GENETICALLY MODIFIED FOODS: WHAT ARE THEY AND IS THERE A FUTURE FOR THEM?

NHD EXTRA

NETWORK HEALTH DIGEST

NHD Extra - January 2019

GENETICALLY MODIFIED FOODS: WHAT ARE THEY AND IS THERE A FUTURE FOR THEM? Alice Fletcher RD Community Dietitian, Countess of Chester NHS Foundation Trust Alice has been a Registered Dietitian for three and a half years, working within NHS communitybased teams.

She is passionate about evidencebased nutrition and dispelling diet myths. Alice blogs about food and nutrition in her spare time at

This article aims to give a general overview of what genetically modified (GM) foods actually are, why they are produced and the possible benefits and risks.

If you enter ‘genetically modified food’ into an internet search engine, you will be bombarded with pictures of people wearing surgical gloves, injecting fruit and vegetables with a fluorescent, radioactive looking substance. You will even encounter apples that when sliced, are actually oranges, and (oddly) even a banana skin that is harbouring a chorizo sausage. Searching for GM animals comes up with even stranger results, including a fish that is half tomato.

REFERENCES For full article references please CLICK HERE . . .

HOW CAN ‘GENETICALLY MODIFIED’ BE DEFINED?

In 1946, scientists first discovered that DNA can be transferred between organisms. It is now known that there are several mechanisms for DNA transfer and that these occur in nature on a large scale, for example, it is a major mechanism for antibiotic resistance in pathogenic bacteria.1 People have been breeding animals and new varieties of plants for hundreds of years to develop or avoid certain qualities. Traditional methods of breeding involve mixing thousands of genes. Belgian Blue cattle, for example, have been selectively bred to take advantage of a genetic abnormality making them unusually

muscular, resulting in a breed that bypasses natural evolution.2 Likewise, commercially purchased fruits and vegetables have been selectively bred over hundreds of years to increase size and improve taste.

Genetic modification, however, can speed up this process, allowing just one individual gene, or a small number of genes, to be inserted into a plant or animal. This enables them to be used in new and very precise ways.

Such plants or animals are known as ‘genetically modified organisms’ (GMOs). The Food Standards Agency defines GM foods as: organisms (ie, plants or animals) in which the genetic material (DNA) has been altered in a way that does not occur naturally by mating and/or natural recombination.

GM foods differ from gene edited products, where the same plant/ animal DNA is used. Some of the most widely found GM foods are corn, rapeseed (canola) oil and soybeans, much of which is used in animal feeds across the globe.3 WHY DO WE GENETICALLY MODIFY ORGANISMS?

Increasing a food’s shelf life, therefore reducing food waste In 1994, the transgenic ‘Flavour Saver

NHD EXTRA: GM FOODS tomato’ was approved by the Food and Drug Administration (FDA) for marketing in the USA. This was the first genetically engineered crop product to be commercialised. The modification allowed the tomato to delay ripening after picking, reducing waste.1 Improve nutritional value of foods, in order to improve nutritional status of human populations Golden rice is a GM variety of rice produced to biosynthesise beta-carotene (a precursor of vitamin A) in the edible parts of rice. It is intended to produce a fortified food to be grown and consumed in areas with a shortage of dietary vitamin A.4 In all developing countries, an estimated 163 million children are vitamin A deficient (measured by low serum retinol), with a prevalence of about 30%.5 Rice is a staple food crop for over half of the world’s population, making up 30-72% of the energy intake for people in Asian countries, therefore, it is the perfect crop for targeting vitamin deficiencies. “This Rice Could Save a Million Kids a Year,” announced a Time Magazine cover back in 2000,6 however, it is yet to become commercially available. The reasoning being that genetic engineering has not yet managed to develop a rice with all desired traits alongside high beta-carotene content (ie, pest and drought resistance). Its efficacy on a population basis is, therefore, unknown.

Another example is omega-3 in salmon.

Levels of omega-3 have decreased by half in farmed salmon in the past 10 years, due to reduced availability of anchovies of which makes up the majority of their feed, (and gives them their omega-3).7 Researchers in the Highlands of Scotland are providing farmed salmon with a feed made from GM crops, having added a gene from a type of marine algae to a camelina plant in order to produce the omega-3 fish oil. Tests show that fish fed on this oil have higher levels of omega-3.7 The development of oral medications to fight diseases, particularly in poorer countries This year scientists successfully developed a strain of rice that has the same HIV-neutralising proteins as the oral medications. Once grown,

the rice produces seeds that can be processed on site to make a topical cream which can then be applied to the skin to allow the proteins to enter the body. Many third world countries lack affordable access to oral medications, so this could have huge implications in impoverished countries. This fascinating research remains in the early stages and the rice is not yet commercially available.8 Increase yields of crops through pest or drought resistance This could in theory reduce malnutrition and poverty in poorer countries, although there remain only a few demonstrable examples9 such as a papaya which is ring spot virus resistant, having been developed by genetic engineering, enhancing the productivity. This was very much in need in the early 1990s as Hawaii’s papaya industry was facing disaster because of the deadly ring spot virus. Without GM, Hawaii’s papaya industry would have collapsed. Today, 80 % of Hawaiian papaya is genetically engineered and there is still not a conventional or organic method available to control ring spot virus.1 HOW ARE GMOS ASSESSED FOR SAFETY?

