The late 1980s represented a high point for the vegetable oil industry. Thanks to decades of marketing efforts by the industry and the lobbying efforts of their friends at the Center for Science in the Public Interest (CSPI), trans fats were everywhere: in cakes, cookies, donuts, salad dressing, imitation dairy products, chips and other snack foods, bread, fried foods, stick margarines and soft spreads, shortening, restaurant and fast-food fries, chicken nuggets, onion rings and even in movie popcorn. When the fast-food industry switched from animal fats to partially hydrogenated vegetable oils for frying, levels of trans fats increased 700 percent in a McDonald’s “Happy Meal” of Chicken McNuggets, a large order of fries, and a danish or pie.1 Butter consumption had reached a low of 4 grams per day—less than a teaspoon—and only recent Hispanic immigrants still used lard.
The food industry viewed trans fats as benign—even healthy—because they could use them in place of liquid vegetable oils, which they knew caused cancer. Early short-term studies showed that trans fats were not acutely toxic. Industry spokesmen claimed that trans fats were not even well absorbed through the intestinal wall, but this view gave way to the observation that humans absorb more than 96 percent of trans fats ingested, incorporating them into the liver, red blood cell membranes, mitochondria, mammary gland—basically everywhere.2 One 1976 study found levels of trans fats up to 18 percent in human breast milk.3 Still, in that same year, a paper prepared by the Life Sciences Research Organization of the Federation of American Societies for Experimental Biology (LSRO-FASEB) declared trans fats to be safe: “There is no evidence in the available information on [partially] hydrogenated soybean oil that demonstrates or suggests reasonable grounds to suspect a hazard to the public when it is used as a direct or indirect food ingredient at levels that are now current or that might reasonably be expected in the future.”4
But during the 1970s and 1980s, research showing the harmful effects of trans fats began to accumulate. Rats fed trans fats had reproductive problems, including lowered testosterone levels in male animals and an increase in abnormal sperm—up to 98 percent by the third generation.5 One early study presented a chilling finding: second generation rats exposed to trans fats in utero and during nursing experienced a greater accumulation of trans fats in the various tissues than in those rats placed on trans fatty acids after weaning.6
The lipids research group at the University of Maryland found that trans fatty acids not only alter enzymes the body uses to neutralize carcinogens, and increase enzymes that potentiate carcinogens, but they also depress milk fat production in nursing mothers and decrease insulin binding.7 In other words, trans fatty acids in the diet interfere with the ability of new mothers to nurse successfully and increase their likelihood of developing diabetes. Unpublished work indicated that trans fats also contributed to osteoporosis.8 Hanis, a Czechoslovakian researcher, found that trans consumption decreased testosterone, caused the production of abnormal sperm and contributed to altered gestation.9 Koletzko, a German pediatric researcher, found that excess trans consumption in pregnant mothers predisposed them to low-birth-weight babies.10 Trans consumption interferes with the body’s use of omega-3 fatty acids found in fish oils, grains and green vegetables, leading to impaired prostaglandin production.11 George Mann confirmed that trans consumption increases the incidence of heart disease.12 In 1995, European researchers found a positive correlation between breast cancer rates and trans consumption.13
Until the 1995 breast cancer study, only the disturbing revelations of Dutch researchers Mensink and Katan, in 1990, received front page coverage. Mensink and Katan found that margarine consumption increased risk factors for coronary heart disease.14 The industry—and the press—responded by promoting tub spreads, which contain reduced amounts of trans compared to stick margarine. For the general population, however, these trans reductions were offset by changes in the types of fat used by the fast-food industry. In the early 1980s, Center for Science in the Public Interest campaigned against the use of beef tallow for frying potatoes. Before that they campaigned against the use of tallow for frying chicken and fish. Most fast-food restaurants dutifully responded by switching to partially hydrogenated soybean oil for all fried foods—leading to deep-fried offerings that contained almost 50 percent trans fat.15
Epidemiologist Walter Willett, head of the Harvard School of Public Health and author of over one thousand published papers, studied the relation of dietary fat and disease for many years using flawed databases, which did not identify trans fats as a dietary component. He found a correlation with dietary fat consumption and both heart disease and cancer. After his researchers contacted lipid researcher Mary G. Enig at the University of Maryland about the trans data, they developed a more valid database, which they used in the analysis of the massive Nurses Study. When Willett’s group separated out the trans component in their analyses, they were able to confirm greater rates of cancer in those consuming margarine and vegetable shortenings—not butter, eggs, cheese and meat.16 This correlation of trans fat consumption with cancer was never published, but was reported at the Baltimore Data Bank Conference in 1992.17 A year later, in 1993, Willett’s research group found that trans contributed to heart disease,18 and this study was not ignored, but received much fanfare in the press. Willett’s first reference in his report was Enig’s work on the trans content of common foods.
