Some science behind the scenes

Trans-unsaturated fatty acids

Trans fat, also called trans-unsaturated fatty acids or trans fatty acids, are a type of unsaturated fat that became widely produced industrially from vegetable fats starting in the 1950s for use in margarine, snack food, and packaged baked goods and for frying fast food.  These compounds are formed generally during partial hydrogenation of vegetable oils, a process that converts vegetable oils into semisolid fats.

The US National Academy of Sciences (NAS) advises the United States and Canadian governments on nutritional science for use in public policy and product labeling programs and they have stated that  "trans fatty acids are not essential and provide no known benefit to human health".

But it is worse than this, as it has been shown that industrially produced trans-unsaturated fatty acids cause serious health problems.

Trans fats also occur naturally in meat and dairy products from ruminants, e.g., vaccenic acid and some isomers of conjugated linoleic acid (CLA).  Butter, for example, contains about 3% trans fat.  BUT, a study by the US Department of Agriculture showed that vaccenic acid raises both HDL and LDL cholesterol, whereas industrial trans fats only raise LDL without any beneficial effect on HDL.  And two Canadian studies have shown that vaccenic acid could actually be beneficial by lowering total LDL and triglyceride levels.

Thus it is not trans fats in general that are the problem, but the industrially produced trans fats – the artificial ones.   As such the World Health Organisation introduced a 6-step guide in 2018, to eliminate industrially-produced trans-fatty acids from the global food supply.  In many countries, there are already legal limits to trans fat content, but whether they are adhered to is another thing.

The Problem with Trans fat


Endothelial dysfunction

Trans fats has been shown to increase the risk of coronary artery disease in part by raising levels of the lipoprotein LDL, lowering levels of the lipoprotein HDL, increasing triglycerides in the bloodstream and promoting systemic inflammation.  A 1994 study estimated that over 30,000 cardiac deaths per year in the United States are attributable to the consumption of trans fats.  By 2006 upper estimates of 100,000 deaths were suggested.

Intake of dietary trans fat perturbs the body's ability to metabolize essential fatty acids (EFAs including Omega 3) leading to changes in the phospholipid fatty acid composition in the aorta, the main artery of the heart, thereby increasing risk of coronary artery disease.

The results of in vitro studies have shown that trans fatty acids cause a significant increase in secretion of reactive oxygen species, interleukin-6, tumor necrosis factor a and metalloproteinase-9, and enhance apoptosis. It indicates that in vivo trans-fatty acids may destroy the endothelium integrity and cause plaque rupture.

Obesity and diabetes

There is conflicting evidence about the propensity of trans fatty acids (TFAs) to cause obesity and insulin resistance.  In one study [see references],the effect of moderately high intake of dietary monounsaturated TFAs on body composition and indices of glucose metabolism was evaluated to determine any pro-diabetic effect in the absence of weight gain.  Male African green monkeys (Chlorocebus aethiops; n=42) were assigned to diets containing either cis-monounsaturated fatty acids or an equivalent diet containing the trans-isomers (approximately 8% of energy) for 6 years. Total calories were supplied to provide maintenance energy requirements and were intended to not promote weight gain.

TFA-fed monkeys gained significant weight with increased intra-abdominal fat deposition. Impaired glucose disposal was implied by significant postprandial hyperinsulinemia, elevated fructosamine, and trends toward higher glucose concentrations. Significant reduction in muscle Akt phosphorylation from the TFA-fed monkeys suggested a mechanism for these changes in carbohydrate metabolism.

Liver problems

The prevalence of non-alcoholic fatty liver disease (NAFLD) is rising.  And there is now a suggestion that trans-fatty acids (TFAs) play an important role in this problem.

One study has shown that dietary trans fatty acids are differentially incorporated into the liver microsomal lipids and act as inhibitors for delta 9 and delta 6 desaturases. The delta 6 desaturase is considered as the key enzyme in the conversion of the essential fatty acids to arachidonic acid and prostaglandins. This indicates that the presence of trans fatty acids in the diet may induce some effects on the EFA metabolism through their action on the desaturases.

Intestine disease

Modern diets such as deep-fried products, frozen foods, and packaged snacks commonly include large quantities of margarine containing TFAs. Although the effects of a diet containing TFAs as a risk factor of metabolic syndrome, diabetes mellitus, and coronary heart disease has been observed in recent years, the influence on intestinal inflammation remained unknown until relatively recently.  Now studies [see references] are starting to show the pro-inflammatory effects of TFAs in our diet on various systemic disorders including gut inflammation.

