Science is in a constant state of flux. Theories are put forth to explain natural phenomena, based on the best knowledge of the day. These theories are tested. If they correctly predict future observations, the theories become more credible. If, however, these theories fail to predict accurately, they require modification or outright dismissal.

What is considered “settled science” one day may be turned upside down the next day as new data comes to light. At one time, it was “settled” that the sun and stars revolved around the earth and that the earth was flat. As science advanced and new data was gathered, these “settled” theories were scrapped.

Recently, three bits of medical “settled science” have come into question. New information does not necessarily disprove the original ideas but throws their veracity into question. And illustrates the folly of proclaiming that the science is settled, cutting off any further disagreement or debate.

First is the dietary recommendation I heard most of my life that dairy fats are bad. Avoid whole milk and butter, instead low fat or skim milk is the way to go. Until a study of over a hundred thousand people in 21 countries for nine years was published in medical journal Lancet with the conclusion that dairy fats may actually be healthy.

“A large new study links whole-fat dairy food consumption to a reduced risk for cardiovascular disease. The findings raise questions about current dietary guidelines, which suggest substituting fat-free or low-fat dairy for full-fat products.”

Second is cholesterol, for decades linked to heart disease and cardiovascular health. The science was settled that high levels of cholesterol were harmful, especially “bad cholesterol” or LDL. A quarter of American adults are taking statins to lower their cholesterol, ostensibly reducing their future risk of a heart attack or a stroke. And many suffer statin side effects, including muscle pains.

Until a study published in the Expert Review of Clinical Pharmacology turned the “settled science” upside down.

“No evidence exists to prove that having high levels of bad cholesterol causes heart disease, leading physicians have claimed. Researchers have warned statins — cholesterol-busting drugs — offer no protection to millions of people and doctors should ‘abandon’ them.”

Third is daily aspirin, long thought to prevent heart attacks, especially low dose or baby aspirin. The Physicians Health Study, from the 1980s, found that “low-dose aspirin decreased the risk of a first myocardial infarction by 44 percent.” The science was settled, and millions of Americans started taking a baby aspirin every day.

Aspirin is a blood thinner and therefore increases the risk of bleeding. A minor fall or injury could lead to excessive bleeding, very problematic if in the head or a joint.

Three recent studies in the New England Journal of Medicine tapped into these unintended consequences, “That amnificant cardiac benefit for those without a history of heart trouble. In this study, 70 and older, no benefit at all and potentially some harm.”

The science was settled for decades. Many of us, including yours truly, a physician, believed and practiced all three directives as I have a family history of heart disease. I don’t believe I harmed myself, but the extra efforts and costs in following these accepted medical recommendations may have been in vain.

The broader lesson is for science in general, especially what’s considered “settled science.” Global warming comes to mind. In President Obama’s 2014 State of the Union address, he told the world, “The debate is settled, climate change is a fact.” Not only is the science settled, but debate or disagreement is heresy, punishable as a crime if the climate warriors get their way.

Medicine, and all branches of science, should follow the scientific method: observation of natural events, an explanation of why they occur, and modification of explanations based on new observations and data. The medical world is doing just that with their new research on diet, cholesterol, and aspirin.

Climate scientists should take a similar approach in their analysis of temperatures, weather, and hurricanes, before proclaiming it’s their way or the highway, in the face of contradictory data and thoughtful disagreement. Unintended consequences are real and blindly following the path of “settled science” can have significant costs to individuals and society.

Brian C. Joondeph is an ophthalmologist and can be reached on Twitter @retinaldoctor. This article originally appeared in the Daily Caller.

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