Soy Vey!

Soy Vey!

    To begin, apologies to the Yiddish pun crowd; but the phrase captured the surprise at discovering that soybean oil might have been part of a marketing campaign whose benefits perhaps weren't as beneficial as originally presented (think back to the days of touting the benefits of margarine replacing butter).  Only now are the studies being released that the linoleic acid (once touted as necessary for our well-being) might actually be contributing to a large part of the growing obesity problem throughout the world...and that oil is getting into us, but not in the way you would think.

    One of the reports of this came from a piece in Mother Earth News as written by Richard Manning.  Starting in the mid-1960s, he writes, the use of soybean oil jumped a thousand-fold in 40 years (while other vegetable oil usage such as corn, olive and coconut remained flat), and much of this made its way into animals raised for meat: Today’s industrially raised livestock, poultry and farmed fish are almost universally fed soybean meal and oil.  Their feed’s components are then found in the meat, milk and eggs sold to consumers.  This study and others like it are explicit about this: Consumers get much of the soy in their diets secondhand from eating industrial meat, eggs and dairy products, as well as farmed fish.  His article echoed a study done by the federal NIH (National Institute of Health) which stated: The estimated per capita consumption of butter and lard decreased (73% and 77%, respectively), whereas the consumption of margarine, shortening, and beef tallow increased appreciably (1038%, 170%, and 371%, respectively) (Figure 1B).  In general, the consumption of oils increased; however, a few specific oils were responsible for this change.  After the market introduction in 1986, the estimated per capita consumption of canola oil increased 167-fold in 13 y from 0.01 to 0.8 kg...The estimated per capita consumption of soybean oil increased from 0.009 kg soybean oil in 1909 to 11.64 kg soybean oil in 1999 (a 1163-fold increase), which made it the primary driver of the overall increase in oil consumption.  Although there were many fluctuations in the availability of all foods, no other notable trends in essential fatty acid sources were observed.  Graphs for oil usage in the next 15 years (2000-2015) show soy oil consumption being roughly matched by palm oil (which is now facing political ramifications due to its harvesting costs), with the other oils consumed still remaining flat.

    So what's the big deal?  And where the heck does linoleic acid fit into the picture?  As it turns out, everything is moderation is the key here; but soybean oil is high in linoleic acid, and studies are apparently showing a link with such intake to obesity.  Says Manning's piece: Nothing is inherently wrong with linoleic acid; it is, after all, an essential fatty acid.  But it’s problematic in excess, as evidenced from a 2012 study published in the journal Obesity.  Feeding lab animals a diet in which 8 percent of their calories come from linoleic acid, a mirror of the modern U.S. diet, made them fat.  Reducing their linoleic acid intake to 1 percent (in line with our ancestral diet), and replacing those calories with calories from other fats, made these same animals skinny again, like throwing a switch.  Same amount of calories, same high-fat diet — but with different kinds of fats — and obesity reversed itself.  But you're not a big user of soy oil, you say?  What Manning and many other authors are now pointing out is you may not think you use a lot of soy oil, but basically, it's everywhere in our diet.

    PLOS is a "nonprofit publisher and advocate of Open Access Research," and recently posted a research paper that talked about soybean oil and its possible role in contributing to obesity (and admittedly it's quite long so if you want, just jump down to the last sentence of this excerpt from the paper): The obesity epidemic in the U.S. has led to extensive research into potential contributing dietary factors, especially fat and fructose.  Recently, increased consumption of soybean oil, which is rich in polyunsaturated fatty acids (PUFAs), has been proposed to play a causal role in the epidemic...There has been an alarming increase in obesity and its associated co-morbidities—diabetes and heart disease—in the U.S. during the last four decades.  Recent estimates suggest that 36% of the U.S. population is currently obese and by 2030 this will increase to ~50%.  Furthermore, obesity is no longer a problem of developed countries but has become a major global health issue with an estimated 3.4 million deaths worldwide being attributed to it annually.  Often associated with obesity are diabetes, insulin resistance (IR) and nonalcoholic fatty liver disease (NAFLD), which along with heart disease and hypertension, are referred to as the Metabolic Syndrome.  There are many contributing factors to obesity, including genetics, lifestyle, environmental factors and microbiota, but diet is still one of the most relevant, both in terms of the number of calories that are consumed as well as the source of those calories...Saturated fatty acids (SFAs) were deemed unhealthy due to studies in the 1950s and 1960s that showed a positive correlation between dietary SFAs and the risk for cardiovascular disease.  As a result, nutritional guidelines were developed that encouraged people to reduce their intake of saturated fat, typically found in meat and dairy products, and increase their intake of polyunsaturated fatty acids (PUFAs) found in plant oils.  These guidelines are still in effect today.   In recent years, however, there has been a shift in the dialogue surrounding which dietary fats are the most harmful, with some studies suggesting a reconsideration of nutritional guideline...The recommendation for decreased saturated fat consumption, as well as other factors, led to a dramatic, >1000% increase in the consumption of soybean oil in the U.S. from 0.01 to 11.6 kg/yr/capita between 1909–1999.  Approximately 40 million tons of soybean oil were produced worldwide in 2007, which is about one half of all the edible vegetable oil and one-third of all fats and seed oils produced.   Soybean oil is heavily used in processed foods, margarines, salad dressings and snack foods, and is the oil of choice in many restaurants and fast food establishments.  While there has been extensive investigation of the role of various other dietary components in obesity, especially SFAs, soybean oil has received relatively little attention.  Soybean oil is high in PUFAs whereas most experimental animal studies employ diets high in saturated fats, typically lard.  While several studies have looked at the effects of soybean oil on obesity and diabetes, the experimental designs were quite variable as were the results.  There has also not been any global transcriptomics or metabolomics analysis of the effects of soybean oil on the liver, a primary metabolic organ...In this study, we examined the effect of both soybean oil and fructose on the development of obesity and its associated co-morbidities in C57/BL6 male mice, in the context of a diet moderately high in total fat...Taken together, these results indicate that while there may be some health benefits to a diet rich in soybean oil, and while fructose induced some negative effects in the gut and kidney, overall soybean oil induced more obesity, diabetes, IR and liver injury than either fructose or saturated fat from coconut oil in mice.

