Health impacts of eating locally

Nutrition and the 100 Mile Diet Health impacts of eating locally 2009 Jayne Trojack Nutrition Option Practicum Intern Manitoba Food Charter 641 St M...
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Nutrition and the 100 Mile Diet

Health impacts of eating locally

2009 Jayne Trojack Nutrition Option Practicum Intern Manitoba Food Charter 641 St Matthew Ave Winnipeg Manitoba Tel:204-943-0823 Fax: 204-774-1847

This study was written by Jayne Trojack and produced in partnership with :

THE MANITOBA FOOD CHARTER INC. The Manitoba Food Charter is both a vision and an organisation. The Charter document emerged from input elicited at over 70 community consultations with stakeholder groups and concerned citizens across Manitoba. As an organization, Manitoba Food Charter Incorporated works to educate Manitobans about food security and the sustainability of our food systems, strengthen networks and partnerships to address local food issues, holds workshops and conferences on food skills including local food production and storage, and coordinates food security programs in rural, urban, and northern communities. To date, over 50 organizations have signed the Charter and, in doing so, have developed concrete work plans to work towards greater food security in their organizations and communities.

NUTRITION OPTION PRACTICUM PROGRAM Faculty of Human Ecology University of Manitoba The Nutrition Option Practicum is a course offered to Human Nutritional Sciences students in the Faculty of Human Ecology at the University of Manitoba. This course provides an opportunity to work in a business, government or community setting, where the concepts learned in the classroom can be applied to practical problems. It is expected that the experience will give students the ability to deliver professional service to both clients and employers.

Contents Introduction .................................................................................................................................................. 1 Transport, Storage and Processing ............................................................................................................... 2 Local Foods and Community Programs ........................................................................................................ 5 100 Mile Diet in Manitoba ............................................................................................................................ 7 Further Research Needed ............................................................................................................................. 9 Conclusion ................................................................................................................................................... 10 References .................................................................................................................................................. 11

Introduction

As highlighted by the popularity of the 100 mile diet, eating locally is a food movement gaining worldwide popularity. The concept of this movement is to consume food which is grown and produced within a certain proximity of one’s residence, a 100 mile radius in the case of the 100 Mile Diet (Smith and MacKinnon, 2007). Eating locally focuses on reducing the environmental impact related to the globalization of food, supporting local farmers and local economies, as well as the enjoyment of eating fresh tasting, delicious food. Although the focus of this diet has been on the environmental and economic impact of eating locally, the consumption of local food has also been promoted by the media as being a healthier, more nutritious choice compared to global equivalents. Could eating locally grown and produced food have health implications for Manitoba residents and the population as a whole? There is substantial information related to the concept of the 100 mile diet, including books and numerous articles highlighting the effects of transport, storage and processing of foods related to the global production and distribution of food. While limited scientific research indicates that increasing the length of the food chain may lead to a decrease in the nutritional value of food (Jones, 2001) a thorough search of research based evidence, reveals a lack of direct information on the nutritional benefits of eating local food. MacLeod and Scott (2007) concluded that “there is a continuing debate as to where or not locally produced foods have greater nutritional value than imported foods; however, there is some evidence to suggest this is the case for certain fruits and vegetables” (p. 10).

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What is known is that increasing servings of fresh fruits and vegetables has positive impacts on nutritional health benefits. There is also research based evidence which indicates programs which involve locally grown and produced food result in increased servings of fruits and vegetables and have a positive impact on the health status of the participants. This evidence may suggest the potential nutritional benefits of eating local food. The findings of this paper indicate that further research is needed regarding this recent trend in food consumption.

