Sorting fat from fiction

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Picture of foods with healthy fats, olive oll, avocado, salmon and nuts.

Beth Meertens and Garry Jennings

Beth Meertens is an Accredited Practicing Dietitian and Heart Foundation spokesperson on healthy eating and dietary patterns. Garry Jennings is the Heart Foundation's Chief Medical Officer.

It seems when healthy eating is the subject, everyone wants to talk about fat. It can be a confusing and polarising topic.

Given this, we have recently summarised contemporary evidence on the topic with a completed an evidence review and position statement. Here we will use this science to answer some of the most common questions asked about fat - sorting the fat from the fiction, so to speak.

Is saturated fat healthy now?

What has fuelled much of the interest in fat are studies which find that saturated fat is not associated with heart disease. And if there is no association, then saturated fat must be healthy, right? But is this really the case?

The short answer is ‘no’. Reducing saturated fat alone, without considering what it is replaced with may not be beneficial and doesn’t tell the whole story.

The evidence

A recent evidence review which underpins the Heart Foundation’s Position on Fat, found that ‘proportional change in energy’ is important when we study the relationship between fat and health.

Say that again?

When we change the amount of a nutrient, like saturated fat, there is a proportional change in the energy from other nutrients in our diet. For example, if the amount of saturated fat in our diet decreases, there is less energy from saturated fat and an increase the proportion of energy from other sources.

The other sources of energy are important.

Evidence demonstrates that reducing saturated fat and:

  • replacing it with unsaturated fat improves cardiovascular risk factors and reduces the risk of heart disease;
  • replacing it with wholegrains improves some cardiovascular risk factors and reduces the risk of heart disease but not to the same extent as unsaturated fat; and
  • replacing it with refined carbohydrate does not improve cardiovascular risk and does not reduce the risk of heart disease.

*Trans-fats, regardless of other sources of energy, are consistently linked to cardiovascular risk and to heart disease.

In short, unsaturated fat is preferred to saturated fat, both of which are preferred to trans-fat. (And wholegrains are preferred to refined carbohydrates.)

The take-home message

Changing saturated fat alone, without considering what it is replaced by is not enough. The ‘neutral’ or ‘no’ associations between saturated fat and cardiovascular disease (CVD) does not mean it is ‘healthy’ and we should eat more, as studies of saturated fat compared to unsaturated fats and wholegrains consistently finds the latter two promote heart health.

The combined evidence suggests that improving the whole eating pattern, not just altering one nutrient is required to promote cardiovascular health.

This concept is embodied in the Heart Foundation’s new position statement on Dietary Fat and Healthy Eating, along with the American Heart Association, the Canadian Heart & Stroke Foundation and the New Zealand Heart Foundation which all recommend that the shift from saturated to unsaturated fat should occur within a healthy eating pattern.

Is Omega-6 good or bad for my heart?

Claims have been made that Omega-6 promotes inflammation or, worse yet, increase the risk of heart disease. So, should we be avoiding Omega-6 fats?

No, from the evidence we know that Omega-6 is an important part of a healthy diet. Not the only part, but an important part.

The evidence

We should not avoid Omega-6 as it is an essential fat, meaning it is a type of fat that the human body cannot make naturally and so it must be sourced from the diet to avoid deficiency. The human body can make saturated fat, monounsaturated fat and cholesterol which means they are not considered essential fatty acids.

Many studies consistently demonstrate the link between intake of Omega-6 and a lower risk of heart disease. For example a systematic review and meta-analysis of prospective cohorts found that increasing Omega-6 by 5% was associated with a 9% lower risk of having heart disease, and a 13% lower risk of dying from heart disease.

Research has not found evidence to support claims about an association between inflammation and Omega-6. A systematic review of randomised controlled trials found no evidence that dietary Omega-6 contributes to inflammation. The American Heart Association also found that Omega-6 fats are not pro-inflammatory and that they are associated with reduced risk of heart disease.

The take-home message

Food sources of Omega-6 include nuts, seeds and their oils (including sunflower, safflower, sesame, canola and to a lesser extent olive oils).

But be careful

Omega-6 is found in many types of oils, this means that it can be found in discretionary foods like biscuits, cakes and takeaway foods (in which oil is a substantial ingredient). The fact that Omega-6 can be found in these foods does not make them healthy.

All Australians would do well to consume less discretionary foods and beverages. As a whole, this group of products contributes the most saturated fat, trans-fat, refined carbohydrates and sodium to the diet which not only raise risk factors for many health complications but also take up space in the diet where healthy foods should be. Read more about the Heart Foundation’s Healthy Eating Principles which promote a good balance of fats, including Omega-6.

Is butter better because it’s less processed?

With headlines suggesting ‘butter is back’ and a sense that ‘less is more’ when it comes to food processing, we are often asked, ‘is butter better’?

Here again, we must ask, ‘what we are being asked to compare it to?’

Put bluntly, butter is not a health food.

The evidence

Butter is made up of 50% saturated fat and 4% trans-fat. Compared to other oils like olive and canola oil, butter raises LDL (bad) cholesterol which is a risk factor for heart disease.

When studies look at the development of heart disease over long periods of time, a relatively small risk or neutral relationship exists between butter – mortality and cardiovascular disease (CVD).

