by Paul Cribb, B.H.Sci HMS
AST Director of Research
Smart bodybuilders understand that a high intake of vegetables is a key “secret” weapon to achieving a lean, muscular physique. Aside from their rich spectrum of nutrients, a high intake of vegetables ensures better gains in lean mass and efficient fat loss by keeping the metabolism elevated. The end-result of a diet rich in vegetables is a lean, muscular physique that just keeps getting leaner and more muscular.
However, there’s one important question I’m often asked, “are fresh vegetables really better for you than frozen?” Frustratingly, for such an important topic in today’s health-conscious society there isn’t a lot of research to draw from to provide an answer. However, what data there is, I’ve studied carefully and the results appear to be quite conclusive. Also, they’re not what most people would expect.
One investigation completed by Dr Trevor Lorman at Silliker Microtech Laboratories in Australia, examined whether fresh vegetables are more nutritious than the frozen variety. Silliker Microtech is a leading independent analytical laboratory and technical consultancy service for food and therapeutic goods industries.
In this study, Dr Lorman analyzed three baskets of vegetables, each containing carrots, peas, corn, spinach, beans and broccoli. One set was bought from the market, one from the supermarket's fresh section and the last from the supermarket's frozen section. The tests were designed to measure the levels of vitamin C and folic acid in the vegetables.
Vitamin C and folic acid are good measures of the freshness of produce, so the higher the value, the more likely the fresher and more nutritious the produce probably is.
With regard to vitamin C content, the various carrots, corn, broccoli and spinach had virtually the same levels of this vitamin regardless of whether they were market fresh, supermarket fresh or frozen. Also, the frozen beans and the frozen peas were higher in vitamin C than their fresh counterparts. These results may have something to do with the way fresh vegetables are stored.
Vitamins B and C are water-soluble and they are affected by light. If the fresh vegetables are stored in the supermarket under lights for a long time then there will be a loss of vitamin C and B. In comparison, freezing and packaging vegetables quickly can actually lock nutrients in. Quite often today in the food industry, a product (such as vegetables) goes straight from harvesting to the processing plant and then to freezing in a fairly short period of time.
Folic acid was the other vitamin assessed. This vitamin is vital to red blood cell formation and the regeneration of all cells. Once again, the results weren't what you’d expect.
There was no difference when it came to folate levels for the beans, carrots, corn, broccoli or peas. The only difference that showed up occurred with the spinach; the market-fresh spinach was significantly higher in folic acid than the frozen spinach. It may just be that it was fresher and just harvested as opposed to the frozen product, which may be older. All in all, the results definitely did not suggest that vegetables bought from the market’s fresh section were superior to those from the supermarket's frozen section.
If we look past this study, others worldwide have shown that frozen vegetables, at the point of consumption, are nutritionally similar to fresh vegetables.
An investigation by Favell, of the United Kingdom, is one of the more comprehensive in this area. Results showed consistently that the nutrient content of frozen vegetables is at least equal to and sometimes better than that of fresh vegetables. Favell analyzed the vitamin C content of fresh produce (peas, green beans, carrots and spinach) against the same vegetables that were harvested, prepared, and then quick-frozen under normal commercial conditions.
The fresh samples showed a rapid loss of vitamin C from all vegetables at ambient temperature (20 degrees Celsius or 68 degrees Fahrenheit), and this rapid loss was also seen under chilled conditions (4 degrees Celsius or 39.2 degrees Fahrenheit) for spinach and green beans.
Interestingly, frozen spinach was higher in vitamin C than fresh spinach stored for more than one day at ambient temperature. Frozen spinach was also higher in vitamin C than fresh spinach stored chilled for more than two days.
Frozen green beans were higher in vitamin C than fresh beans stored at ambient and chilled temperatures for more than one day.
Frozen peas were higher in vitamin C than fresh peas that were stored at room temperature for three days. Frozen peas were equal in vitamin C to fresh peas stored chilled for 14 days.
Frozen carrots were higher in vitamin C than fresh carrots stored at both chilled and ambient temperatures.
Vegetables contain an array of vitamins and minerals and phytonutrients (potent health promoting plant-derived compounds). As I mentioned previously, while these investigations may have only analyzed one or two vitamins, those selected (vitamin C and folate) are considered good measures of freshness and nutritional quality. Therefore, based on the data, it’s safe to assume that the nutrient content of frozen vegetables is at least equal to and sometimes better than that of fresh vegetables.
I admit that I like the taste of fresh produce. However, this research did open my eyes and I hope it cleared up a few questions for you too. It’s good to know that the frozen variety is definitely not a compromised choice, and for people that like to eat a number of small meals each day, it may be a much more convenient (even healthier) choice.
Source: Heinz Wattie's Australasia/ New Zealand Institute for Crop and Food Research/ Nutrition Australia/ New Zealand Nutrition Foundation. Favell, United Kingdom, 1998.
