Coconut oil has been said to provide better immunity, cause weight loss, protect against cancer and heart disease, and even slow down or prevent dementia.

"Some people might even ask, 'Well, what can't it do?'" said Sharon Basaraba, a medical journalist and North by Northwest's longevity consultant.

But is it really the miracle food that its fans really think it is?

Basaraba said a number of studies have been done, but they've mostly been small studies for relatively short periods of time.

Preventing heart disease?

Basaraba said there was a study done in 2011 in which nearly 2,000 Filipino women aged 35 to 69 cooked with virgin coconut oil (non-hydrogenated or processed).

The participants were found to have improved levels of high-density lipoprotein cholesterol, "the healthy kind of cholesterol levels," Basaraba said, compared to those women who used less coconut oil.

Coconut oil

Coconut oil contains 90 per cent saturated fats, but from a plant source. (Meal Makeover Moms [Flickr])

"So that does suggest better health, better blood markers."

Weight loss?

Basaraba said the claim that coconut oil can assist in weight loss hasn't been proven conclusively, and many of those studies have been done on mice, so the findings may not translate to our species.

However there is a 2009 study which showed that dieting women who took coconut oil lost slightly more belly fat than those who weren't consuming it.

Slowing the effects of dementia?

Basaraba said the belief that coconut oil could slow or even prevent dementia such as Alzheimer's stems from a testimonial from Florida physician Mary Newport.

Newport's husband was diagnosed with Alzheimer's in his fifties, and she began giving him a few tablespoons of coconut oil every day.

Newport claimed that he showed steady improvement with a clock drawing test — a type of cognition test where a person puts the numbers and hands of a clock in the correct position.

"The theory behind why it could make a difference is that coconut oil might provide a kind of alternate fuel for the brain — ketones, instead of sugar, for fuel ... because brain cells in Alzheimer's seem to lose the ability to use sugar for metabolism for its fuel."

Promising, but not a miracle yet

Newport went on to write a book about what she believed were the benefits of coconut oil for people with Alzheimer's, and also pushed for more research.

Basaraba said that research has begun, with a study from U.S. National Institutes of Health that began in June 2013.

"They've got the first randomized, double-blind trial — that's the gold standard of research design — investigating coconut oil as a potential treatment for mild to moderate Alzheimer's," she said

The study has 65 participants, half of whom will take 30 milliliters of the oil three times a day for three months, while the others take a placebo.

The study is expected to be completed in December this year.

"If you are choosing coconut oil, do pick virgin or extra virgin coconut oil [and] make sure it's unprocessed and non-hydrogenated," Basaraba said.

Until this study — and more like them — evidence for all the widely claimed benefits of coconut oil are unsubstantiated.

"It does look promising, but I would say [coconut oil is] probably not a miracle, or not yet a miracle."

To hear the full interview listen to the audio labelled: Is coconut oil really the world's healthiest oil, as some fans claim?