At that time, the industry argued that American trans consumption was a low 6 to 8 grams per person per day, not enough to contribute to the modern epidemic of chronic disease. Total per capita consumption of margarine and shortening then hovered around 40 grams per person per day. If these products contained 30 percent trans (many shortenings contain more), then average consumption was about 12 grams per person per day. In reality, consumption figures were dramatically higher for some individuals. A 1989 Washington Post article documented the diet of a teenage girl who ate twelve donuts and twenty-four cookies over a three-day period. Total trans worked out to at least 30 grams per day, and possibly much more. The fat in the chips that teenagers consume in abundance can contain up to 48 percent trans, which translates into 45.6 grams of trans fat (about 3 tablespoons) in a small 10-ounce bag of snack chips19—which a hungry teenager can gobble up in a few minutes. High school sex education classes do not teach American teenage boys that the altered fats in their snack foods could severely compromise their ability to have normal sex; nor do girls learn that trans fats may inhibit their ability to conceive, give birth to healthy babies and successfully nurse their infants. The eating habits of young Americans—packaged snacks, fast food, premade meals—meant exposure to trans fats at a far greater level than adults using a tablespoon of margarine daily.
Enig and the University of Maryland group were not alone in their efforts to bring their concerns about the effects of partially hydrogenated fats before the public. Fred Kummerow at the University of Illinois, blessed with independent funding and an abundance of patience, carried out a number of studies indicating that the trans fats increased risk factors associated with heart disease, and that vegetable-oil-based fabricated foods such as Egg Beaters cannot support life.20 George Mann, formerly with the Framingham Study, possessed neither funding nor patience—he was, in fact, very angry with what he called the “diet/heart scam.” His independent studies of the Maasai in Africa,21 whose diet is extremely rich in cholesterol and saturated fat, and who are virtually free of heart disease, had convinced him that the lipid hypothesis was “the public health diversion of this century… the greatest scam in the history of medicine.”22
EARLY STUDIES WITH SWINE FOUND that trans fats caused undesirable changes in markers for atherosclerosis. Rats fed trans fats accumulated 30 percent more fat in their hearts than rats fed saturated beef tallow, and studies were showing that trans fats could not provide the heart with the energy it needed in times of stress. These studies showed that trans fats built into the cell membranes altered their properties.
What is interesting about these studies is the finding that undesirable effects on cholesterol levels (increased LDL-cholesterol and decreases HDL-cholesterol) occurred only when the levels of saturated fat in the diet were low. With increasing proportions of saturated fats, the undesirable effects were mitigated, but with increasing proportions of unsaturated fatty acids, the kind in vegetable oils, these effects were enhanced. Swine with the highest level of saturated fats in the diet had the lowest amount of undesirable lipids in their aortas. Thus, partially hydrogenated coconut oil, which contains high levels of saturated fats, had fewer adverse effects than partially hydrogenated soybean oil, which is high in unsaturated fatty acids.23 According to these findings, an occasional serving of fast-food fries in a diet that contains mostly saturated fats like butter, meat fats and coconut oil would not be as harmful as that same serving of French fries in a diet based on so-called “good” fats like sunflower, canola or safflower oil, or even olive oil.*
In her doctorate thesis, published in 1984—just as CSPI was pushing for the use of partially hydrogenated fat in fast-food fryers, and the same year spokesmen for the Lipid Clinic Research trials declared that animal fats were the proven cause of heart disease—Mary G. Enig presented opposing research, describing how trans fats interfere with the cytochrome P450 enzyme system. These enzymes are present in most tissues of the body, and play important roles in the synthesis of sex and steroid hormones, cholesterol formation and vitamin D metabolism. Cytochrome P450 enzymes also function to rid the body of potentially toxic and carcinogenic compounds, including drugs. Thus, these enzymes play a key role in protecting us against cancer—and Enig’s work showed that trans fats interfere with this system, making us more vulnerable to cancer.24 Enig’s work—which was largely ignored—also explains why trans fats interfere with reproduction, lower testosterone production and damage sperm.
