My Oh-Megas!

Fat is an essential part of our diet and supports many metabolic processes. To achieve optimal health and reduce risk for chronic disease it is important to include fat in your diet. The principle is to focus on the best types and the correct quantity of fats to get the benefit from them.

Let’s take a look at three types of omega fatty acids namely omega 3, 6 and 9.

What are omega-3 fats?

Omega-3 is a family of fats that are important for health and come in different forms:

  • ALA (alpha-linolenic acid) cannot be made in the body so must be eaten in our diet. ALA is found mainly in vegetable oils, rapeseed and linseed (flaxseed), nuts (walnuts, pecans and hazelnuts) and green leafy vegetables.
  • EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are long-chain fats that can be made from ALA in our bodies. They have the most direct health benefits. Making EPA and DHA from ALA happens slowly and only small amounts are formed. The best way of ensuring we are taking in an adequate amount of EPA and DHA is to eat foods rich in these fats.

Which foods are rich in EPA & DHA?

Fish, and especially fatty fish (e.g. pilchards, sardines, salmon) are good sources of EPA and DHA. White fish contains some omega-3 but at much lower levels than fatty fish. Canned versions of fatty fish such as tuna can be a source of omega-3’s but may have most of these fats removed during processing.

What are the key benefits of omega-3 fats?

Marine-derived omega-3’s has been linked to a number of benefits in various disease and inflammatory-related conditions. For example, people from the Mediterranean, Japan and Greenland with a diet rich in omega-3 have been shown to have a lower risk of heart disease than Western countries such as the US and UK. EPA and DHA promote heart health in via numerous mechanisms and it is considered essential for good heart health. To name only two it keeps the arterial cells healthy and correct heart rate variability. The American Heart Association (AHA) recommends a fatty fish consumption of 3 portions per week. Because of this and other health benefits such as the fact that they support the healthy development of a baby during pregnancy and breastfeeding and may be protective in maintaining a good memory as well as in the prevention and treatment of depression, it is recommended that we eat more foods containing omega-3. We should try to eat two portions of fatty fish per week.

A word about Sustainability

Whilst the main sources of omega-3 are from marine fish oils, the amount of fish available for consumption globally is declining for certain species of fish. It is important to choose fish from sustainable sources. You can do this by looking for Marine Stewardship Council (MSC) certified products or consulting the Southern African Sustainable Seafood Initiative (SASSI) at http://wwfsassi.co.za/

What are omega-6 fats?

Omega-6’s are also essential fatty acids, like the omega-3 fats, in that our bodies can’t make them and we therefore need to take them in through our diet. Arachidonic acid (AA) is an end product of the conversion of essential long-chain fats in the Omega-6 family. The results of biological pathways that include AA can have anti-inflammatory effects but can also promote inflammation.

Which foods are sources of omega-6 fats?

Corn, sunflower, safflower and soy bean oils are sources of omega-6 fats. These are mostly used in pre-packaged foods too. Meat, poultry and eggs are also sources of AA.

How much of these kinds of fats should I be eating?

Our usual diet generally tends to include higher amounts of omega-6 fats, as we use these oils in cooking. They are also used by the food industry, and if we consume pre-packaged foods frequently, which tends to be the case in South Africa it contributes to a higher intake of omega 6.

What are omega-9 fats?

Unlike the omega-3 and omega-6 fats, omega-9 fats do not need to be taken in from the foods we eat, as they can also be created by our bodies from unsaturated fats. Examples include oleic acid which is found in oils like olive oil and macadamia oil and erucic acid which is found in rapeseed oil.

To supplement or not to supplement?

The best source of the fats you need are food sources of these. Supplementation should only be considered when you find it difficult to take in the correct amount of these foods. It is important to consult with your healthcare professional before taking supplements of any kind. When it comes to omega fat supplementation, it would only be advisable to consider taking a pure omega-3 supplement which provides the correct amount of EPA and DHA when your fatty fish intake is low. The South African diet tends to be higher in omega-6’s and therefore supplementation is less likely to be recommended. Due to the fact that omega-9 fats are made by the body, it is not necessary to take these in through supplements.

References

  1. The Academy of Nutrition & Dietetics (2014). Position of the Academy of Nutrition and Dietetics: Dietary Fatty Acids for Healthy Adults. J Nutr Diet 114(1): 136 – 149.
  2. Omega 6 Fatty Acids and Risk for Cardiovascular Disease: A Science Advisory from the American Heart Association Nutrition Subcommittee of the Council of Nutrition, Physical Activity, and Metabolism; Council on Cardiovascular Nursing and Council on Epidemiology and Prevention. Harris et al, Circulation 2009.
  3. What health professionals should know about omega 3 fatty acid supplements. Opperman M, SAJCN 2013
  4. Smuts CM & Wolmarans P. (2013) The importance of the quality or type of fat in the diet: a food-based dietary guideline for South Africa. SAJCN 26(3): s87-99.
  5. Mahan LK, Escott -Stump S, Krause’s Food Nutrition and Diet Therapy 14th edition Philadelphia, Saunders 2016