In my recent articles I have been discussing dietary fats. So far I have covered the three naturally occurring types of fat which are saturated fat, monounsaturated fat and polyunsaturated fat. Today I am going to cover the fourth and final type of fat – the man made trans fat.
WHAT ARE TRANS FATS?
All fats are made from a combination of carbon and hydrogen atoms. The two main types are saturated fats and unsaturated fats (which can be broken down further into monounsaturated fats and polyunsaturated fats). With saturated fats all the carbon atoms are bonded to (or ‘saturated’ with) hydrogen atoms. With unsaturated fats there are some double bonds between the carbon atoms so they are not fully saturated (or they are ‘unsaturated’) with hydrogen atoms. Monounsaturated fats have just one double carbon bond whilst polyunsaturated fats have two or more.
Trans fats (or trans fatty acids) are a type of unsaturated fat. The double carbon bond on most naturally occurring unsaturated fats is arranged in a cis formation which means the hydrogen atoms are all on the same side of the bond. However, with trans fats the double carbon bond is arranged in a trans formation which means the hydrogen atoms are on opposite sides of the bond.
Trans fats have a higher melting point than cis unsaturated fats and are generally solid at room temperature. The majority of trans fats are artificially created through a process called hydrogenation although there is a naturally occurring form called vaccenic acid:
Hydrogenated Trans Fats:- These types of trans fats are man made through a process called hydrogenation. Hydrogenation removes a double carbon bond from naturally occurring cis unsaturated fats and replaces it with a hydrogen atom. So in other words the process of hydrogenation artificially creates trans fats by making cis unsaturated fats more saturated. Hydrogenated trans fats have a much longer shelf life than other types of fats hence the reason they are often added to processed foods.
Vaccenic Acid:- This type of trans fat is found naturally in very small amounts in certain meat and dairy products. It can also be sourced from human milk.
WHICH FOODS CONTAIN TRANS FATS?
Although trans fats can be sourced naturally from certain foods the vast majority are added to foods in their unnatural hydrogenated form. This means that trans fats are largely found in processed products. Some examples of foods containing trans fats are listed below:
- Baked foods such as cookies and doughnuts.
- Fast foods such as burgers and fries.
- Frozen foods such as pies and pizza.
- Packaged processed foods such as biscuits and cakes.
ARE TRANS FATS HEALTHY?
As I have discussed in previous blog posts dietary fat is often given an unwarranted bad reputation. Saturated fats have been blamed for many health ailments including cancer and heart disease. Even monounsaturated and polyunsaturated fats were perceived negatively until very recently. However, research has now come to the defence of dietary fat and revealed that they actually have a number of health benefits.
Unfortunately, the majority of trans fats do not share these health benefits. Whilst the naturally occurring vaccenic acid has been linked with reducing the risk of diabetes, heart disease and obesity, hydrogenated trans fats have no reported health benefits. In fact they can be damaging to your health.
WHAT ARE THE HEALTH RISKS OF TRANS FATS?
1) INCREASED HEART DISEASE RISK:- Multiple studies have highlighted the link between heart disease and trans fats. The most significant of these is a paper published by Dr Hu and his colleagues. Hu followed 120,000 nurses from 1976 till 1990 and investigated 900 coronary events that occurred during that time. He concluded that every 2% increase in trans fats consumed doubled your heart disease risk.
Another study published in the New England Journal of Medicine in 2006 estimated that trans fats caused between 30,000 and 100,000 cardiac deaths in the United States each year. The results also showed that trans fats increased your risk for heart disease more than any other macronutrient on a calorie for calorie level.
2) POOR BLOOD CHOLESTEROL LEVELS:- There are two types of cholesterol; low density lipoprotein (LDL) and high density lipoprotein (HDL). LDL cholesterol builds up on your blood vessel walls and can lead to a number of problems in your body including heart disease, high blood pressure and organ damage. HDL cholesterol collects LDL cholesterol from the blood and transfers it to the kidneys where it is processed and excreted.
The different types of fat have different effects on your cholesterol levels. Saturated fats increase levels of both LDL and HDL cholesterol. Unsaturated fats reduce LDL cholesterol levels whilst increasing HDL cholesterol levels. Trans fats increase LDL cholesterol levels whilst lowering HDL cholesterol levels. This means that by consuming trans fats you are most at risk of the negative symptoms linked to LDL cholesterol consumption.
3) INCREASED ALZHEIMER’S DISEASE RISK:- A study from the Archives of Neurology published in February 2003 suggests that trans fats could be linked to Alzheimer’s disease. The study looked at the dietary habits of 815 people aged 65 and over who were unaffected by Alzheimer’s when the study began and then followed up with these same people 3.9 years later.
4) INCREASED CANCER RISK:- In recent years a number of studies have highlighted the link between trans fats and cancer. A study published in the American Journal of Epidemiology in April 2008 concluded that consumption of trans fats could lead to breast cancer. The study followed 25,000 women between 1995 and 1998. The results showed that women with the highest levels of trans fats in their blood were twice as likely to develop breast cancer as those with the lowest levels of trans fats in their blood.
Another study published in the American Journal of Epidemiology in August 2008 concluded that trans fats could increase colon cancer risk. This study looked at the dietary habits of 622 people who had colonoscopies between 2001 and 2002. It revealed that people who consumed high levels of trans fats (6.5g or more daily) were 86% more likely to develop colon polyps (which can then go on to develop into cancerous tumours) than those who consumed lower levels of trans fats.
HOW CAN I REDUCE THE HEALTH RISKS ASSOCIATED WITH TRANS FATS?
As I discussed above hydrogenated trans fats are artificially created and found in processed goods. Therefore, the best way to avoid the health risks associated with this fat type is to reduce your intake of processed goods and instead get your fats from natural sources. Where possible avoid packaged goods. When you do eat them look out for phrases such as “partially hydrogenated vegetable oil” and “vegetable shortening” as these are both hydrogenated trans fats.
Instead of packaged goods try to eat foods that are as close to their natural form as possible. Some of the best natural sources of dietary fat are fresh meat, fresh fish, eggs and olive oil. Natural fats have a number of fantastic health benefits that I have discussed in previous articles so by replacing unnatural trans fats with these natural fats you can enjoy all the fantastic health benefits whilst avoiding the risks.
TRANS FATS SUMMARY
Unlike the other types of dietary fat, hydrogenated trans fats have no reported health benefits and provide no nutritional value. They are used by food manufacturers as a cheap way to extend the shelf life of processed foods. I hope this article has helped you realise the health risks of trans fats and encouraged you to reduce your consumption.
Now I want some feedback from you. Did you know about the dangers of trans fats already? Are there any health risks I have missed. Leave a comment and let me know your thoughts.
Dietary Fat and the Risk of Incident Alzheimer Disease (Archives of Neurology)
Natural Trans Fats Have Health Benefits (Science Daily)
Top 10 Foods with Trans Fats (Organic-Coconut-Oil.com)
Trans Fats (Natural Health Information Center)
Trans Fat (Wikipedia)
Trans Fats, Heart Disease Risk: ‘Strong Link’ (Web MD)
Trans Fats Linked To Breast Cancer Risk In Study (BreastCancer.org)