Trans fat: a danger lurking in fast food
It appears that the fast food culture has swept the whole world like a storm that is becoming fiercer with time. Top five fast food consuming countries in the world are USA, France, Canada, UK and South Korea. In the fast and ever-changing world of ours, people just do not have time any more to prepare and enjoy food like olden days. Everyone tries to grab a bite whenever and wherever they can in order to ensure that there will be more free hours to do something else.
The primary dietary source for trans fat in processed foods is partially hydrogenated oils, which is the worst kind of fat human beings consume. Trans fat can be found in many foods, including fried foods like doughnuts, French fries, fried chicken and baked goods, including cakes, pie crusts, biscuits, frozen pizza, cookies, crackers, and stick margarines and other spreads.
In food production, liquid unsaturated fats such as vegetable oils are hydrogenated to produce saturated fats, which have more desirable physical properties. Hydrogenation is a chemical process, in which unsaturated fats are treated with hydrogen in the presence of heavy metal catalyst such as palladium, resulting in the formation of saturated fat.
The process of partial hydrogenation of unsaturated fats produces trans fats. Partially hydrogenated vegetable oils are cheaper than animal fats and give desirable taste and texture to the food. They are available in a wide range of consistencies, and have other desirable characteristics such as increased oxidative stability and longer shelf life. They are the predominant fats used in most commercially baked and cooked foods.
You can determine the amount of trans fats in a particular packaged food by looking at their packaging. However, products can be listed as “0 grams of trans fats” if they contain 0 grams to less than 0.5 grams of trans fat per serving. You can also spot trans fats by looking for the ingredients referred to as “partially hydrogenated oils.” Selecting foods with even small amounts of trans fat can add up a significant intake.
It has been unequivocally accepted that trans fat is the worst kind of dietary fat because it can give rise to a number of diseases, which are listed below:
Increases risk of coronary heart disease – Trans fat consumption raises the risk of coronary heart disease (CHD). According to a review of studies published in the New England Journal of Medicine in 2006 concluded 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 (1 to 3% of total energy intake). It has been found that consumption of trans fat is linked to an increase in mortality in persons with CHD, whereas consumption of polyunsaturated fats is linked to a decrease in mortality.
Raises inflammation – Consumption of trans fat is known to raise inflammation in the body, thereby increasing the risk of inflammation related illnesses. A study of over 700 nurses showed that those in the highest quartile of trans fat consumption had blood levels of CRP that were 73% higher than those in the lowest quartile. CRP (C reactive protein) is an indicator of inflammation in the body.
Causes obesity – It has been found that consumption of trans fat causes increase in weight and abdominal obesity in spite of a similar calorie intake. There is no strong scientific consensus associating trans fat with obesity in humans but a 6-year animal study in 2006 showed that monkeys fed on a trans fat diet gained 7.2% of their body weight, as compared to 1.8% for monkeys on a mono-unsaturated fat diet. The monkeys were given the same amount of daily calories, with 35 percent of the calories coming from fat. The amount of calories they got should only have been enough to maintain their weight, not increase it.
Disturbs cholesterol ratio – This ratio compares levels of LDL and HDL in blood. Trans fat behaves like saturated fat by raising the level of LDL (bad cholesterol) but, unlike saturated fat, it has an additional effect of decreasing levels of HDL (good cholesterol). The net increase in LDL/HDL ratio with trans fat is approximately double than that due to saturated fat.
Causes type-2 diabetes – Researchers have concluded that consumption of trans fats increase risk of type-2 diabetes, whereas consumption of polyunsaturated fats reduce the risk. Therefore, substituting non-hydrogenated polyunsaturated fatty acids for trans fatty acids would likely reduce the risk of type 2 diabetes substantially. Research from the University of Maryland utilizing a primate model (Barnard et al 1990) is suggestive of an adverse effect of consumption of trans fats on insulin receptors and insulin binding. However, consensus has not been reached about the association of consumption of trans fats and type-2 diabetes.
Promotes atherosclerosis - Scientists have discovered how dietary trans-fats cause hardening of the arteries. A study on mice suggests that high levels of trans-fats cause atherosclerosis by reducing the responsiveness of a key protein - transforming growth factor (TGF)-beta, which controls growth and differentiation in cells. Inflammatory response to the consumption of trans fat also contributes to atherosclerosis. So, consumption of trans fats can be linked to the diseases that have atherosclerosis as an underlying causative factor.
Reduces immunity - Consumption of trans fat can cause inflammation, which leads to an overactive immune system that can contribute to heart disease, diabetes, stroke and other chronic diseases. Unhealthy dietary trans fats can also indirectly compromise immune function by contributing to obesity.
Increases risk for Alzheimer’s disease - A study published in Archives of Neurology in February 2003 suggested that the intake of both trans fats and saturated fats promote the development of Alzheimer’s disease. It has been found that trans fats impaired memory and learning in middle-age rats. Inflammation was detected in rats in and around the hippocampus, the part of the brain responsible for learning and memory. These are the exact types of changes normally seen at the onset of Alzheimer's disease.
Raises risk for cancer – Trans fats have been hypothesized to cause cancer but there are limited data in humans for this hypothesis. In a study involving 25,000 European women, those who had the highest levels of trans fats in their blood were about twice as likely as those with the lowest trans fat levels to develop breast cancer. In a study conducted in Utah, North Caroline and Minnesota an association between trans fats and colon cancer has been revealed.
Raises risk of infertility – There exists evidence that consumption of trans fats can raise the risk of infertility in women. A study in 2007 revealed that every 2% increase in the intake of energy from trans fats, as opposed to that from carbohydrates, was associated with a 73% greater risk of ovulatory infertility.
Affects memory – A recent study showed that in younger adults below the age of 45 years greater consumption of trans fats is linked to worse word recall. It is notable that this is the age of high productivity for an adult. Moreover, consumption of trans fats inhibits body’s production of omega-3 fatty acids, which play a crucial role in brain function.
Causes liver dysfunction – Trans fats are metabolized differently by the liver than other fats, and, therefore, their consumption can lead to liver dysfunction. Trans fats consumption interferes with delta 6 desaturase, which is an enzyme involved in converting essential fatty acids to arachidonic acid and prostaglandins that are important to functioning of liver cells. In a study, the researchers have found that mice fed the normal calorie chow diet remained lean and did not have fatty liver disease. Mice fed on high calorie diets - trans-fat alone or a combination of trans-fat and high fructose - became obese and had fatty liver disease.
Causes depression - In a study, Spanish researchers analyzed the diets of 12,059 people over six years and found those, who ate the most trans fats, had a 48 % higher risk of depression than those, who did not eat trans fats.
The bottom line –
The experts agree across the board that trans fats are detrimental to the health of the people. But, concurrently, it is also a distressing fact that the consumption of trans fats is increasing rapidly in all sections of society worldwide. The respective governments of different countries are trying their best to implement the regulations set up to ensure the safety of fast foods by limiting the contents of trans fats to a minimum. But it appears that such regulations need to be revised and implemented strictly. It has also been observed that people do check ingredients of foods about their nutritional value while purchasing, but neglect to pay attention to the amount of trans fat. Therefore, it is the need of the hour that people should develop awareness towards trans fats and their detrimental effects on health in order to avoid them.