Dietary guidelines in Ireland: current perspectives

In the Republic of Ireland, it is currently estimated that 60 % of adults and 25 % of children are overweight or obese^{( 1 , 2 )}. In 2017, the total lifetime cost of childhood overweight and obesity alone was estimated at €4·6 billion⁽ Reference Perry, Millar and Balanda ^{3 )}.

We live in an obesogenic environment where work pattern changes, increased computerisation and improved infrastructure have changed the way we produce, process and distribute food, enabling easier access to unhealthful food choices⁽ Reference Ley, Hamdy and Mohan ^{4 )} driving obesity and metabolic diseases. Population physical activity levels have also decreased⁽ Reference Ipsos ^{5 )} with technological advancements and reliance on motorised ways of transportation.

In Ireland, the leading cause of death is CVD^{( 6 )}, with diet being a known modifiable risk factor. The purpose of the dietary guidelines in the Republic of Ireland is to encourage a healthy dietary pattern, to achieve optimal nutrition to maintain a healthy weight with the goal to promote a positive lifestyle for everyone and to prevent nutrition-related diseases such as CVD. The guidelines are depicted by a food pyramid display and while it has been found that the overall messages are well understood, the findings of the recent Healthy Ireland Survey 2015 demonstrate that they do not seem to be translated into daily food choices or population dietary pattern changes⁽ Reference Ipsos ^{5 )}. In that survey, just 26 % of the Irish population reported that they eat ≥5 portions of fruit and vegetables daily and 65 % reported that they consume snack foods or sugar-sweetened drinks daily⁽ Reference Ipsos ^{5 )}. Not only do the guidelines seem to be followed loosely, their evidence base and translational potential may need to be revisited in the light of the more recent evidence base presented in the current commentary. However, eating behaviours are complex in nature and a country’s dietary guidelines do not solely determine consumption. Factors to be considered include an individual’s preferences, lifestyle, culture, and the accessibility and affordability of food, which may impact upon the nutritional adequacy of the diet with other far-reaching effects on the environment and economic landscapes⁽ Reference Brug ^{7 )}.

The Mediterranean diet: evidence of benefit for health and disease

The best international evidence should be at the core and foundation of the development and redevelopment of all dietary guidelines. The Mediterranean diet (Med Diet) is one of the most globally researched and healthiest dietary patterns promoted for the management of chronic diseases and longevity⁽ Reference Trichopoulou, Martínez-González and Tong ^{8 ,} Reference Dinu, Pagliai and Casini ^{9 )}.

The traditional Med Diet is predominantly a plant-based diet, characterised by a high consumption of vegetables, fruits, nuts, legumes and unprocessed cereals; a low consumption of red meat, meat products and sweets; a moderate consumption of fermented dairy (cheese and yoghurt), poultry and fish; and with red wine consumed in moderation and with meals. As a percentage of energy, total fat content can be as high as 40 % with over half being monounsaturated fat (>20 %). This is predominantly due to the liberal use of extra virgin olive oil (EVOO), the main source of added fat, which occupies a central position in the diet⁽ Reference Trichopoulou, Costacou and Mamja ^{10 )}.

While the Med Diet differs in its definition across the literature and regions, findings are consistent with respect to its many health benefits⁽ Reference Sofi, Macchi and Abbate ^{11 )}. The beneficial health effects are owing primarily to the low intake of saturated fat and increased intakes of fibre, functional fatty acids and lipids, antioxidants and bioactive compounds.

