“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