Enig and her colleagues then carried out a market-basket survey to determine the levels of trans fats in common foods such as margarine, shortening, snack foods and baked goods. Up to that point, the government databases did not list trans fats, but lumped them together with saturated fats, calling them all saturated fats. When researchers like Willett used these databases, they came up with positive—but false—correlations between saturated fat consumption and cancer and heart disease.25
Reports of adverse effects from trans fats continued to accumulate. Many researchers showed that trans fats increased markers for heart disease.26 Other studies showed decreased immune response† and decreased insulin levels or decreased response to insulin, which would lead to type 2 diabetes.27 Trans fats interfere with enzymes needed to convert omega-6 and omega-3 fatty acids into their elongated versions (arachidonic acid and DHA); in studies they also caused adverse changes in the cell membranes, escalated adverse effects of essential fatty acid deficiency and increased free radical formation.28
A 1994 study estimated that over thirty thousand heart disease deaths per year in the United States are attributable to the consumption of trans fats.29 By 2006, some researchers were suggesting that trans fats caused one hundred thousand deaths per year.30 A comprehensive review of studies of trans fats published in 2006 in the New England Journal of Medicine reported a strong and reliable connection between trans fat consumption and heart disease, concluding that “On a per-calorie basis, trans fats appear to increase the risk of CHD more than any other macronutrient, conferring a substantially increased risk at low levels of consumption.”31
The latest establishment theory on heart disease posits low-grade inflammation in the arteries as a cause, leading to the release of blood clots followed by heart attack—and studies indicate that trans fats provoke inflammation. A 2002 study found that consumption of stick margarine in human subjects increased the production of inflammatory prostaglandins associated with atherosclerosis. Neither liquid soy oil nor butter had the same inflammatory effect.32 In a cross-sectional study of participants in the Nurses’ Health Study, researchers found that those with the highest trans fat consumption also had higher markers of inflammation. The most significant biomarker, C-reactive protein (CRP), was up 73 percent in those with the highest level of consumption compared to those with the lowest.33 Scientists believe that high levels of CRP indicate inflammation in the lining of the arteries and endothelial dysfunction, leading to heart disease.
Most seriously, several reports associated trans fat consumption with increased risk of cancer. For example, mice fed margarine had more mammary tumors than rats fed butter.34 One study found that the relative risk of breast cancer associated with fat used for frying was increased with margarine and decreased with butter and vegetable oil,35 while another noted a positive association between breast cancer risk and “fat from cakes, biscuits and snacks.”36 The most convincing study, published in 1995, found that women with breast cancer had more trans fats in their adipose tissue compared to controls.*37
Recently, a seven-year European study, published in 2008, which followed almost twenty thousand women, documented three hundred sixty-three cases of breast cancer during the course of the study, and matched these cases to breast cancer–free controls according to age, menopausal status at baseline, date and collection center. Increasing blood levels of trans fatty acids were associated with a 75 percent increase in breast cancer risk.38 And researchers from Harvard have reported that increased intakes of trans fatty acids may increase the risk of nonaggressive prostate tumors by about 100 percent.39
Trans fats seem to contribute to weight gain as well. A 1993 report indicated that women who consumed more trans fats were several kilograms heavier that women who consumed less, even though the caloric intake was the same in both groups.40 Research on monkeys carried out at the Wake Forest School of Medicine indicates that weight gain is accelerated by consumption of trans fats compared to other fats. “Diets rich in trans fat cause a redistribution of fat tissue into the abdomen and lead to a higher body weight even when the total dietary calories are controlled,” said Lawrence L. Rudel, PhD, head of the Lipid Sciences Research Program. “What it says is that trans fat is worse than anticipated. I was surprised.” Monkeys given trans fats rather than monounsaturated fat deposited 30 percent more fat in their abdomen, even though both diets contained the same amount of calories.41
When Mary G. Enig and her colleagues studied trans fats in the late 1970s, they noticed that rats fed trans fats seemed more aggressive than controls; lack of funding prevented them from following up on this observation, but in 2012, researchers found a strong relation between trans fat consumption and self-reported behavioral aggression and irritability.42
In short, trans fats mess with your body, they mess with your moods—and they mess with your mind. In a 2015 article, researchers reanalyzing results from the 1999–2005 UCSD Statin Study found that greater dietary trans fatty acid consumption “is linked to worse word memory in adults during years of high productivity,” that is, in adults under the age of forty-five.43
It was this accumulation of evidence—only some of which was covered in the mainstream media—that led the FDA to require mandatory trans fat labeling, effective January 2006. That same year, the National Academy of Sciences (NAS) concluded that there is no safe level of trans fat consumption, quoting a 2006 New England Journal of Medicine (NEJM) scientific review, which stated, “From a nutritional standpoint, the consumption of trans fatty acids results in considerable potential harm but no apparent benefit.”44
THESE REVELATIONS HAVE BEEN EMBARRASSING for organizations like the American Heart Association, which for many years assured the public that industrial trans fats were a benign substitute for saturated fats like butter* and lard. The organization’s new spin is that yes, trans fats are bad, but so are saturated fats.
