'Superfoods' term is misleading: University of NSW's Jayashree Arcot

But will eating kale four times a week really help your bone health or did someone just pull off the greatest marketing campaign ever? And how much do you need to eat before it starts working?

Food and nutrition expert Associate Professor Jayashree Arcot from UNSW School of Chemical Engineering, said the term superfoods is sometimes thrown around loosely by 'lifestyle gurus'.

While there is no universally agreed definition for 'superfoods', there is an appreciation of the health benefits due to the presence of bioactive substances and compounds found in them.

"Scientifically, there is no such thing as a superfood - they're basically referring to nutrient-rich foods or compounds that have properties that can impact health - but with a noticeable label," she said.

"However, the term can unfortunately mislead people into thinking that certain foods have incredible nutritional and health properties and consuming them can solve every health problem.

"While there is no singular food group that holds the key to unlocking great health benefits, we do know that some foods are better for us than others. As we become more focused on looking after our health, naturally we start to pay more attention to what we eat.

"Food alone cannot address health concerns - but it can play a role as part of a holistic treatment plan. If the goal is to lose weight, eating a superfood like blueberries will not achieve that on its own.

"However, it's finding the balance of the right combination of these foods and in moderate quantities for it to have some sort of a health impact."

Kale is probably one of the most common foods mentioned when superfoods are spruiked.

While several studies have shown that kale contains antioxidant and anticarcinogenic potential, there is still a lack of evidence to find that consuming kale provides more health benefits than, say, cauliflower.

"If you start eating a lot of kale, nobody's going to tell you it's bad for you. Unless you're somebody that is prone to kidney stones, for instance, then you're probably having too many oxalates - a compound found in leafy vegetables when you're advised to have less of it in your diet," said Prof Arcot.

"So there really isn't a one-size-fits-all approach to this."

Prof Arcot said we need to pay close attention to the nutritional profile of the food to determine whether it's the right fit for the health concern we're addressing.

"There's no denying that having a balanced diet is good for a person's overall health," she said.

"For example, the Mediterranean diet is a heart-healthy eating plan which includes foods such as whole grains, fruits, vegetables and seafoods, and is believed to support brain function and promote heart health."

One of the latest 'superfoods' is turmeric, a common spice used in cooking, which contains a powerful compound called curcumin known for its potent anti-inflammatory properties.

But how much of this compound do we actually need to consume before it has some effect on the body?

Prof Arcot said this is a complex area and more research is needed.

"Sometimes the compounds that we need only exist in minute quantities in the food we eat," she said.

"There's still a long way to go in terms of research before we know the exact quantities needed to bring these sorts of changes in the body. But we do know that the effects can be cumulative over time," she said.

"It's all about prevention of ill-health - and a healthy diet with the right foods will contribute to overall wellbeing."