Health: true or false?

Are all vegetable oils heart-healthy?

PUBLISHED : Monday, 14 July, 2014, 3:13am
UPDATED : Friday, 17 April, 2015, 1:08pm

Are all vegetable oils heart-healthy?

The straight answer: No

The facts: You've heard of the dangers for the heart from animal and dairy fats. But are you aware that some vegetable oils can push your cholesterol levels up, too? That's because contrary to popular belief, not all vegetable oils are good for you.

Depending on how they were processed, some plant-based oils can actually increase your risk of heart disease.

According to Susie Rucker, a nutritional therapist at Body With Soul in Singapore, the most destructive processing method is hydrogenation or hardening. "Hydrogenation is a process used to turn oils into margarine or shortening," Rucker says.

"All vegetable oil spreads - even olive oil based ones - and margarines are so indigestible that you may as well eat the tub they come in.

"These products contain both oxidised and trans fats. The body absorbs these fats but once in the cell wall, the cell is unable to use this altered form of oil and dysfunction ensues. As a result there is a rise of cardiovascular disease, all from a spread that is marketed to do the exact opposite," says Rucker.

Another process that makes vegetable oils unhealthy is the kind used to make refined, bleached and deodorised cooking oils.

These are commonly used in kitchens everywhere - think safflower oil, soya bean oil, canola oil, rice bran oil and sunflower oil.

Rucker says these oils are unstable, heat-treated and partially hydrogenated, and, in some cases, the plant is also genetically modified.

"These oils are toxic to the body, and need to be replaced with good saturated fats that are heat stable for cooking," she says. "Try organic butter or ghee, unrefined coconut oil, which is anti-viral and anti-bacterial, and known to boost immunity and create fat burning in the body.

"Or try sesame oil mixed with coconut oil, fats from animals that have been organically raised, and palm oil which comes from sustainable sources."

Hydrogenated vegetable oils are found in many popular processed foods, says Sally Poon, a registered dietitian at Private Dietitian.

Crackers, chips, cakes, salad dressings, pastries, dried or powdered non-dairy creamers, bread, and fried products such as French fries are all loaded with these heart-harming vegetable fats.

Trans fats are unhealthy because they increase the level of low-density lipoprotein (LDL) cholesterol - harmful cholesterol - while at the same time reducing the level of high-density lipoprotein (HDL) cholesterol, the beneficial cholesterol.

This increases the risk of heart disease, which is the second biggest killer in Hong Kong. "The World Health Organisation and the Food and Agriculture Organisation of the United Nations suggest that diets should provide a very low intake of trans fats," says Poon.

"Less than one per cent of your daily energy intake should be from trans fats. So, for example, if you have a daily energy intake of 2,000 calories, you should limit your intake of trans fats to less than 2.2 grams per day."

Rucker says that, as well as increasing the risk of cardiovascular disease, trans fats increase chances of developing type 2 diabetes and cancer, lower intelligence by interfering with your cerebral cortex, and affect the detoxification pathway in your liver.

What's more, in animal studies, trans fats have been shown to reduce fertility. "We not only need to make better food choices, we also need to change the oils we cook with at home," says Rucker.

She recommends using healthy oils - unsaturated oils that are not heated and can be used raw, such as olive, flax seed, walnut, pumpkin and hemp seed. These must be extra virgin and cold-pressed.