“Americans’ Knowledge of Fats Growing, Still Insufficient” was the title of an American Heart Association (AHA) press release issued October 9, 2007, which describes an AHA survey showing that “consumer awareness of the ‘bad’ fats—trans fats and saturated fat—is at an all-time high. But consumers still need key information to improve how they eat.” The survey found that “awareness of the link between the bad fats and increased heart disease risk is up from 63 percent in 2006 to 73 percent in 2007 for trans fat, and from 73 percent to 77 percent for saturated fat.” However, “only” 21 percent of consumers could name three food sources of trans fats, and only 30 percent could name three food sources of saturated fat on their own—that is, without prompting from AHA propagandists. “We’re encouraged to see that consumer awareness of saturated and trans fats is higher than ever and that more people understand the link between these fats and increased heart disease risk,” said Robert H. Eckel, MD, past president of the AHA, chair of its trans fat task force and professor of medicine at the University of Colorado at Denver Health Sciences Center. “But it’s clear consumers need to know which foods contain what [sic] fats to minimize both saturated and trans fats, and make heart-healthier food choices. Food labels help, but it goes far beyond that, in knowing more about the food products without labels we purchase in the grocery or when eating out.”
The American Heart Association states clearly that the bad fats are saturated fats found in beef, pork, chicken, butter, cheese and the tropical oils. According to the AHA, trans fats are “just as bad” as saturated fats. Yet science supports the fact that saturated fats have opposite effects from the trans fats. For example, trans fats cause or encourage inflammation, whereas saturated fats suppress inflammation; trans fats are associated with more cancer, especially breast cancer, while stable saturated fats protect against breast cancer.
Saturated versus Trans Fats45
Cell membranes
Saturated Fats: Essential for healthy function
Trans Fats: Interfere with healthy function
Hormones
Saturated Fats: Enhance hormone production
Trans Fats: Interfere with hormone production
Inflammation
Saturated Fats: Suppress
Trans Fats: Encourage
Heart disease
Saturated Fats: Lower Lp(a), raise “good” cholesterol
Trans Fats: Raise Lp(a), lower “good” cholesterol
Omega-3
Saturated Fats: Put in tissues and conserve
Trans Fats: Reduce levels in tissues
Diabetes
Saturated Fats: Help insulin receptors
Trans Fats: Inhibit insulin receptors
Immune system
Saturated Fats: Enhance
Trans Fats: Depress
Prostagandins
Saturated Fats: Encourage production and balance
Trans Fats: Depress production; cause imbalances
Cancer
Saturated Fats: Provide protection
Trans Fats: Encourage
All of this bad news about trans fats has sent manufacturers scrambling to find substitutes for the ubiquitous, trans-laden partially hydrogenated oils used in their products. Bayer CropScience, a German firm, teamed with Cargill of the United States to develop a hybrid rapeseed with “desirable oil traits” for producing high-oleic rapeseed oil. Archer Daniels Midland launched a line of trans-free and low-trans oils using enzymatic interesterification technology (discussed in Chapter 2). U.S. firms Dow AgroSciences, Bunge and DuPont have all launched their own brands of zero-or low-trans oils.
By and large, these efforts to remove trans fatty acids from the food supply have succeeded.46 You’ll still get them if you use margarine, eat certain brands of crackers and pastries or eat large amounts of almost any processed food or industrial oil, but in many products, the industry has successfully replaced trans fats with monounsaturated or polyunsaturated fatty acids and—ironically—with saturated fats from fully hydrogenated oils.
UNFORTUNATELY, THE FOOD INDUSTRY AND influential groups like the American Heart Association (AHA) have sent Americans from the frying pan of trans fatty acids to the fire of polyunsaturated oils—this in spite of all that scientists have uncovered on the dangers of liquid vegetable oils.