The Med Diet is associated with reduced mortality⁽ Reference Trichopoulou, Orfanos and Norat ^{12 ,} Reference Trichopoulou, Bamia and Trichopoulos ^{13 )}, reduction in the risk of CVD⁽ Reference Martínez-González, Soledad Hershey and Zazpe ^{14 )} and incidence of CHD⁽ Reference Mente, de Koning and Shannon ^{15 )}, cancer⁽ Reference Benetou, Trichopoulou and Orfanos ^{16 –} Reference Bamia, Lagiou and Buckland ^{19 )} and stroke⁽ Reference Misirli, Benetou and Lagiou ^{20 )}, and prevention of type 2 diabetes⁽ Reference Martinez-Gonzalez, de la Fuente-Arrillaga and Nunez-Cordoba ^{21 ,} Reference Salas-Salvado, Bullo and Estruch ^{22 )} and metabolic syndrome⁽ Reference Kastorini, Milionis and Esposito ^{23 )}. While the studies are largely observational, the landmark Spanish PREDIMED randomised controlled trial demonstrated a reduction in the risk of cardiovascular events by approximately 30 % and a 52 % reduction in diabetes incidence when participants followed a Med Diet supplemented with either nuts or EVOO⁽ Reference Estruch, Ros and Salas-Salvadó ^{24 ,} Reference Salas-Salvadó, Bulló and Babio ^{25 )}. Components of the Med Diet are also beneficial for weight loss in obesity and for maintaining a healthy weight in non-obese populations⁽ Reference Shai, Schwarzfuchs and Henkin ^{26 ,} Reference Mozaffarian, Hao and Rimm ^{27 )} and in type 2 diabetes mellitus⁽ Reference Ajala, English and Pinkney ^{28 )}. The Med Diet has been shown to be beneficial in the treatment of depression⁽ Reference Jacka, O’Neill and Opie ^{29 )} and for global cognition⁽ Reference Loughrey, Lavecchia and Brennan ^{30 –} Reference Singh, Parsaik and Mielke ^{32 )}, with emerging evidence for benefits in disability and overall quality of life⁽ Reference Fransen, Beulens and May ^{33 ,} Reference May, Struijk and Fransen ^{34 )}. In a recent umbrella review of meta-analyses of observational studies and randomised controlled trials, the associations between adherence to a Med Diet and health outcomes for a population of over 12·8 million people were identified and affirmed⁽ Reference Dinu, Pagliai and Casini ^{9 )}. A reduced risk of mortality, CVD, CHD, myocardial infarction, overall cancer incidence, neurodegenerative disease and diabetes with greater adherence to the Med Diet was found. Of note, the majority of these studies were carried out in Mediterranean countries; however, evidence is now emerging as to the beneficial effects of the Med Diet in non-Mediterranean areas.

Beyond its nutrient profile the Med Diet is palatable, sustainable and has low impact on the environment. This holistic diet provides opportunities for conserving food biodiversity and raising awareness of how to better use current agricultural systems, aiming to revive activities that minimise waste of natural resources in producing food for local and seasonal consumption⁽ Reference Burlingame and Demini ^{35 )}.

Feasibility of translating the Mediterranean diet to an Irish population: lessons learned from overseas

From epidemiological and interventional analysis, adoption of the Med Diet varied between 14·0 and 65·5 % in Canada and North America⁽ Reference Abdullah, Jones and Jones ^{36 –} Reference Zbeida, Goldsmith and Shimony ^{41 )}. In a Swedish cohort, high adherence to a Med Diet was associated with lower cardiovascular mortality in women⁽ Reference Tognon, Nilsson and Lissner ^{42 )}, and in the EPIC (European Prospective Investigation into Cancer and Nutrition)–Norfolk study, adherence to a predefined Med Diet showed an inverse association with incident CVD and all-cause mortality⁽ Reference Tong, Wareham and Khaw ^{43 )}. In Australia, a group of researchers employ a Cretan-based Med Diet protocol in dietary interventions in non-Med Diet populations to assess the effects on metabolic conditions⁽ Reference Papamiltiadous, Roberts and Nicoll ^{44 –} Reference Itsiopoulos, Brazionis and Kaimakamis ^{46 )}. Recently, this group has published strategies for translating the traditional Med Diet into non-Mediterranean settings, which include meal plans, practical strategies and examples to attain the key principles of the diet with foods that are available and accessible locally⁽ Reference George, Kucianski and Mayr ^{47 )}. The Healthy Eating Pyramid in Australia^{( 48 )} incorporates the principles of the Med Diet. Herbs and spices are included; legumes are in the ‘eat most’ section; a predominance of fruits and vegetables is supported; and olive oil has a place in the pyramid. The UK National Institute for Health and Care Excellence recommends a Mediterranean-style diet for the secondary prevention of CVD^{( 49 )}. A UK population reported that the Med Diet allowed them to redefine cultural eating habits, introduced a better quality of food and reported several physical benefits⁽ Reference Middleton, Keegan and Smith ^{50 )}. However, barriers to its implementation in this and in a Northern Irish at-risk population included difficulty adapting to the eating pattern, limited knowledge of the diet, perception of expense and availability of foods, expectation of the time commitment to the diet, and resistance to dietary change and established eating habits⁽ Reference Middleton, Keegan and Smith ^{50 ,} Reference Moore, McEvoy and Prior ^{51 )}. The latter study serves well for policy makers to identify practical strategies to influence perceived barriers to bring about dietary behaviour changes towards a Med Diet in an Irish population.

