Fruits and vegetables sold in Canadian supermarkets today contain far fewer nutrients than they did 50 years ago, according to an analysis conducted by The Globe and Mail and CTV News.
Vital vitamins and minerals have dramatically declined in some of our most popular foods, including potatoes, tomatoes, bananas and apples, the analysis reveals.
Take the potato, by far the most consumed food in Canada. The average spud has lost 100 per cent of its vitamin A, which is important for good eyesight; 57 per cent of its vitamin C and iron, a key component of healthy blood; and 28 per cent of its calcium, essential for building healthy bones and teeth.
It also lost 50 per cent of its riboflavin and 18 per cent of its thiamine. Of the seven key nutrients measured, only niacin levels have increased.
The story is similar for 25 fruits and vegetables that were analyzed. But Health Canada refused to comment on the findings, saying the debate was an academic one.
The academics, for their part, are intrigued, but not alarmed.
Modern farming methods, long-haul transportation and crop-breeding practices are all believed to be contributing to the drop in vitamins and minerals.
Phil Warman, an agronomist and professor of agricultural sciences at Nova Scotia Agricultural College, said there is no doubt the nutritional content of food is different today, due to the emphasis on producing cheap food.
"The emphasis is on appearance, storability and transportability, and there has been much less emphasis on the nutritional value of fruits and vegetables," he said.
Dr. Warman said crops are bred to produce higher yields, to be resistant to disease and to produce more visually attractive fruits and vegetables, but little or no emphasis is placed on their vitamin or mineral content. While there is little evidence, anecdotal or otherwise, that the changes are resulting in major nutritional deficiencies in the general population, Dr. Warman emphasized that consumers should care about the issue because it is the nutrients, not the appearance, that give food value.
"I care because I want to eat a product that is as high in nutritional value as possible. Otherwise, I would eat sawdust with nitrogen fertilizer," he said.
Tim Lang, a professor at the Centre for Food Policy in London, England, agreed. "It's an issue of consumer rights," he said. "We think of an orange as a constant, but the reality is it isn't."
In fact, you would have to eat eight oranges today to get the same amount of vitamin A your grandparents got from a single orange. And you would need to eat five to get the same level of iron. However, the amount of vitamin C has increased slightly.
Dr. Lang said declining nutrient levels may prove to be a health issue because we are only beginning to understand how important micronutrients are to disease prevention. "The argument that it doesn't matter because we overconsume is complacent. . . . Nutrient density might also be important."
Alison Stephen, director of research at the Heart and Stroke Foundation of Canada, said the biggest nutritional problem is that most Canadians do not eat anywhere near the recommended five to 10 servings of fruits and vegetables daily.
But she is not unduly worried about today's consumers failing to get their required vitamins and minerals. "A lot of our foods today are fortified -- milk, bread, apple juice, cereal," she said.
In other words, grains and dairy products are far more important sources of essential nutrients than they were in the past.
To conduct the analysis, The Globe and Mail and CTV examined food tables that were prepared by government researchers in 1951, 1972 and 1999, and compared the nutrients available from 100 grams of the given food.
The results were almost identical to similar research conducted in the United States and Britain. The U.K. research was published in the British Food Journal, a peer-reviewed, scientific publication, while the U.S. data have been published only in alternative-health journals.
According to the Canadian data, almost 80 per cent of foods tested showed drops in calcium and iron; three-quarters saw drops in vitamin A, and half lost vitamin C and riboflavin; one-third lost thiamine and 12 per cent lost niacin.
But some experts said the explanation for the decline might be found in testing and sampling methods.
Len Piché, an associate professor of nutrition at Brescia College in London, Ont., questioned the accuracy of the numbers, saying testing methods were not great in 1951, so we may only now be getting a true idea of the nutrients in fruits and vegetables. "Did they really go down, or do we just have better techniques for analyzing those nutrients?" he wondered.
However, Dr. Piché said the issue is one Health Canada should examine. "If there's a problem, I'm confident the government will take it seriously and do the necessary research to address it," he said.
In the analysis, the biggest loser was broccoli, a food that epitomizes the dictates of healthy eating. All seven of its measurable nutrients declined, notably calcium, which fell 63 per cent, and iron, which dropped 34 per cent. Broccoli is often cited as an excellent source of calcium and iron. Nutrition by the numbers
Percentage change in the nutrient content of fruits and vegetables in Canada between 1951 and 1999.
Food...... Calcium... Iron... Vitamin A.. Vitamin C.. Thiamine.. Riboflavin.. Niacin
Apple 20.0 -55.3 -41.1 16.0 -75.0 -66.7 -30.0 Banana -23.8 -41.7 -81.2 -13.0 0 -100.0 -1.4 Broccoli -62.8 -33.9 -55.9 -10.1 -40.0 -42.9 -2.7 Onion -37.5 -52.9 -100.0 -54.8 56.9 -41.2 135.3 Potato -27.5 -58.6 -100.0 -57.4 -14.6 -50.0 44.9 Tomato -55.7 -18.8 -43.4 -1.6 0 21.8 46.3
André Picard