Fatty Acids; Erythrocytes

Description

Fatty acids (FAs) are primarily derived from triglycerides in the food and oils that we consume. Non-essential FAs are also biosynthesized in the body, especially during times when carbohydrate intake exceeds the body's needs for glucose and glycogen repletion. Non-essential FAs are most commonly recognized as an important source of energy, and when caloric intake exceeds expenditure, these FAs are stored in adipose tissue as triglycerides. However, FA metabolism is much more complex and it is well established that appropriate balance among essential and non-essential FAs, as well as avoidance of harmful trans-FAs, is required for optimal health and wellness.
What are Fatty acids? What is Omega 6, Omega 3, Linoleic acid, α-linoleic acid?

Fatty acids are natural components of fats and oils. Based on their chemical structure they can be differentiated into three groups: ‘saturated’, ‘mono-unsaturated’ and ‘poly-unsaturated’ fatty acids. Saturated fatty acids (fats) are mainly found in animal foods, such as (fatty) meat, lard, sausage, butter and cheese but even in palm kernel and coconut oil, which are used for frying.

Most unsaturated fatty acids (fats) are of plant and fatty fish origin. Foods containing unsaturated fatty acids include avocado, nuts, vegetable oils (corn, soy, and algal-oil), herring, and salmon. Meat products contain both saturated and unsaturated fats.

Of particular interest are ‘polyunsaturated fatty acids’. Within the family of polyunsaturated fatty acids (PUFAs), there are two different groups: the ‘omega-3-fatty acids ‘and ‘omega-6-fatty acids’ (1). Both are considered essential fatty acids because they cannot be synthesized by humans.

Essential fatty acids, or EFAs, are fatty acids that humans and other animals must ingest because the body requires them for good health but cannot synthesize them. Those not essential are non-essential fatty acids.

An unsaturated fatty acid that is essential to human health, but cannot be manufactured in the body is abbreviated as EFA. There are three types of EFAs: arachnoidic acid, linoleic acid , and linolenic acid.

Arachnoidic acid may lower the seizure threshold. For that reason, it is important to consult a physician and test its levels before starting a program of EFA supplementation.

Other two types of Essential fatty acids that your body is unable to synthesize are linoleic acid (omega-6 fatty acid) and alpha-linolenic acid (omega-3 fatty acid).

Alpha-linolenic acid is converted in the body to the active forms of omega-3 fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA).

Linoleic acid and alpha-linolenic acid are considered essential fatty acids because you need to obtain them through your diet since your body can’t create them.

What is Omega 9, Oleic Acid?

Omega-9 fatty acids are from a family of unsaturated fats that are commonly found in vegetable and animal fats. These fatty acids are also known as oleic acid, or monounsaturated fats, and can often be found in canola oil, safflower oil, olive oil, mustard oil, nut oils and, nuts such as almonds. However, unlike omega-3 and omega-6 fatty acids, omega-9 fatty acids can be produced by the body, which means the need to supplement is not as important as the popular omega-3.

FAs are monocarboxylic acids that may be either saturated (no C=C double bonds) or unsaturated (one or more C=C double bonds). Humans make saturated fatty acids and a monounsaturated fatty acid with a double bond at the omega-9 position but do not have the enzymes necessary to introduce a double bond at the omega-3 (ω-3) or omega-6 (ω-6) positions. The essential fatty acids (EFAs) linoleic acid (18:2) and α-linoleic acid (18:3) are polyunsaturated fatty acids (PUFAs) that are precursors of the ω-6 and ω-3 fatty acid series, respectively. The ω-6 and ω-3 FAs compete for desaturase and elongation enzymes that produce longer-chain, more highly unsaturated FAs. The typical Western diet contains an undesirable preponderance of ω-6 fatty acids that impedes elongation and desaturation of ω-3 FAs.

Omega-6 fatty acids compete with omega-3 fatty acids for use in the body, and therefore excessive intake of omega-6 fatty acids can inhibit omega-3s. Ideally, the ratio of omega-6 to omega-3 fatty acids should be between 1:1 and 4:1. Instead, most Americans consume these fatty acids at a ratio of Omega-6:Omega-3 between 10:1 and 25:1, and are consequently unable to reap the benefits of omega-3s. This imbalance is due to a reliance on processed foods and oils, which are now common in the Western diet.

FAs derived from EFAs or taken in via diet or supplements are essential components of cell membrane phospholipids, and appropriate membrane fatty acid content is pivotal for optimal membrane fluidity, receptor activity and cellular metabolism.

The same FAs eventually give rise to hormone-like substances (eicosanoids) that are involved in the regulation of blood pressure and coagulation, lipid levels, immune response, tumor growth and inhibition, and the inflammatory response to injury and infection, and may play a role in seizure disorders and dementias such as Alzheimer's disease.

Appropriate balance of membrane phospholipid EFAs is important because the biological effects of the ω-3 and ω-6 FAs metabolites are mediated by their mutual interactions.

What is tested in this “Fatty Acids; Erythrocytes” test?

This test measures the primary ω-6 and ω-3 PUFAs, and monounsaturated, saturated and trans FAs that are present as constituents of phospholipids in the membranes of erythrocytes. Each FA is reported as a percentage of the total FAs measured and important FA ratios are presented. The commentary is provided for results exceeding reference intervals.

Is it better to measure fatty acid in plasma or erythrocyte?

In American Journal of Clinical Nutrition, “Comparison between plasma and erythrocyte fatty acid content as biomarkers of fatty acid”  its article was published both in AJCN and PubMed whose URL is given below, which stated that measuring fatty acid in erythrocyte is more accurate biomarker than to test for fatty acid in plasma.

Source : https://www.ncbi.nlm.nih.gov/pubmed/17616765