GM foods either contain, or consist of, GMOs, or are produced from GMOs. The WHO note that the safety assessments of GM foods are carried out by the European Food Safety Authority and include a detailed study of: • direct health effects (toxicity); • potential to provoke allergic reaction (allergenicity); • specific components thought to have nutritional or toxic properties; • the stability of the inserted gene; • nutritional effects associated with genetic modification; • any unintended effects which could result from the gene insertion.3 GM foods are only authorised for sale if they are judged not to: • present a risk to health; • mislead consumers; • have less nutritional value than their nonGM counterpart.3

WHAT CONCERNS DO PEOPLE HAVE REGARDING GM FOODS?

In the 1990s, GM foods burst onto the market with a lot of negative press in Europe, with much of this centring around GM corn and its purported cause of the demise of the monarch butterfly (since found to be negligible10).These days, GM foods are something we occasionally hear about in the press and on social media usually still negatively. Interestingly, a large systematic review and meta-analysis from 2013 on the perception of GMOs found GM plants to be more accepted than animal foods.11 Also, the younger population have less concerns about GMOs. A recent poll of more than 1600 18 to 30 year olds, carried out for the Agricultural Biotechnology Council, found that two thirds of under 30s believe technology is a good thing for farming and support futuristic farming techniques.12 Only 20% of millennials in this poll expressed concerns about the benefits of gene editing or genetically modifying crops, despite years of opposition and media warnings. Perhaps the younger generation are more aware of our dwindling resources, or have received better education around this topic in schools.

The three most commonly reported public concerns debated are outlined below: Allergenicity Although some people are concerned that consuming GM products will lead us to grow an extra ear, most concern leans towards increasing incidence of food allergies. As a matter of principle, the transfer of genes from commonly allergenic organisms to non-allergic organisms is discouraged unless it can be demonstrated that the protein product of the transferred gene is not allergenic (ie, mixing genes from peanut plant with another plant).

While foods developed using traditional breeding methods are not generally tested for allergenicity, protocols for the testing of GM foods have been developed by the Food and Agriculture Organisation of the United Nations (FAO) and WHO. No allergic effects have been found regarding GM foods currently on the market.3

Although some people are concerned that consuming GM products will lead us to grow an extra ear, most concern leans towards increasing incidence of food allergies.

Gene transfer Horizontal gene transfer (HGT) from GM foods to cells of the body, or to bacteria in the gastrointestinal tract, would cause concern if the transferred genetic material adversely affects human health. This would be particularly relevant if antibiotic resistance genes, used as markers when creating GMOs, were to be transferred. Mammals have been shown to take up dietary DNA from the gastrointestinal tract, but stable integration and expression of internalised DNA has not been demonstrated.13,14 15 Although the probability of transfer in the first place is low, the use of gene transfer technology that does not involve antibiotic resistance genes is encouraged to reduce risk. In most cases the occurrence of HGT from GM crops to other organisms is expected to be lower than background rates. Therefore, HGT from GM plants poses negligible risks to human health or the environment.3

NHD EXTRA: GM FOODS Outcrossing The migration of genes from GM plants into conventional crops or related species in the wild (referred to as ‘outcrossing’), as well as the mixing of crops derived from conventional seeds with GM crops, may have an indirect effect on food safety and food security. Cases have been reported where GM crops approved only for animal feed or industrial use were detected at low levels in the products intended for human consumption. The GM Contamination Register contains records of GM contamination incidents since 1997 and forms a unique database. By the end of 2013, 396 incidents across 63 countries had been recorded.16 WHAT GM FOODS ARE CURRENTLY AVAILABLE IN THE UK?

GM crops are not commercially grown in Britain, but there have been experimental trials of GM potatoes and wheat in recent years. A trial in Norwich in 2017,17 to stop potatoes developing blight, reported successful results, but there have been no moves to bring these potatoes to market. However, we have all probably purchased GM foods in UK supermarkets; most common products are rapeseed oil and processed products containing GM soya beans. There are no fresh GM fruit and vegetables approved for consumption by humans in the EU, but there are in the USA.1 For many years, most UK supermarkets did not sell own-brand products that contained GM modified products (or animals fed on it), proudly declaring this to the nation. In 2013, however, supermarkets began (quietly) changing their policies. Morrisons and Asda were the first to allow GM-fed animal products onto their shelves and Tesco, Sainsbury’s, the

Co-op and Marks & Spencer have followed suit. Some of them pledge to continue to ensure that their own-brand products remain GM free (Morrisons and Waitrose state this on their website).

HOW ARE GM FOODS LABELLED?

In the EU (including in the UK), foods must state on their label if they contain or consist of GMOs, or contain ingredients produced from GMOs. This means that: • all GM foods, including flour, cooking oils and glucose syrups from a GM source, have to be labelled as GM; • for GM foods sold ‘loose’, information must be displayed immediately next to the food indicating that it is GM; • foods produced with the help of GM technology do not have to be labelled; an example of this is cheese produced with the help of GM enzymes which are used to clot the milk in the production process but are not ingredients in the cheese itself; • products such as meat, milk and eggs from animals that are fed on GM animal feed also do not need to be labelled; this includes a large percentage of animal products available in UK supermarkets.18 SUMMARY

All in all, many GM foods have been found to be safe for human consumption following rigorous testing, but some apprehension still remains.

Perhaps as focus upon sustainability of the planet increases, public opinion will continue to evolve and more GM products will become commercially available. I strongly recommend reading reference 1 for a more thorough overview of this topic.

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