Transport, Storage and Processing Unless food has been grown or produced locally it is usually transported, stored and/or processed before it reaches the consumer. It has been estimated that the food we eat travels an average of 1500 to 2000 miles from farm to table (Kirschenmann, 2006). Depending on the type of food and processing method, food may also be stored for several months prior to consumption. As a result of transportation and storage, the nutrients in several foods are subject to changes (Health Canada, 2007). Nutrient levels may also be affected during storage and transport due to “changes in temperature, light conditions, humidity and exposure to air” (Health Canada, 2007, p. 35). Nutrients include the carbohydrate, fat, protein, vitamins and minerals found in food sources. Health Canada (2007) recommends adults aged 19-50 consume seven to 10 servings of vegetables and fruit per day (seven to eight for females and eight to ten for males). These vegetables contain essential nutrients including vitamins and minerals which are important in daily metabolic functions as well as preventing chronic diseases. There is also evidence that indicates food transported long distances will dilute the nutritional value of food (Jones, 2001).

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Storage conditions are also an important factor in maintaining nutrient quality. The amount of nutritional losses will depend on the type of food and nutrient; however, nutrient losses will occur even under ideal storage conditions, particularly in vitamin C, vitamin A, riboflavin and vitamin E (Jones, 2001). Some fruits and vegetables, such as apples carrots and oranges will keep their nutritional value during storage, while other products such as broccoli and green beans will be more susceptible to nutrient losses (MacLeod & Scott, 2007). A study researching the nutrient content of green beans revealed that the vegetable lost 10% of their vitamin C in 24 hours at a storage temperature of 10oC and lost 24% of this vitamin when stored at room temperature for 24 hours (Jones, 2001). A study researching the effect of storage length on nutrient the nutrient value of broccoli indicated a significant decrease of vitamin C after only seven days of storage at 6oC, with up to a 39% loss after 21 days (Galagano, Favati, Caruso, Pietrafesa & Natella, 2007). Bruising of fruits of vegetables may occur during the transport and storage of these foods, and this may also result in a decrease of nutritional value. Lee and Kader (2000) found a decrease in vitamin C content of up to 15% in tomatoes as a result of bruising to the tissue.

Research indicates that canning is one of the most detrimental methods of processing vegetables

Research evidence also indicates the nutrient value of foods may be adversely affected by processing methods including canning and freezing. Health Canada (2007) advises during processing of food products “nutrients may be altered or destroyed in reactions involving heat, light, oxygen, enzymes, micro-organisms and other food components” (p. 34). Research indicates that canning is one of the most detrimental methods of processing vegetables as a result of extended heating (Prochaska, Nguyen, Donat & Piekutowski, 2000). The process of canning leads to decreases in nutritional value of several types of foods including vegetables, fruits and meats. Evidence indicates that “losses up to 90% of the vitamin content of vegetables can occur during this processing, depending on the vitamin and the vegetable processed” (Prochaska et al., 2000, p. 298). Canning also has detrimental effects to nutrient value in fruits. Peaches, for example, may loose 40% to 70% of niacin, riboflavin, thiamine and vitamins A and C during the canning process as compared to their raw equivalents (Prochaska

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et al., 2000). Canning also affects the nutritional value of meats, including the destruction of amino acids, niacin and biotin (Prochaska et al., 2000). The process of freezing also causes a decrease in nutritional value in most foods. Freezing requires the process of blanching, a method where fruits or vegetables are boiled in

The freezing process may cause nutrient losses, however, of all the processing methods, it decreases the nutritional content the least

water for a few minutes and then plunged into ice water. The blanching process may destroy vitamins and other nutrients depending on the time of exposure (Prochaska et al., 2000). For example, blanching will decrease the water-soluble vitamins in spinach by 35% (Prochaska et al., 2000). While blanching does reduce the nutrient content of food it will limit further nutrient decreases during the freezing of horticultural products (Lee & Kader, 2000). When vegetables are blanched, there is an initial loss of 28% of vitamin C, with further losses of 3% to 10% due to freezing. However, the unblanched product may loose up to 97% of vitamin C within a month of freezing (Lee & Kader, 2000). The freezing process may cause nutrient losses, however, of all the processing methods, it decreases the nutritional content the least (Prochaska et al., 2000). The loss of nutrient content of any food is a nutritional concern as these nutrients are essential in daily metabolic functions as well as in preventing or reducing the risk of disease. Galagano et al. (2007) found epidemiological data indicating a diet rich in vegetables, such as broccoli, may reduce the risk certain diseases. Vitamin C, found in many fruits and vegetables is an antioxidant important in “activity against free radicals, carcinogenesis and cardiovascular diseases as well as in stimulating the human immune system” (Galagano et al., 2007, p. S130). Vitamin C is also vital in the maintenance of healthy skin, gums and blood vessels as well as in the reduction of plasma cholesterol levels (Lee & Kader, 2000).