    Loren Cordain (Ph.D.) noted the study on his Paleo diet page (he is considered a founder of the Paleo Diet movement): Since the 1930s, the US government has been heavily subsidizing corn, soy, wheat, and other so-called staple crops. Subsequently, these foods have remained artificially cheap for decades, leading to enormously increased consumption...For a new study, just published in PLOS One, scientists at UC Riverside compared the effects of diets high in soybean oil with those high in fructose and/or coconut oil.  They concluded that soybean oil, when consumed at typical American consumption levels, causes significant liver damage and promotes obesity and diabetes even more so than fructose...“This was a major surprise for us—that soybean oil is causing more obesity and diabetes than fructose—especially when you see headlines everyday about the potential role of sugar consumption in the current obesity epidemic,” said Poonamjot Deol, the study’s lead scientist...This study is believed to be the first comparing the effects of unsaturated fat, saturated fat, and fructose on obesity, diabetes, insulin resistance and nonalcoholic fatty liver disease.

    Confused?  Isn't soy supposed to be good for you, an all-around protein?  Well, yes, says the International Journal of Medical Sciences, an offshoot of the NIH.  But soybean protein (think tofu and such) is way different than soybean oil.  Here's a simpler explanation as offered by Kris Gunnars, BSc, at Authority Nutrition: The main problem with most of these oils is that they are way too high in Omega-6 polyunsaturated fatty acids.  Both Omega-3 and Omega-6 fatty acids are so-called essential fatty acids, meaning that we need some of them in our diet because the body can’t produce them.  Throughout evolution, we got Omega-3 and Omega-6 in a certain ratio.  Our Omega-6:Omega-3 ratio used to be about 1:1.  However, in the past century or so, this ratio in the Western diet has shifted drastically, all the way up to 16:1 (1).  When the Omega-6:Omega-3 ratio shifts too high...the excess Omega-6 fatty acids build up in our cell membranes and contribute to inflammation...When we refer to saturated, monounsaturated or polyunsaturated fats, we’re referring to the number of double bonds in the fatty acid molecules.  Saturated fats contain no double bonds.  Monounsaturated fats contain one double bond.  Polyunsaturated fats contain two or more double bonds...The problem with polyunsaturated fats is that all these double bonds make them susceptible to oxidation.  The fatty acids react with oxygen and this damages them.  If we have a lot of these fatty acids in our bodies (remember: they get stored) – then our cell membranes are more sensitive to oxidation.  Basically, we’ve got our bodies loaded with very fragile fatty acids that can easily be degraded to form harmful compounds.   

    Still puzzled?  Here's the basics: 1) soybean oil is highly subsidized in the U.S. (about 1/3 as much as corn is) and thus, quite cheap; 2) because it is cheap, it is fed to cattle, pigs and chickens, as well as restaurants and food producers; 3) soybean oil is high in linoleic acid, which is good in itself but; 4) we now get too much soybean oil because it is in so many products and we weren't really aware of that; 5) too much linoleic acid is not good for us, apparently leading to everything from obesity to liver damage, according to recent studies; and 6) as author Manning says in his article, "We have been victims in this complex interplay that's led to ill health."

    Again, this is a blog so keep that in mind.  There are all sorts of research papers out there, some in favor of soybean oil and some against, so do your own investigating.  My goal here was simply to start the ball rolling, to perhaps make you check that ingredient label one more time and see if soybean oil is showing up again, and again, and again in what you're eating.  Dive into looking at linoleic acid and see what it's good for and what too much of it can or can't do to your body...the lid has been taken off of this subject, and all that's left is for you to decide what, if anything, you want to do to what you're eating.  Victims?  Maybe, maybe not.  But as a consumer, you can decide what you want to buy and what to eat and from who...and you can also decide if you even want to bother reading an ingredient label.  Mooo...