Vegetarians have a lower overall risk of common chronic diseases, possibly due to a lower saturated fat and cholesterol intake than non-vegetarians (1). However, vegetarians (and those who eat minimal amounts of oily fish) may be at a disadvantage where intake of essential fatty acids (EFAs) are concerned, and this could potentially counteract some health benefits of the vegetarian diet.
EFAs are called ‘essential’ because our body cannot synthesis them, we MUST get them from our diet.
The two EFA’s are linoleic acid (LA) and 𝛼-linolenic acid (ALA). LA is a precursor of arachidonic acid (AA) an Omega 6 fatty acid. ALA is a precursor of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA) which are Omega 3 fatty acids (2).
- DHA and EPA are found in fish and other seafood.
- ALA is found mainly in plant oils such as flaxseed, soybean, and canola oils.
- LA & AA are found in sunflower, cottonseed, and soybean oils as well as the processed foods made from these oils.
So, what does this all mean? Why do we need these fatty acids?
Well, Omega 3 fatty acids have been shown to help prevent heart disease and stroke, and certain skin conditions such as eczema and acne and improve mental and cognitive function (2).
Omega 6 on the other hand, is needed but not in as high quantities as Omega 3 as they are very potent, and overproduction is associated with increased risk of disease (2).
The recommended ratio of omega-6 to omega-3 fatty acids in the diet is 4:1 or less. However, the Western diet has a ratio between 10:1 and 50:1 (4). This is not great and reducing Omega 6 consumption is recommended.
What does this mean for vegans and vegetarians?
ALA (the vegetarian source of Omega 3) is converted by the body into EPA & DHA (omega 3’s). However, this process is quite inefficient and excess LA consumption (omega 6) can suppress conversion of ALA to EPA and DHA and increase production of AA (omega 6). As Omega 6 is pro-inflammatory, this can have significant adverse consequences for health (2).
Excess consumption of alcohol and caffeine also affects the ALA conversion process. As well as nutritional inadequacies such as protein deficiency or lack of vitamin and mineral cofactors, especially zinc, magnesium, niacin, pyridoxine and vitamin C (2).
Non-dietary factors that negatively affect conversion are genetics, sex (young males convert less efficiently than young females), advancing age, chronic disease (eg, diabetes, metabolic syndrome, hypertension and hyperlipidaemia) and smoking (2).
How can vegans and vegetarians get enough EPA & DHA?
In Australia, adequate intakes (AIs) for ALA have been set at 1.3 g/day for men and 0.8 g/day for women, and AIs for Omega 3 are 160 mg/day for men and 90 mg/day for women (115 mg/day during pregnancy, and 145 mg/day during lactation) (4).
Suggested dietary targets for Omega 3 aimed at reducing chronic disease risk, are 610 mg/day for men and 430 mg/day for women (4). Consumption values as high as 3000 mg/day reduce other cardiovascular risk factors and have not had adverse effects in short- and intermediate-term randomised trials (4). The upper level of intake of combined EPA, DHA and DPA is 3000 mg/day.
There are no official separate recommendations for Omega 3 intake in vegetarians or vegans. Current intakes of ALA and LA in vegetarian populations are not consistent with optimal conversion to EPA and DHA (5), and the predictable result is reduced EFA status. While the health consequences of this are not known, there is a clear inverse association between EPA and DHA intake and risk of cardiovascular disease (5).
There are two possible means of achieving improved EFA status — by adjusting intakes of LA and ALA to improve conversion, and by adding DHA and EPA supplements derived from microalgae, like the Bioceuticals EFA tablets.
If the diet does not provide sufficient DHA and EPA, it is suggested that the current AI for ALA be doubled to help shift the balance of LA : ALA towards more efficient conversion (5). This would mean a minimum ALA intake of 2.6 g/day for vegetarian men and 1.6 g/day for vegetarian women
Check out the below infographic to see what this would look like
- Craig WJ, Mangels AR. Position of the American Dietetic Association: vegetarian diets. J Am Diet Assoc 2009; 109: 1266-1282.
- Saunders, A.V., Davis, B.C. and Garg, M.L. (2013), Omega‐3 polyunsaturated fatty acids and vegetarian diets. Medical Journal of Australia, 199: S22-S26. doi:10.5694/mja11.11507
- National Health and Medical Research Council, New Zealand Ministry of Health. Nutrient reference values for Australia and New Zealand including recommended dietary intakes. Canberra: NHMRC, 2006. http://www.nhmrc.gov.au/guidelines/publications/n35-n36-n37 (accessed Apr 2012).
- Davis BC, Kris-Etherton PM. Achieving optimal essential fatty acid status in vegetarians: current knowledge and practical implications. Am J Clin Nutr 2003; 78 (3 Suppl): 640S-646S.