× Didn't find what you were looking for? Ask a question
Top Posters
Since Sunday
5
o
5
4
m
4
b
4
x
4
a
4
l
4
t
4
S
4
m
3
s
3
New Topic  
rb40gte rb40gte
wrote...
13 years ago
What is a trans-fat and why do think it is harmful? In terms of biology, can you give me some insights for my own knowledge and self-study for my class?

Thanks everyone..
Read 2861 times
4 Replies

Related Topics

Replies
wrote...
13 years ago Edited: 13 years ago, Biology-Forums.com
This is my field of study!  Grinning Face

A trans-fat can be either naturally produced or synthetically produced in a laboratory.

The natural trans-fat is produced mainly in bovine species, such as cows. Bacteria found in their 4-chambered stomachs biochemically convert unsaturated fat into fat molecules that have a trans-chemical formation (see attached photo).

Trans formation is far more stable than fat molecules with the cis formation (ordinary unsaturated fat). This is partly due to their shape; the straighter shape of the trans isomer leads to hydrogen intermolecular forces that make the molecule more stable. A fat molecule that is more stable will not readily become digested in the body. In fact, lipases, the enzymes that digest fats (lipids) is specific to the cis configuration, rendering the human body unable to metabolize or remove trans fat! The human lipase enzyme is ineffective with the trans configuration, so trans fat remains in the blood stream for a much longer period of time and is more prone to arterial deposition and subsequent plaque formation. The longer a fat remains in the blood, the more likely it will become oxidized (activated) by free radicals.

The synthetically produced trans-fat, called hydrogenated fat, is far more dangerous. The process called hydrogenation of an unsaturated fatty acid refers to the addition of hydrogen atoms to fat molecule, causing double bonds to become single ones, as carbon atoms acquire new hydrogen partners (See attached illustration). Full hydrogenation results in a molecule containing the maximum amount of hydrogen (in other words, the conversion of an unsaturated fatty acid into a saturated one). Partial hydrogenation results in the addition of hydrogen atoms at some of the empty positions, with a corresponding reduction in the number of double bonds. Eating too much hydrogenated fat leads to high blood cholesterol -> higher chances of a heart attack.

Some foods such as beef and cheese contain small amounts of trans-fat. This does not mean it has been artificially produced, since some foods naturally contain small amounts. However, unlike hydrogenated trans-fat, natural trans-fat is metabolized similarly to saturated fats. Therefore, although the consumption of trans-fat should be avoided entirely, it is generally safer to eat the natural form, as opposed to the hydrogenated form.

Next time you go out to purchase a jug of vegetable cooking oil, make sure it contains absolutely no trans-fat. If it does, you know that it has been hydrogenated (artificially produced) because no vegetable on earth has the capability of producing trans-fat. The same rule applies to pastries and snacks, such as chips, chocolate, or anything prepared in oil or contains oil but does not contain meat or dairy products.
 Attached file(s) 
Thumbnail(s):
You must login or register to gain access to these attachments.
B.Sc. (Biology)
rb40gte Author
wrote...
13 years ago
unsaturated fats (natural form - cis) are better than saturated fats?
wrote...
Valued Member
Educator
13 years ago Edited: 13 years ago, bio_man
Yes. Unsaturated fats (whether cis or trans) are liquid at room temperature because they have many double bonds. The more double bonds in a lipid molecule (in the cis form), the healthier it is. Monounsaturated means one double bond, polyunsaturated means many double bonds (very low viscousity and healthy!). Saturated means no double bonds, only single bonds, and so these kind of fats are typically solid at room temperature or have high viscosity. When you heat up saturated fat, say in a pan, it become liquidy, that is, until it cools down again.

A little advice, always try to get unsaturated fats in your diet and eliminate the trans-fat. Limit your saturated fat intake (such as the white fat you see on meat or bacon).

Bio_man 8)
wrote...
Donated
Valued Member
13 years ago
rb40gte, here's an excellent case study.

Assume you want to buy a prepackaged microwavable meal. As shown on the box, the meal contains grilled chicken and vegetables, and is advertised as low in fat. You examine the nutrition label and discover that it contains 0.5 grams of trans fat, except that 'hydrogenated oil' is not listed as an ingredient on the ingredients list. If the product really contained only grilled chicken and vegetables, it would be free of trans fat, because only beef products, not chicken products, have the possibility of containing trans fat. Thus, it is likely that either the chicken or vegetables (or both) were marinated with hydrogenated oil prior to being cooked, and since the package is advertised as being low in fat (targeting consumers mainly on diets), the company was reluctant to mention this fact on the package.

As a consumer, this form of dishonesty should not be tolerated. If anything, it should perpetuate the impression that the company is presently cheating on labels of its other products as well. Unfortunately, in the United States and Canada, if a product contains less than 0.5 grams of trans fat per serving, companies have a right to declare it as being 'trans fat-free.' Any products that fails to mention what type of vegetable oil used should be avoided - this is a recent trend being used on the labels of fried foods such as chips, including some top-selling snack-food brands like Doritos and Lays, as a way to avoid telling its consumers whether it contains pure (i.e. canola oil) or hydrogenated oils. Since most Doritos brand flavours contain some type of cheese (predominantly cheddar), being labeled as trans fat-free is arguably a misnomer.

Drinks like POM Wonderful, which are made from pomegranates, contains high levels of antioxidants. Antioxidants, as the name implies, neutralize chemicals in the bloodstream that cause oxidation to occur. Oxidants are highly reactive chemicals and can cause inflammation and sickness if antioxidants are not present. Although the body does synthesize its own antioxidants such as glutathione, antioxidants obtained from one's diet are still required to maintain a healthy body. Antioxidants, however, cannot be stored in the body, but can be recycled. Therefore, drinking one bottle of POM Wonderful a year will not protect you from the dangers of oxidants on a daily basis.
New Topic      
Explore
Post your homework questions and get free online help from our incredible volunteers
  933 People Browsing
 113 Signed Up Today
Related Images
  
 801
  
 133
  
 245
Your Opinion