Even if you eat a healthy diet — including lots of fruits and vegetables — you may be surprised to learn that you’re not getting the amount of nutrients you think you are. That’s because research shows the vitamin and mineral content of many common fruits and vegetables has been declining in the last decades.
You would need to eat 2½ times as much broccoli today to get the same amount of calcium as you would have in 1950. And twice as many onions to get the same amount of iron. In fact, a study comparing the nutrient value for 43 garden vegetables from 1950 to 1999 shows an average decrease in nutrient content of 25-50%.
Research on popular fruits like apples and oranges shows the same significant losses of vitamin and mineral content. Eleven of 12 fruits showed reduced amounts of iron, 10 with loss in calcium and 9 with loss of vitamin A. The drop in iron in several fruits — including oranges, tangerines and strawberries — was quite extreme. Tangerines dropped 65% for calcium content and 75% for iron (I’m not sure what caused the increase for vitamin A — perhaps it’s related to the fertilizers used).
Here are more examples of nutrient loss in vegetables and fruit using the USDA’s standard nutrient data for 1950 and for 1999.
Here’s another intriguing example about nutrient decline. During the 1960s scientists found an Arctic campsite of explorers from 100 years earlier, which included a can of peaches frozen in heavy syrup. Somebody had the forethought to test the peaches. Even accounting for the food value lost from being frozen, the canned peaches from the 1860s were 50% higher in every measurable nutrient than modern canned peaches.
If you are concerned about getting enough nutrients to maintain good health and build bone, it’s still a good idea to increase your intake of vegetables and fruits. That said, I strongly suggest you consider supplementation to make sure you’re getting all the nutrients you need — no matter what you eat — especially if you are trying to build bone and overcome years of neglect.
References:
Davis, D. R., M. D. Epp, and H. D. Riordan. 2004. Changes in USDA food composition data for 43 garden crops, 1950 to 1999. Journal of the American College of Nutrition 23(6):669–682.
Jack, A. 1998. Nutrition under siege. One Peaceful World Journal, Spring:1, 7–8.
Jack, A. 2005.America’s vanishing nutrients- Decline in fruit and vegetable quality poses serious health and environmental risks. Amberwaves, Becket, MA.
Mayer, A. M. 1997. Historical changes in the mineral content of fruits and vegetables. British Food Journal 99(6):207–211.