Replacing the cheese in New Zealanders' sandwiches with sesame seed paste could help to cut the nation's rate of heart disease by 10 per cent, a new analysis indicates.
The Otago University researchers calculate, based on overseas studies involving more than 300,000 people, that a one-in-10 reduction in New Zealand's high rate of heart attacks and related heart disease could be achieved by replacing some of the bad fat in our diet with good fat.
But simply decreasing the bad fat was not linked to reduced rates of heart attack or stroke in the US and European research.
Many of our favoured foods - such as butter, cream, cheese, bacon, fatty lamb chops, coconut cream and potato crisps - are high in saturated fat. It can boost the amount of bad cholesterol in the blood, which can harm the arteries supplying oxygen to the heart muscle.
Conversely foods rich in poly-unsaturated fat can reduce the level of bad cholesterol in the blood and also have other beneficial effects on health.
Good sources include sunflower, safflower and canola oils, walnuts, sesame seeds, fresh salmon, and tuna canned in oil. Some margarines are good sources too, but also contain a significant amount of saturated fat.
In the New Zealand diet, 13 per cent of our energy comes from saturated fats, which is significantly more than recommended by international authorities. Five per cent - too little - comes from poly-unsaturated fats.
The study is based on reducing that bad-fat energy intake by 5 percentage points, and upping the good by the same amount.
That equates to about 14g of fat in a man's diet and 10g in a woman's.
Based on 15g of fat for simplicity, the researchers, Rachel Foster and Associate Professor Nick Wilson, suggest examples of healthy switches, such as just under two tablespoons of safflower oil for two of butter; or 45g of sunflower seeds for 65g of cheddar cheese.
Replacing fatty red meat with oily fish is also suggested, but additional sources of the good fats would be needed.
There isn't enough data to know whether replacing bad fats with mono-unsaturated fats helps prevent heart disease, although "olive oil may be an exception because of its wide-ranging beneficial cardiovascular effects", the authors say in the Australian and New Zealand Journal of Public Health.
They urge more research before considering introduction of a Hungary-style tax on unhealthy food ingredients, targeted subsidies for healthy-fat foods, or maximum permitted levels of saturated fat in foods.
Auckland University nutrition expert Professor Cliona Ni Mhurchu told the Science Media Centre that Denmark's saturated fat tax, which was in place for a year, reduced consumption of targeted fats by 10 to 15 per cent, but such schemes had to be carefully studied before introduction. "It is important to assess substitution effects to know whether or not food taxes have positive effects on the whole diet as opposed to just the targeted foods."