6 Medical Therapies We Thought Work But Actually Might Not

04/13/2015 04:00 pm ET | Updated Jun 13, 2015

The world of medicine changes rapidly. In fact, people estimate that there is a doubling time of medical knowledge every 3.5 years. And it keeps getting shorter --- by 2020, experts predict medical knowledge will double every 73 days!

With this explosion of new information, it can be hard to keep up with the latest innovations. Doctors may not always be well-informed about new therapies to treat medical conditions. Equally important, everyone may not know when to stop therapies, or not to recommend interventions that recent research show simply does not work as we once expected.

Here are six medical therapies that you should know don't work:

1. Tylenol for back pain -- Back pain is one of the most frequent reasons for doctor visits and also one of the most complicated conditions to manage both short and long-term. We used to think that acetaminophen (brand name Tylenol) was the best medicine to take when the lower back ached. But recent data has shown that acetaminophen works no better than placebo in some people.

So how did we get this wrong? Well, we have learned a lot more about back pain in recent years. And many times it is due to inflammation. As a result, in the acute setting of low back pain, we most likely should use NSAIDS -- they help reduce inflammation, which is usually the cause of the pain. These are medicines like ibuprofen and naproxen. We can also use ice alternating with heat, acupuncture, as well as biofeedback. The medical community traditionally dismisses these therapies although the good data to support their use.

2. Salt is your enemy and needs to be avoided -- Well, that's not completely true anymore. Conventional wisdom is to reduce the amount of salt in your diet. Even though recommendations age 51 years and older is less than 1,500 mg of salt, consuming up to 2,300 mg isn't associated with greater mortality and heart disease. In fact, sugar is our enemy. A recent study published found that sugar, not salt, appears to contribute to the majority of the hypertension risk associated with processed food. There still may be some reasons to lower the amount of salt you consume especially if you have poorly functioning kidneys, but a blanket prohibition doesn't make sense. And worse -- it likely makes you consume high-sugar foods that aren't any healthier.

3. Selenium and vitamin E for prostate cancer -- Before 2008, there was some preliminary data that these could prevent prostate cancer. We even learned about that when I was in medical school. However, by 2008, researchers found that that selenium and vitamin E, taken alone or together for an average of 5.5 years, did not prevent prostate cancer. In 2011, updated trial data showed that the men taking vitamin E had a 17 percent increased risk of prostate cancer compared to men taking the placebo. And just last year an analysis showed that men who started the trial with high levels of selenium doubled their risk of developing a high-grade prostate cancer by taking selenium supplements and men who had low levels of selenium at the start of the trial doubled their risk of high-grade prostate cancer by taking vitamin E. This shows the importance of doing well-designed studies to find out the answers and then to effectively publicize the information.

4. An aspirin a day -- This has been a classic. Along with "an apple a day," an aspirin a day seemed to be a mainstay of getting older. There is still some truth to that but, it all depends. Aspirin is beneficial for people who already have heart disease. But we are not sure how useful it is for people who have never had a heart attack or don't have a lot of risk factors. A recent study showed that in patients older than 60 years, taking a daily aspirin did not prevent a first heart attack or stroke. The problem here is that all drugs have side effects, and aspirin causes bleeding. That can sometimes lead to bleeding in places that can be very harmful such as the brain or the stomach. As a result, you need ask your doctor shows about your individual risks vs. benefits when taking a drug.

5. Eating foods high in cholesterol will raise your cholesterol and might cause a heart attack -- We have all been told for years that eggs and bacon are forbidden foods if you have high cholesterol. Many folks had a belief that eating an egg -- especially a yolk -- put them one step closer to chest pain. Well, that doesn't seem to be the case anymore. Just a few months ago, the federal government put out new dietary guidelines. In these guidelines, they completely reverse their long-standing view on the role of cholesterol in the food we eat and how it impacts our body.

We now believe that dietary cholesterol still has a small effect but the effect may be less than genetics -- and the real culprit is saturated fat. Saturated fat is what can contribute to a heart attack -- likely not the omelettes you've been avoiding.

6. Do not give toddlers peanut butter -- There has been an explosion in the number of kids with peanut allergies in recent years. The exact cause is unknown but the end result is that peanut butter and jelly sandwiches and peanuts at baseball games are often avoided in children. Now we're beginning to think that might be doing more harm than good. Current research suggests that that exposing kids at risk for peanut allergy to peanuts may actually help prevent an allergy. This could be a huge change of thinking. The recent data look good, but we need more research. Parents should be cautioned not to do anything on their own but to consult with their doctor/immunologist. And who knows -- in 74 days we just might change our mind.