Vegetable and seed oils are highly processed oils that are easily damaged during cooking. Some studies suggest that they can cause harm and contribute…. Canola and vegetable oil may seem interchangeable. But they actually have different…. This is a detailed article about trans fats and why they are bad for your health. They can cause heart disease and lead to all sorts of metabolic…. Though the FDA's ban of trans fats went into effect in June , some foods may still contain this unhealthy fat due to certain exemptions.
Here are…. A detailed guide to healthy cooking oils. There are several things to keep in mind, including how stable these oils are when they're heated. Hydrogenation is a process in which a liquid unsaturated fat is turned into a solid fat by adding hydrogen.
It's best to avoid foods with hydrogenated…. Shortening is a type of fat used in cooking and baking. This article reviews what shortening is and whether it is good or bad for your health. Partially hydrogenated oils are most commonly found in foods that also have saturated fat , such as:.
According to the U. Food and Drug Administration FDA , a company can label a food free of trans fats if the actual content is 0. Some food labels claim no trans fats have been added, but partially hydrogenated oil may still be listed as one of the ingredients.
Margarine and shortening are easy to cook with, but they contain partially hydrogenated oils. Opt for heart-healthy vegetable or plant oils , such as safflower , olive , or avocado oil instead. One study from showed safflower oil may improve blood glucose levels and lipids and decrease inflammation. Olive oil and avocado oil have also been shown to be heart-healthy oils. Partially hydrogenated oils go hand in hand with food preservation, so hydrogenated fat often ends up in packaged foods.
Decrease your dependence on packaged foods. Start by eliminating one food group at a time. For example, cook your own rice or potatoes from scratch instead of relying on seasoned, boxed versions.
The Food and Drug Administration, using the American Oil Chemists Society method, labeled the isomers in partially hydrogenated fat as only one peak elaidic acid. It is only with a GC equipped with a meter column that it is possible to further separate the fatty acid isomers of partially hydrogenated fat into at least 14 separate isomeric fatty acids [ 5 ]. During hydrogenation, the double bond at any of these 9,12 or 9, 12, 15 positions can be shifted to form new cis and trans unsaturated fatty acid isomers not present in soybean oil.
Thus hydrogenated soybean oil contains They were identified as cis and trans octadecenoic and octadecadienoic isomers on a GC equipped with a meter column and by their mixed melting points with authentic octadecenoic and octadecadienoic acids. None of these fatty acids are present in natural soybean oil.
The 14 isomers in hydrogenated fat can be used as a source of energy but they cannot substitute for EFA because they do not have the required double bond structure [ 5 ]. It was unknown until that linoleic n 6 and linolenic n 3 acids were essential fatty acids EFA , and like the nine essential amino acids and the vitamins, cannot be synthesized in the human body; they must come from a diet that includes natural fats and oils.
In one study, pregnant rats were fed linoleic, linolenic, and arachidonic acids by dropper. This was a sufficient amount for the mother rats to wean their young, but those pups from mothers fed only linolenic acid died before weaning. Although linolenic acid is considered an essential fatty acid, these data indicate that it may not be an essential fatty acid [ 6 ].
An increase in the sales of soy food is largely credited to the Food and Drug Administration's approval of soy as a cholesterol-lowering food [ 7 ]. A literature review argued that these health benefits were poorly supported by available evidence, and noted that data on soy's effect on cognitive function of the elderly existed [ 8 ]. The FDA issued the following claim for soy: "25 grams of soy protein a day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease.
Solae also submitted a petition on the grounds that soy can help prevent cancer. On February 18, , Weston A. Price Foundation submitted a petition for the removal of this health claim. An American Heart Association review of a study of the benefits of soy protein casts doubt on the FDA claim for soy protein.
However, AHA concludes "many soy products should be beneficial to cardiovascular and overall health because of their high content of polyunsaturated fats, fiber, vitamins, and minerals and low content of saturated fat" [ 11 ].
