Long dispelled are the myths of inadequate protein intake in vegetarian diets. We now know that a balanced and varied vegetarian diet, containing nuts, seeds, organic tofu, eggs, legumes, and quinoa will provide us with all our body needs. One uncertainty that continues to linger is whether or not a vegetarian diet can provide sufficient omega-3 fatty acids. Seafood is the highest source of omega-3 fatty acids, but there are plenty of plant-based sources as well. I’ve outlined the recommended intake of plant-based omega-3s for vegetarians and vegans, and have included tips on how to ensure the maximum amount of this important nutrient is absorbed by the body.
What’s All the Fuss About Fish?
Omega-3 fatty acids in the form of EPA and DHA can only be found in seafood (lesser amounts in seaweed). It is these compounds that have been well researched for their important role in reducing inflammation, blood clots, and blood pressure. They are also a major component of our retina, brain, cell membranes and sperm. Studies have linked DHA deficiencies to several neurological and behavioural disorders such as depression, schizophrenia, Alzheimer’s disease and Attention Deficit Hyperactivity Disorder (ADHD).
Omega-3s for Vegetarians and Vegans – What About Flaxseeds?
Chia seeds, flaxseeds, soybeans, hemp hearts and walnuts are all good sources of omega-3 fatty acids. They contain the less potent alpha-linolenic acid (ALA), unlike the powerful DHA and EPA found in seafood. ALA can be converted into DHA and EPA but unfortunately, the conversion isn’t always very efficient; only 2% to 10% of ALA converts to DHA and EPA.
A number of factors can block the conversion of ALA into DHA and EPA; this includes excess omega-6 fatty acids, trans fats (more on these two fats below), and alcohol. Insufficient energy or protein intake also decreases the conversion of ALA to EPA and DHA as well as deficiencies of pyridoxine, biotin, calcium, copper, magnesium and zinc.
“Where ever flaxseeds become a regular food item among the people, there will be better health”
Some Fats Are Good, Some Fats Are Better
Vegetarians are likely to have a higher intake of omega-6 fatty acids which are found in vegetable oils including sunflower, safflower, grapeseed, corn and soy oil. Omega-6s are also found in healthier foods including nuts and seeds. Current estimations for intake of omega-6s to omega-3s for the general population is a ratio of 10:1. Researchers have found a ratio of 2:1 is required for maximum conversion of ALA to both EPA and DHA.
Trans fats are created through the hydrogenation of vegetable oils, which turns a liquid fat into a solid. Trans fats can be found in margarine, store-bought baked goods, crackers, fried foods including doughnuts, frozen pizzas and pie crusts and in many fast food restaurants. Aside from decreasing the conversion of ALA to EPA and DHA, trans fats have also been shown to increase our LDL or bad cholesterol and decrease our HDL good cholesterol. They have been strongly linked to increased risk of heart attack and stroke.
How Much Plant Based Omega-3s Do Vegetarians and Vegans Need?
There have been no Recommended Dietary Intakes (RDIs) set for any of these essential fatty acids. Based on the available evidence we should be aiming for at least 650 milligrams per day of EPA and DHA and a minimum of 300mg of DHA/day during pregnancy and lactation. Although these are not official recommendations, they are the best we have based on the current research.
Theoretically, those following a vegetarian diet would not able to reach the recommended targets for both EPA and DHA through diet alone. Even with the use of DHA-enriched eggs and some seaweed, the best a vegetarian could do is to meet the recommended target for DHA. Though vegetarians may be in luck. Interestingly, some current research suggests that approximately 10% of DHA is retro-converted back to EPA. This is suggesting that if sufficient ALA and DHA are consumed, total EPA production would be sufficient and therefore all needs met.
But I Thought Vegetarians Were Healthier?
