factors that go into dairy breeding and — voila — you come out with this single number. For example, a bull that could help a cow make an extra 1000 pounds of milk over her lifetime only gets an increase of $1 in net merit while a bull who will help that same cow produce a pound more protein will get $3.41 more in net merit. An increase of a single month of predicted productive life yields $35 more.
. . . One reason for the change in breeding emphasis is that our cows already produce tremendous amounts of milk relative to their forbears. In 1942, when my father was born, the average dairy cow produced less than 5,000 pounds of milk in its lifetime. Now, the average cow produces over 21,000 pounds of milk. At the same time, the number of dairy cows has decreased from a high of 25 million around the end of World War II to fewer than nine million today. This is an indisputable environmental win as fewer cows create less methane, a potent greenhouse gas, and require less land. . .
. . . While we may worry about the use of antibiotics to stimulate animal growth or the use of hormones to increase milk production by up to 25 percent, most of the increase in the pounds of milk an animal puts out over the pastoral days of yore come from the genetic changes that we’ve wrought within these animals. It doesn’t matter how the cow is raised — in an idyllic pasture or a feedlot — either way, the animal of 2012 is not the animal of 1940 or 1980 or even 2000. A group of USDA and University of Minnesota scientists calculated that 22 percent of the genome of Holstein cattle has been altered by human selection over the last 40 years.
In a sense that’s very real, information itself has transformed these animals. The information did not accomplish this feat on its own, of course. All of this technological and scientific change is occurring within the social context of American capitalism. Over the last few decades, the number of dairies has collapsed and the size of herds has increased. These larger operations are factory farms that are built to squeeze inefficiencies out of the system to generate profits. They benefit from economies of scale that allow them to bring in genomic specialists and use more expensive bull semen.
No matter how you apportion the praise or blame, the net effect is the same. Thousands of years of qualitative breeding on family-run farms begat cows producing a few thousand pounds of milk in their lifetimes; a mere 70 years of quantitative breeding optimized to suit corporate imperatives quadrupled what all previous civilization had accomplished. And the crazy thing is, we’re at the cusp of a new era in which genomic data starts to compress the cycle of trait improvement, accelerating our path towards the perfect milk-production machine, also known as the Holstein dairy cow.
Lastly, I think one of the things that becomes blindingly obvious from both pieces is how carefully all the input and health markers for these animals are recorded and monitored. The idea that the addition of biotech crops into their feed could be producing adverse health outcomes that have somehow evaded notice is preposterous. Unsurprisingly, when three decades of this data was reviewed, a complete absence of any problems was exactly what they found.
A new scientific review from the University of California, Davis, reports that the performance and health of food-producing animals consuming genetically engineered feed, first introduced 18 years ago, has been comparable to that of animals consuming non-GE feed.
The review study also found that scientific studies have detected no differences in the nutritional makeup of the meat, milk or other food products derived from animals that ate genetically engineered feed.
The review, led by UC Davis animal scientist Alison Van Eenennaam, examined nearly 30 years of livestock-feeding studies that represent more than 100 billion animals.
When it comes to the potential adverse effects that current biotech crops could have on birds or mammals, the argument that “We just don’t know” just doesn’t hold any water.
Study Of 1.5 Million Cows Shows Daughters Get More Milk Than Sons
Ed Yong | Phenomena | National Geographic | 23 January 2014
The Perfect Milk Machine: How Big Data Transformed the Dairy Industry
Alexis C. Madrigal | The Atlantic | 1 May 2012
An Evolutionary Whodunit: How Did Humans Develop Lactose Tolerance?
Helen Thompson | The Salt | NPR | 28 December 2012
10 Things You Didn’t Know About Bull Semen
Brian Cathcart | The Independent | 9 June 1996
Creating Tastier and Healthier Fruits and Veggies with a Modern Alternative to GMOs
Ferris Jabr | Scientific American | 23 January 2014
No sign of health or nutrition problems from GMO livestock feed, study finds
UC Davis | 25 September 2014
Prevalence and impacts of genetically engineered feedstuffs on livestock populations
Van Eenennaam and Young | Journal of Animal Science | 20 November 2014
Ferris Jabr | Scientific American | 23 January 2014
Marion Nestle had a piece earlier this week on how the American Society for Nutrition (ASN), (the organization that publishes the American Journal of Clinical Nutrition (AJCN) and the Journal of Nutrition) should deal with conflicts of interest, especially in the journals that they publish. Her points are sound and I don’t have much to add except that I’ve never understood how the sugar industry has been able to warp the conventional wisdom via sponsorships of organizations, research and research departments but the meat and dairy industries got rolled on fat and cholesterol.
The dairy industry I can understand, because they actually benefited from the low-fat milk nonsense. The admonishment to eat low fat dairy functions more like punctuation than actual advice in standard nutritionspeak. You’d think this would drive the dairy industry crazy until you look at the price of milk in the grocery store. A gallon of full fat, 2% and skim are all the same price. They got to sell people crappy reduced fat milk for the same price as the good stuff and sell the fat as butter, cream and half & half without skim milk as a by product. (Health conscious humans trying to watch their weight are willing to pay more for skim milk than hog farmers looking to fatten their hogs [pdf].)
But it’s seems weird that if the science was for sale, why didn’t the meat and egg people buy it? It should have come cheap as the evidence was mostly on their side when it came to fat and cholesterol.
Conflicts of interest in nutrition societies: American Society of Nutrition
Marion Nestle | Food Politics | November 20, 2013
Big Sugar’s Sweet Little Lies
Gary Taubes and Cristen Kearns Couzens | Mother Jones | November 2012
A Big Fat Debate
Kristen Wartman | Civil Eats | March 4, 2011
What’s Cholesterol Got to Do With It?
Gary Taubes | The New York Times | January 27, 2008
New Review Paper by Yours Truly: High-Fat Dairy, Obesity, Metabolic Health and Cardiovascular Disease
Stephan Guyenet | Whole Health Source | July 22, 2012
How to Fatten Hogs for Market [pdf]
Oregon State Agricultural College | 1930