The fresher the better - part I 11/01/2017, Health & Lifestyle
As we enter the new year, many of us are looking to make positive changes to improve health and happiness for good. In a series of three blogs, nutritional therapist and author Sally Beare asks the question: “What’s the evidence that fresher local produce can be nutritionally richer?”
Sally Beare, dip BCNH, CNHC
Sally Beare is a nutritional therapist and the author of The Live-Longer Diet, 50 Secrets of the World’s Longest-Living People and The Stacking Plan. Sally is also the nutrition columnist for Juno natural parenting magazine. She currently practices in Bristol, UK. www.sallybeare.com
Fresh and local - why bother?
We all know that fresh, local food is best…don’t we? If we could look into a crystal ball at ourselves and see whether eating fresh food over the next ten or twenty years kept us vibrant and illness-free, versus ageing rapidly by eating non-fresh food, perhaps that would swing it. We’d make the effort.
If we could line up, say, a head of broccoli from the supermarket, one just picked from high-quality soil, and some from a ready meal, and put on special goggles which enabled us to see exactly how many micronutrients were in each sample, then that might also help us to decide how to shop. However, we don’t yet have such a crystal ball or goggles. So let’s have a look at what the research says and find out if eating fresh, local food is just a fashionable lifestyle choice - or if it really does offer extra benefits.
When ‘fresh’ means fresh
There is a difference between ‘fresh’ supermarket produce, and fresh produce that has been picked just a day or two earlier. ’Fresh’ supermarket produce is often kept in cold storage or semi-frozen for days, weeks or even months, so that it can travel for hundreds or even thousands of miles, and be stored for as long as necessary before being put on the supermarket shelves. This means we have a constant supply of ‘fresh’ food all year round, but it may not actually be truly fresh at all.
A shiny red supermarket apple is likely to be six months to a year old by the time you buy it, lettuce up to four weeks old, meat up to several weeks old, bread several days old, eggs a week old or more, green vegetables between three and ten days old, potatoes twelve months old, and fish up to two weeks old. A large prawn may even be a year old. All of these supermarket products can be labelled ‘fresh’.
There is a price to pay for this convenience, since produce loses nutrients over time, even in cold storage. Sugars turn to starches, plant cells shrink, and antioxidants are lost. One US study showed that local broccoli had double the amount of vitamin C than that of imported broccoli, and another that spinach lost half of its folate after eight days, even when refrigerated. 1, 2
Another study of apples kept in cold storage showed that their antioxidant phytochemicals decreased enough over three months to significantly reduce their destructive effect on cancer cells. The researchers concluded: ‘an individual would probably need to consume at least two apples stored for six months or more to obtain the health benefits provided by one freshly picked apple.’ 3
Similar results have been found for meat and poultry products, with one study showing that storage time exerted ‘significant effects’ on packaged chicken, causing a change in pH value due to the proliferation of bacteria. The researchers concluded that storage time has ‘a negative effect’ on meat. 4
Food from local suppliers, on the other hand, is genuinely fresh. Much of it will have been picked just a day or two before you buy it; sometimes hours. This means that it can be of exceptionally high quality in terms of both taste and nutrient value.
Look out for Sally's second blog next week - No more cardboard.
1. Wunderlich, SM et al (2008). Nutritional quality of organic, conventional, and seasonally grown broccoli using vitamin C as a marker. Int J Food Sci Nutr. 59(1):34-45.
2. Pandrangi, S; LaBorde, L.F (2004).Retention of Folate, Carotenoids, and Other Quality Characteristics in Commercially Packaged Fresh Spinach. Journal of Food Science 69(9): C702-C707.
3. Tarrozzi, Andrea et al (2004). Cold-Storage Affects Antioxidant Properties of Apples in Caco-2 Cells. The Journal of Nutrition 134(5):1105-1109.
4. Marcinkowska-Leziak, Monika et al (2016). Effect of packaging method and cold-storage time on chicken meat quality. CYTA Journal of Food 14 (1):41-46.