Saturday, March 22, 2008

How Fresh is Fresh? (Vital vitamins)

Almost every day, we're bombarded by television and radio programmes, books, newspapers and magazine articles, all telling us that the way to good health is a low-fat, high-fibre diet loaded with fresh vegetables and fruit. So we scour the supermarket shelves for the cream of the crop and (hopefully) plan our family menus around the suggested mix of 12% protein, 30% fat with the 58% balance made up of complex carbohydrates in the form of breads and other grains, pulses, fruits and vegetables. Many of us have taken things one step further, reducing animal protein, lowering fats and upping the quota of fresh produce. In theory at least, we're doing all the right things.

There's just one potential fly in the ointment. Optimum nutrition relies on optimum foods - in many instances, ones that are as close to their natural state as possible and that are on our forks almost as soon as they're out of the ground. In this respect we are in the hands of our suppliers and we owe it to ourselves to shop wisely, to make informed choices on available options (wilted 'fresh' carrots - or would frozen or canned be better?) and to prepare and cook fresh foods as carefully and conservatively as we can.

Diet Start

But before we begin to look at the passage of produce from farmer to family, let's consider the foods in which freshness is a real priority:

Vital vitamins

First on the list has to be the fruit and vegetable group. Although this group is one of our most important sources of vitamins (notably A and C) and minerals, we know there is a deterioration in the nutrient content of the produce that starts as soon as it's harvested and which can be accelerated by poor storage, inadequate transportation and excessive exposure to climatic extremes. Whilst few would suggest that a four-day-old carrot isn't worth eating, none would argue with the fact that a four-minute old carrot has more to offer!

Remembering that one of the most critical factors affecting vitamin loss is the storage of vegetables and fruits after harvesting. Asparagus can lose up to 50% of its vitamin C after one week of storage at 0 °C and a staggering 91% if stored at 21 °C. Potatoes, too, are vulnerable: stored at room temperature they lose about 15% of their vitamin C content each month. And apples, when stored under domestic conditions, are reduced to about one-third of their vitamin C value after only 2-3months.

Even worse, green cabbage loses almost all of its vitamin C after just a few days. Orange juice, as long as it is stored in sealed containers, retains almost all of its vitamin C, but once thecontainer is opened, between 30-50% will be lostin one week.

However, since munching away in a farmer's field isn't a practical option for most of us, we need to know how to make the best and freshest choices from available produce. Let's consider a quick comparison between the food values of vitamins A and C, plus the iron and calcium content, of 8 popular fruits and vegetables in their fresh state and when they are cooked.

The most interesting fact to emerge is that in almost every case, the fresh foodstuff offers higher values (in the few cases where cooked values appear to be higher, it's primarily because the raw food has become more compact as part of the cooking process).

Apart from fruits and vegetables, however, there are other foodstuffs in which freshness is unquestionably a desirable factor. Top of the list are the protein foods - meat, chicken, fish and eggs. Freshness here doesn't relate so much to the nutrient value of the foodstuff as to its safety. (For example, egg consumption in the UK recently took a terrific tumble when the then Minister of Health, Edwina Currie,linked them to possible salmonella risk.)

Then there are the foods presented to us as fresh yet which have undergone some form of processing, preserving or packaging treatment. These include fresh fruit juices, fresh milk and herbs and spices, which have been subjected to vacuum packaging, pasteurisation or irradiation, among other processes.

Finally, there are frozen foods. Not technically fresh, for many of us some frozen products have become more a question of necessity than convenience. Really fresh fish is difficult to obtain inland, while fresh peas, for example, have a limited season and an even more limited availability countrywide, yet offer excellent sources of fibre, minerals including iron (commonly inadequate in women), and vitamins. In the absence of fresh, the frozen variety, which retain most of these benefits, are the closest to the real thing that we may be able to get.

Having established that fresh is undeniably best, and extending that principle to the point of saying freshest is best, let's now look at the methods whereby fruit and vegetable produce makes its way from the farm to your shopping basket, for this is where we need to know who, among all our suppliers, is going to give us the freshest of choices.

... andjoyohoxing