EFA are required to synthesize the eicosanoids that are needed to regulate blood flow in the arteries and veins. Linoleic acid n-6 is synthesized into arachidonic acid, and linolenic acid n-3 is synthesized into eicosapentaenoic acid. Both in turn are made into prostacyclin or thromboxane. Prostacyclins are synthesized in the endothelial cells that line the blood vessel wall.
Thromboxanes are synthesized in the platelets in the blood. The balance between prostacyclin for flow and thromboxane for clotting is a very delicate one and can be changed by different diets and different drug prescriptions.
Fish have already converted the linolenic acid they get from seaweed into eicosapentaenoic acid. Hence, fish oil is often recommended as a dietary supplement. Prostacyclin and thromboxane can be made from linoleic acid as well. The least expensive source of omega-3 and omega-6 is soybean oil, which is sold as vegetable oil in a supermarket [ 12 ]. However, this vegetable oil is stripped of Vitamin E, which is then sold in capsules.
The removal of Vitamin E leaves the oil more susceptible to oxidation, which harms the natural fatty acids that are needed for good health. How soybean oil is used in modern humans was developed in prehistoric humans to assure their survival.
There must have been long periods of time between meals, that is fasting periods, and there were times in which they had food available, the "fed" period. During this fed period, carbohydrates were used within two hours as a quick source of energy. Extra carbohydrates were stored first as glycogen in the muscles and liver and then any excess converted to fat and stored in the adipose tissues the fat around your middle and elsewhere. This stored fat was then available for energy during the long fasting periods.
Modern humans have inherited this way of handling these fed and fasting periods. This process assured the survival of prehistoric humans but has now become one way that obesity is developing in humans today. Too much food is available all hours of the day and night, and eating it is a pleasure. To avoid adding fat to your body, any carbohydrates you eat should be used up as a calorie source before the next meal.
Any carbohydrates that have already turned into fat and any fat in your diet itself should be used for energy within the cell during the fasting period. Eating a snack between meals means adding additional carbohydrates into the system before any of the fat from the previous meal has been used for energy. It ends up adding to your adipose tissue. If you weighed yourself before a hearty meal and again the next day, you may find you have gained a pound or two, the amount depending on how much food you ate and the fat you stored.
As such a meal may also contain excess salt, some of the weight gain can be due to excess water you stored. Millions of dollars are spent to try to get rid of this stored fat, and the government is planning to spend millions more dollars to solve the obesity problem.
Prehistoric humans had no choice in controlling the time between fasting and fed periods because they had no refrigerators, fast food outlets, or supermarkets to run to. Modern humans do have this choice.
More time between the fed periods, that is between meals, may help with the obesity problem [ 12 ]. The fat in the intestinal tract is first converted into tiny droplets of fat chylomicrons by the intestinal cells. The intestinal tract is not just a through highway, but is actively involved in the process of metabolizing fat so that the body can use it. The chylomicrons diffuse from the intestinal tract into the lymph system and into the veins through the thoracic duct and end up in the blood.
The blood, during the fed period, carries these chylomicrons for deposit where they are resynthesized into adipose tissue and stored fat around the stomach, hips, and other locations. The fat triglycerides in adipose tissue is "mobilized" when the glycogen in the muscle and liver has been reduced. The glycerin portion goes to the liver. The free fatty acids take a different route and are combined with a protein named albumin. Therefore, there must be enough albumin in the blood to carry the free fatty acids in the blood.
This fatty acid albumin complex is water-soluble enough in the blood to be carried to cells of all kinds that use the fatty acid portion as an energy source. Any excess fatty acid goes to the liver and is remade into triglycerides. The cellular organelle the endoplasmic reticulum in the liver cells participates in coating the very small triglyceride droplets with protein and adds phospholipid and cholesterol to produce very low density lipoprotein VLDL , which furnishes the fatty acid for the approximately 50 thousand trillion cells in the body [ 12 ].
