This blog post was researched and written by our summer Warehouse & Delivery Coordinator, Conor Nedelec. Conor has worked in foodservice for several years and, as a U of M student going into his third year of Nutrition Sciences, has brought a lot of knowledge about plant physiology and nutrition to our team. He is currently learning to ferment hot sauce.
Photos by Marti Sarbit
Why choose local food?
Among the many excellent reasons to purchase locally grown food, there is one important yet invisible reason that is often overlooked: nutrition. The nutritive value of a piece of produce is determined in part by the amount of micronutrients like minerals and vitamins present within it. But these nutrients can be delicate; from the first day after a fruit or vegetable has been picked, the countdown starts and it begins to lose nutrients. This loss is because the fruit or vegetable is no longer connected to the plant and therefore no longer receiving the nutrients it needs to stay alive. Yet, even though the fruit or vegetable has been detached from the living plant, its cells are still alive and going about their normal functions. These cells must then break down compounds within themselves to stay alive. The breakdown of these compounds is what results in a loss of nutrients over time, in particular the content of vitamins C, A and E. Spinach, for instance, can lose up to 10% of its vitamin C content every day once harvested.
Because of this, many vegetables are only considered desirable between one and seven days after harvest. Yet, it is reasonable to expect that produce you buy from the grocery store has already been on a many weeks-long journey from the moment of its harvest, including transportation to the grocery store and sitting on shelves until it is bought and finally consumed. Buying foods locally minimizes the time from when the food is harvested to when it is on your plate ready to be eaten.
Also contributing to nutrient loss over time is the temperature at which food is stored and the oxidative damage, which is the same process in which an apple will begin to turn brown once it is cut and exposed to air. Further processing of food, (usually used to extend the food's shelf life), can also further degrade the content of some nutrients. Many fruits and vegetables may also be harvested before they are fully mature and left to ripen in stores to ensure a longer shelf life, but this also decreases the nutritional density of those foods because the fruit or vegetable does not develop the same amount of nutrients It would if it were to fully mature still attached to the plant. So, as food goes through the process of being transported long distances and is left on shelves for even more time, nutrients are being lost.
Healthy soils also contribute to the nutritive quality of our foods. Soils provide nutrients, water and oxygen to the plant, the better quality of soil the plant is grown in, the more nutrients the plant receives while growing. In conventional farming (aka farming that relies heavily on pesticides and chemical fertilizers), the practices of harvesting from soil too frequently without amending, or using pesticides and fertilizers can deplete the nutritive quality of the soil. Studies have shown a decline from 1950-1999 in protein, calcium, phosphorus, iron, riboflavin, and vitamin C in modern conventionally-farmed soils. Conventional farmers use many methods such as pesticides and fertilizers to prolong the shelf life of foods as well as increase their size and growth rates. These additives can strip nutrients from the soil thus negatively impacting the nutrition of the fruit or vegetable
One of our goals at Fireweed Food Co-op is to support local farmers who use regenerative, non-chemical based farming practices such as Organic, spray-free, and no-till. This makes their soils-- and therefore the foods that grow from them-- much more nutrient-dense. Additionally, when customers purchase from local farmers (whether it be at a Farmers’ Market, through the Food Hub, or from a retailer selling locally produced food) they can be sure that the time in between the farmers harvesting the vegetables to when they are delivered is much shorter than conventional grocery store produce, usually a few days at most. This means maximum nutrient retention, freshness and flavour. That’s a delicious and nutritious reason to support local!
References:
Amisson, L. (2020, June 23). Is Eating Locally Grown Food Healthier for You? Retrieved July 28, 2020, from https://www.virtua.org/articles/is-eating-locally-grown-food-healthier-for-you
The benefits of eating local foods. (2012, March 06). Retrieved July 28, 2020, from https://www.mcgill.ca/foodservices/sustainability/green/local
Dirt Poor: Have Fruits and Vegetables Become Less Nutritious? (2011, April 27). Retrieved July 28, 2020, from https://www.scientificamerican.com/article/soil-depletion-and-nutrition-loss/
Driskell, J. A., Kim, Y., Giraud, D. W., Hamouz, F. L., Mello, A. S., Erickson, G. E., & Calkins, C. R. (2011). Vitamin and mineral content of value cuts from beef steers fed distiller's grains. Journal of Food Composition and Analysis, 24(3), 362-367. doi:10.1016/j.jfca.2010.08.013
El-Ramady, H., Alshaal, T., Amer, M., Domokos-szabolcsy,, E., Elhawat, N., Prokisch, J., & Fári, M. (2014). Sustainable Agriculture Reviews 14. Sustainable Agriculture Reviews, 345-447. doi:10.1007/978-3-319-06016-3
Greenwood, B. (n.d.). How Do Fruits and Vegetables Lose Their Nutrients After Picking? Retrieved July 28, 2020, from https://www.livestrong.com/article/447449-how-do-fruits-and-vegetables-lose-their-nutrients-after-picking/
Holford, P. (2005). The new optimum nutrition bible. Berkeley, CA: Crossing Press.
Karmas, E., & Harris, R. S. (1988). Nutritional evaluation of food processing. New York: Van Nostrand Reinhold.
Rickman, J. C., Barrett, D. M., & Bruhn, C. M. (2007). Nutritional comparison of fresh, frozen and canned fruits and vegetables. Part 1. Vitamins C and B and phenolic compounds. Journal of the Science of Food and Agriculture,87(6), 930-944. doi:10.1002/jsfa.2825