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alpha-linolenic acid
 

What Is It?
Health Benefits

Forms

Dosage Information
Guidelines for Use
General Interaction
Possible Side Effects
Cautions
References
Evidence Based Rating Scale 

What Is It?

Alpha-linolenic acid, or ALA, is an essential fatty acid and the parent fatty acid of the omega-3 family. Essential fatty acids (EFA) are not produced by the body and must be present in the diet to maintain health. ALA is the major omega-3 found in the typical North American diet in foods such as seed and vegetable oils, leafy vegetables, soybeans, walnuts, and flaxseed. Alpha-linolenic acid is similar to the fish oil omega-3's eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and can be converted to them in the body. (1)

Health Benefits

Essential Fatty Acids such as alpha-linolenic acid are extremely important for healing and maintaining good health. Compounds made from alpha-linolenic acid have been shown to decrease blood clotting and lower blood pressure. The anti-inflammatory properties of ALA combined with its ability to inhibit cell growth may help protect against the formation of cardiovascular plaques. (2) High intake of ALA from plant sources protects the body from insufficient vitamin E intake, and in normal weight individuals, has been associated with a lower prevalence of insulin resistance—one of the risk factors for type 2 diabetes. (3-5)

Specifically, alpha-linolenic acid may help to:

Reduce the risk of developing high blood pressure. Research suggests that a diet high in linolenic acid intake is associated with a reduced risk of high blood pressure. (The majority of linolenic acid is alpha-linolenic acid—only a fraction is gamma-linolenic acid.) The risk of developing high blood pressure may be reduced by approximately one-third with adequate intake. (6-7)

Slow the development of heart disease. In the early stages of heart disease, calcium plaques form in the arterial walls. In a sub-study of participants in the National Heart, Lung, and Blood Institute (NHLBI) Family Heart Study, 845 men and 1159 women aged 32-93 years old had Coronary Artery CT scans (CAT) to determine the association between dietary linolenic acid intake and the formation of coronary arterial plaques. There was a highly significant decrease in coronary artery calcification on CT scan with increasing consumption of dietary linolenic acid as measured by a food frequency questionnaire. In the group with the highest consumption (0.96-3.48 grams/day), prevalence of coronary calcification was only 40% of those with the lowest consumption (less than 0.47 grams/day). (8) It is unclear whether similar benefit is derived from supplements. More research is needed.

Protect against the risk of some cancers. In 123 women with invasive non-metastatic breast cancer and similar control subjects, a study of ALA levels in biopsies of breast adipose (fat) tissue indicated an inverse association between fat levels of ALA and the risk of contracting breast cancer. Further studies are needed to determine the effects of dietary ALA on breast cancer risk.(9)

There is conflicting evidence concerning ALA and prostate cancer. In some studies, ALA derived from meat and dairy products was associated with an increased risk of prostate cancer while plant-derived ALA had no effect on cancer risk. (10-11) In contrast, a review of studies published up to December 2008 indicated that individuals who consume more than 1.5g/day of ALA had a slightly lower risk of prostate cancer than those who consume less than 1.5g/day. However, more studies are needed to determine the nature of the association between ALA from various sources and prostate cancer risk. (12)

Reduce the symptoms of depression. There is data suggesting a link between the consumption of omega-3 fatty acids and the prevalence and severity of depression. In a recent animal study, mice were supplemented for five weeks with an omega-3 blend consisting of 70% ALA. The blend induced anti-depressant effects in the animals. More studies are needed in humans to determine the effects of ALA on depression. (13)

Protect against stroke. Observational studies suggest that ALA is the essential fatty acid with the most efficient protective effect against stroke. (14) In animal studies, a diet enriched in rapeseed (canola) oil—a rich source of ALA--was associated with stroke prevention. (15) More studies are needed to determine the beneficial dosage for humans.

Some signs of alpha-linolenic acid deficiency include loss of motor coordination, tingling in the extremities, vision impairment, and behavioral changes.

Forms

  • Oils
  • Capsules

Dosage Information

The primary sources of ALA are seed oils including flaxseed, canola, soybeans, and walnuts. Other sources include leafy vegetables, red meat, dairy products, and chocolate.

 

  • For high blood pressure: 800mg per day was found to lower the risk of developing high blood pressure. (7)

  • For heart disease: 800mg per day was associated with a reduced prevalence of coronary arterial plaques which may slow the development of coronary artery disease. (8) A Mediterranean diet which includes 1600mg/day ALA was beneficial in preventing heart disease. (16)

Guidelines for Use

ALA should comprise about 1% of daily caloric intake, which is 2 grams/day on a 2000 calorie diet.

General Interaction

ALA may increase triglyceride levels. 

Possible Side Effects 

Dietary alpha-linolenic acid is well-tolerated but excess ALA could cause weight gain since it is high in calories. It's best to substitute ALA for other fats in the diet, especially saturated fats.

Cautions

Men with or at high risk for prostate cancer should probably avoid non-dietary ALA supplementation due to conflicting data on altered risk for prostate cancer.  

Although ALA is a precursor to EPA and DHA, their effects are not always similar. Data regarding the effects of one should not be extrapolated to the others.

References

1. Anderson BM, Ma DW. Are all n-3 polyunsaturated fatty acids created equal? Lipids Health Dis. 2009 Aug 10;8:33.
2. Bassett CM, Rodriguez-Leyva D, Pierce GN. Experimental and clinical research findings on the cardiovascular benefits of consuming flaxseed. Appl Physiol Nutr Metab. 2009 Oct;34(5):965-74.
3. Simopoulos AP. Omega-3 fatty acids and antioxidants in edible wild plants. Biol Res. 2004;37(2):263-77.
4. Devaraj S, Kasim-Karakas S, Jialal I. The effect of weight loss and dietary fatty acids on inflammation. Curr Atheroscler Rep. 2006 Nov;8(6):477-86.
5. Muramatsu T, Yatsuya H, Toyoshima H, Sasaki S, Yuanying L, Otsuka R, Wada K, Hotta Y, Mitsuhashi H, Matsushita K, Murohara T, Tamakoshi K. Higher dietary intake of alpha-linolenic acid is associated with lower insulin resistance in middle-aged Japanese. Prev Med. 2010 Mar 4.
6. Ogawa A, Suzuki Y, Aoyama T, Takeuchi H. Dietary alpha-linolenic acid inhibits angiotensin-converting enzyme activity and mRNA expression levels in the aorta of spontaneously hypertensive rats. J Oleo Sci. 2009;58(7):355-60.
7. Djousse L, Arnett DK, Pankow JS, et al. Dietary linolenic acid is associated with a lower prevalence of hypertension in the NHLBI Family Heart Study. Hypertension 2005;45:368-73.
8. Djoussé L, Arnett DK, Carr JJ, Eckfeldt JH, Hopkins PN, Province MA, Ellison RC; Investigators of the NHLBI FHS. Dietary linolenic acid is inversely associated with calcified atherosclerotic plaque in the coronary arteries: the National Heart, Lung, and Blood Institute Family Heart Study. Circulation. 2005 Jun 7;111(22):2921-6. Epub 2005 May 31.
9. Klein V, Chajès V, Germain E, Schulgen G, Pinault M, Malvy D, Lefrancq T, Fignon A, Le Floch O, Lhuillery C, Bougnoux P. Low alpha-linolenic acid content of adipose breast tissue is associated with an increased risk of breast cancer. Eur J Cancer. 2000 Feb;36(3):335-40.
10. Giovannucci E, Rimm EB, Colditz GA, Stampfer MJ, Ascherio A, Chute CC, Willett WC. A prospective study of dietary fat and risk of prostate cancer. J Natl Cancer Inst. 1993 Oct 6;85(19):1571-9.
11. Laaksonen DE, Laukkanen JA, Niskanen L, Nyyssönen K, Rissanen TH, Voutilainen S, Pukkala E, Hakkarainen A, Salonen JT. Serum linoleic and total polyunsaturated fatty acids in relation to prostate and other cancers: a population-based cohort study. Int J Cancer. 2004 Sep 1;111(3):444-50.
12. Carayol M, Grosclaude P, Delpierre C. Prospective studies of dietary alpha-linolenic acid intake and prostate cancer risk: a meta-analysis. Cancer Causes Control. 2009 Nov 18.
13. Venna VR, Deplanque D, Allet C, Belarbi K, Hamdane M, Bordet R. PUFA induce antidepressant-like effects in parallel to structural and molecular changes in the hippocampus. PUFA induce antidepressant-like effects in parallel to structural and molecular changes in the hippocampus. Psychoneuroendocrinology. 2009 Feb;34(2):199-211.
14. Renaud SC. Diet and stroke. J Nutr Health Aging. 2001;5(3):167-72
15. Nguemeni C, Delplanque B, Rovère C, Simon-Rousseau N, Gandin C, Agnani G, Nahon JL, Heurteaux C, Blondeau N. Dietary supplementation of alpha-linolenic acid in an enriched rapeseed oil diet protects from stroke. Pharmacol Res. 2009 Dec 29.
16. de Lorgeril M, Renaud S, Mamelle N, et al. Mediterranean alpha-linolenic acid-rich diet in secondary prevention of coronary heart disease.  Lancet 1994;343:1454-9.

17. Paolisso G, Tagliamonte MR, Barbieri M et al. Chronic vitamin E administration improves brachial reactivity and increases intracellular magnesium concentration in type II diabetic patients. J Clin Endocrinol Metab 2000;85:109-115.

18. Negrisanu G, Rosu M, Bolte B, Lefter D, Dabelea D. Effects of 3-month treatment with the antioxidant alpha-lipoic acid in diabetic peripheral neuropathy. Rom J Intern Med. 1999 Jul-Sep;37(3):297-306.

 

Evidence Based Rating Scale

The Evidence Based Rating Scale is a tool that helps consumers translate the findings of medical research studies and what our clinical advisors have found to be efficacious in their personal practice into a visual and easy to interpret format. This tool is meant to simplify the information on supplements and therapies that demonstrate promise in the treatment of certain conditions.

 

Condition

Rating

Explanation

 

Cancer Prevention

   

Lower levels of ALA are noted in the breast tissue of women with breast cancer. (12)

 Diabetes  

 Small human and animal trials have shown efficacy in treating diabetic retinopathy. (17-18)
Heart Disease  
A large-scale study indicated ALA intake is associated with less calcium plaque associated with heart disease. (8)
High Blood Pressure  

A large-scale study indicated ALA intake is associated with a lower prevalence of high blood pressure (7)


Stroke  
Studies indicate ALA is the most beneficial omega-3 for preventing stroke; more studies are needed to determine the beneficial dosage in humans. (14-15)

 


Date Published: 04/18/2005
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