Dear Dr. Roach: I’ve started using coconut oil instead of milk and sweetener in my coffee. I find that a quarter teaspoon of coconut oil blended with 12 ounces coffee is pretty yummy. But I want to make sure I’m not doing any harm, since my own LDL has risen and my HDL has fallen since December. I have heard that coconut oil is healthy, but also that it’s saturated fat.
Compared with a similar amount of a nontropical vegetable oil, coconut oil does raise both total and LDL cholesterol. The effect is not large. In a review of many studies, the increase in cholesterol was about 10 points in people who started using coconut oil, but the amount that people use will of course be critical: A quarter teaspoon a day is unlikely to have much of an effect on your blood cholesterol levels.
The effect on HDL cholesterol in these studies was different from what you saw, as coconut oil tends to raise the healthy HDL levels. Overall, most experts believe that coconut oil is not as healthy for you as other vegetable oils, such as olive or sunflower oil, but is not as bad for you as saturated animal oils, such as butter or lard.
Dear Dr. Roach: Now that transoceanic travel will resume in the near future, I would welcome your opinion regarding the benefit (if any) of flying business class for reducing risk of DVT versus flying economy class.
Does lying down overnight in business class mitigate the formation of blood clots, especially in elderly passengers, as opposed to sitting up in economy with ones feet on the floor? Or should business class passengers also be advised to get up and walk around the cabin each hour to avoid DVT (and sleep)?
This has been studied, although there were not enough blood clots in either group to be able to show a difference. The study authors looked at D-dimers, a blood test known to correlate with blood clot risk. In this study, business class did not differ significantly from economy class for development of an elevated D-dimer.
Most people do not need to worry about developing a clot during travel. The risk of a clinically significant blood clot is small, less than 0.05%. Even so, for people who have never had a blood clot and who otherwise do not have risk factors, general advice for people concerned about a blood clot would be to walk on an hourly basis as you suggest; drink enough fluids to keep from getting depleted (the dry air on planes can cause you to lose fluid faster than you might think); and doing leg exercises while sitting.
People who are at increased risk for a blood clot — for example, those with a history of blood clots in the past; pregnant women; people with active cancer; and those who have just undergone surgery — should consider additional maneuvers that have been shown to reduce blood clot risk during flights. These include wearing compression stockings, as well as following the advice above. Those who are at very high risk should discuss with their doctors about using medication prior to a long flight.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu