Australians are spending millions on "designer" foods they believe will boost their health and make them live longer but actually have limited nutritional value, researchers at the Queensland University of Technology (QUT) have warned.

Key points: QUT researchers found nutritional claims about many super foods don't stand up to close scrutiny

QUT researchers found nutritional claims about many super foods don't stand up to close scrutiny Foods examined barely included one or two of the five core food groups

Foods examined barely included one or two of the five core food groups Products often target vulnerable people and can prove to be incredibly expensive

The researchers found nutritional claims made by some food manufacturers were based on "weak and flimsy" evidence, with many products not tested on humans.

The team set out to myth bust the hype by drilling down into scientific claims on popular foods and supplements that were being "up sold" through social media and mummy blogs.

From breastfeeding biscuits that supposedly increase milk supply, to the gut-restoring powers of fermented drinks or mood-changing protein balls — the researchers found clever marketing won out over health benefits.

QUT Faculty of Health nutritionist Dr Helen Vidgen said many packaged super foods made nutritional claims to help sell the product and then went one step further.

"By promising to change you or your children for the better, often at an exorbitant price," she said.

"There are always products that are claiming a quick fix.

"Many of these products claim to benefit health but when you go back to the research they claim supports them, it's weak and unfounded, having been extrapolated in a way that's not very relevant."

The research team looked at five popular products — lactation biscuits, protein balls, kombucha, green "vegie" powder and toddler milk.

So-called 'super foods' are a massive and unnecessary drain on people's wallets, QUT researchers found. ( Supplied: QUT )

Dr Vidgen said while there were more than 30,000 scientific studies and peer-reviewed papers to support the Australian Dietary Guidelines of five core food groups, the team found the products they examined barely included one or two food groups.

"Don't be tricked by these foods because they are just emptying your wallet," Dr Vidgen said.

Breastfeeding biscuits 'a waste of money'

New mum Amanda Hall bought a packet of breastfeeding biscuits online when she was struggling to keep up her milk supply for baby, Flynn.

Ms Hall said she stumbled upon lactation biscuits during a sleep-deprived trawl of social media.

"Late one night, I felt my supply was dropping so I jumped online to see what I could do — and mums were talking about these biscuits, so it was just my first go too," Ms Hall said.

"You're desperate, you'll try anything.

"When I had them I was expecting to have a biscuit and two hours later have this big supply.

"It took over a week and I did other things like had more oats, so I can't say if they worked or not."

New mum Amanda Hall bought a packet of breastfeeding biscuits online. ( ABC News: Lexy Hamilton-Smith )

Dr Vidgen said at a cost of $20 for six biscuits, she considered the product a waste of money.

The QUT researchers looked at studies cited by the manufacturer but found little basis for their claims.

"Some of the studies were not even on milk supply," Dr Vidgen said.

"For example, the study that is on coconut, it looks at the flavour of breast milk and not supply.

"The study on the benefit of oats was very small, and we could not find one at all on brewers yeast.

"The one we did find was on 30 people and did not control for the age of the child and how often the mother fed."

Evidence 'flimsy' on protein balls

Billed as a nutritious, guilt-free snack for people on the go, especially after exercise, some manufacturers of protein balls claimed mood-boosting properties due to the product containing cashew nuts.

"There is a really tenuous link between the cashew nuts that are in that protein ball and your mood further down the track," Dr Vidgen said.

Dr Vidgen said there was not a lot of evidence in favour of calling protein balls a 'super food'. ( Supplied: QUT )

"Cashew nuts contain nutrients that increase secretion of serotonin.

"But no studies have looked at the relationship between cashews and their effect on anxiety, mood or stress.

"The nuts containing nutrients are such a small component of the ball that no effect is likely on mood.

"The evidence gets more and more flimsy the further along the track you go, and you would have to eat an awful lot of cashew nuts to get that benefit.

"High in saturated fat, sugar and calories, they could also lead to weight gain if you eat too many."

