According to two studies published in The BMJ, higher consumption of fruit, vegetables and whole grain foods is linked with a lower risk of developing type 2 diabetes.
In the first study, a team of European researchers examined the link between vitamin C, carotenoids and type 2 diabetes.
The findings were based on 9754 participants with type 2 diabetes, compared with a group of 12,622 individuals who were free of diabetes. All of the participants were part of the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort totalling 340 234 people.
The results revealed that individuals with the highest intake of fruits and vegetables reduced the risk of developing diabetes by up to 50%.
Fresh fruit and vegetables
The results also showed that increasing intake of fruit and vegetables by 66g per day was linked with a 25% decreased risk of developing type 2 diabetes.
In the second study, researchers in the United States examined the association between whole grain food intake and type 2 diabetes.
Their research involved 158,259 women and 36,525 men who were diabetes, heart disease and cancer free and who took part in the Nurses’ Health Study, Nurses’ Health Study II, and Health Professionals Follow-Up Study.
Those with the highest intake of whole grains had a 29% lower rate of developing type 2 diabetes compared with those who consumed the least amount. With regards to individual whole grain foods, those with an intake of one or more servings a day of whole grain cold breakfast cereal or dark bread, were associated with a 19% or 21% lower risk of type 2 diabetes, compared with the participants consuming less than one serving a month.
Although both studies took into account several well-known lifestyle risk factors and markers of dietary health, both studies are observational, therefore it should be considered that some of the results may be due to unmeasured factors.
These new research findings provide more evidence that increasing fruit, vegetable and whole grain foods can lower the risk of developing type 2 diabetes.
The banana colour scheme distinguishes seven stages from ‘All green’ to ‘All yellow with brown flecks’. The green, unripe banana peel contains leucocyanidin, a flavonoid that induces cell proliferation, accelerating the healing of skin wounds. But once it is yellowish and ready to eat, the chlorophyll breaks down, leaving the recognisable yellow colour of carotenoids.
Unripe (green) and ready-to-eat (yellow) bananas.
The fruits are cut from the plant whilst green and on average, 10-30 % of the bananas do not meet quality standards at harvest. Then they are packaged and kept in cold temperatures to reduce enzymatic processes, such as respiration and ethylene production.
However, below 14°C bananas experience ‘chilling injury’ which changes fruit ripening physiology and can lead to the brown speckles on the skin. Above 24°C, bananas also stop developing fully yellow colour as they retain high levels of chlorophyll.
Once the green bananas arrive at the ripening facility, the fruits are kept in ripening rooms where the temperature and humidity are kept constant while the amount of oxygen, carbon dioxide and ethene are controlled.
The gas itself triggers the ripening process, leads to cell walls breakdown and the conversion of starches to sugars. Certain fruits around bananas can ripen quicker because of their ethene production.
By day five, bananas should be in stage 2½ (’Green with trace of yellow’ to ‘More green than yellow’) according to the colour scale and are shipped to the shops. From stage 5 (’All yellow with green tip’), the fruits are ready to be eaten and have a three-day shelf-life.
A fruit market. Image: Gidon Pico
The very short shelf-life of the fruit makes it a very wasteful system. By day five, the sugar content and pH value are ideal for yeasts and moulds. Bananas not only start turning brown and mouldy, but they also go through a 1.5-4 mm ‘weight loss’ as the water is lost from the peel.
While scientists have been trying out different chemical and natural lipid ‘dips’ for bananas to extend their shelf-life, such methods remain one of the greatest challenges to the industry.
In fruit salads, to stop the banana slices go brown, the cut fruits are sprayed with a mixture of citric acid and amino acid to keep them yellow and firm without affecting the taste.
Bananas are a good source of potassium and vitamins.
The high starch concentration – over 70% of dry weight – banana processing into flour and starch is now also getting the attention of the industry. There are a great many pharmaceutical properties of bananas as well, such as high dopamine levels in the peel and high amounts of beta-carotene, a precursor of vitamin A.
Whilst the ‘seven shades of yellow’ underpin the marketability of bananas, these plants are also now threatened by the fungal Panama disease. This vascular wilt disease led to the collapse of the banana industry in the 1950’s which was overcome by a new variety of bananas.