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As nutrients found in foods are critical to our health and well being, it is important to maintain nutrient levels in foods at a high level when possible. As the transportation, storage and processing of food has been shown to decrease the nutritional value of many types of foods, this may suggest that eating fresh, locally grown and produced foods would be beneficial to the health of individuals due to their higher level of nutrients. However, in remote areas such as northern Canadian communities where fresh fruits and vegetables may not be readily available all year round, consuming frozen and canned produce is a good alternative to obtain essential nutrients.

Local Foods and Community Programs Programs such as farmers, markets programs, community gardens and nutrition programs using locally grown and produced foods at the community level have shown that participants increase their nutritional status as a result of involvement in the program. The results of these studies indicate that by making local food available through community programs, there is an increase in vegetable and fruit intake amongst the target group. Through increasing their intake of this food group, these individuals are increasing the nutritional value of their diet, thereby improving their health status.

Farmers’ Markets The South Carolina Senior Farmers’ Market Nutrition Education Program is an example of a community based program which used local food to increase the fruit and vegetable consumption of its participants (Kunkel, Luccia & Moore, 2003). This program provided vouchers to low-income seniors which could be used at local produce stands farmer’s markets. A nutrition education brochure was also provided to the participants as part of the program (Kunkel et al., 2003). Funding for this project was provided by the state department of social services and served as a pilot project for

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this type of program. The results of this program indicated the participating seniors increased their overall fruit and vegetable consumption (Kunkel et al., 2003), thereby improving the quality of their diet. In 2008, the United States Department of Agriculture announced $3.4 Million in grants in order to spread the use of farmers markets (United States Department of Agriculture, 2008). This is a nationwide program in the United States of America similar to the previously mentioned South Carolina Seniors Farmers Market Nutrition Education Program. The goal of this initiative is to promote healthy diets and sound nutrition as part of the United States Department of Agriculture’s Food Stamp Program. The program is designed to assist lowincome Americans to make nutritious choices and encourage individuals to purchase health foods (United States Department of Agriculture, 2008). A similar project in British Columbia also resulted in program participants increasing their consumption of healthy food as a result of access to local food at B.C. Farmers’ Markets (B.C. Association of Farmers’ Markets, 2008). The province provided $750,000 to the B.C. Association of Farmers’ Markets in order to expand the associations Market Nutrition and Coupon Project (B.C. Association of Farmers’ Markets, 2008). As with similar programs, this project is aimed at providing low-income families with increased access to local and nutritious food. Participants involved in similar programs indicated that they were consuming healthier foods and had increased their awareness of using locally grown food. Community Gardens Another important tool in providing access to local food is community gardens. A study conducted in South-East Toronto found that community gardens had several positive health benefits including improved access to food and better nutrition, increased physical activity and improved mental health (Wakefield, Yeudall, Taron, Reynolds & Skinner, 2007). Participants indicated that they consumed

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more vegetables as a result of the community garden (Wakefield et al., 2007). This is an important finding as “higher consumption of vegetables and fruits is known to promote health and prevent disease, but may be harder for people with limited incomes to attain” (Wakefield et al., 2007, p.97). Community gardens have shown to be another important tool in promoting the health benefit of consuming locally grown and produced foods. Community food studies Additional evidence supporting the nutritional benefit of consuming local foods is provided from a study researching the relationship of eating home grown produce among rural parents and children and their overall intakes of fruits and vegetables (Nanney, Johnson, Elliot, & Haire-Joshu, 2007). The results indicated that parents who frequently consumed home grown produce were “3.2 times likely to eat five daily servings of fruit and vegetables” (Nanney et al., 2007, p. 581). It was concluded that consuming home grown fruits and vegetables improved the overall nutritional intake of the participants (Nanney et al., 2007). As fruits and vegetables are important sources of several essential vitamins and minerals, this would suggest the consumption of local food improved the overall health of the study participants. These community programs using locally grown and produced foods have provided strong evidence to support the nutritional benefits of eating local food. Through these programs, participants increased their daily consumption of fruits and vegetables, which provide essential nutrients necessary for maintaining optimal health as well as preventing disease (Galagano et al., 2007). Through new government funding of similar programs, local food will be used in increasing the nutritional status of participants as well as their over health.