Alzheimer’s, Dementia and brain damage

Trans unsaturated fatty acids can damage the intestine causing inflammation, and once the intestine is damaged any number of substances – pathogens, toxins or just food may leak into the blood stream.  Generally the brain is protected by the blood brain barrier, but if this has in any way been compromised then brain damage may result.  In one study that investigated the effects of dietary fats on the development of Alzheimer disease in a random sample of 815 community residents aged 65 years and older who were initially unaffected by Alzheimer disease, after 3.9 years, 131 persons developed Alzheimer disease. And intake of trans-unsaturated fat was positively associated with a risk of Alzheimer disease.  Intakes of total fat, animal fat, and dietary cholesterol were not associated with Alzheimer disease.

Infertility

Is intake of fatty acids related to semen quality among young men?  The answer appears to be yes.

Spain has seen an increase in the proportion of calories consumed as fat over the same period that a downward trend in semen quality has been observed. Rodent models suggested that trans fat intake may severely affect testicular function and in a study with humans between October 2010 and November 2011, where the association between intake of fatty acids with semen quality (sperm concentration, motility, morphology and total count) was assessed Trans fatty acid intake was inversely related to total sperm count after adjusting for potential confounders. 

Cholesterol is an essential ingredient in the making of all female and male hormones, as such what may be happening is that, at the urging of the medical profession, men have cut their cholesterol intake and increased their margarine and other fat intake and by doing this unwittingly made themselves infertile. 

Why is there transfat in food?

Prior to 1910, dietary fats in industrialized nations consisted primarily of butter, suet, tallow [a rendered form of beef or mutton fat], and lard, all of which were in short supply.  The method of ‘hydrogenating’ fat and turning a liquid oil into a solid one had already been discovered, and thus the need was met with the invention.  Hydrogenated fat such as Crisco and Spry, sold in England, began to replace butter and lard in the baking of bread, pies, cookies, and cakes in 1920.  Once the refrigerator became more commonplace in homes, margarine was introduced as a cheaper and more convenient replacement for butter on bread as, unlike butter, it could be taken out of the refrigerator and immediately spread on bread.

Use of hydrogenated fats increased steadily during the 1960s, ‘70s and ‘80s, as processed vegetable fats replaced animal fats in Western countries. At first, the marketing of the products was based simply on cost to the consumer, however, despite any evidence to support the claim, manufacturers started to sell unsaturated trans fats on the basis they were ‘healthier’ than the saturated fats of butter.  This, despite the fact that as early as 1956 there were suggestions in the scientific literature that trans fats could be a cause of the large increase in coronary artery disease.  For three decades the concerns were unaddressed.  The situation is made more tragic when one knows that ill-informed activists forced the fast food industry to switch to transfats by campaigning and advertising.

The reasons trans fats are actually used now therefore, is a different one to that which first gave them a market.  It is certainly not a shortage of butter. 

By far the largest amount of trans fat consumed today is created by the processed food industry as a side effect of partially hydrogenating unsaturated plant fats (generally vegetable oils). Hydrogenation increases product shelf life and decreases refrigeration requirements. Many baked foods require semi-solid fats to suspend solids at room temperature; partially hydrogenated oils have the right consistency to replace animal fats such as butter and lard at lower cost. They are also an inexpensive alternative to other semi-solid oils such as palm oil.  So this has nothing to do with consumer demand, it has everything to do with reducing manufacturer’s costs and thus increasing profit.  What consumer demand exists has been created by dubious marketing methods.

Where is trans-fat still found?

By far the largest amount of trans fat consumed today is created by the processed food industry as a side effect of partial catalytic hydrogenation of unsaturated plant fats (generally vegetable oils) with cis carbon-carbon double bonds. Up to 45% of the total fat in those foods containing artificial trans fats formed by partially hydrogenating plant fats may be trans fat. 

These partially hydrogenated fats have displaced natural solid fats and liquid oils in many areas, the most notable ones being in the fast food, snack food, fried food, and baked goods industries.  For example:

·       Baking shortenings, unless reformulated, contain around 30% trans fats compared to their total fats, meaning that ‘cookies’, biscuits, donuts, wafers, waffles, factory made cakes, pies, tarts and so on may all contain trans fats.  More trans fats are used in commercially baked products than any other foods. Doughnuts contain shortening in the dough and are cooked in trans fat. Cookies and cakes (with shortening-based frostings) from supermarket bakeries have trans fat

·       Margarines not reformulated to reduce trans fats may contain up to 15% trans fat by weight.  Many spreads and margarines may contain trans fats