While adopting a Med Diet in non-Mediterranean countries is a challenge, it is achievable. In 2016, the US National Heart, Lung, and Blood Institute agreed the importance of testing the translation of the Med Diet in the USA and proposed an alternative healthy Mediterranean-style eating pattern^{( 52 )}, cognisant of local dietary practices and foods that do not have negative health effects and may be consumed alongside a Med Diet. For example, despite it not being an integral component of the Med Diet, the Dietary Guidelines for Americans 2015–2020 do not impose restrictions on egg consumption, because dietary cholesterol is not considered a concern⁽ Reference Trichopoulou, Bamia and Trichopoulos ^{13 , 52 )}. This acknowledgement of incorporating aspects of local dietary practices may lead to better adoption and adherence to the new promoted guidelines and lead to significant changes to health. In addition, practical resources to promote the diet have been disseminated, aiming to easily apply the diet into the American setting. Authors have outlined practical recommendations as to how to shift current dietary practices in non-Mediterranean countries to more Med Diet pattern approaches, from replacing processed snacks with mixed tree nuts to substituting red or processed meat with seafood and legumes⁽ Reference Martínez-González, Soledad Hershey and Zazpe ^{14 )}.

Proposing a MedÉire food pyramid

Despite the substantial evidence in favour of a high-fat Med Diet, population and clinical guidelines continue to focus on low fat messages⁽ Reference Stone, Robinson and Lichtenstein ^{53 )}. In the current Irish Food Pyramid^{( 54 )} increased consumption of fruits, vegetables and whole grains with small amounts of fats and oils are encouraged. The guidelines advise to replace high-fat foods that contain predominantly saturated fat (such as butter and cream) with foods that contain predominantly polyunsaturated and monounsaturated fats such as oils and spreads. Olive oil is grouped with other fats (‘Choose rapeseed, olive, canola, sunflower or corn oils’) and the message is to always cook with as little fat or oil as possible^{( 54 )}, a message that is entirely opposite to the recommendations of the Med Diet pyramid. Seed oils are susceptible to oxidation when heated, due to the high polyunsaturated fat content and low levels of phenolics⁽ Reference Choe and Min ^{55 )}. In contrast, EVOO is stable on prolonged heating, remaining rich in phenolic compounds and producing few potentially harmful polar compounds⁽ Reference De Alzaa, Guillaume and Ravetti ^{56 )}. In recent years, evidence indicates that bioactive polyphenols present in EVOO contribute substantially to many health benefits⁽ Reference Visiolo and Martinez-Gonzalez ^{57 )}. The advice to consume 1 teaspoon of oil when cooking is in stark contrast and falls well below the recommended 50 ml per person per day that has been associated with reduction in the risk of CVD as found in the landmark PREDIMED study⁽ Reference Estruch, Ros and Salas-Salvadó ^{24 )}.

While we have positively moved away from a single-nutrient to a whole-of-diet approach with the Irish 2016 dietary guidelines and recommendations, there are still some inadequacies in the messages conveyed. It needs to be recognised that foods with similar fat contents can have very different nutritional values. Grouping together red meat with poultry and fish in the current Irish Food Pyramid, in the frequency promoted, is not reflective of the current evidence base and conveys to the public that these foods are of similar nutritional value; a message that is not entirely scientifically valid. Previous work has shown that fish⁽ Reference Nasopoulou, Karantonis and Perrea ^{58 )}, olive oil⁽ Reference Karantonis, Antonopoulou and Perrea ^{59 ,} Reference Tsantila, Karantonis and Perrea ^{60 )}, fermented dairy products⁽ Reference Poutzalis, Anastasiadou and Nasopoulou ^{61 –} Reference Megalemou, Sioriki and Lordan ^{63 )} and red wine⁽ Reference Xanthopoulou, Kalathara and Melachroinou ^{64 )} have strong anti-inflammatory activities protective against CVD. While red meat contains proteins of high biological value and important micronutrients such as B vitamins, iron (both free iron and haem iron) and zinc, in comparison to oily fish it has a higher saturated fat and lower n-3 fat content. Regular consumption of red meat has been associated with cancer risk^{( 65 )}, heart disease⁽ Reference Abete, Romaguera and Vieira ^{66 )} and when cooked to a high temperature, type 2 diabetes risk⁽ Reference Liu, Zong and Wu ^{67 )}. Fish consumption, however, has been associated with a lower risk of CVD and CVD death⁽ Reference Zheng, Huang and Yu ^{68 )}. For MedÉire, it is proposed to consume two or more servings of fish, less than two servings of red meat (preferably lean cuts) and less than one serving of processed meat every week. This frequency of consumption will provide the nutritional benefits that meat favours. This contrasts with the potential two servings of meat per day that the Irish population could consume according to the current recommended guidelines^{( 54 )}.

