The ins and outs of unsaturated fats

Unsaturated fats are considered the ‘healthy’ fats and they’re important to include as part of a healthy diet. These fats help reduce the risk of high blood cholesterol levels and have other health benefits when they replace saturated fats in the diet.

Unsaturated fats are liquid at room temperature, unlike saturated fats that are solid at room temperature. Healthy unsaturated fats come in two main forms, polyunsaturated and monounsaturated. These differ in their chemical structure and they have slightly different health benefits as a result.

Polyunsaturated fats

Two main types of polyunsaturated fats are omega-3 fats and omega-6 fats, which act slightly differently to provide health benefits. Omega-3 and omega-6 fats are essential in the diet as they can’t be made in the body.

Omega-3 fats

Omega-3 fats have been shown to be protective against heart disease in a number of ways, including lowering blood triglyceride levels and blood pressure. Omega-3 fats are found in marine, animal and plant sources.

Fish and seafood are the best sources of omega-3, particularly for heart health. Research has found that people who have a higher intake of fish have a lower risk of developing heart disease1. Choose oily fish such as salmon, sardines and blue-eye trevalla. Omega-3 fats are also found in free range eggs, beef and chicken, but only in small amounts.

Plant sources contain a different type of omega-3 fat to fish and other animal sources. Our bodies can convert some omega-3 from plant sources into the more beneficial form found in fish, but the conversion rate is low. That’s why it’s important to include both marine and plant sources of omega-3 fats in your diet. Plant sources of omega-3 fats include linseed/flaxseed, walnuts, chia seeds, soybean oil and canola oil.

How much should I be having?

The Heart Foundation recommends adults have 250 – 500mg of omega-3 (marine source) everyday to reduce their risk of heart disease. This is also the recommendation for those with existing heart disease. By consuming 2-3 serves (each 150g) of oily fish a week, this can be achieved.

In addition to marine omega-3 fats, the Heart Foundation recommends having 1g daily of omega-3 from plant sources.

Due to the mercury content in larger fish, pregnant and breastfeeding women must be mindful not to consume more than the recommended amounts of fish. Check out Nutrition for pregnancy for details.

Supplementation is only recommended in some specific cases, and should be done in consultation with your health professional:

For people who already have heart failure, the Heart Foundation suggests supplementing 1,000mg of marine omega-3 fats daily, in addition to standard therapy.

Those with very high triglycerides may benefit from additional supplementation of marine omega-3 fats.

Supplements also provide some marine omega-3 for people who do not eat fish.

Omega-6 Fats

Omega-6 fats have been shown to decrease the risk of heart disease when they are consumed in place of saturated and trans fats. Omega-6 fat sources include:

  • Margarine spreads (use in place of butter to replace saturated fats)
  • Sunflower, soybean, sesame oils (use in place of lard, tallow, copha)
  • Nuts (such as walnuts, pecans, brazil and pine nuts)
  • Sunflower seeds.

Most Australians get enough omega-6 fats from their diet. We generally need to focus more on improving fish intake to ensure adequate intake of omega-3 fats from marine sources.

Monounsaturated fats

Food sources of monounsaturated fats include:

  • Olive oil
  • Canola oil
  • Peanut oil
  • Nuts
  • Avocados.

Replacing unhealthy saturated fats with monounsaturated fats has a cholesterol lowering effect.

An Accredited Practising Dietitian (APD) can provide individual dietary advice on the most appropriate types of fat to eat and how much you need each day. An APD can also teach you how to read food labels to help you choose the best foods for you and your family.