·       Fast foods in restaurants -Trans fats are used in shortenings for deep-frying in restaurants, as they can be used for longer than most conventional oils before becoming rancid.  As fast-food chains routinely use different fats in different locations, trans fat levels in fast food can have large variations. For example, an analysis of samples of McDonald's French fries collected in 2004 and 2005 found that fries served in New York City contained twice as much trans fat as in Hungary, and 28 times as much as in Denmark, where trans fats are restricted. At KFC, the pattern was reversed, with Hungary's product containing twice the trans fat of the New York product. Even within the United States there was variation, with fries in New York containing 30% more trans fat than those from Atlanta.  Even if the chains use liquid oil, fries are sometimes partially fried in trans fat before they're shipped to the restaurant. Pancakes and grilled sandwiches also have some trans fat, from margarine spread on the grill to prevent them sticking

·       Deep fried foods – French fries, hamburgers, chicken nuggets etc

·       Crisps, Chips and Crackers -  Shortening provides crispy texture. Even "reduced fat" brands can still have trans fat. Anything fried (like potato chips and corn chips) or buttery crackers have trans fat. A small bag of potato crisps has 3.2 grams of trans fat.

·       Dehydrated soups and noodles - Many noodles and cup soup products contain very high levels of trans fat

·       Cake mixes -  and other pre baking mixes all have several grams of trans fat per serving.

·       Microwave oven popcorn

·       Breakfast food -  Breakfast cereal and energy bars are quick-fix, highly processed products that contain trans fats, even those that claim to be "healthy." For example Kellogg's Oat Bran Cereal has 1.5 grams per 3/4 cup serving

·       Vegetarian and vegan foods – such as imitation cheese and mock cheese spreads, veggieburgers

·       Sauces, Toppings and Dips -  Nondairy creamers, whipped toppings, bean dips, gravy mixes, and salad dressings contain trans fat

·       Chocolate bars - one of ingredients of snickers bars, for example,  is partially hydrogenated soybean oil. And partially hydrogenated soybean oil is a source of trans fats. 

·       Frozen Food - many frozen meals, pot pies, waffles, pizzas, even breaded fish sticks contain trans fat. Even if the label says it's low-fat, it still has trans fat. Frozen reduced fat Apple Pie has 4 grams trans fat in every slice.

And many more processed foods …………..

Labelling doesn’t work

In theory, manufacturers should state categorically that a product contains  "partially hydrogenated vegetable fat" on the food label.  But unfortunately, the many countries of origin of food with the numerous regulations of various laxity in place, means that often this essential information is omitted or wrongly stated.  The term "Partially Hydrogenated Oil" may also be used.

If we take the USA, Trans fatty acids should be listed as "Trans fat" or "Trans" on a separate line under the listing of saturated fat in the nutrition label. Trans fat content must be expressed as grams per serving to the nearest 0.5-gram increment below 5 grams and to the nearest gram above 5 grams.  BUT, if a serving contains less than 0.5 gram, the content, when declared, can be expressed as "0 g." which of course is misleading labeling, because it is inaccurate.

In order to efficiently reduce the health risk related to TFA, Denmark decided to impose a maximum level of 2 g/100 g fat on industrially produced TFA (IP-TFA) with the Danish Order no. 160 of March 2003.  In other words they placed a blanket ban on its use.  They did this because they rightly realised that labelling was deemed wholly inadequate as a means of protecting consumers, especially risk groups like children, the old, or people with high intake of snack foods, fast or restaurant foods.

Instead, the content of trans fatty acids (TFA) in Danish food has been monitored for the last 40 plus years.  And it has worked, partly because the Danes realise that health is more important than profit, and partly because their monitoring system is a good one. 

The investigations show that the TFA content has been reduced or removed from the products with high TFA content originally, so IP-TFA are now without any significance for the intake of TFA in Denmark.

At the time that the legislation was introduced in Denmark, a "high trans menu" provided more than 20 g in 17 out of 18 countries, with Hungary, Czech Republic, Poland, Bulgaria, and USA, ranking highest with 42, 40, 38, 37, and 36 g, respectively.

The legislation in Denmark has reduced the exposure of IP-TFA at the individual level without noticeable effect on availability, price, and quality of foods previously containing high amounts of IP-TFA.

So what to do?

Avoid pre-processed food and make your own using natural unprocessed oils and butter, lard, tallow and all the natural products.

And if you buy processed foods, only buy from countries which have a blanket ban in place.

