The definitive, scientific answers to 20 health questions everyone has

It seems every week there's a new study or report that contradicts everything you know about how to manage your health.

In 2016 alone, we got more evidence that coffee isn't a cause of cancer and the debate over the health effects of sugar became even more heated.

To help you parse out what works from what's merely myth, we compiled the definitive (at least for now) answers to some of the most pressing health questions, based on the book "Your Health: What Works, What Doesn't."

Here's what the science has to say.

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Does sugar make you hyper?

Short answer: No

The National Institute of Health has made it pretty clear that additives and dyes added to food have effects that are "small and do not account for most cases of ADHD."

The myth started back in the 1970s when a doctor wrote into the American Academy of Pediatrics that he had become aware that sugar was a leading cause of hyperactivity. But research has shown otherwise: A 1995 meta-analysis of sugar studies found that it didn't have an effect on the behavior or cognitive performance of children.

Does cough syrup work?

Short answer: No

It's been a while since doctors came to agree that most over-the-counter cough medicines don't work. In 2014, Australian researchers published similar conclusions that the syrups typically contain doses of codeine and antihistamines that are too small to be effective and can be harmful for children.

Prescription cough suppressants such as levodropropizine, however, might have a better shot. 

Does olive oil prevent heart disease?

Short answer: Yes

As if you need more of an excuse to put olive oil on everything, scientists have found a connection between eating more olive oil and a lower risk of coronary artery disease. Studies that are happening right now are testing out how a Mediterranean diet rich in olive oil compares to low-fat diets when it comes to heart disease recurrence.

In general, olive oil's antioxidant and anti-inflammatory effects have also been well documented. And in a study of older women published in 2015 in the medical journal JAMA, Spanish scientists found that a Mediterranean diet supplemented with extra olive oil appeared to help reduce the participants' risk of breast cancer when compared with two other groups of women on a low-fat diet and a Mediterranean diet supplemented with nuts.