If trans fats are bad, liquid oils are even worse. Early studies (up to the 1980s) showed that because polyunsaturates are highly subject to rancidity, they increase the body’s need for vitamin E and other antioxidants. Excess consumption of vegetable oils is especially damaging to the reproductive organs and the lungs—both of which are sites experiencing huge increases in cancer in the United States. In test animals, diets high in polyunsaturates from vegetable oils inhibit the ability to learn, especially under conditions of stress; they are toxic to the liver; they compromise the integrity of the immune system; they increase levels of uric acid in the blood; they cause abnormal fatty acid profiles in the adipose tissues; they have been linked to mental decline and chromosomal damage; they accelerate aging—one study found that women who consumed mostly vegetable oils had far more wrinkles than those who used traditional animal fats. Polyunsaturates turn to a varnish-like substance in the intestines. Excess consumption of polyunsaturates is associated with increasing rates of cancer, heart disease and weight gain; excess use of commercial vegetable oils interferes with the production of prostaglandins, leading to an array of complaints ranging from autoimmune disease to PMS. Disruption of prostaglandin production leads to an increased tendency to form blood clots, and hence myocardial infarction, which has not retreated from epidemic levels in America, in spite of relentless anti–saturated fat propaganda.47
As early as 1957, in a letter to The Lancet, Denham Harman, a founder of the hypothesis that free radicals cause aging, warned of the negative effects of oxidation products (the creation of free radicals) in polyunsaturated oils. He noted that many important enzymes and vitamins are easily oxidized and warned that increasing the amount of easily oxidized polyunsaturated oils in the diet could “actually increase the severity of atherosclerosis.” The present enthusiasm for these unsaturated oils should “be curbed,” he wrote, and called for additional study on the possible adverse health effects that could be expected with this dietary change.48
Those who have most actively promoted the use of polyunsaturated vegetable oils as part of the Prudent Diet were well aware of their dangers. In 1971, William B. Kannel, former director of the Framingham Study, warned against including too many polyunsaturates in the diet. A year earlier, Dr. William Connor of the American Heart Association issued a similar warning, and Frederick Stare reviewed an article which reported that the use of polyunsaturated oils caused an increase in breast tumors. As far back as 1969, researchers discovered that the use of corn oil caused an increase in atherosclerosis.49
As reported by Nina Teicholz in The Big Fat Surprise, at a symposium on the topic attended by industry scientists in 1972, teams of food chemists from Japan reported that heated soybean oil produced compounds that were “highly toxic” to mice. A pathologist from Columbia University also reported that rats fed “mildly oxidized” oils suffered liver damage and heart lesions, compared to rats fed tallow, lard, dairy fats and chicken fat, which caused no such damage.50
A Finnish study found that children who consumed lots of vegetable oils were more prone to allergies.51 Researchers in Australia discovered that consumption of vegetable oils is associated with increased rates of asthma.52 Another study found that mice fed excessive corn oil had increased caloric intake and obesity.53 Researchers have also found that high vegetable oil consumption is associated with increased rates of macular degeneration, the leading cause of irreversible blindness in adults.54 These are just several of hundreds of studies indicating that modern vegetable oils are bad news indeed—they’ll make you prone to allergies, asthma and weight gain, and possibly give you cancer and make you blind as well.
Such research rarely receives media coverage, and when it does, it often gets spin doctored. For example, in a 2010 study, mice fed a standard rat chow diet plus 10 percent corn oil exhibited increased body weight, total body fat mass and abdominal fat mass along with reduced bone mineral density compared to controls on rat chow alone. The title of the study describes the corn oil diet as a “high-fat” rather than a “high-oil” diet.55 When a diet high in corn oil but low in fiber, vitamin D and calcium triggered inflammation in the mouse colon, Peter Holt, one of the study authors, stated that the study lent support to the hypothesis that “red meat, processed meat and alcohol can increase the risk of colorectal cancer.”56 But the study did not look at red meat, processed meat and alcohol; it looked at corn oil!
Monounsaturated fatty acids, found in olive oil and canola oil, are the current darling of the research establishment, but researchers at Lund University in Sweden really got tongue-tied when a recent study showed that olive oil and a “new type of canola and flaxseed oil” raised cholesterol levels more than butter. According to a spokesperson for the university, the short-and medium-chain fatty acids in butter are stored preferentially in the intestinal cells. “However, butter leads to a slightly higher content of free fatty acids in the blood, which is a burden on the body… Olive oil is good, to be sure, but our findings indicate that different food fats can have different advantages.”57
Modern diets can contain as much as 30 percent of calories as polyunsaturated oils, an amount that is far too high. The best evidence indicates that our intake of polyunsaturates should not be much greater than 4 percent of the caloric total, in approximate proportions of 1.5 percent omega-3 linolenic acid and 2.5 percent omega-6 linoleic acid.58 EFA consumption in this range is found in native populations in temperate and tropical regions whose intake of polyunsaturated oils comes from the small amounts in legumes, grains, nuts, green vegetables, fish, olive oil and animal fats, but not from commercial vegetable oils.
