Boots WebMD Partners in Health
Return To Boots

Healthy eating health centre

Select a topic to explore more.
Select An Article

Omega-3 fatty acids: Fact sheet

Omega-3 fatty acids are 'good' fats found in some foods, such as oily fish.

Just what are omega-3 fats exactly? How much do you need? And what do all those abbreviations, EPA, DHA and ALA, really mean? Here's a guide to essential omega-3 fat facts.

Omega-3 basics

Omega-3 health benefits

When eaten as part of a healthy diet, omega-3 fatty acids, mainly those found in oily fish, can help maintain a healthy heart and blood vessels.

Oily fish also provide us with vitamin D, vitamin A and protein.

The brain contains a lot of omega 3, especially DHA. DHA is essential for the brain and memory, and may reduce the risk of depression as well.

Omega-3 helps a growing baby develop in the womb and during breastfeeding. However, some oily fish are not recommended during pregnancy because of the risk of mercury and other contamination. The risk of contamination increases with the age and size of the fish. Shark, swordfish or marlin should be avoided. Smaller fish, which are younger when eaten (such as sardines, mackerel and salmon) are less of a health risk. Despite these cautions during pregnancy, experts say the small risk of contamination is outweighed by the health benefits of these fish.

Omega-3 benefits have also been studied in relation to:


How much omega-3 do I need?

There is no specific recommendation as to the amount of omega-3 we should have a day but the SACN committee which advises Public Health England on nutrition suggests around 450mg a day, or 3g a week. Having 2 portions of fish a week, one of which is omega-3 rich oily fish, will provide 2-3g of omega-3 fats per serving. Using vegetable oil made from rapeseed in cooking also provides omega-3 as ALA. Each teaspoon of rapeseed oil will provide around 450mg of ALA.  

Omega-3 supplements

The omega-3 you get from food is the best type, but supplements are another option if you don't get enough from your diet or don’t eat fish.

The British Dietetic Association recommends omega-3 oil over fish liver oil.

Omega-3 supplements contain vitamin A (retinol). Too much vitamin A (as retinol) in pregnancy can damage limb formation in the baby. Too much vitamin A long-term increases your risk of osteoporosis. Always check the label and avoid any supplement that provides more than 100% RDA (800mcg) of retinol per dose. Don’t ‘double up’ on supplements containing retinol as you might easily take too much. A maximum intake of 1.5mg (1500ug) of vitamin A as retinol each day from food and supplements being the maximum recommended. General multivitamin and mineral supplements provide vitamin A as beta-carotene, a form of vitamin A that is totally safe. It is the retinol version of vitamin A we should take care not to have too much of.

Vitamin A supplements are not suitable when pregnant or planning a pregnancy.

If you are picking supplements for children, make sure they are age-appropriate.

In high doses, omega-3 supplements can increase the risk of bleeding and may not be suitable for people taking blood thinning medication.

Always seek medical advice before starting any new supplement in case it may interfere with medications or may not be suitable for people with certain health conditions.

Dietitian reviewed by Catherine Collins RD


Next Article:

WebMD Medical Reference

Medically Reviewed by Dr Rob Hicks on November 10, 2016

Stay informed

Sign up for BootsWebMD's free newsletters.
Sign Up Now!

Popular slideshows & tools on BootsWebMD

How to help headache pain
rash on skin
Top eczema triggers to avoid
boost your metabolism
Foods to lower LDL (bad) cholesterol
Tips to support digestive health
woman looking at pregnancy test
Is your body ready for pregnancy?
sick child
Dos and don'ts for childhood eczema
couple makigh salad
Nutrition for over 50s
bucket with cleaning supplies in it
Cleaning and organising tips
adult man contemplating
When illness makes it hard to eat
Allergy myths and facts
woman holding stomach
Understand this common condition