α-Linolenic acid (ALA) is an n−3 fatty acid used to produce longer ω-3 fatty acids, namely docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). It is two essential fatty acids so called because they are crucial for health and could not be formed within human body. It should be obtained through diet. In terms of structure, it is called all-cis-9,12,15-octadecatrienoic acid. In physiological literature, it is recorded by its lipid number, 18:3, and (n−3); its isomer GLA is 18:3 (n−6). It is a carboxylic acid having with an 18-carbon chain and 3 cis double bonds. The first double bond is discovered at the third carbon from methyl end of the fatty acid chain, known as n end. Thus, α-linolenic acid is a polyunsaturated n−3 (omega-3) fatty acid and isomer of gamma-linolenic acid (GLA), a polyunsaturated n−6 (omega-6) fatty acid.
History
α-Linolenic acid was first confined by Rollett as cited in J. W. McCutcheon’s synthesis in 1942, and referred to in Green and Hilditch’s 1930s survey. In 1995, first it was first artificially synthesized from C6 homologating agents. A Wittig reaction of the phosphonium salt of [(Z-Z)-nona-3,6-dien-1-yl] triphenylphosphonium bromide with methyl 9-oxononanoate, followed by saponification and completed the synthesis.
Food Sources
| Food name | Weight (g) | α-Linolenic acid (g) |
| Flaxseed oil | 13.6 | 7.258 |
| Margarine | 232 | 5.104 |
| Chia seeds | 28.35 | 5.055 |
| Walnuts | 125 | 3.346 |
| Hemp seeds | 30 | 2.605 |
| Canola oil | 14 | 1.279 |
| Coleslaw | 91 | 0.997 |
| Soybean oil | 13.6 | 0.923 |
| Edamame | 155 | 0.555 |
| French fries | 71 | 0.454 |
| Navy beans | 182 | 0.375 |
| Pistachio | 123 | 0.261 |
| Teff | 193 | 0.261 |
| Avocados | 230 | 0.255 |
| Cherimoya | 160 | 0.254 |
| Plantains | 118 | 0.250 |
| Kielbasa | 85 | 0.209 |
| Swiss cheese | 132 | 0.165 |
| Pine nuts | 135 | 0.151 |
| Mamey sapote | 175 | 0.144 |
Health Benefits of α-Linolenic acid
- Heart ailments
Diet low in saturated and trans fats and rich in polyunsaturated and monounsaturated fats are the best way to prevent and treat heart disease. Evidence shows that foods rich in alpha-linolenic acid are helpful too. Diet rich in alpha-linolenic acid helps to lower the chances of heart attack. Other study shows that women with high levels of alpha-linolenic acid had 46% lower risk of sudden cardiac death than those who consume low amount of alpha-linolenic acid.
- Maintain cholesterol level
People with Mediterranean style diet have high good cholesterol levels. Moreover, walnuts have rich content of alpha-linolenic acid which helps to reduce cholesterol as well as triglycerides in people with high cholesterol.
- Prevent obesity
Like other fatty acids, ALA is attached to two or three glycerols and are classified as triglyceride or diglyceride which depends on number of glycerols they have. Study conducted on 177 obese people shows that supplemental ALA for 12 weeks lowered body weight, intra-organ fat mass, blood triglycerides and waist size. Similar study conducted on 114 overweight people for 12 weeks of ALA supplementation shows that it lowered body weight, fat mass, triglyceride blood levels and waist size by promoting fat burning. It activates genes which is involved in fat break down and promotes heat production in gut resulting in increased calorie burning.
- Improve skin
Low ALA is correlated with dry and uncomfortable skin and poor skin quality. Flaxseed has high content of ALA which supports skin health. It lowers skin cell inflammation and promotes regeneration. Study conducted on 13 women shows that supplementation of flaxseed oil promoted skin sensitivity, overall condition and hydration. Other study conducted on 45 women when ingested flaxseed oil for 12 weeks lowers skin roughness and redness. It lowers skin cell inflammation and promotes skin cell repair. It is a common skin disorder with dry, red and uncomfortable skin. It lowers saturated fatty acid levels in both horses and human skin cells that could lower rash areas and help clear irregular skin. In mice, supplementation of ALA protects skin from UV damage.
- Lowers risk of cancer
Study shows that high levels of ALA in blood are related with lowering chances of colon cancer and rectal cancer. Study conducted on 121 female breast cancer patients with high ALA in breast tissue have 80% reduction in chances of cancer spreading to other tissues. In mice, flaxseed oil lowers development, severity, number and size of skin cancer. It promotes antioxidants and enhances detoxification enzyme levels in liver and skin tissue. In lab, ALA exposure lowers colon and breast cancer cell spread and growth and increase cancer cell death. High level of ALA in prostate tissue is related with more aggressive prostate cancer.
- Prevent diabetes
The daily intake of one gram of flaxseed daily, lowered inflammation, improved wound healing and increase insulin sensitivity and lowered fasting levels of insulin in study of 60 patients with diabetic foot ulcers. ALA storage in fat tissue lowered the chances of insulin resistance in study conducted on 716 people. Supplements of ALA improved insulin sensitivity and enhanced in protein involved in metabolism in study of 20 patients with type 2 diabetes.
- Helpful against stroke
High intake of ALA is related with lowering 35 to 50% stroke risk in cohort study conducted on 20,069 middle aged people living in Netherlands. In rats and mice, ALA lowered stroke symptoms, tissue damage, protects brain damage, improve blood circulation and blood flow, protect neurons from cell death and improve chances of survival after stroke.
- Lowers high blood pressure
Supplements of ALA with strict diet lowered blood pressure in a study conducted on 127 patients having mild hypertension. High blood pressure is caused due to deficiencies of omega-3. Supplemental ALA as flaxseed oil or canola oil helps to prevent deficiency of omega-3 associated to high blood pressure in mice. In rats, both flaxseed oil and flaxseed lowered blood pressure. In mice, ALA was effective as well as safe with blood pressure medications.
- Reduce inflammation
Inflammation is the major cause and severity of diseases such as diabetes, heart disease, brain conditions, cancer, autoimmune diseases and depression. ALA helps to lower inflammation by improving these disease outcomes. ALA supplemented diet for four weeks helps to lower inflammatory markers by 30% in comparison to diet rich in omega-6 fats in study conducted on 645 healthy volunteers. Supplementation of ALA by way of linseed oil helps to lower inflammatory markers in study that was conducted on 50 people having high levels of cholesterol. Both omega-6 fats and ALA in diet is associated to lowering levels of inflammation in men while only intake of omega-3 as a whole lowered inflammation in women. Both omega-6 fats and ALA in diet is associated to lowering levels of inflammation in men while intake of omega-3 as a whole lowered inflammation in women. In pigs, high intake of ALA lowered production of inflammatory marker in the body by 40%.
- Gut health
Addition of omega-3 rich foods with ALA to the diet increased blood ratios of omega-3 to omega-6 which lowered inflammation and it lowered disease activity and promoted disease absence rates. In rats, sage oil lowered colon tissue damage, decreased amount of dying tissue and increased repair. Both sage and fish oil lowered inflammatory markers when compared to corn oil. Lowering omega-6 to omega-3 ratios by providing high ALA diet lowered disease activity and inflammation in rats with induced colitis. Flaxseeds are rich in ALA which protects gut lining, reduced oxidative stress and increased antioxidant enzymes in mice with colitis. In mice, whole flaxseed could promote injury and inflammation in acute colitis.
References:
https://en.wikipedia.org/wiki/Alpha-Linolenic_acid
https://pubchem.ncbi.nlm.nih.gov/compound/linolenic_acid#section=Top
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