Alpha-linolenic acid is an essential fatty acid which cannot be produced in the body and must be taken through diet. Both in animals and humans, alpha-linolenic acid is desaturated and elongated into eicosapentaenoic and docosahexaenoic acid.

The principal biological role of alpha-linolenic acid (18:3n-3) appears to be as a precursor for the synthesis of longer chain n-3 polyunsaturated fatty acids (PUFA). Increasing alpha linolenic acid  intake for a period of weeks to months results in an increase in the proportion of eicosapentaenoic acid (EPA; 20:5n-3) in plasma lipids, in erythrocytes, leukocytes, platelets and in breast milk but there is no increase in docosahexaenoic acid (DHA; 22:6n-3), which may even decline in some pools at high alpha linolenic acid intakes. Stable isotope tracer studies indicate that conversion of alpha linolenic acid to EPA occurs but is limited in men and that further transformation to DHA is very low. The fractional conversion of alpha linolenic acid to the longer chain n-3 PUFA is greater in women which may be due to a regulatory effect of estrogen. A lower proportion of alpha linolenic acid is used for beta-oxidation in women compared with men. Overall, alpha linolenic acid appears to be a limited source of longer chain n-3 PUFA in humans. Thus, adequate intakes of preformed long chain n-3 PUFA, in particular DHA, may be important for maintaining optimal tissue function. Capacity to up-regulate alpha linolenic acid conversion in women may be important for meeting the demands of the fetus and neonate for DHA.

Alpha Linolenic Acid in Food
The omega 3 polyunsaturated fatty acids have had a major impact on thinking in medicine in the last twenty years. The parent fatty acid in the omega 3 fatty acid family is alpha-linolenic acid (ALA) which is an essential fatty acid found in high concentrations in certain plant oils, such as flaxseed oil, walnut oil and canola oil. Several longer chain or derived omega 3 fatty acids are formed from alpha-linolenic acid and these are mainly found in fish, fish oils and from other marine organisms.

Black currant seed oil has a high amount of GLA, gamma linolenic acid.
Flax seed oil has alpha linolenic acid, for more Flaxseed Oil information.
Beans have alpha linolenic acid fatty acid
Nuts, such as walnuts
Seeds, such as pumpkin seeds
Purslane is an herb that has alpha linolenic acid

Fish oil or alpha linolenic acid - which is healthier?
Evidence suggests that increased consumption of omega3 fatty acids from fish or fish-oil supplements, and less so of alpha-linolenic acid, reduces the rates of all-cause mortality, cardiac and sudden death, and possibly stroke. Most of the studies have been carried out with fish oils [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)]. However, alpha-linolenic acid, found in green leafy vegetables, flaxseed, rapeseed, and walnuts, desaturates and elongates in the human body to EPA and DHA and by itself may have some beneficial effects in health and in the control of chronic diseases.
 

Alpha Linolenic Acid Research
Dietary alpha-linolenic acid increases brain but not heart and liver docosahexaenoic acid - DHA - levels.
Lipids. 2005 Aug;40(8):787-98. Barcelo-Coblijn G, Collison LW, Jolly CA, Murphy EJ.
Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota, Grand Forks, North Dakota
Fish oil-enriched diets increase n-3 FA in tissue phospholipids; however, a similar effect by plant-derived n-3 FA is poorly defined. To address this question, we determined mass changes in phospholipid FA, individual phospholipid classes, and cholesterol in the liver, heart, and brain of rats fed diets enriched in flax oil (rich in 18:3n-3), fish oil (rich in 22:6n-3 and 20:5n-3), or safflower oil (rich in 18:2n-6) for 8 wk. In the heart and liver phospholipids, 22:6n-3 levels increased only in the fish oil group, although rats fed flax oil accumulated 20:5n-3 and 22:5n-3. However, in the brain, the flax and fish oil diets increased the phospholipid 22:6n-3 mass. In all tissues, these diets decreased the 20:4n-6 mass, although the effect was more marked in the fish oil than in the flax oil group. Although these data do not provide direct evidence for 18:3n-3 elongation and desaturation by the brain, they demonstrate that 18:3n-3-enriched diets reduced tissue 20:4n-6 levels and increased cellular n-3 levels in a tissue-dependent manner. We hypothesize, based on the lack of increased 22:6n-3 but increased 18:3n-3 in the liver and heart, that the flax oil diet increased circulating 18:3n-3, thereby presenting tissue with this EFA for further elongation and desaturation.

