Fatty acid supplements

There are a number of different fatty acid supplements available, with some being significantly more popular than others. The full extent of the means by which these fatty acids exert their effects is far beyond the scope of this course, and so here we will simply speak in very broad terms about the real-world effects seen upon supplementing with the different products available.

CLA

Conjugated Linoleic Acids (CLA) are a group of 28 different isomers (molecules with the same molecular structure but different molecular shapes) of the Omega-6 polyunsaturated fat, linoleic acid. Conjugation simply denotes that one or more of the double bonds seen on the fatty acid’s carbon chain are separated by a single bond between them.

CLA supplementation is purported to impact on the action of a group of proteins known as Peroxisome Proliferator Activated Receptors (PPAR). These act as transcription factors, which are a group of proteins that bind to DNA sections to stimulate the expression of genes. PPAR’s bind to free fatty acids within a cell’s nucleus, travel to the DNA and then cause the expression of genes involved in fatty acid transport and oxidation, meaning that (in theory at least) the activation of this process can reduce bodyfat. Unfortunately, the evidence for this is contradictory and wholly underwhelming, meaning that although CLA can indeed activate this system, that doesn’t necessarily lead to any meaningful loss of bodyfat.

This is an example of a supplement which does in fact have some effect, and when that effect is extrapolated using logic, it would seem that a purchase would be justified, but when human trials are done this does not hold out. The mechanistic effect being in contradiction is something that is often seen in supplement science, and CLA was included in this module as an example of this.

Omega 3 fatty acids

The Omega 3 fatty acids include Alpha Linoleic Acid (ALA – not to be confused with Alpha Lipoic Acid), Docosahexaenoic Acid (DHA) and Eicosapentaenoic Acid (EPA). The latter are found in oily fish but increasingly commonly found in supplemental form. The former is found in nuts and seeds, as well as seed oils such as flax.

ALA is an essential fatty acid meaning that it cannot be synthesised, but it is EPA and DHA which carry the most evidence of beneficial effects and ALA’s main role appears to be simply as a parent molecule. ALA is converted into EPA and DHA thanks to a cascade of enzymes which both elongate it’s 18 carbon chain to 20 or 22 carbons and add additional double bonds as per the below.

This process is highly inefficient, resulting in only a 21% conversion of ALA to EPA and 9% to DHA in women, and even less in men. Additionally, this process shares enzymes with the process which converts the parent Omega-6 essential fatty acid linoleic acid into the various forms that it can take, and therefore a high Omega 6:Omega 3 fatty acid ratio within the diet can result in increased oxidation of ALA and decreased EPA and DHA conversion.

This unfavourable ratio is highly common due to consumption of numerous linoleic acid rich foods (such as nuts, seeds and vegetable oils including sesame and rapeseed/canola oils) and so conversion is unlikely to be high. As such, supplementation with EPA and DHA directly is the only realistic way of achieving an intake high enough to reap the benefits typically associated with Omega 3 fatty acids.

Supplementation seems to result in reduced arthritic pain, reduced post-exercise soreness and reduced symptoms of depression (specifically in those who respond well to fluoxetine, and when both are combined the effects seem to stack somewhat) as well as reduced total triglycerides in those who have elevated levels. Omega 3 fatty acids seem to reduce symptoms of systemic inflammation in women using HRT or individuals post-surgery, and increase the beneficial effects of exercise on blood lipid markers in overweight individuals.

There is also some inconsistent data to show that supplementation may result in reduced incidence of cardiovascular events without exercise, and mild evidence that it can help improve the results an obese individual will see from a hypocaloric diet. However, inconsistent data should be taken with a pinch of salt.

Overall Omega-3 supplementation appears to be beneficial in doses of 2-3g per day. Though this is unlikely to be life changing, it is one of the more robustly supported products currently available to benefit human health.