References

  • Fred A. Kummerow (2008). Cholesterol Won't Kill You — But Trans Fat Could.
  • Bassett, C. M. C.; Edel, A. L.; Patenaude, A. F.; McCullough, R. S.; Blackwood, D. P.; Chouinard, P. Y.; Paquin, P.; Lamarche, B.; Pierce, G. N. (Jan 2010). "Dietary Vaccenic Acid Has Antiatherogenic Effects in LDLr-/- Mice". The Journal of Nutrition. 140 (1): 18–24. doi:10.3945/jn.109.105163. PMID 19923390.
  • Wang Y, Jacome-Sosa MM, Vine DF, Proctor SD (20 May 2010). "Beneficial effects of vaccenic acid on postprandial lipid metabolism and dyslipidemia: Impact of natural trans-fats to improve CVD risk". Lipid Technology. 22 (5): 103–106. doi:10.1002/lite.201000016.
  • Booyens J, Louwrens CC, Katzeff IE (1988). "The role of unnatural dietary trans and cis unsaturated fatty acids in the epidemiology of coronary artery disease". Medical Hypotheses. 25 (3): 175–182. doi:10.1016/0306-9877(88)90055-2. PMID 3367809.
  • Mozaffarian D, Katan MB, Ascherio A, Stampfer MJ, Willett WC (2006). "Trans Fatty Acids and Cardiovascular Disease". New England Journal of Medicine. 354 (15): 1601–1613. doi:10.1056/NEJMra054035. PMID 16611951
  • Kummerow FA1, Zhou Q, Mahfouz MM, Smiricky MR, Grieshop CM, Schaeffer DJ (2004). "Trans fatty acids in hydrogenated fat inhibited the synthesis of the polyunsaturated fatty acids in the phospholipid of arterial cells". Life Sci. 74 (22): 2707–23. doi:10.1016/j.lfs.2003.10.013. PMID 15043986
  • Menaa F, Menaa A, Menaa B, Tréton J (2013). "Trans-fatty acids, dangerous bonds for health?". Eur J Nutr. 52 (4): 1289–302. doi:10.1007/s00394-012-0484-4. PMID 23269652.
  • Lopez-Garcia, Esther; S; M; M; R; S; W; H (2005). "Consumption of Trans Fatty Acids Is Related to Plasma Biomarkers of Inflammation and Endothelial Dysfunction". The Journal of Nutrition. 135 (3): 562–566. PMID 15735094.
  • Morris MC, Evans DA, Bienias JL, Tangney CC, Bennett DA, Aggarwal N, Schneider J, Wilson RS (2003). "Dietary fats and the risk of incident Alzheimer disease". Arch Neurol. 60 (2): 194–200. doi:10.1001/archneur.60.2.194. PMID 12580703.
  • Trans fat diet induces abdominal obesity and changes in insulin sensitivity in monkeys- Kavanagh K1, Jones KL, Sawyer J, Kelley K, Carr JJ, Wagner JD, Rudel LL. PMID: 17636085
  • Acta Biol Med Ger. 1981;40(12):1699-1705.  Effect of dietary trans fatty acids on the delta 5, delta 6 and delta 9 desaturases of rat liver microsomes in vivo.  Mahfouz M. PMID:  7345825
  • Int J Cardiol. 2018 Jul 30. pii: S0167-5273(18)31104-5. doi: 10.1016/j.ijcard.2018.07.061. [Epub ahead of print]  Link between plasma trans-fatty acid and fatty liver is moderated by adiposity.  Mazidi M1, Katsiki N2, Mikhailidis DP3, Banach M4. PMID:  30072152
  • J Gastroenterol Hepatol. 2013 Dec;28 Suppl 4:29-32. doi: 10.1111/jgh.12270. Trans fatty acids in diets act as a precipitating factor for gut inflammation? Okada Y1, Tsuzuki Y, Ueda T, Hozumi H, Sato S, Hokari R, Kurihara C, Watanabe C, Tomita K, Komoto S, Kawaguchi A, Nagao S, Miura S.  PMID: 24251700
  • Arch Neurol. 2003 Feb;60(2):194-200.  Dietary fats and the risk of incident Alzheimer disease.  Morris MC1, Evans DA, Bienias JL, Tangney CC, Bennett DA, Aggarwal N, Schneider J, Wilson RS.  PMID: 12580703
  • Hum Reprod. 2014 Mar;29(3):429-40. doi: 10.1093/humrep/det464. Epub 2014 Jan 12.  Trans fatty acid intake is inversely related to total sperm count in young healthy men. Chavarro JE1, Mínguez-Alarcón L, Mendiola J, Cutillas-Tolín A, López-Espín JJ, Torres-Cantero AM.  PMID:  24419496
  • Acta Microbiol Pol. 2003;52 Suppl:75-81.  Trans-unsaturated fatty acids and acrylamide in food as potential atherosclerosis progression factors. Based on own studies. Naruszewicz M1, Daniewski M, Nowicka G, Kozłowska-Wojciechowska M. PMID:  15058816

Observations

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