Trans fatty acids, part I
Trans fatty acids: let’s get to know trans fats. What are they, where are they found and why should we avoid them? A thorough overview is provided by the research paper “Trans fatty acids” written by powerlifter Eleri Õisma.
Unfortunately, the food industry often uses alternatives to natural foods in order to keep food prices lower and, as a result, widen its customer base. Milk fat is frequently replaced with hydrogenated vegetable fat, which brings with it an undesirable addition in the form of trans fatty acids.
The product becomes cheaper and can be sold for longer, and people often opt for the lower price. Many organic dairies are “dying out”. A low price is preferred over food quality, and people are not aware of health-conscious consumption. As a result, several serious diseases are becoming more widespread among humankind: obesity, heart and vascular diseases and other cardiovascular problems.
The following table gives an overview of the trans fatty acid content of oils and fats:
Trans fatty acids are also formed through the bacterial transformation of polyunsaturated fatty acids, for example in the gut of ruminant animals. An example of the latter is mammalian milk fat (up to 20% of the monounsaturated fatty acids in cow’s milk fat). Most trans fats, however, are formed in chemically solidified, i.e. hydrogenated, vegetable fats. This is a reaction in which the unsaturated double bonds in the chains of fatty acids are saturated with hydrogen in the presence of a catalyst at elevated pressure and temperature. The result is a firmer fat that is easier to store and transport. This in turn lowers the price of the fat. During hydrogenation, however, even healthy vegetable fats lose their good properties and trans fatty acids are formed, which are hazardous to health. Hydrogenating vegetable oil does not have to produce very much trans fat, because the process can also be carried out in a way that keeps the share of trans fats to a minimum, but it is cheaper to produce hydrogenated fats without limiting the formation of trans fats.
Trans fatty acids in the food industry
The gradual advance of food technology created a need to make various foods cheaper. One way of doing this with fats, for example, is hydrogenation. The hydrogenation method was developed as early as the 1890s by Nobel laureate Paul Sabatier. The technology has been continuously refined since then. Throughout this time, little attention was paid, or for a long time people did not know to pay attention, to the appearance of trans fatty acids in processed products. People only began to think about the situation when the amount of trans fats in some foods began to reach up to half of the total fat. The problem was first raised in the 1980s, when American scientists found a link between a diet rich in trans fatty acids and mortality from vascular diseases. The problem has gradually been addressed, and it has been assumed that excessive consumption of trans fatty acids can lead to disorders of fat metabolism.
Physiological properties of trans fatty acids
Over the past 8 – 10 years, scientists have intensively debated the impact and effects of trans fatty acids. One reason is that, despite the main emphasis being placed on reducing saturated fatty acids for several years, it has not been possible to reduce the share of heart and vascular diseases. This has cast doubt on trans fatty acids formed as a result of the hydrogenation of vegetable fats, and the conclusion has been reached that trans fatty acids are terribly harmful to human health.
Trans fatty acids are formed in food in three ways:
a) through the bacterial transformation of unsaturated fatty acids in the digestive tract of ruminants;
b) through the industrial hydrogenation, i.e. solidification, and deodorization of unsaturated fatty acids; and
c) when oils are heated and fried at high temperatures.
Health problems caused by trans fatty acids
The exact biochemical mechanism by which trans fats affect health is still under investigation. One theory is that the human lipase enzyme works only in the cis configuration, and that the human body does not metabolize trans fatty acids when they are consumed. Lipase is a water-soluble enzyme that helps transport and process dietary lipids, e.g. triglycerides, fats and vegetable oils. While the link between trans fats and coronary heart disease has been substantiated, the effect on diabetes, for example, is still being studied, although it is believed that consuming trans fats also influences the development of diabetes. Consuming trans fatty acids also slows down the synthesis of polyunsaturated fatty acids. A deficiency of polyunsaturated fatty acids, in turn, is a precondition for the development of various cardiovascular diseases.
The greatest health risk caused by consuming trans fats is coronary heart disease. A study compiled in 1994 showed that in the United States, more than 30,000 deaths a year were caused specifically by the consumption of trans fats. A thorough study on the harmfulness of trans fatty acids was published in 2006 by the New England Journal of Medicine, which found a strong link between coronary heart disease and trans fatty acids.
Consuming trans fats has been found to affect health even further, for example in the form of Alzheimer’s disease. In February 2003, a study was published in the journal Archives of Neurology which found that consuming trans fats causes memory impairment and learning difficulties already at a young age. Experiments were carried out on young rats that were fed trans fatty acids, and mild inflammation in the temporal lobe of the brain (where memory is stored) and memory gaps developed after just 6 weeks, even though the rats were young. All the signs that appeared in the rats also appear in the early stage of Alzheimer’s disease.
The American Cancer Society says that a link between trans fats and cancer has not been established. One study did, however, show a connection between trans fat consumption and the development of prostate cancer. Studies by the European Prospective Investigation into Cancer and Nutrition also show that excessive trans fat consumption raises the risk of developing breast cancer by almost 75%.
There is growing concern that trans fat consumption increases the risk of type II diabetes. One study, for example, found that the risk is higher in people who consume more trans fats. One of the causes of this form of diabetes is calcification of the blood vessels, and trans fats attaching to the vessel walls is exactly what brings it about.
Studies also show that trans fat consumption increases the amount of body fat and visceral fat. In an experiment lasting 6 years, monkeys fed trans fats gained 7.2% of their body weight, compared with monkeys that received the same amount of monounsaturated fatty acids over the same period and gained just 1.8% of their body weight.
A study conducted in 2007 found that every 2% increase in trans fat consumption raises women’s risk of infertility by 73%.
Spanish researchers studied the diets of 12,059 people for 6 years and found that those who ate more trans fatty acids had a 48% higher risk of developing depression than those who did not eat trans fats.
To be continued…
Author: Eleri Õisma
Source: Turg.Fitness.ee
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