Correction of the inhibition of lipoprotein lipase by protein binding of free fatty acids permits normal protein transport of FFA into the cellular mitochondrial oxidative phosphorylative cycle with the resultant production of high-energy phosphate which is the cellular fuel. Without this fuel, in addition to oxygen, the life process comes to a halt. Bacteria have used this method of providing energy for at least two billion years Ratz.
Another issue with fats is the preparation of foods by frying them in fat. There are problems with deep fat fried food that affect our nutrition. These problems occur because of chemical alterations in the fat that happen as a consequence of deep fat frying food.
This frying process is as follows:. Food picks up oxygen from the air during frying that negatively alters the fat composition. The length of time it was exposed to heat—in commercial operations, the length of time a food is fried leads to how much fat is absorbed on the cooked food item;.
The exact composition of the fat used, such as corn oil, cottonseed oil, soybean oil, beef tallow, or hydrogenated fat, and. Feeding the fats fried at varying lengths of time led to very different outcomes in the nutrition of animals. Those fed the fats fried the shortest period of time were healthier than those fed the fats fried for the longest times.
Those fed fats heated at higher temperatures were not as healthy as those fed on fat heated to lower temperatures. It was interesting also that animals fed on heated margarine did not grow as well as those on fresh margarine and that their plasma cholesterol level increased.
Those fed on heated butter oil grew as well as those on fresh butter oil. Oil from commercial fat fryers was used in a set of experiments that clearly showed that poor nutrition resulted. This is important because used fat from commercial operations is typically collected and fed to animals, such as pigs, to provide energy for rapid growth.
When we conducted experiments feeding the commercially used fat for frying to rats, they did not do well. When we added protein to their diets, the effect of the "bad" heated fat was countered because the added protein provided more adequate nutrition. We tried to fortify the diets with adequate vitamins, but that could not counter the growth-depressing effect of the heated oil. A few vitamins, such as riboflavin, helped a bit. Fish contain high amounts of polyunsaturated fat that are not present in the fat of chicken or beef.
Thus, when fish are fried, the polyunsaturated fat in them can leak into the frying fat, causing the fat to be changed more radically into a less healthy version. Chicken and hamburger have less of this polyunsaturated fat and thus are healthier choices to fry.
Eating excessive amounts of fried food also slows down digestion. People may get stomachaches as a result. As early as , a link that heated fats may lead to cancer was shown. What we don't know yet is whether heated fats by themselves lead to cancer or whether the heated fat combined with specific foods cause cancer.
Animals fed heated fat combined with a known carcinogen developed cancer, whereas those fed fresh fat combined with a known carcinogen did not. Thus the heated fat was a co-carcinogen. Commercial frying of food has increased worldwide since our studies on heated fats.
In Germany, fat fryers are required by law to test their frying fat for its freshness by a method approved by the German government. In the U. Free radicals are produced from oxidized linoleic n-6 and linolenic acid n-3 ; they are fragments of unsaturated fatty acids. This is especially likely to happen when the essential fatty acids are heated, especially the n-3 variety. All oils change structures when they are heated, but hose high in n-3 fatty acids have more problems than those high in n Free radicals provide another reason to avoid fried food.
The first sign of fats becoming free radicals is that they are rancid, and they begin to smell "off" and their taste becomes bitter. Roasted peanuts, for example, can become rancid and then shouldn't be eaten. Free radicals are "bad" since they destroy vitamins A, D, C, and E, thus preventing these vitamins from doing positive things in the body. Free radicals also destroy both the essential fatty acids and the essential amino acids.
These oxLDL are very powerful components in the blood that have been considered since about as involved in the development of heart disease [ 12 ]. Essential fatty acids do more than regulate the blood; they are also a key to reproduction. Since the 's, we've known that reproduction always fails on fat-free diets. In studies on rats, reproduction continues under low fat conditions because the rats have enough linoleic acid stored in their bodies. They manufacture arachidonic acid from the linoleic acid in their own fat, so they can reproduce healthy young even after a fat-free diet.
