It is clear now, that since trans fats first were introduced into the human diet at the beginning of the 20th century, they may have been singularly involved in the extraordinary rise in a vast number of chronic illnesses. The entire story of trans fats cannot be told because the story is still unfolding. Chapters are still being added by thousand of researchers the world over as they work to define the metabolic pathways of living organisms.

The story of trans fats begins with the 20^th century. Nobelist Paul Sabatier worked in the 1890s to develop the chemistry of hydrogenation which is a process that adds hydrogen atoms to molecules containing double bonds. Sabatier believed that only gasses could be hydrogenised. In 1901, Wilhelm Normann, looking for a ready and affordable substitute for lard, showed that liquid oils containing unsaturated fatty acids could also be hydrogenated to form hardened fat. He patented the process in 1902, calling it "fat hardening" and started the first manufacturing facility.

Chemically, fatty acids are hydrocarbons (composed of carbon, oxygen and hydrogen) that begin with a carboxyl group (COOH) and end with a methyl group (CH3). In between these two components, a chain of CH2 groups (as many as two to twenty two) complete the molecule. They come in saturated and unsaturated molecules. The difference between saturated and unsaturated molecules is that the unsaturated molecules are missing a hydrogen (H) atom from some of the CH2 groups which causes the carbon atoms to form double bonds.

To understand the difference between trans fats and other kinds of fats it's easiest to compare the shapes of the fatty acid molecules.

Saturated fatty acids are straight chain molecules that interconnect forming rigid lattices, storing maximum energy within the smallest volume. It is the lattice structure that makes butter and lard solid at room temperature.

The shape of unsaturated fatty acids, also called omega fatty acids, deviates from the straight chain depending on how many double bonds are present. Omega-9s with only one double bond have a kink in the chain. Omega-6s have two double bonds and are more L shaped. Omega-3s have three double bonds and they are more J shaped. The shapes of unsaturated fatty acids prevent those molecules from forming the same rigid lattices. They are more flexible and that property lowers their melting points and lends them their oiliness.

In modern chemistry, the ultimate goal of partially hydrogenating unsaturated fatty acids is to extend product shelf life. The intention is the breakdown of molecular double bonds with the addition of as many hydrogen atoms as possible creating a substance that retards spoilage but still melts at baking temperatures. If all the double bonds are broken and hydrogen atoms are successfully integrated into the molecule, then a saturated fatty acid is created.

Trans fatty acids are a by product of the partially hydrogenation process. In the creation of trans fatty acids, attempting to add hydrogen atoms to an omega fatty acid molecule, does not break the carbon double bond. Partial hydrogenation more or less flips one side of the carbon double bond in the opposite direction of the other so that one hydrogen atom aligns itself on the opposite side of the kink. What happens is rather like walking down a hallway that turns right and then turns left. Overall, you end up going in the one direction but you make a jog along the way. This side effect of partial hydrogenation creates a nearly straight fatty acid molecule with a twist.

Wilhelm Normann and the industrialists who cashed in on partial hydrogenation could never have guessed that the displacement of a single little atom would have such extraordinary detrimental effect to human health.

The metabolism of fatty acids is highly specific, which means that each set of molecules has a specific set of enzymes, amino acids, precursor molecules, derivatives and other intermediates associated with it. Early on, it was theorized that trans fatty acids were relatively benign because they would be unable to enter the normal metabolic pathways. At best, it was thought they might be metabolized similar to the omega fatty acids from which they are derived.

As early as 1988, there was scientific evidence that trans fats are a major contributor to coronary heart disease. Since then, it has been determined that children are getting a surprising number of chronic diseases that were previously thought to be adult illnesses and that young adults are more susceptible to age related diseases. Also, trans fats may figure heavily as a risk factors in infertility rates. They have been linked to prostate cancer but whether they cause other cancers has not been determined.

There seem to be two main ways that trans fats can potentially affect health.

• 1. By interfering with the interactions of other molecules.
• 2. By not interacting at all

It's easiest to explain the role that trans fats play in human health by looking at the way it is linked to coronary heart disease. This mechanism is fairly well understood. It is necessary to have a rudimentary understanding of how low density lipoproteins (LDL) and high density lipoproteins (HDL) interact with cholesterol.

LDL and HDL are not cholesterol. They are transport molecules that assign themselves to cholesterol in order to move it around. Contrary to popular belief, LDL is not bad and HDL is not good. It is the serious imbalance of LDL concentrations compared to HDL concentrations that is very bad.

LDL molecules pick up cholesterol molecules, or other molecules that have been coated in cholesterol, and moves them to locations in the body where they may be needed. HDL molecules go to these locations and pick up unneeded cholesterol or the chemical artifacts of molecules that have been partially metabolized and returns them to the liver where they can be reprocessed to form other molecules or disposed of. Unsurprisingly, low levels of HDL are associated with high levels of serum cholesterol.

