The oldest running monthly magazine in the US and one of the staples of popular science highlighted the declining nutritional value of American produce in a 2011 blog post called “Dirt Poor: Have Fruits and Vegetables Become Less Nutritious?”
Here at Hygeia we are a part of this discussion, having recently created a new Nutrient Decline section that discusses the generally negative nutritional impact of industrial agriculture, which prioritizes yield, shelf life, pest control, and other crop and food attributes over nutritional quality.
Our friend and colleague Don Davis, who is quoted in the Scientific American post, conducted a seminal study on the topic, published in 2004. His team analyzed USDA nutritional data from 1950-1999 for 43 different fruits and vegetables and found median declines in protein, calcium, phosphorus, iron, vitamin B-2, and vitamin C.
Davis chalks this loss in nutritional value up to modern crop varieties that grow larger and more quickly, “but their ability to manufacture or uptake nutrients has not kept pace with their rapid growth.”
The 2004 paper reported the following median declines in key nutrients:
- Calcium levels down 16%
- Iron down 15%
- Vitamin B-2 down 38%
- Vitamin C down 15%
The Scientific American piece reported something we cover extensively on Hygeia Analytics – organic farming. The article stated that organic farming is “good for the soil, the produce and its consumers. Those who want to get the most nutritious fruits and vegetables should buy regularly from local organic farmers.”
Several studies have clearly shown higher concentrations of essential nutrients and phytochemicals in organic foods, including some nutrients that are generally deficient in typical American diets. In particular, a 2013 large-scale and systematic review of existing data concluded that organic plant-based foods had almost 20% more antioxidants on average, and over 50% more of certain flavanones and anthocyanins.
Researchers have also measured nutritional differences in milk, and found significant variation between organic and conventional milk, and more recently between conventional milk and the grassmilk produced by cows who eat only grass and forage-based feeds. They found that organic whole milk has 62% more heart-healthy omega-3 fatty acids than conventional whole milk. Whole grassmilk was even more nutritious, with a whopping 146% more omega-3s than conventional milk. See our suite of dynamic presentations and graphics about the grassmilk study here.
As with nutrient decline in fruits and vegetables, several factors appear to play a role in the nutritional quality of milk. The way cows are fed, what breed they are, and the amount of milk they produce each day all play a role in overall nutrient content.
This latest story shines badly needed light on the degree of nutrient decline in the U.S. food supply. Another negative trend runs parallel to nutrient decline — rising sugar and starch levels in fruits and vegetables. This is why organic fruit often delivers substantially more nutrients per calorie of fruit consumed, in effect delivering more nutrition bang for the space taken up within a person’s daily need for calories. This is another reason why both food choices and food quality matters.
Roddy Scheer and Doug Moss (eds), “Dirt Poor: Have Fruits and Vegetables Become Less Nutritious?,” Scientific American, 2011.