Palm oil: Well-balanced and nutritious...time to review

By Theresa Manavalan - 21 November 2014 @ 8:04 AM

“IT’S time for scientists to step a back and look at all palm oil research holistically,” says Tony Ng Kock Wai, associate professor at International Medical University’s Department of Nutrition and Dietetics.“ We need to look at the entire landscape of research findings on palm oil.” Now could be a good time as next year, Malaysia will be due for a review of national diet recommendations.

Most countries do a review of its national recommended nutrient intakes every 10 years or so.

Our last one was in 2005,a project Ng and other scientists in the National Technical Working Group on Dietary Guidelines worked on.

It is the guide of diet recommendations that we currently use.

Early observational epidemiological studies which commenced in the 1950s such as the Framingham Heart Study and the Seven Countries Study reported a positive link between saturated fat intake and coronary heart disease (CHD) mortality.

Ever since then a saturated fat phobia spread across the globe which lasted till the present day.

But Ng says we need not fear saturated fats as all types of fats have a role to play in our daily diet.

He says that some recent meta-analyses on the effects of saturated fats on CHD and stroke showed that saturated fats are not bad after all, only misunderstood and may even protect against stroke! Palm oil is traditionally regarded as saturated oil but it has several nutritional benefits and is an ideal frying oil because of its balanced fatty acid composition and its micronutrients content.

Ng would know.

He has spent most of his career studying palm oil.

FAT CHALLENGE

Human feeding studies done here, in China, the United States and Europe have established that palm oil does not raise the blood cholesterol levels of healthy people.

“Yet some studies done on Caucasians say otherwise,” says Ng.

This means that the same fat challenge can induce different plasma lipid responses in different human subjects.

This could be due to the different “LDL receptor set-point” and the “apolipoprotein E phenotype” of the human subjects concerned.

For his PhD at Universiti Malaya,Ng studied the nutritional and biochemical properties of palm oil as dietary fat in rats. Over five years,he investigated the digestibility and absorption of palm oil and its fractions, palm olein and palm stearin. He also compared the frying stability of palm oil with other vegetable oils, monitoring the rate of production of non-volatile polar compounds.

Polar compounds are substances that develop and stay in the pot during high temperature frying.

Other kinds of compounds evaporate and become “friedflavours” and other sorts of smells.

It takes 10 days for non-volatile polar compounds to reach 25 per cent - the level which renders the oil “unfit for human consumption” but only about six days in other cooking oils compared.This means that palmoilis very stable when heated, making it an excellent oil for cooking and frying.

“I sacrificed hundreds of rats in my PhD studies.

I’m born in the year of the Rat and there may be a day of retribution!” he says.

By 1990, Ng’s study of “yau char kuey” stalls (fried pastry crullers found in local markets) showed that only two out of 30 stalls in KL and Petaling Jaya had exceeded the acceptable 25 percent of polar compounds in their giant woks.

“The vast majority of fryers were well within acceptable levels,” says Ng, “and the majority of the yau char kuey sellers use palm oil because of its affordable price.” Typically, they would top up the wok with new oil through the course of working day, which has a dilution effect.

This finding showed that palm oil really is a stable oil.

“I chose yau char kuey stalls because they are high profile fryers,” says Ng, “and all Malaysians are familiar with them.” “I have also published a review on the safety of repeatedly used frying oils in Malaysia and found them to be generally safe”.

Diet and nutrition was the career path Ng chose after studying biochemistry, physiology and botany for his basic degree, biochemistry for his honours major at Universiti Malaya and a Master’s in Community Health at Queensland University.

When he joined IMR in 1972, the late Dr Bhagwan Singh was its director and research was focused on malaria, filiarasis and malnutrition.

Dengue was an emerging disease.

At IMR, Ng’s area of expertise was in the area of cardiovascular nutrition and conducted the first palm oil study in healthy Malaysians comparing the cholesterolemic effects of palm oil with corn oil and coconut oil.

He was also the first in the country to compare the effects of palm oil versus virgin olive oil on lipid and inflammatory markers of CHD risk in healthy human subjects.

Both these studies were published in high impact factor American journals which secured recognition by local and overseas scientists for Ng in the area of palm oil research.

UNDERSTANDING FAT

Ng moved into the area of nutrition, spending his days doing nutrition surveys all over the country, sometimes walking through remote villages.

“We measured consumption behaviour and nutritional status by a combination of anthropometry and biochemical tests,”says Ng.“We know that malnutrition is a multi-factorial problem.

If there’s poverty, there will be malnutrition.

Still, the highlight of my IMR years was studying palm oil, its digestability and its absorption.

And every day, I can see how palm oil can alleviate both poverty and malnutrition because palm oil is the most versatile of oils. It’s biodegradable.

As we are a major producer, I do see palm as nature’s gift to us.” Fats have an important role to play in our lives.

The human body has its highest demand for fat components called “essential fatty acids” during pregnancy and lactation.

“Over the years, we have been taught that fats are bad and saturated fats are especially bad, in fact there’s a kind of fat phobia out there,” says Ng. “This is so wrong.

If I removed all saturated fat from my diet to-day, I will fall sick in a matter of weeks”.

“You cut back fats only if you are overweight, or if you are consuming excessive amounts of fat and food in general.

If your weight is in an acceptable range, you must eat an acceptable amount of fat to stay healthy.” The typical Malaysian diet is a plate of rice and three dishes, often cooked with palm oil which is an important source of dietary fat forming 20-45g of fat per day, which is about 27 per cent of total calories from fat.

“This is healthy,” says Ng, “the WHO recommends 30-35 per cent.” All vegetable oils, basically plant products, are technically cholesterol free.

Most vegetable oils have some vitamin E content but palm oil has high amounts of tocotrienols (a particularly powerful antioxidant form of Vitamin E) which have a statin like cholesterol-lowering action and anti-thrombotic properties.

Newer research is saying it is protective of the body’s neuro systems, meaning it could prevent conditions like dementia.

These features make it an excellent oil for cooking.

Reference:

Friday, 21 November 2014, 6:24 PM