Category: Natural chemicals
Introduction and description
Linoleic acid (LA, 18:2) is an omega-6 fatty acid and is classified as an Essential Fatty Acid meaning that as it cannot be produced by the body directly it is needed as part of the diet in order to remain healthy.
It is not used by the body in its original form. It is converted by the body into the required long-chain polyunsaturated fatty acids
- GLA - gamma-linolenic acid (GLA, 18:3),
- DGLA - dihomo-gamma-linolenic acid (DGLA, 20:3) and
- AA - arachidonic acid (AA, 20:4)
The first step in the metabolism of LA converts LA into gamma-linolenic acid (GLA). GLA itself also occurs naturally in food stuffs, a list of which is shown below.
GLA is then used to produce dihomo-gamma-linolenic acid (DGLA), which in turn is used to produce arachidonic acid (AA). Finally, AA itself may be used to produce prostaglandins, thromboxanes, and leukotrienes.
- Leukotrines have an absolutely essential role in our immune system. They help us fight disease and invaders. Leukotrienes attract certain white blood cells (leukocytes) that are key to defenses – storm troopers. They are not the only defense, but they are a major part of our defences
- Prostaglandins are a group of hormone-like lipid compounds that are key to regulating the contraction and relaxation of smooth muscle tissue. Prostaglandins are locally acting messenger molecules. They differ from hormones in that they are not released from a specific organ but in many places throughout the human body. Also, their target cells are present in the immediate vicinity of the site of their secretion. So the beating of your heart is regulated by prostaglandins and you could not get more key than this!
- Thromboxane – is used by the body when we are injured to help form ‘scabs’ or blood clots on the wound. In effect it helps platelet aggregation. It is in homeostatic balance in the circulatory system with prostacyclin, a related compound. It has a two fold action, as if there is heavy bleeding and a possible loss of much blood, it not only act in the formation of blood clots to stench the flow from the wound, but also helps to reduce the blood flow to the site of a wound and thus prevent further bleeding.
So, as we can see any deficiency of LA will affect the correct functioning of every muscle in our body, from the intestines to the heart, as well as opening us up to infection by parasites, bacteria, viruses, fungi, toxins and so on as our immune system is compromised. It also means that if we have surgery or are in an accident, our wounds won't heal properly.
The following lists the food sources of LA and GLA. Although the list mentions oils, the seeds from which the oils are derived are obviously also a source.
The source of this information is Wikipedia, so must be treated with caution, unfortunately, the USDA Nutrient database does not include any information which is easily used on this aspect.
- Safflower oil
- Evening Primrose oil
- Poppyseed oil
- Grape seed oil
- Sunflower oil
- Hemp oil
- Corn oil
- Wheat germ oil
- Cottonseed oil
- Soybean oil
- Walnut oil
- Sesame oil
- Rice bran oil
- Argan oil
- Pistachio oil
- Peanut oil
- Chicken fat
- Egg yolk
- Linseed oil
- Olive oil
- Palm oil
- Cocoa butter
- Macadamia oil
- Coconut oil
The sources are as follows, again the list does not come from as reliable source as I would like, but is the best I can do for the moment
- Evening primrose oil (Oenothera biennis) - GLA was first isolated from the seed oil of evening primrose. This herbal plant was grown by Native Americans to treat swelling in the body. In the 17th century, it was introduced to Europe and became a popular folk remedy. Evening primrose oil ranges from 8% to 10% GLA
- Blackcurrants – from their seeds - black-currant oil contains 15-20%
- Borage seeds and oil - Borage oil contains 20% GLA
- Hemp seeds
- Spirulina [possibly sources conflict]
How it works
By eating the foods mentionned [no supplements] it helps to heal you and keep essential functions working.
It is not possible scientifically to produce a trial of LA and see its effects. If LA is denied a control group, they are likely to die - so ethically this is not a trial one could undertake.
But all the observations on the positive benefits of eating nuts and seeds, and using for example, olive oil or rice bran oil can probably be traced back to the fact that one of their constituents is LA.
- ALA and depression in women 011999
- Depression and nutritional deprivation 011995
- Dermatitis and Evening primrose oil 012139
- Dose-dependent effects of evening primrose oil in children and adolescents with atopic dermatitis 012140
- Dr Duke's list of chemicals and activity for the Shallot 017969
- Dr Duke's list of Chemicals and their Biological Activities in: Morus alba L. (Moraceae) -- Sang-Pai-Pi, White Mulberry 027433
- Dr Duke’s list of Chemicals and their Biological Activities in: Cucurbita pepo L. (Cucurbitaceae) -- Zucchini 027494
- Essential fatty acids and the brain 011998
- Essential Fatty Acids, Viral infections and Eczema 012001
- Fish oil, evening primrose oil, linoleic acid and psoriasis 012002
- Gooseberries and blackcurrants as a source of GLA 012369
- Is Postpartum Depression a Disease of Modern Civilization? 027731
- Linoleic acid and heart disease 011996
- Lipids, low cholesterol, depression and suicide 011997
- Mercury in foods and fish and selenium as a chelation agent 013083
- Omega-3 and omega-6 content of medicinal foods for depressed patients: implications from the Iranian Traditional Medicine 017018
- Omega-3 fatty acids for cystic fibrosis 020179
- Rheumatoid arthritis, Evening Primrose oil and Fish oil 012003
- Scotch thistle root and cancer 017236
- Traditional Iranian medicinal foods for depressed patients 011994