Greenland Eskimos, for instance, take in 60-70% of their
diet from fat, but they have very low rates of heart disease and cancer. It
turns out that in cold-water fish, or the "fatty fishes", there is a
substance called omega-3 fatty acid, which seems to protect the arteries. It
lowers triglyceride levels. It improves glucose control in diabetics.
Do you also recommend that
cardiac patients take supplements that contain these fats?
SAM BENJAMIN, MD: It depends on the patient, and what other problems they have
in addition to heart disease. I would encourage people to really talk to their
doctor, rather than use some single, general rule of thumb. Some people can't
tolerate fish oils. Hemp oil is another rich source of omega-6 fatty acids,
another helpful fat, as is flaxseed oil. These are good alternatives to fish
oil.
What about the monosaturated fats
that are found in olive oil and avocados. Are they good?
NATE LEBOWITZ, MD: The Mediterranean diet contains a very high amount of olive
oil, and has for over 5,000 years, and yet they have relatively low rates of
heart disease. It turns out that the polyunsaturated fats in general are good.
Monounsaturated fat in olive oil can be fairly beneficial. It can lower and
certainly stabilize LDL levels (the "bad cholesterol"), while not
affecting HDL (the "good cholesterol"), and in some cases it may keep
HDL stable, even raising it a little bit.
Why are trans-fats, which are
found in many processed foods, detrimental to cardiac health?
NATE LEBOWITZ, MD: If the ingredients list "partially hydrogenated"
oils, that's a good way to identify a trans-fat. The trans-fats don't exist in
nature. They're manufactured, and they exist in a lot of processed foods-things
that are in cans and things that are in boxes. They help keep things solid at
room temperature.
In some observational studies, such as the Nurses' Health
Study, which was a study of several hundred thousand post-menopausal women with
no history of coronary heart disease, if you simply shift your energy intake by
2% or 5% away from the trans-fats in favor of another kind of fat, a
polyunsaturated fat, the risk of coronary heart disease drops dramatically to
upwards of 50%. So it turns out that trans-fats may well be very, very toxic
chemicals.
What role does fiber play in
heart health?
NATE LEBOWITZ, MD: Fiber in general is good. Essentially, if you're taking in a
lot of fiber, you're not taking in a Big Mac. So from that perspective alone,
it's good.
There is soluble fiber and insoluble fiber. Both reduce
colon cancer rates, and both will lower cholesterol somewhat. A good example of
the soluble fiber, which means it dissolves in our bloodstream, are the oat
grains-oat bran, as opposed to the wheat bran, which is an insoluble fiber. The
soluble fiber is beneficial because it lowers cholesterol dramatically. Flax is
excellent because it has both soluble fiber and omega-3s. Oat grains, oat bran,
pectins, like grapefruit pectin, fruit pectin are also soluble fibers. You can
take in a lot of it very safely, and lower your cholesterol dramatically.
The problem is that, as a nation, we take in very little
fiber in our diet. In one study, if we increased our amount to about 100 grams a
day from the average of 10-20 grams, cholesterol levels dropped dramatically and
colon health improved dramatically.
SAM BENJAMIN, MD: But soluble fibers affect absorption of
medications that people might be taking. Even though these products can be
gotten without a prescription, they need to remember to discuss with their
physician whether or not they might in some way affect the levels of the
medication in their bloodstream.
What role do soy products play in
heart health?
SAM BENJAMIN, MD: Soy substantially decreases the risk of cardiovascular events.
And it improves recovery afterward. Soy products can be responsible for
decreasing levels of what are called apolipoproteins, which are parts of the
lipids that are offensive to our body and increase our chances of heart disease.
For people concerned about
cardiac health, what must they know about "good carbohydrates" vs.
"bad carbohydrates"?
NATE LEBOWITZ, MD: The bad carbohydrates are the things from refined white
flour, like cakes, cookies, muffins, and white bread. These things release their
sugars into the body very quickly, and provide a big rise in sugar levels, which
is followed soon after by a big rise in insulin. And insulin can be very
damaging to the lining of the artery. Insulin lays down fat in the truncal
region. And then it crashes down your sugar, so that a few hours later, you're
starving and you have no energy and you have this so-called carbohydrate
craving, which leads to the vicious cycle again. A lot of people who have a
muffin or bagel for breakfast are starving by mid- to late morning, and they
have no energy.
The good carbohydrates, like whole grains, legumes,
garbanzos, kidney beans, and whole grain oatmeal, are harder to break down, and
therefore release their sugars more slowly throughout the day. There's never
that insulin peak, which is a good thing, because insulin peaks are bad. And
they also don't cause that carbohydrate craving, and you're less hungry
throughout the day, you eat less.