If the rats did not have enough linoleic acid stored in their bodies such as rats born to mothers on fat-free diets , we found they could not make enough of the arachidonic acid needed for healthy reproduction, and their young die. Women need the essential fatty acids for reproduction. The easiest way to supply them is from plant oils [ 5 ]. Data from ADM shows the composition of three different hydrogenated fats, based on a serving size of 14 grams.
The first two were made of enzymatically interesterified soybean oil, and contained 0 grams of trans fat per serving. The take away message is that due to effective food industry lobbying, food labeling rules allow foods with up to half a gram of trans fat per serving to be labeled "0 trans fat". So look for "partially hydrogenated vegetable oil" on the label. Several researchers have documented the effects of foods without trans fat and their positive effects on lowering CHD.
Mozaffarian et al. They found lower death rates among those with high seafood and plant-based diets. Kris-Etherton et al. They also suggested that higher intake of trans fat could adversely affect endothelial function, which might partially explain why the positive relationship between trans fat and cardiovascular risk is greater than one would predict based solely on its adverse effects of plasma lipids [ 12 ].
Two mechanisms may be involved in CHD: One, the oxidation of the fatty acids and cholesterol in LDL leading to a change in sphingomyelin concentration in the arteries, which is a process that occurs over a life time; two, the deposition of trans fat in the cardiovascular system.
Trans fat calcifies both the arteries and veins and causes blood clots. Trans fat leads to the reduction of prostacyclin that is needed to prevent blood clots in the coronary arteries. A blood clot in any of the coronary arteries can result in sudden death. Oxysterols were present at higher concentrations in the plasma of patients who had coronary artery bypass grafting CABG surgery.
These patients had 40 times more calcium in their bypassed veins than normal veins in the same patient. When purchased oxysterols were added to plasma from patients who did not need CABG surgery, endothelial cells cultured in their blood and tested with radioactive calcium the incorporation of radioactive calcium did not differ from that of plasma from CABG patients. The oxidation of cholesterol and deposition of calcium is the primary cause for the development of atherosclerosis in the arteries and veins.
In a review article entitled "The pathogenesis of atherosclerosis: Perspectives for the s" Ross stated "Atherosclerosis of the extremities is most apparent at branching points of the arterial tree where blood flow is irregular with current and back currents. The cellular events that occur during the progression of lesions in hypercholesterolemic animals are almost exactly mirrored by those observed in human atherosclerotic coronary arteries in hearts removed in transplant operations" [ 13 ].
De Bakey et al. Keaney stated that the gene expression pattern in the arterial wall is subject to influence by modified forms of LDL [ 15 ], which altered both scavenger reception CD36 expression and the expression of pro-inflammatory genes [ 16 ]. The disturbed laminar flow pattern of fluids occurs near branch points [ 17 ], bifurcations, at major curves and at arterial geometries [ 18 ] that are typically associated with the earliest appearance and subsequent progression of atherosclerotic lesions [ 19 ].
The transient application of shear stress showed that the initial stimulation of shear stress was sufficient for induced expression of LOX-1 and that sustained application of shear stress was not required [ 22 ].
The over-expression of LOX-1 receptors at the bifurcation and the higher level of modified LDL and oxysterols in the plasma of persons needing CABG surgery could lead to a higher uptake of modified LDL, resulting in a greater delivery of oxysterols to the endothelial cells at the bifurcations. Hydrogenation is a chemical process that converts liquid vegetable oil into solid fat. Partially hydrogenated oils, such as shortening and soft margarine, are semi-soft. Oils that are fully hydrogenated are firmer, and don't contain any of the dangerous artery-inflaming trans fat found in partially hydrogenated oils.
But they do harbor some saturated fat in the form of stearic acid, which is created during the hydrogenation process. Both trans fats and saturated fats contribute to your risk of heart disease. So it's best to avoid hydrogenated oils in general, especially since they tend to show up in high-fat dishes that aren't that good for you anyway, such as fried food, fast food, and processed baked goods.
For more, see our article on good and bad fats.
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