Dr. Roach: Essential oil and immune support: many claims, limited study

Keith Roach
To Your Health

Dear Dr. Roach: Many of my friends assert that the use of essential oils “supports” their immune system and reduces their risk of getting sick. They diffuse them into the air at home, add them to water or tea and apply them to the soles of their feet. Are there studies to back up these claims?

— K.M.

Dear K.M.: There are studies that show that, in some cases, essential oils stimulate some of the body’s immune cells. Blood levels of immunoglobulins, cytokines and other molecules that indicate a robust immune response can increase with exposure to essential oils.

However, no studies show what I would want to see before recommending their use in general, which is that people who use essential oils have less infections or less disease than people who don’t. In an ideal world, it would be great to know who should use what essential oils, and under what conditions. Many sources provide such advice, oftentimes conflicting, but none is supported by the kind of evidence I would accept.

Further, the immune system is not something you can dial up or dial down, nor would you want to. There is always a balance between a powerful defense against invaders like bacteria, viruses and cancer cells — things we want our immune system to fight off — and the negative effects of overzealous activity, such as allergies and autoimmune diseases. Science currently lacks the knowledge to precisely improve the good parts of the immune system while at the same time reduce the harm an overactive immune response can cause.

Some essential oils may be absorbed through the skin, but these can have negative as well as positive effects. The ability to use essential oils as medicine is limited. With increasing scientific study, we may learn more about how better to use this large and complex group of compounds.

Essential oils have been shown to have benefits when used as aromatherapy, reducing anxiety in some studies.

Dear Dr. Roach: I started to have enlarge prostate issues more than 20 years ago, I am now 70. I started on Flomax, which worked great for a while, but then it just stopped working. My urologist switched me to Cardura (doxazosin). I started at 2 mg and have been taking 4 mg for many years.

This drug works very well for me and also has the side effect of controlling high blood pressure, which was the origin of this drug.

— S.K.

Dear S.K.: Before tamsulosin (Flomax), there was terazosin (Hytrin), doxazosin (Cardura) and prazosin (Minipress). There are also alfuzosin (Uroxatral) and silodosin (Rapaflo). These are all members of the same class, called alpha blockers. Alpha receptors are found in the prostate but also in blood vessels. The drugs relax the smooth muscle, allowing for better urine flow in the prostate and reducing blood pressure by relaxing small arteries.

Any of these may work well for a given man with prostate issues, even if another drug in the class does not. Sometimes, however, none of the alpha blockers work and a completely new treatment needs to be considered.

Tamsulosin tends to be prescribed more frequently because it is less likely to affect blood pressure, and consequently causes lightheadedness on standing less frequently than the others. But for men with both blood pressure and prostate issues, a drug like doxazosin might work very well.

Readers may email questions to ToYourGoodHealth@med.cornell.edu.