100 Mile Diet in Manitoba

The food movement to consume locally produced and grown food is also prominent in Manitoba. In 2007, over 100 individuals participated in 100 days of eating foods from within a 100 mile radius of

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their residence (100 Mile Manitoba, 2007). A small portion of individuals who completed this challenge participated in a survey and the results were compiled by Jennifer deGroot (personal communication, January 20, 2009). The results from these surveys indicate that participation was motivated for a number of reasons including environmental concerns, connecting with local growers, and a desire to see the food system change. Some participants indicated they felt better during the diet as they ate less processed food, enjoyed the taste of local food, and enjoyed the experience of growing their own food at home. There were also challenges to eating within 100 miles of one’s residence in Manitoba, including certain foods that were unavailable, as well as the seasonal challenges of living in the climate of Manitoba. The participants worked with these challenges and made local substitutes for foods normally consumed as well as trying new foods and used the preservation methods of canning and freezing to overcome the climate challenges of living in Manitoba where local fresh produce may not be available year round. The growing popularity of consuming local food rather that globally produced equivalents provides justification for further research into the benefits of locally grown and produced foods. Consumers of local food are using various preservation methods to include local foods in their diet throughout the year as the climate of many regions, including Manitoba, do not provide a year round growing season. Due to local growing limitations, available local food may require local food consumers to make modifications to their food consumption in order to follow a true local diet. Further research and nutrition education is needed to ensure consumers are using the preservation methods which retain optimal nutrient content as well as to ensure nutritional needs are met year round. As there is currently a lack of evidence regarding the health benefits of consuming a local diet, further research is needed to provide conclusive evidence on the nutritional benefits of eating local food.

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Further Research Needed A thorough search of research-based studies provided a significant lack of scientific information regarding the difference in nutrient value between locally grown and globally produced food. Although there is evidence related to the potential benefits of consuming local food, it is clear further research is still needed in this area. Several of the above mentioned studies looking at the benefit of programs using local food concluded that while there was evidence to show an increase in fruit and vegetable consumption as a result of their program, further research is needed regarding the specific health benefits of such programs. Information from local food producers in Manitoba also indicates that further research is needed regarding the health implications of consuming local food. Local Manitoba producers were asked what information their organization had regarding the nutritional value of consuming local food. Brenda Baz at the Manitoba Egg Producers (personal communication, October 1, 2008) indicated that the storage of eggs affected the quality and performance of eggs, and that was no evidence to suggest the nutritional content suffered as a result of storage or transportation. Karen Armstrong at the Manitoba Chicken Producers (personal communication, October 1, 2008) indicated that there was no known significant difference between the nutrient composition of a chicken raised in Manitoba versus a chicken raised in any other part

Information from local Manitoba food producers suggests that there is no additional nutritional value in consuming locally grown and produced foods; rather it is the quality and freshness of the food that is different in local food.

of Canada or the United States. The benefit of consuming local chicken was in regards to freshness and the support of local farmers. Sarah Cahill from the Dairy Farms of Manitoba (personal communication, October 9, 2008) indicated that there was currently no information regarding the nutritional benefit of locally produced dairy products, and that the benefit of consuming local dairy products was found in the quality of the milk. Ken Krowchenski at Peak of the Market (personal communication, October 28th, 2008) indicated that due to changing harvest conditions, changing varieties of certain products and fluctuating government regulations

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regarding produce content, their organization was unable to make claims on the nutritional benefits of eating local food. Information from local Manitoba food producers suggests that there is no nutritional value in consuming locally grown and produced foods; rather it is the quality and freshness of the food that is different in local food. This lack of information from local food producers may also suggest that further research is needed regarding the nutritional differences between locally and globally produced foods.