Why do vegetarians enjoy a longer life expectancy and reduced risk of chronic diseases if they are at a higher risk of EPA and DHA deficiency? Epidemiologic and randomized controlled clinical studies have studied the effects of marine and plant sources of omega-3 fatty acids and have found that both marine and plant-derived omega-3 fatty acids have cardio-protective effects. So it seems there is a great unknown as to why we can’t find anything wrong with vegetarians despite them not getting direct sources of EPA and DHA – maybe flaxseeds really are the wonder-food of all wonder-foods.
Did Someone Say Seaweed?
Seaweed and microalgae are the only plant sources of EPA and DHA – but at a very low concentration due to their extremely low total fat content (except in supplement form). Blue-green algae (spirulina) are low in EPA and DHA and rich in omega-6’s. A 100 gram serve of macroalgea, or seaweed, provides about 100mg of EPA, but little DHA. This is more beneficial in countries where there is a large consumption of seaweed on a daily basis.
How Much Alpha-Linolenic Acid (ALA) Omega-3s Do Vegetarians and Vegans Need?
If you choose to source omega-3 fatty acids from plant-based sources aim for at least 2 to 5 grams per day of ALA for males or 2 to 4 grams per day of ALA for females.
- 1 tbsp Flaxseed Oil – 7 grams ALA
- 1 tbsp Hemp Oil – 2.7 grams ALA
- 1 tbsp Flaxseed, ground* – 2.4 grams ALA
- 1/4 cup Walnuts, Persian, English – 2.3 grams ALA
- 1 tbsp Chia Seeds – 1.9 grams ALA
- 1 tbsp Canola Oil, organic – 1.2 grams ALA
- 1 cup Soy Beans, dried – 1.0 gram ALA
- 1/4 cup Walnuts, black – 0.85 grams ALA
- 1 cup So Good Essential Soy Milk – 0.6 grams ALA
- 100g Tofu, firm – 0.4 grams ALA
- 1/4 cup Edamame, shelled – 0.3 grams ALA
- 1/4 cup Pecans – 0.2 grams ALA
- 1 tbsp Hemp Hearts – 0.2g grams ALA
- 3 sheets Nori Seaweed – 0.01 grams ALA
*As a seed, very little of the Omega-3 fat is absorbed because the seed is very hard to digest by the body. Try grinding the flaxseed to improve absorption.
Five Tips for the Best Conversion of Alpha-Linolenic Acid to EPA and DHA for Vegetarians and Vegans
- Limit intake of processed foods and deep-fried foods rich in trans fats and omega-6 fatty acids,
- For cooking at medium temperatures, use an oil high in monounsaturated fat such as olive oil in place of polyunsaturated omega-6 rich oils such as sunflower, safflower and grapeseed. Camelina Oil is best for high heat cooking,
- Eat other foods rich in monounsaturated fats including avocado, almonds, macadamias, cashews, and hazelnuts instead of foods high in polyunsaturated omega-6 fatty acids,
- Incorporate foods rich in omega-3 fatty acids into your diet each day including flaxseed oil, flaxseeds, chia, hemp seeds, green leafy vegetables, walnuts and organic soy products,
- Limit alcohol intake.
Vegetarian DHA Supplements
There are many situations were supplementation is extremely important. If you don’t think you can consume the recommended intake of ALA while following a plant-based diet, consider supplementing with an algae-based omega-3 supplement to ensure you DHA and EPA requirements are being met. During pregnancy and lactation, it is extremely important that a mother is consuming a DHA based algae supplement with a minimum of 300mg DHA. Insufficient intake during pregnancy and lactation has been linked to poor brain development in infants, as well as maternal anxiety and postpartum depression.
- NutraVege- Vegetarian Omega-3 Supplement contain EPA and DHA, available here
- Omega-Zen-3 – Available from Nutru
Website:Brenda Davis RD
Website: Dietitians Association of Australia
Rachel Dickens, The Conscious Dietitian, is a Registered Dietitian and Certified Diabetes Educator. She graduated with her Masters in Nutrition and Dietetics in 2010 from Griffith University. She strives to provide evidence-based nutrition information with a focus on plant-based nutrition, and share some of her favourite seasonal recipes and sustainable eating tips.