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Rebecca Wilson, a registered dietitian whose focus ranges from public health, sports and clinical nutrition, to corporate health, says there is plenty of confusion around the subject of saturated fat.
"There have been several studies published over recent years that have called into question current dietary guidelines, particularly around recommended saturated fat intake.
"We have seen a steady flow of sensationalised headlines claiming ‘butter is back’, ‘not all saturated fat is equal’ and ‘scientists got it wrong’, as well as calls to overturn dietary guidelines.
"Unfortunately, it is not that clear-cut. Nutrition science is a minefield and, rather than cherry-picking papers or even specific findings within a paper, it’s important to look at the research in its entirety. This is something that is often overlooked."
Wilson, who runs a private practice in Dunedin (Rebecca Wilson Nutrition) and is the dietitian for Otago Rugby, points out that not all saturated fats are created equal.
"Some may not be as detrimental to our health as originally thought.
"However, there is clear evidence showing that replacing saturated fat with mono or polyunsaturated fats has positive effects on blood cholesterol levels and heart health."
According to the latest national nutrition survey, the average New Zealand adult’s total energy intake comprises 13% of saturated fat.
"For most people, using a small amount of butter here and there shouldn’t be a problem. However, with Kiwis being the highest butter consumers in the world, making a simple swap from butter to mono- or polyunsaturated margarines is one way to lower total saturated fat intake."
The debate shouldn’t be reduced to a question of butter versus margarine, she says.
"There are many other nutritious alternatives such as using avocado, hummus, nut butters or plant oils (such as olive or avocado oil), which may be the way to go given food purchasing trends sending the price of butter soaring.
"Putting the saturated fat debate aside, I would say the most important thing that nutrition science has shown us is that it is our whole dietary pattern that counts.
"Rather than focusing on specific nutrients we should look to the foods we are getting them from —we eat food, not nutrients.
"If you are basing your food choices largely on a variety of minimally-processed foods and including plenty of vegetables and fruit, then for most people a little bit of butter here and there won’t hurt.
"However, there is definitely no need to start labelling it as a ‘superfood’ and putting it in your coffee."
There are three major types of dietary fats in our food:
• monounsaturated and
The difference between these lies in their chemical structure and physical properties. In simple terms, these variations in structure affect how our body metabolises them, and hence how they impact on our health; in particular heart health through their effect on blood cholesterol levels.
"Saturated fats are generally solid at room temperature and are linked to increasing levels of total and LDL cholesterol in the blood, which is associated with an elevated risk of heart disease," Rebecca Wilson explains.
"Saturated fats are most commonly found in animal products such as meat and dairy (including milk, butter, cream and cheese), as well as in coconut and palm oil.
"Mono- and polyunsaturated (omega 3 and omega 6) fats are considered ‘heart-healthy’ as they help balance the cholesterol in your blood by decreasing the LDL-cholesterol and increasing HDL-cholesterol. Sources include avocados, nuts, seeds, plant oils (eg, olive or avocado) and oily fish."
A fourth type of dietary fat — trans fats — should be limited because of their negative effects on blood cholesterol levels and heart disease risk, Wilson notes.
"Trans fats occur naturally in small amounts in some foods such as butter and dairy. The good news is that currently Kiwis eat below the World Health Organisation’s recommended upper level of trans fat (less than 1% of total energy intake)."