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Fats – the good and the bad
Fats are categorised into different groups – saturated, trans, polyunsaturated and monounsaturated. No food is completely one type of fat, but foods are classed according to the main type of fat they contain.
Generally speaking, saturated and trans fats are not so good for you. They are found mainly in animal foods such as full cream dairy products, meats and many processed foods such as pastries, commercial biscuits and takeaway foods. Too much of these fats (or any, in the case of trans fats) in the diet is undesirable as they increaase blood cholesterol and are therefore strongly linked with heart disease.
It is recommended that we replace the saturated fat in our diet with mono- and polyunsaturated fats, which can help to lower blood cholesterol when they replace saturated fat in the diet. Foods high in monounsaturated fat include olives and olive oil, nuts, avocados and canola oil.
Polyunsaturated fats can be further categorised to omega-3 and omega-6 types. There is a desirable balance between our intake of omega-3 and omega-6. Western diets are generally rich in omega-6 fats (which we get mainly from polyunsaturated margarines and vegetable oils such as sunflower and sesame oil) but too low in omega-3’s and it is this imbalance that has been linked to many chronic diseases.
Omega-3 Fats – the benefits
Omega-3 fats are essential in our diets. This means that since omega-3’s have many important roles in our bodies, we need to eat them regularly as our body cannot make them. It is the long chain omega-3’s known as EPA (eicosapentaenoic acid), DPA (docosapentaenoic acid) and DHA (docosahexaenoic acid), which are particularly beneficial.
Heart protection
Protection from heart disease is one of the benefits of consuming both long and short chain omega-3 fats. Interestingly, the protective effect of marine sources of omega-3’s was first recognised through observations of the health status of Greenland Eskimos. The diets of this population were very high in fats from seals, whales and fish, but they had a low rate of heart disease.
Omega-3’s protect our heart and blood vessels through a number of actions including their anti-inflammatory properties, ability to reduce blood triglyceride and cholesterol levels, reduce blood pressure, regulate heart rhythm and prevent the formation of blood clots.
Diabetes
Omega-3’s and in particular the long chain types, may also improve insulin sensitivity in patients with type 2 diabetes, thereby helping people to manage their blood sugar levels more effectively.
Mental and behavioural health
Research is now suggesting a link between depression and omega-3's. Some studies have found that people with major depression or suicidal behaviour, have lower levels of omega-3 fats and a higher ratio of omega-6 to omega-3 fats in their blood and body cells.
While more research is needed, preliminary findings also suggest that omega-3's may be beneficial in the treatment of other mood disorders and conditions such as bipolar disorder, dementia, Attention Deficit Hyperactivity Disorder and schizophrenia.
Growth and development
Long chain omega-3's are essential nutrients for optimal growth and development of infants and children, particularly of the brain and retina. This is another interesting area of research, which is leading to the addition of omega-3’s to infant formulas and pregnancy supplements.
Inflammatory diseases
The use of omega-3 fats in the management of inflammatory diseases such as rheumatoid arthritis has been widely studied. Some studies have even suggested a discontinuation of conventional anti-inflammatory medication for those who respond well to omega-3 supplementation for arthritic pain and other conditions such as back and neck pain.
Cancer
While the research into cancer risk and omega-3’s is still in its infancy, there is increasing evidence that omega-3 fats, particularly the long chain types, may help to prevent or slow the development of some cancers.
How much do we need?
Health authorities recommend that we consume more omega-3 fats, in place of other fats in our diet. This recommendation was formalised in 2006 with the release of the Nutrient Reference Values (NRV’s) for Australia and New Zealand.
The following basic values are recommended, to prevent deficiency of omega-3’s:
ALA Men 1.3 g/day
Women 0.8 g/day (higher for pregnancy and lactation)
Long chain omega-3 Men 160 mg/day
(DHA/EPA/DPA) Women 90 mg/day (higher for pregnancy and lactation)
For further protection from chronic diseases in adults, much higher amounts of long chain omega-3’s are suggested:
Men 610 mg/day
Women 430 mg/day
Omega- 3 Food sources
Current research shows that it is the long chain omega-3’s EPA, DPA and DHA that provide us with the most health benefits. These long chain fats are found mainly in fish and seafood with the richest sources being oily fish such as salmon, tuna and sardines, and smaller amounts found in eggs and foods especially enriched with long chain omega-3’s.
But, I don’t eat fish! Are there other food sources?
Yes - there are other foods that contain omega-3. Canola oil and margarines, walnuts, linseeds and linseed oil, soybeans, soy beverages enriched with omega-3, dark green vegetables, as well as some fortified food products, are all sources.
The omega- 3 fat in these plant food sources is known as ALA (alpha-linolenic acid), which is a short chain fat and they are then converted by the body, to the long chain omega-3’s.
This conversion is essential and it is important that if you don’t directly consume the long chain fats from fish and other seafood make sure you make this process as efficient as possible. To maximise your conversion of ALA to EPA and DHA:
· Limit your intake of Omega 6 fats, found especially in processed foods and sunflower, safflower and corn oils – use olive, canola, macadamia and avocado oils instead
· Limit - or avoid altogether - trans fats and alcohol which inhibit conversion
· Focus on a wide variety of whole plant foods as minimally processed as possible
· Include rich ALA food sources like walnuts and linseeds regularly
Do we have enough omega-3’s?
Health authorities are advising that as a population we don’t consume enough long chain omega-3’s for optimal health.
Given that there have been changes in our food supply and taste preferences – as well as concerns regarding the affordability and long-term sustainability of fish as a regular menu item, health experts are looking at how we can access a wider range of plant sources of long chain omega-3’s.
In the meantime, it is important to consider that enjoying a plant-based diet has fantastic benefits for health. Vegetarians, who don’t necessarily eat fish, suffer less from some of the diseases that omega-3’s work to protect against – including heart disease, cancer and diabetes.
Food Ideas
To increase your intake of omega-3’s, why not try the following:
- Enjoy a simple stir-fry with plenty of green leafy vegetables and firm tofu
- Snack on green soybeans, also known as Edamame (available frozen from Asian supermarkets).
- Pack some dried fruit and walnuts as a mid morning or afternoon snack.
- Ground linseeds are a great addition to homemade muesli or muffins. You could also toss a tablespoon over your morning breakfast cereal.
- Try soy and linseed bread for toast and sandwiches.
- Use an omega-3 fortified soymilk in place of dairy milk in fruit smoothies, with breakfast cereal and in hot drinks.
- Choose canola oil or margarines for cooking or spreads instead of polyunsaturated varieties.
- Add canned soybeans to tomato based pasta sauces, casseroles and curries.
- Try a hard-boiled egg and salad as a sandwich filling.
- Use linseed oil in homemade salad dressings.
- Stir baby spinach through scrambled eggs and serve on soy and linseed bread for a simple weekend breakfast
- If you eat fish, the National Heart Foundation recommends at least 2 fish meals (preferably oily fish) per week. You could try canned fish in salads, pasta or sandwiches or simply steam, barbeque, grill or bake whole fish fillets.
- Look out for Omega-3 enriched foods in your supermarket.
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