The Med Diet with its basic themes is easily adaptable to an individual country’s culture. In 2009 and 2010, through an international scientific consensus process, a new revised Med Diet pyramid was developed as a simplified main frame to be adapted to different countries’ specific variations related to geographical, socio-economic and cultural contexts⁽ Reference Dernini and Berry ^{69 )}, focusing on local, accessible and seasonal produce. Although not produced in Ireland, the staple component, EVOO, is readily accessible in all supermarkets, food stores and markets at a reasonable price, as are other key components such as canned or dry legumes and nuts. Other fundamental foods that constitute the Med Diet pattern – such as whole grains, leafy greens and all other vegetables, beans, fish, red and white meat, fresh fruit and dairy – are grown or produced in Ireland and are abundant and affordable, highlighting that the Med Diet can be adapted for the Irish context. A recent study examining the association between dietary cost and adherence to the Med Diet in a UK population found that adherence to the diet was associated with marginally higher dietary cost, but that the potential economic barriers of high adherence would be offset by cost saving from reducing unhealthy food consumption⁽ Reference Tong, Imamura and Monsivais ^{70 )}. With many scientific and media reports increasingly being published on the health benefits of the Med Diet⁽ Reference Trichopoulou, Martínez-González and Tong ^{8 ,} Reference Dinu, Pagliai and Casini ^{9 , 71 )}, the key principles and ways of incorporating it into everyday life are becoming more culturally acceptable in non-Mediterranean populations⁽ Reference Abdullah, Jones and Jones ^{36 –} Reference Gardener, Wright and Gu ^{38 ,} Reference Tong, Wareham and Khaw ^{43 –} Reference Moore, McEvoy and Prior ^{51 )}.

The Med Diet frame also takes account of the concept of sustainability with the promotion of a predominantly plant-based dietary pattern, making use of natural resources and skills, conserving a fragile and strained ecosystem⁽ Reference Dernini and Berry ^{69 ,} Reference Bach-Faig, Berry and Lairon ^{72 )}. The base of the MedÉire food pyramid would be comprised of plant-origin foods; foods that sustain the diet and foods that the Irish agricultural and food systems could support^{( 73 )}. Continued meat production is inefficient in terms of use of agricultural land, as more plant-based food is required for rearing of livestock^{( 73 )}. The external costs of the current system in terms of climate change and food and nutrition security are increasing^{( 73 )}. A redirection of land for the purposes of supporting growth of plant-based foods for human consumption is needed^{( 74 )}.

The high nutritional quality of the Med Diet with its low environmental impact is a unique selling point of this diet. For the MedÉire diet, we propose the adaption of the current Irish Food Pyramid to incorporate its key principles. Consumption of vegetables, fish, olive oil and legumes in the MedÉire diet needs to be further encouraged. Given the findings of the Healthy Ireland Survey and recent studies in non-Mediterranean populations, reasons for suboptimal consumption of vegetables and barriers to adopting a Med Diet need to be explored. Information and education are key to implementation for it to become a feasible and sustainable diet for the Irish people and to overcome the main barriers including limited knowledge, expense, availability, and time and skill commitment⁽ Reference Moore, McEvoy and Prior ^{51 )}.

Addressing the education and knowledge components, incorporating the MedÉire diet into national policies and associated action plans around existing food- and diet-related programmes is key to its uptake across all ages and stages.

The Healthy Eating and Active Living policy priority programme established in 2016^{( 75 )} aims to improve the health and well-being of service users, with a particular focus on families and children. Through the implementation of A Healthy Weight for Ireland: Obesity Policy and Action Plan 2016–2025^{( 76 )}, the number of people in Ireland eating a healthier diet by increased consumption of fruit and vegetables, reduced consumption of foods high in fat, salt and sugar, and achieving and maintaining a healthier weight, is encouraged. Activities as part of these programmes are ideal platforms for the promotion of a MedÉire diet. For example, healthy eating standards for school meals^{( 77 )} and the Schools Meals Programme^{( 78 )} are initiatives that can be easily targeted to teach and translate to young populations the staples of a Med Diet. Accessing main food staples such as olive oil, nuts, legumes, fish and fresh vegetables, and promoting the affordability of the Med Diet⁽ Reference Drewnowski and Eichelsdoerfer ^{79 )} to quell misconceptions that the cost is significantly more, also need to be promoted.