Alpha-linolenic acid content of commonly available nuts in Hangzhou.

Int J Vitam Nutr Res. 2006 Jan;76(1):18-21.

Department of Food Science and Nutrition, Zhejiang University, Hangzhou, China.
The total lipid content of eight species of nuts available in Hangzhou ranged from 49 g/100 g weight in Cannabis sativa to 75 g/100 g in walnut. The predominant content of lipid is triacylglycerol, ranging from 91% in Cannabis sativa to 98% in macadamia. There were two polyunsaturated fatty acids (PUFA) in all nuts analyzed; 18:2n-6 and 18:3n-3. The content of 18:3n-3 ranging from 0.2% in almond to 15.2% in Cannabis sativa, 18:2n-6 ranged from 2.5% in macadamia to 61% in pine nut. The proportion of total PUFA in analyzed eight nut species ranging from 2.8% in macadamia to 71% in walnut. Monounsaturated fatty acid composition ranged from 18% in Cannabis sativa to 82% in macadamia. The proportion of saturated fatty acid ranged from 7% in filbert to 14% of total fatty acids in macadamia. No C20 fatty acids were detected in any of the samples in the present study. The lipids content and fatty acid compositions in analyzed samples were varied between nut species. Cannabis sativa and walnut contained relatively high 18:3n-3, consumption of several these nuts each day can contribute to n-3 PUFA intake, especially for the vegetarian population.

[Alpha-linolenic acid and cardiovascular diseases]
Med Pregl. 2003;56 Suppl 1:19-25.
It is also incorporated into plasma and tissue lipids and its conversion is affected by levels of linoleic acid. Diet enriched in n-3 fatty acids, especially alpha-linolenic acid, reduces the incidence of cardiac death. Studies have shown that alpha linolenic acid prevents ventricular fibrillation which is the main cause of cardiac death. Studies in rats suggest that alpha-linolenic acid may be more effective in preventing ventricular fibrillations than eicosapentaenoic and docosahexaenoic acid. Furthermore, alpha-linolenic acid is the main fatty acid decreasing platalet aggregation which is an important step in thrombosis i.e. non-fatal myocardial infarction and stroke. Dietary sources include flaxseed and flaxseed oil, canola oil, soybean and soybean oil, pumpkin seed and pumpkin oil, walnuts and walnut oil. Strong evidence supports beneficial effects of alpha-linolenic acid and its dietary sources should be incorporated into balanced diet for prevention of cardiovascular diseases. The recommended daily intake is 2 g with a ratio of 5/1 for linoleic/alpha-linolenic acid.

Walnuts as source of alpha linolenic acid
New Study Shows Walnuts Improve Bone Health
2007-01-17 - California Walnut Marketing Board
SACRAMENTO, Calif., Jan 17, 2007 (BUSINESS WIRE) -- Published in the January 16, 2007, edition of Nutrition Journal Penn State clinical research suggests walnuts, rich in alpha-linolenic acid, an essential omega-3 fatty acid, are beneficial to the skeletal system by decreasing the breakdown of bone. This is the first human study evaluating the effect of plant-based sources of omega-3 fatty acids alpha-linolenic acid on bone health. The results suggest higher consumption of alpha-linolenic acid leads to a reduction in bone turnover, and a shift in the balance of bone degradation/formation toward formation. Walnuts are unique as one as one of the most nutrient-dense whole food sources of alpha-linolenic acid. Numerous studies have already suggested that omega-3s, found in walnuts, reduce inflammation, heart and vascular disease risk, decrease insulin resistance, assist with weight management and may be beneficial in brain function.

Alpha linolenic acid eye drops for dry eyes
Research conducted by Massachusetts Eye and Ear Infirmary (MEEI) Cornea Service Director and Harvard Medical School Professor Reza Dana, M.D., M. Sc., MPH, and colleagues at the Schepens Eye Research Institute have found topical drop application of alpha-linolenic acid (ALA) led to a significant decrease in clinical signs of dry eye syndrome in animal models. The alpha linolenic acid study was published in the February 2008 issue of Archives of Ophthalmology.
 

Linolenic acid emails
Q. What do you hear about Gamma Linolenic Acid as an anti-inflammatory?
   A. I would like to see more human research. For the time being, I prefer fish oils for anti-inflammatory purposes.

Q. Please tell me the difference between linolenic Acid, linoleic Acid, and alpha lipoic acid.
   A. Linolenic acid and linoleic acid are not the same as alpha lipoic acid.