Conclusion The global food movement of consuming locally grown and produced food is gaining worldwide popularity. A thorough search of researched based evidence presented a lack of scientific information regarding the nutrient value differences between locally and globally grown food. There was related evidence that revealed the detrimental effects of transport, storage and processing on nutrient content of food, indicating potential benefits of consuming local fresh food. Research studies looking at programs using local food at the community level have shown participants increase their nutritional status as a result of involvement in the program. If adopting a household philosophy of eating locally results in increased consumption of fresh fruits and vegetables in season this could also have positive implications for health. Although there is some related information indicating that there may be nutritional benefits related to eating local food, further specific research is needed before conclusions can be made regarding the health effects of consuming a diet of locally grown and produced food.

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References 100 Mile Manitoba. (2007). 100 Manitobans, 100 Mile Eating Radius, 100 Days. Retrieved January 24, 2009 from http://www.100milemanitoba.org/ B.C. Association of Farmers’ Markets. (2008). Local families to benefit from farmer’s market grant. Retrieved October 31, 2008 from Http://bcfarmersmarket.org/media/ 2008_06_14.htm) Canada. Health Canada (2007). Eating Well With Canada’s Food Guide. Ottawa: Health Canada. Canada. Health Canada. (2007). Guide to Developing Accurate Nutrient Values. Ottawa: Health Canada. Galagano, F., Favati, F., Caruso, M., Pietrafesa, A., & Natella, S. (2007). The Influence of Processing and Preservation on the Retention of Health-Promoting Compounds in Broccoli. Journal of Food Science, 72 (2), S130-S135. Jones, A. (2001). Eating Oil: Food Supply in a Changing Climate. Sustain & Elm Farm Research Centre. Retrieved October 3, 2008 from http://www.sustainweb.org/pdf/ eatoil_sumary.PDF. Kirschenmann, F. (2006). Farming Food and Health. Gleanings: A Publication of Glynwood Centre, Summer 2006, 1-5 (in conjunction with Leopold Centre for Sustainable Agriculture, Iowa State University). Kunkel, M. E., Luccia, B., & Moore, A. (2003). Evaluation of the South Carolina Seniors Farmers’ Market Nutrition Education Program. Journal of the American Dietetic Association, 103 (7), 880-883. Lee, S. K., & Kader, A. A. (2000). Preharvest and postharvest factors influencing vitamin C content of horticultural crops. Postharvest Biology and Technology 20 (2000) 207220. MacLeod, M., & Scott, J. (2007). Local Food Procurement Policies: A Literature Review. Prepared by the Ecology Action Centre, for the Nova Scotia Department of Energy. Retrieved October 3, 2008 from http://www.atlanticsustainability.ca/downloads/ procurement/LocalFoodProcurement Policies.pdf Nanney, M. S., Johnson, S., Elliot, M, & Haire-Joshu, D. (2007). Frequency of Eating Homegrown Produce Is Associated with Higher Intake among Parents and Their Preschool-Aged Children in Rural Missouri. Journal of the American Dietetic Association, 107 (4), 577-583. Prochaska, L. J., Nguyen, X. T., Donat, N., & Piekutowski, W. V. (2000). Effects of food processing on the thermodynamic and nutritive value of foods: literature and database survey. Medical Hypotheses, 54(2), 254-262. Smith, A., & MacKinnon, J. B. (2007). The 100-Mile Diet: A Year of Local Eating. Toronto: Vintage Canada. United States Department of Agriculture. (2008). USDA Grants $3.4 Million for Farmers. Retrieved November 17, 2008 from http://www.usda.gov/wps/portal/!ut/p/_s.7_0_ A/7_0_1OB?contentidonly=true&contentid=2008/09/0235.xml Wakefield, S., Yeudall, F., Taron, C., Reynolds, J., & Skinner, A. (2007). Growing urban health: Community gardening in South-East Toronto. Health Promotion International, 22 (2), 92-101.

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