In fact, omega-3s and omega-6s are so
important to body function that they are called essential fatty
acids, and they are critical to fetal development and to skin, nerve
and brain function. Omega-3s can reduce the clotting factors that
precipitate stroke and heart disease, and they can lower blood
triglycerides, another risk factor of heart disease.
Furthermore, our bodies can't make
these essential fatty acids, so we have to consume them in our
diets. "Fatty fish, such as salmon, is a good source of omega-3s,
and I recommend cooking with canola or soybean oil. Consumers can
already purchase eggs that are rich in omega-3s, and other enhanced
products should be available soon," he said.
Omega-6s can be consumed in pistachios
and sunflower seeds or consumed in borage oil or evening primrose
oil, available as dietary supplements. Nakamura said it's important
to keep omega-3s and 6s in balance, and he added that genetic
modifications to soybeans and other oilseeds are under way that will
help us do that.
Saturated fats, on the other hand,
found in animal fats and fried and processed foods, are the "bad"
fats, implicated in everything from heart disease to breast cancer.
Nakamura has been investigating the way
in which essential fatty acids regulate the production of certain
enzymes in the liver. "We know that the essential fatty acids help
regulate body fat deposition, increasing the body's use of fat by
causing fat-burning enzymes to kick in," said Nakamura.
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"Although it looked promising at first,
we are finding that this phenomenon is mostly restricted to the
liver, not to fat storage tissue in the body. The liver seems to
regulate fat synthesis in such a way that it makes just enough
unsaturated fat to promote flexibility in human cell membranes," he
Nakamura is also investigating the way
two types of carbohydrate -- glucose and fructose -- are metabolized
in the body. Table sugar, he said, contains about half glucose and
half fructose. Most soft drinks contain a lot of high-fructose corn
sugar because fructose is sweeter than glucose and makes a better
sweetening ingredient in beverages.
"Although it's still early to talk
about the results, one of our animal studies seems to show that
fructose may not be as good as glucose for the body. Fructose may
actually have a strong effect on whether food is used as energy or
stored as body fat," he said.
Although the metabolism of fat is still
not fully understood, scientists know enough to be able to say that
some types of fat are beneficial while others cause health problems.
While research continues in Nakamura's
lab and others, he suggests eating one to three servings of fish
weekly for the essential fatty acids that our bodies need and
avoiding the saturated fats found in fried and processed foods,
which have unhealthy effects on our bodies.
[University of Illinois news release]