However, the uncontrollable disease has evolved to infect Cavendish bananas and has been rapidly spreading from Australia, China to India, the Middle East and Africa.
The future of the banana industry relies on strict quarantine procedures to limit further spread of the disease to Latin America, integrated crop management and continuous development of banana ‘dips’ for extending shelf-life.
Food safety refers to handling, preparing and storing food in a way that best reduces the risk of people becoming sick, and it’s a topic that’s high on everyone’s agenda. Here we explore three recent scientific advances in the area of food safety.
Antibiotic detection in dairy products
Antibiotics are the largest group of medicines and, due to their use in treating animals, they have been making their way into the food chain and into food products. Consuming food that contain antibiotics could result in poor health outcomes, such as allergic reactions and other events. Antibiotics that accumulate in cattle milk can transfer into dairy products and so it’s urgent that we detect and address the issue.
A new test has been developed that showed, in a recent study, that it can detect antibiotics in food products. The precision of the test means that it can test for a wide range of antibiotics and the testing process is very simple and easy to conduct. It could also detect antibiotics at all stages of the food production process, which is great news in the fight to reduce antibiotics in the food chain.
Reducing contamination of smoked fish
Smoked fish is very popular in developing countries, as it is a good source of protein. The preparation of it involves hot‐smoking on traditional kilns using wood fuel. This practice is associated with high levels of a substance known as polycyclic aromatic hydrocarbons (PAHs) in the food, which has an impact on health.
An improved kiln has been introduced by the Food and Agriculture Organization of the United Nations to address the levels of PAHs in smoked fish. A recent study showed that the improved kiln not only works just as well at smoking the fish, but does so with safer levels of PAHs. This means that people can continue to consume this valuable protein source without the potentially cancer-causing chemicals.
The safest way to prepare fruit and veg?
Pesticides have been reported to find their way into our fruit and vegetables, albeit at minimal amounts. A recent study looked at food preparation techniques to compare what methods were the most effective in removing pesticides, with interesting results.
The simplest and most effective way was shown to be peeling the skin of fruit or trimming the outer layers of vegetables before cooking. Whilst this is the most effective, most of the vitamins may be stored close to the skin surface and so these are lost in this process.
Washing and soaking were sometimes effective and sometimes not. Washing causes less loss of nutrients and is less time consuming than peeling and it reduces the pesticide residue by a reasonable amount but it wasn’t always shown to be effective. How effective it could depended on the type of skin of the food.
Blanching was another method that was explored. Blanching vegetables in boiling water for one minute loses less nutrients than cooking, whilst removing pesticides very efficiently.
The results certainly give us food for thought in our meal preparation!
In the build up to our SCI Agri-Food Early Career Committee’s 2019 #agrifoodbecause Twitter competition, we are looking back over the best photos of the 2018 competition. Entrants were asked to take photos and explain why they loved their work, using the hashtag #agrifoodbecause on Twitter.
Our 2018 winner, Claire Dumenil from Rothamsted Research, won first prize for her visually striking image of a fruit fly on a raspberry. She received a free SCI student membership and an Amazon voucher.
#agrifoodbecause invasive pests threaten food production and food security, worldwide! #SWD #drosophilasuzukii #Rothamsted #cardiffuni – Claire Dumenil (@CnfDumenil)
#agrifoodbecause I work on reducing aphid infestations on wheat. From the lab to the field – Amma Simon (@amma_simon)
With their fluffy body bumblebees are fantastic pollinators! Work with them can improve crop pollination !! #agrifoodbecause – Sandrine Chaillout (@100chillout)
#agrifoodbecause I can develop drought tolerant wheat varieties – Samer Mohamed (@samer313)
#agrifoodbecause My Research looks at wild pollinators and how we can build a sustainable farming future with them and us in mind! – Laura James (@JamJamLaura)
#agrifoodbecause our improving understanding of the devastating pest, whitefly Bemisia tabaci s.l., will help farmers to increase yields and feed their children <3 – Sona Vyskocilova (@VyskocilovaS)