Dear doctors: I have always known that fish oil is beneficial for its omega-3 content. I see that krill oil is now being sold, claiming to have the same beneficial properties, but krill are high in cholesterol. How can that be beneficial?
J.B.
The benefits of omega-3 fatty acids have been extremely controversial in the past few years, with studies showing conflicting results and a recent study concluding omega-3 has only a small effect.
My take, after reading all this data, is that omega3-containing foods, such as fatty fish like salmon, have a modest benefit in reducing heart disease. Fish-oil supplements may be of benefit, especially for people with high cholesterol or heart disease.
One study showed that krill oil supplements reduced cholesterol levels, but I would not recommend taking a supplement until there is clear data not only that blood numbers improve, but that people live longer or are healthier taking a supplement compared with not. We don't yet have that certainty with krill oil.
Finally, the big effect on your blood cholesterol comes from the cholesterol your body makes, not from the cholesterol you eat.
Fish oil and, it appears, krill oil seem to affect the way your body makes cholesterol.
Dear doctors: I have a male relative with diabetes. He takes his diabetes medicine, but he eats five or more servings of fruit per day. Should he be restricting his daily fruit intake? Is there too much sugar in five or more fruits per day?
R.E.
Sugar from whole fruits acts differently in your body from the way added table sugar or even fruit juice does. Sugar from fruit is absorbed more slowly due to the fibre of whole fruit.
Most diabetes authorities recommend two to four servings of fruit daily. However, each person may react a little differently, and it is pretty easy to check blood sugar before and after eating fruit to see what the effect is on an individual's blood sugar.
Some fruits may be better than others. Many diabetics find apples, which have more fibre and less sugar than some others, to have little effect on their blood sugar.
Dear doctors: Does a heart murmur (I have had one for years) cause atrial fibrillation?
J.T.
A heart murmur is an abnormal sound heard by your doctor or nurse with a stethoscope.
There are many kinds of heart murmurs, and although some of them represent serious disease, many are benign and don't need any testing.
However, one cause of a heart murmur is a defective heart valve. One of these valves, the mitral valve, prevents blood from leaking back into the left atrium from the left ventricle.
If this valve is partially blocked (we use the term "stenotic," and it can be from calcification, rheumatic heart disease or some other cause), then it may lead to enlargement of the left atrium.
If the atrium is too big for too long, it can cause atrial fibrillation, which is an abnormal, irregular heartbeat.
In other words, there is one kind of heart murmur that can lead to atrial fibrillation, but it's one of many. Ask your doctor for the cause of your murmur.
Doctors Donohue and Roach regret that they are unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may write the doctors or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475.