Drink results not replicated in humans

"It's claimed the fermented drink benefits gut health by increasing the diversity of gastrointestinal flora which, in turn, improves overall wellbeing," Dr Vidgen said.

But researcher Justine Bastow found all documented effects on wellbeing for drinks like kombucha were from animal studies.

"Rats, mice and ducks, so no human studies," Ms Bastow said.

Evidence to show that kombucha increases the diversity of human gastrointestinal flora is also weak. ( Flickr: Nan Palmero, CC BY 2.0 )

The researchers found a study that decreased blood sugar levels in mice and regulated cholesterol in ducks, but these results had not been replicated in humans.

"Evidence to show that kombucha increases the diversity of human gastrointestinal flora was also weak," Dr Vidgen said.

Nutritionists said the best way to improve gut health is to eat plant foods instead, such as legumes, wholegrains, vegetables, fruit and nuts.

No evidence supporting green powder

Sprinkled on food like a bowl of fruit, marketers have claimed super-boosted green powder was an easy way for parents to provide toddlers with enough fruit and vegetables during mealtimes, without the stress of a fussy eater rejecting their greens.

Researcher Hayley Bowyer said it was also claimed a single serve provided the antioxidant equivalent of six serves of fruit and vegetables.

"I was really surprised at the lack of scientific evidence and when we did find studies often they were very old, really flimsily designed," Ms Bowyer said.

Dr Vidgen agreed, saying there was "no evidence" to support the nutritional claims.

"Dehydrated vegetable powder is a poor source of nutrients found in F&V [fruit and vegetables], especially fibre," Dr Vidgen said.

"The temperatures required for dehydration reduce the levels of the antioxidant vitamins A, C and E."

The team said the powders were also overly expensive, at $15 for just 100 grams.

Toddler milk unnecessary, according to guidelines

Dr Vidgen said toddler milk formula was seen as a quick fix when a child's diet was inadequate, and was appealing for parents concerned their children were not eating enough or getting the right nutrients.

Nutritionists says the best way to improve gut health is to eat plant foods instead. ( ABC News: Clare Rawlinson )

"However, some studies have found the emergence of toddler formula being used as a marketing strategy for brand awareness of infant formula products," Dr Vidgen said.

"In response to the prohibition on advertising infant formula, it had twice the sugar content in the form of lactose and was much more expensive than cow's milk."

Researcher Grace Financio said national dietary guidelines stated that children did not need formula after their first birthday.

"They also need to learn to like the texture of food, flavour and chew, rather than have a powdered milk product," Ms Financio said.

Producers 'not breaking any laws'

QUT business school marketing expert Dr Gary Mortimer said "super food" producers were not breaking any laws.

"Marketers certainly are not making false claims they are just promoting particular trends," he said.

"We've certainly moved from gluten-free to organics all the way through to protein, now Kombucha and super foods are the big terms.

"Obviously we can see products that are jumping on these very important terms, and I guess profiteering a little bit out of it."

Dr Vidgen said Australia had very strong laws around food labelling, which ensured marketers needed to be wary of claims like "miracle cures".

All of the documented effects of fermented drinks have come from studies on animals. ( Supplied: QUT )

"But what we are finding with these products is they have a huge following on social media," Dr Vidgen said.

"It is the association with influencers and those sorts of benefits that is really leading consumers to think they are going to get a health benefit from these products.

"They are listening to people who are in similar situations to them, who seem they have it all together, and it seems this product is the thing that made it all come together for them.

"With most of these products, particularly when you look at ones targeting pregnant women or ones targeting younger mums, they are really targeting you at a time when you are feeling really vulnerable."

Nutritionists are not against manufactured super foods, saying the national dietary guidelines are reviewed every 10 years in case a new "designer food" has proven scientific health benefits.

But the researchers are yet to find any such food living up to its marketing claims, arguing the hype continues to outweigh the science.