Lipoproteins make up a substantial part of your body's little trucking company and ideally, you might expect them to exist in a natural ratio 1:1. Omega fatty acids and trans fats radically alter this ratio. Omega-6 fatty acids tend to increase LDL where as omega-3 fatty acids tend to increase HDL. Trans fats on the other hand, increase LDL and decrease HDL.

In North America, the ratio of omega-6 fatty acids to omega-3 fatty acids can be anywhere from 10:1 to 30:1. This ratio should as close to 1:1 as possible but no greater than 4:1. The result is that we Americans already lack enough HDL to do the job. There are a lot of molecules being transported in and not nearly enough being packed up and shipped out. Our arteries have turned into poorly managed warehouses with plaques piled up along the walls to the point that blood has trouble circulating. Blood pressure is high. Artery walls become harder and less elastic. Vital organs are starved for both energy and oxygen. Enter trans fats into this problem and it becomes many times worse.

Unlike cholesterol and omega fatty acids, industrially processed trans fats have no nutritional value. Naturally occurring trans fats are found in small amounts in dairy products but these are consumed along with other types of organic molecules present in the same foods. These ruminant trans fats may have some use to us since they come to us with some of what is needed to metabolize them. But, industrially processed trans fats can't be processed by the human body except in limited instances and not without interfering the other interactions. Unwanted trans fats cannot be transported out very easily. Over time, they deteriorate into more plaque.

By 1984, science pointed the finger at saturated fats and high cholesterol as the likely culprits behind dramatically escalating rates of heart disease. Public pressure worked to increase the demand for trans fats as restaurants, hospitals and other institutions reduced the number of saturated fats on their menus. Ironically, it turns out that saturated fats are a better food choice than the trans fats that were used to replace them. By some estimations, the overall increase in the LDL/HDL ratio attributed to trans fats is almost double that caused by saturated fats.

How trans fat increase heart disease, demonstrates that it may affect overall health. It is not known that trans fatty acids replace omega fatty acids in normal metabolism. It is believed that they may compete with omega fatty acids for desaturase enzymes delta 6 and delta 5. This competition could be a reason why they reduce HDL.

It is also why trans fat could be linked to so many other illnesses.

Omega fatty acids are important to human health in many ways.

• They are incorporated in cellular membranes and act as second messenger signals within the cell. These second messenger signals allow the cell to respond signals sent to it by other cells and also allow for "communication with the cell's mitochondria.
• They also act as second messenger signals within the brain and imbalances are thought to be linked to Alzheimer's, ADHD, depression and schizophrenia along with other types of similar disorders.
• Omega fatty acids also play an important part in the regulation of the body's immune system response and in inflammation. Currently being studied is the imbalance of omega fatty acids and rising rates allergies, arthritis, irritable bowel syndrome, hypertension, glaucoma, and early miscarriage.
• Some omega fatty acids are important to male sperm formation.
• The breakdown of fatty acids releases ATP, the currency of energy used throughout the body. They form triglycerides which are stored in the form of body fat and are released into the bloodstream during times of high activity.

By competing for the same enzymes, trans fatty acids tend to limit the body's ability to utilize these vital omega fatty acids and would therefore increase the incidence of disease associated with low numbers of them.

Because trans fatty acids can combine with glycerol to form triglycerides, it can replace fatty acids as components of body fat. Trans fat is being studied in relation to increased obesity and the production of leptin, a hormone that regulates hunger and fat storage. More or less, the fatter you are the less leptin you have and the less you have the fatter you get.

• Trans fatty acids are also being studied for their possible effect on insulin levels and the rise in type 2 diabetes.
• Trans fatty acids have been directly linked to prostate cancer.
• In addition, the Harvard Medical School has recently taken part of in a study of infertility in women. Their final results suggested that as little as a 2% increase in trans fat consumption could result in a 73% greater risk of ovulatory infertility.

In 2007 the US government determined a level of 0.5g/serving as an equivalent for 0 trans fat. Prior to 2007, shortenings and margarines could consist of more than 40% trans fat relative to their total fat content. The 0.5g/serving level was accepted because it limits the amount of industrial trans fat used in food to be no more than that of naturally occurring ruminant trans fats found in dairy products which is usually less than 5% .

There is no known instance when ruminant trans fatty acids posed a risk to human health. But, on the other hand, there is no known safe level for industrially processed trans fat. As manufacturers scramble to reduce industrially processed trans fat in their products, this drastically reduced level is probably still not entirely safe.

Even should this level prove safe, or if new processes are found that render the hydrogenation of unsaturated molecules obsolete, it is still a fact that body fat undoubtedly stores a high volume of trans fat and so trans fatty acids could be released into our blood streams for years to come.

If you want to reduce the impact of trans fat on your health, do three things starting from today.

1. Check product labels and do not buy any foods that include partially hydrogenated oils.
2. Eat more foods rich in omega-3 fatty acids, especially those with DHA and EPA. These include, salmon, tuna, mackerel, catfish, shrimp and a long list of others. You don't need mega supplements to make a difference.
3. Lose weight. Get those trans fatty acids out of your system. If you can't take off weight and keep it off, at least you'll be regaining better fats.