Positive Health Online

Scan through any weekly output of national newspapers and lifestyle magazines and you will probably come across several articles describing the benefits of omega-3 fatty acids and including more fish in the diet. In addition, we are now seeing similar information included in adverts promoting the health benefits of food products. However, there is another family of essential fatty acids, the omega-6s that do not seem to gain so such prominence. This article therefore tries to redress this imbalance by giving a simple explanation of the omega-6 mechanism at work, some reasons for potential deficiency and the importance that this group of essential fatty acids plays in keeping us healthy.

The Linoleic Acid (LA) Metabolic Pathway

Although we will concentrate on the importance of the omega-6 fatty acid Gamma Linolenic Acid (GLA), the key fatty acid in this family is Linoleic Acid (LA) as it is the precursor of all other omega-6s. LA is called an Essential Fatty Acid (EFA) since the body cannot manufacture it so we essentially need a source of it in our diet for healthy body function. Good sources of LA include nuts, sesame and sunflower seed and most cooking oils. It is even present in some processed foods.

METABOLIC PATHWAY

CENLinoleic Acid (LA)
(Found in vegetable oils, seeds and nuts.)
|
Gamma Linolenic Acid(GLA)
(GLA is also found in borage and primrose oil.)
|
Dihomogamma Linolenic Acid (DGLA)
|
Arachidonic Acid (AA)
(AA is also found in meat.)
|
Leukotrienes and Prostaglandins

In contrast to this, GLA is rarely found in the diet but is synthesized from LA as shown in the metabolic pathway diagram.

GLA therefore is essential to our health since it is converted into Dihomogamma Linolenic Acid (DGLA), thence to Arachidonic Acid (AA) and finally into a range of leukotrienes and hormone-like substances called prostaglandins, which have wide-ranging functions in the body. These include maintaining hormone balance, controlling inflammation, reducing platelet stickiness and regulating the reproductive cycle. In addition, GLA is an important structural component of cell membranes, providing fluidity and flexibility to skin cells as well as assisting with moisture retention.

Why Might We Be Deficient in GLA?

As stated above, LA is readily available in the diet so any deficiency of GLA through lack of LA is highly unlikely. A more likely reason would be a reduction or inhibition in the activity of the D6-desaturase enzyme (see diagram), the active enzyme in converting LA into GLA. The main factors that are known to adversely affect this enzyme include high alcohol intake, smoking, high caffeine intake, ageing, excess cholesterol, excess saturated fats, high sugar consumption and a deficiency in key vitamins and minerals such as zinc, chromium and pyridoxine. Viral infections and diabetes may also affect the activity of this enzyme.

With some people then, the benefits of a well-balanced diet complete with all the correct sources of EFAs, may be upset by a metabolic pathway blockage caused by the inhibition of D6-desaturase, leaving an individual with a deficiency of GLA and its metabolite, DGLA. Introducing more LA-rich foods into the diet can offer no benefit in such cases so a dietary source of either GLA or DGLA is required. DGLA is an extremely rare and short-lived fatty acid so is not a good candidate but GLA, whilst not found in significant amounts in common foods, is abundant in the seed oils of a range of plants, the most popular being evening primrose.

With such a range of common factors that can give rise to a functional deficiency of GLA, supplementing with evening primrose oil (EPO) seems expedient since it ensures input of this crucial fatty acid. This is especially important if you are showing some of the typical signs of GLA deficiency; dandruff, dry hair, soft or brittle nails, rough or dry bumpy skin (often on the upper arms or legs).

GLA and Pregnancy

As a good deal of the brain and retina are made of long chain fatty acids, it is essential that an adequate supply of GLA is present in the diet to ensure good development in the growing baby. This is particularly important during the third trimester (when fetal brain and nervous system growth are very rapid). A good quality supplement, rich in GLA will ensure a supply of the fats relevant for eye and brain growth, especially AA and DHA. The active ingredient in mother's breast milk is DGLA, the derivative of GLA that is eventually converted into AA, a vital ingredient for all sensitive nerves and tissues, particularly the brain. Long chain fatty acids are also important for the pregnant mother and the prostaglandins created by GLA and EPA are known to bring a whole range of positive benefits.

I recommend you use only products where the manufacturer can guarantee organic source material. In addition some supplements of EFAs are produced using solvent extraction techniques which may leave traces of hexane in the oil and conventional so called cold-pressing actually utilizes very high temperatures, high enough to damage the oil and even introduce harmful trans-fatty acids.