Weekly costs for fruit and vegetables for 2 adults and 2 children from different outlets.

A family of four could save as much as $49 per week by buying their fruit and vegetables at markets other than from a supermarket, a University of Otago Wellington study shows.

The study collected 3120 prices for fruit and vegetables at markets and in Wellington and Christchurch. It found that commonly purchased produce such as apples, oranges, broccoli, cabbage, carrots and tomatoes were on average significantly cheaper at fruit and vegetable markets compared to supermarkets in Wellington and Christchurch.

The researchers developed a hypothetical weekly "shopping basket" for a two adult, two child family containing ideal amounts of from a health perspective. They then compared the costs of the basket at various outlets.

Fruit and vegetable markets were the cheapest at $76 per weekly basket. Online supermarkets were the next cheapest at $113, although this could be offset by delivery charges, says one of the study's authors, Dr Amber Pearson. The difference between the cost of the basket at a fruit and vege market compared to a supermarket was $49 less at the market.

Farmers' markets that sell from local growers were the most expensive of the outlets studied, at $138 per basket. But a third of the items in the basket were still significantly cheaper than supermarkets, including cauliflower, silverbeet, spinach, cucumber and pumpkin.

The researchers note that also have the advantages of expanding consumer choice by providing more access to local produce and more "organic" produce – with such having lower pesticide levels.

Another author of the study, Associate Professor Nick Wilson, says there is strong scientific evidence that high fruit and vegetable consumption protects against heart disease, stroke and some cancers, but the reality is that it isn't always easy for to buy enough of this produce.

One way to overcome this cost barrier is for New Zealand to explore following the approach of some US jurisdictions where fruit and vege vouchers are provided to low-income people, he says.

"If these are usable at markets, then this can help support local growers as well – so it can be good for regional employment."

Another approach is for local government to increase support for fruit and vege markets in various ways – something that some Councils in parts of the country have already done by providing free space for holding markets.

In summarising the research, Dr Pearson says there is a need for society to better understand the benefits of and vegetable markets for health – "but also in terms of wider benefits such as supporting local agriculture and building community cohesion".

More information: Pearson AL, Winter PR, McBreen B, Stewart G, Roets R, et al. (2014) "Obtaining Fruit and Vegetables for the Lowest Prices: Pricing Survey of Different Outlets and Geographical Analysis of Competition Effects." PLoS ONE 9(3): e89775. DOI: 10.1371/journal.pone.0089775

Journal information: PLoS ONE