However, this is in stark contrast to the corresponding benefits of fruits, nuts, legumes, healthy oils, and fish.

Often the merits of butter rest on its perceived status as a ‘natural’ product compared to alternatives like margarine.

While research suggests that the degree of processing is relevant to the healthiness of a product, it’s not as black and white as processed=unhealthy and unprocessed=healthy.

Technically, processed just means a deliberate change in a food that occurs before it is available for us to eat it, for example, canned and frozen vegetables are processed but are arguably healthy foods.

The take-home message:

Be discerning about the term ‘processed’; processing is not a proxy for unhealthy.  

A better, ‘natural’ alternative to butter would be olive oil, avocados, nut butters or tahini which provide unsaturated fats, minimally saturated fats and no trans-fat, and are all linked to having a healthier heart.

Is coconut oil the ultimate superfood?

Remarkable claims have been made about the health benefits of coconut oil. While coconut oil is 92% saturated fat, some claim that because the saturated fat in coconut oil is slightly different to that in animal products, it is a healthy choice. Is this the case?

Simply put, there is no evidence to support the consumption of coconut oil for heart health.

The evidence

Coconut oil consumption raises total cholesterol, high density lipoprotein (HDL) and low-density lipoprotein (LDL) when compared with other fat sources, except butter which raises them further.

Evidence does not support the claim that saturated fat in coconut oil acts differently to other saturated fats. Studies that relate to medium chain triglycerides (namely MCT oil - a type of manufactured fat used for some clinical conditions) cannot be used to support coconut oil consumption in general, as coconut oil has a much higher level of lauric acid (a long-chain saturated fat). Lauric acid is the main fatty acid in coconut oil and similar to other types of saturated fat it raises LDL(bad)-cholesterol.

Take home message

Like butter, coconut oil is not a health food. Health food status is reserved for foods which are proven to promote health such as vegetables, legumes, fruit and nuts.

Eating spoonsful of coconut oil is not healthy and may indeed be harmful.

There’s better alternatives to coconut oil - include olive and canola oils and spreads, avocado and nut butters regularly instead.

Should I choose reduced fat or full fat dairy products?

Two of the most common questions about fat are if full fat or reduced fat milk is the healthier option? And are milk, cheese and yoghurt actually good for your heart?

In short, milk, yoghurt, and cheese are healthy snack options in preference to discretionary foods and can contribute to healthy meals when eaten with vegetables, wholegrains or fruit.

Choosing reduced fat unflavoured varieties of milk and yoghurt, and cheese over added sugar/flavoured and high fat varieties is the healthier choice.

The evidence

Similar to other foods like eggs and poultry – milk, cheese and yoghurt are not associated with cardiovascular risk. This means that they do not increase risk which is a good thing, but they do not decrease the risk in the same manner that vegetables, legumes, fruits and nuts do.

In a review of dietary patterns linked to heart health, some but not all dietary patterns included milk, cheese and yoghurt and when they do, they are usually the reduced fat and unflavoured varieties. There is some evidence that reduced fat dairy (usually milk and yoghurt) is associated with a reduced risk of hypertension as part of a broader healthy eating pattern and evidence that replacing dairy fat with plant-based fat (i.e. nuts, oils etc.) is associated with a reduced risk of adverse lipoproteins and risk of heart disease.

Take home message

On balance, dairy products (milk, cheese and yoghurt) can be included in a healthy eating pattern. This evidence for milk, cheese and yoghurt does not translate to other dairy foods like butter, cream or other high-fat dairy products like ice cream which should be limited.

Essentially, adding dairy fat (by choosing full fat products) to your eating pattern won’t make it healthier while removing some (by choosing reduced fat products) to make room for fat from plant sources such as olives, nuts and seeds is a healthier choice.

Conclusion

In sorting the fat from fiction, we find:

  • The whole eating pattern, not just one nutrient, is important for heart health.
  • Unsaturated fat is preferred to saturated fat, both of which are preferred to trans-fat.
  • Adopting the Heart Foundation’s Healthy Eating Principles will help achieve the balance of fats the evidence demonstrates are important for heart health.

The Heart Foundation’s Healthy Eating Principles promote a healthy eating pattern based a combination of foods, chosen regularly, over time. This optimal combination is based on research into dietary patterns including the Mediterranean and DASH diet. It has been categorised into five healthy eating principles for ease of reference:

  1. Fruits, vegetables and wholegrains
  2. A variety of healthy protein sources including fish and seafood, lean meat and poultry, legumes, nuts and seeds
  3. Reduced fat dairy such as unflavoured milk and yoghurt, and cheese
  4. Healthy fat choices with nuts, seeds, avocados, olives and their oils for cooking
  5. Herbs and spices to flavour foods, instead of adding salt

This style of eating is naturally low in saturated and trans fats, salt and added sugar and rich in wholegrains, fibre, antioxidants and unsaturated fats (omega-3 and omega-6). Eating this way will improve the heart health of all Australians by reducing cardiovascular disease (CVD) risk factors such as high blood pressure and blood lipids and decreasing the risk of CVD events and mortality.

For more information watch the Heart Foundation’s Healthy Eating Principles Webinar along with the “Where does fat fit in healthy eating” Webinar.

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