Can the nutritional value of UK grown produce be raised?

A major new study launched in February revealed that eating ten, rather than five portions of fruit and vegetables a day, could reduce health risks such as heart disease and cancer considerably. The research, conducted by scientists at Imperial College, London, showed that although a high fruit and vegetable intake has been recommended for the prevention of cardiovascular disease and some cancers, questions remain with regard to the amounts and types of fruits and vegetables that are most strongly associated with a reduced risk of cardiovascular disease, total cancer or all-cause mortality; and with regard to the burden of disease and mortality that may be attributed to a low fruit and vegetable intake.

Some other notable observations were also made. During the study, a meta-analysis of 95 studies of fruit and vegetable consumption was undertaken. Reductions in risk of cardiovascular disease and all-cause mortality were observed up to an intake of 800g/day of fruit and vegetables combined, whereas for total cancer no further reductions in risk were observed above 600g/day.

Inverse associations were observed between intake of apples and pears, citrus fruits, green leafy vegetables and salads and cruciferous vegetables and cardiovascular disease and mortality; and between green-yellow vegetables and cruciferous vegetables and total cancer risk. It also revealed that an estimated 5.6 and 7.8 million premature deaths worldwide during 2013 may be attributable to a fruit and vegetable intake below 500 and 800 g/day, respectively.

“A change in the diet towards a higher intake of fruit and vegetables and other plant foods could also have other important health as well as environmental benefits. Our meta-analysis provides further support for public health recommendations and interventions to increase fruit and vegetable intake for prevention of cardiovascular disease, cancer and premature mortality,” says the report.

Lead author, Dr Dagfinn Aune said that several potential mechanisms could explain why fruit and vegetables have such profound health benefits: “Fruit and vegetables have been shown to reduce cholesterol levels, blood pressure, and to boost the health of our blood vessels and immune system. This may be due to the complex network of nutrients they hold. For instance they contain many antioxidants, which may reduce DNA damage, and lead to a reduction in cancer risk.”

He went on to say that compounds called glucosinolates in cruciferous vegetables, such as broccoli, activate enzymes that may help prevent cancer. Furthermore, fruit and vegetables may also have a beneficial effect on the naturally-occurring bacteria in our gut. “Most likely it is the whole package of beneficial nutrients you obtain by eating fruits and vegetables that is crucial is health. This is why it is important to eat whole plant foods to get the benefit, instead of taking antioxidant or vitamin supplements (which have not been shown to reduce disease risk).”

So here we have confirmation from a major new study that could be advantageous to fresh produce marketing departments, to help enhance their story about the benefits of eating increased amounts of home grown produce.

But the truth is, eating five portions a day can be a challenge in today’s society, let alone ten, especially in relation to feeding children. This can mean a lot of fruit and veg is wasted in households across the UK and eating a large amount every day can be very expensive.

So, what if it were possible to raise the nutritional levels in a single piece of fruit of vegetable, or adapt or change the specific nutrients within it to increase the benefits it offers? The NFU’s Board for Horticulture and Potatoes is about to kick-start a project looking at just this. Leading the project will be board member, Sarah Dawson. She thinks if this can be achieved, it will bring benefits to all involved.

“The health benefits of what we grow is undoubtedly our biggest USP as an industry and there is a real opportunity here to enhance our British brand by findings ways of increasing the nutrients levels in every single piece of produce we grow. That will have benefits for the consumers buying it and also for the growers producing it.

“The potential difference it could make to growers if we can increase the value of each acre they grow because we can prove we have increased the nutritional value of that crop is huge for them and every other stakeholder in the industry. This would give us another reason to tell consumers why buying British is a really good idea,” she says.

Jack Ward, Chief Executive of British Growers, thinks work like this can only help the industry and the UK in general. “I think there is a real opportunity to still have a closer connection between UK fresh produce production and consumption and the UK’s health agenda,” he says. “I don’t think we have paid enough attention to this, considering that health issues such as heart disease and obesity are costing the NHS £5bn a year to treat. We know consumption of fruit and vegetables is good for us; what is less clear is what nutrients are really good for us and what types of fruit and veg we should be eating to consume more of them,” he adds.

“Raising and/or identifying these key nutrients would be a good thing for the whole industry and perhaps lead to producing and marketing more ‘super-foods- from the fresh produce category.” Mr Ward says the challenge will come during the breeding process. “I think the challenge will be that if we increase the nutrient levels then that might bring into question whether disease resistance can be as strong or other factors such as taste and texture might change.”

But how could the raising of nutrient levels actually be done? Scientists in other food sectors are already making progress in this area. Dr Brittany Hazard is a Research Leader at the Quadram Institute (previously known as the Institute of Food Research) and the John Innes Centre. She has been studying how to improve cereal grain quality for human health. This involves building strong connections between the fields of plant breeding and genetics with food and health. The work focuses on studying starch composition and structure in wheat because this can influence its digestibility. Starch that is resistant to digestion can play an important role in maintaining healthy blood sugar levels in humans.

A key aim of Dr Hazard’s research is to develop wheat genotypes with novel starch compositions and structural properties which can help improve health. “Starch is the main component of wheat grain and processed refined flours, and with this project we want to understand how different starch genes control the starch structure and digestibility in different wheat based foods like bread and pasta,” Dr Hazard tells The Vegetable Farmer.

“But it is also very important to consider how the new starch traits could affect agronomic performance and end-use quality for milling and baking. Thus, a lot more research has to be done to ensure that the new starch traits are commercially viable to achieve desirable levels of resistant starch for a positive health impact while maintaining good yields and quality.”

Importantly, Dr Hazard thinks this method could be applied elsewhere. “I think this crop genetics approach could be applied to developing nutritional traits for healthier vegetable varieties,” she says.

“We would welcome the chance to explore this in more detail,” says Sue Kennedy, Head of Research & Development at Elsoms Seeds. “We think it is a sensible way forward to start identifying areas of breeding that could in the future help increase the nutrients in UK grown crops because that could bring many benefits for the sector.”

“For us, this is something that could certainly have massive potential but for it to work we need every stakeholder in the sector on-board. It needs to work for growers, the supermarkets and other retailers as well as the consumer and also for us at the start of the process to be a success that guarantees benefits for everyone. To start to develop this we need a greater clarity and understanding of what the industry needs and how it will work for each stakeholder,” she adds.

Ms Kennedy says the science and technology is already there to select certain characteristics in seeds to help raise the nutrition value. “The challenge will be to avoid working in silo with specific nutrients but to find a way to raise all the levels of nutrients in the crop without affecting the other characteristics that are so important such as pest and disease resistance and flavour,” she says. “But, there will certainly be more focus on the health benefits of produce in the future.”

The NFU plans to conduct a round table discussion in a few months’ time, to discuss how different stakeholders in the industry can identify the way forward to help raise nutrient levels in UK grown fresh produce.

Reported by Adrian Tatum.