We know polyunsaturated oils are bad; we’ve known that for a long time. But the dietary gurus have fallen back to recommending them as “heart healthy,” more so today now that we know the truth about trans fats. In fact, in 2015 for the first time, the USDA Dietary Guideline Committee recommended increasing polyunsaturated oil consumption. Up until then, the guidelines had stressed carbohydrates over fats of any kind.
IT CANNOT BE STRESSED ENOUGH that polyunsaturated oils degrade into dangerous oxidation products such as free radicals. These breakdown products can include aldehydes, including formaldehyde—that’s right, formaldehyde, the same chemical used to preserve dead bodies. In one analysis, a total of one hundred thirty volatile compounds were isolated from one piece of chicken fried in vegetable oil.59
As revealed in the research of Nina Teicholz, of particular concern is the fact that fast-food chains and manufacturers of donuts and potato chips are now frying in liquid vegetable oils. The breakdown products of liquid oils heated to frying temperatures are particularly toxic.* The residue that accumulates in the bottom of the fryers is a thick gunk, like paint shellac—formed because the unsaturated fatty acids polymerize—that is, they join together to make varnish. The gunk comes off the fryers and settles on surfaces throughout the restaurant, creating a thriving business for industrial cleaning companies. Uniforms on which the gunk settles sometimes catch fire, even after the clothes have been cleaned.
Remember that fast-food workers are breathing this stuff in! A report published in 2010 by the International Agency for Research on Cancer (IARC), which is part of the World Health Organization, determined that emissions from frying oils at the temperatures typically used in restaurants are “probably” carcinogenic to humans.60
In a 1991 review, the Austrian biochemist Hermann Esterbauer summarized the evidence that aldehydes cause “rapid cell death,” interfere with DNA and RNA, and disturb the basic functions of the cell. Aldehydes cause extreme oxidative stress to every kind of tissue, with a “great diversity of deleterious effects” to health. Aldehydes cause LDL-cholesterol to oxidize, and it is oxidized cholesterol that initiates the process of atherosclerosis.61 Considerable evidence implicates aldehydes in the development of Alzheimer’s and other neurodegenerative diseases.62
In one experiment mice were fed a type of aldehyde called acrolein, named for its acrid smell when produced by overheated oils. (It is also present in cigarette smoke.) The mice suffered injuries to their gastrointestinal tracts as well as a whole-body response called “acute phase response,” an attempt by the body to avoid septic shock. Markers of inflammation and other signs of acute infection also went up dramatically—sometimes by a hundredfold—and this at a dose equivalent to what humans can typically consume in one day, even if they are not eating fried foods.63
The industry is hoping that new interesterified blends will not have the negative health effects of trans fats or of liquid polyunsaturated oils. These blends typically contain some saturated fatty acids created from vegetable oils through full hydrogenation. But a 2007 study gives great cause for concern. The researchers compared trans-rich and interesterified fats with saturated fat for their relative impact on blood lipids and blood sugar levels. Thirty human volunteers participated in the study, which strictly controlled total fat and fatty acid composition in the subjects’ diet. Each subject consumed all three diets in random rotation during the four-week diet periods. HDL-cholesterol dropped slightly with both the trans fat and interesterified blends but the real problem concerned blood glucose and insulin levels. Insulin levels dropped 10 percent on the partially hydrogenated soybean oil diet but dropped more than twice as much on the interesterified fat diet, causing blood sugar to rise by an alarming 20 percent.64 Thus it seems that these interesterified blends affect the production of insulin by the pancreas rather than the receptors for insulin in the cell membranes.
The trade-off of type 2 diabetes from trans fats for type 1 diabetes from interesterified vegetable oils does not seem like a good one. There seems to be no trade-off whatsoever in the switch from stick margarine loaded with trans fats to soft spreads loaded with toxic vegetable oils in preventing cancer, heart disease and other chronic ailments. And all this comes from research on adults. What happens to children fed trans fats and rancid vegetable oils is the subject of the next chapter.