Industrial Farming is Giving us Less Nutritious Food

[Guest guest]

Industrial Farming is Giving us Less Nutritious Food

By Cheryl Long

_http://www.motherearthnews.com/Sustainable-Farming/Nutrient-Decline-Industr

ial-Farming.aspx?page=2_

(http://www.motherearthnews.com/Sustainable-Farming/Nutrient-Decline-Industrial-\

Farming.aspx?page=2)

 

 

We now have solid, scientific evidence of this troubling trend. For

example:

* In wheat and barley, protein concentrations declined by 30 to 50

percent between the years 1938 and 1990.

* Likewise, a study of 45 corn varieties developed from 1920 to

2001, grown side by side, found that the concentrations of protein, oil and

three amino acids have all declined in the newer varieties.

* Six minerals have declined by 22 to 39 percent in 14 widely grown

wheat varieties developed over the past 100 years.

* Official U.S. Department of Agriculture (USDA) nutrient data shows

that the calcium content of broccoli averaged 12.9 milligrams per gram of

dry weight in 1950, but only 4.4 mg/g dry weight in 2003.

All of this evidence has been assembled and rigorously reviewed by Dr.

Donald R. Davis, a now (mostly) retired chemist from the University of Texas.

So what’s causing these declines?

The evidence indicates there are at least two forces at work. The first is

what agriculture researchers call the environmental “dilution effect.â€

Davis notes that researchers have known since the 1940s that yield increases

produced by fertilization, irrigation and other environmental means used in

industrial farming tend to decrease the concentrations of minerals in

those plants. These techniques give growers higher yields, and consumers get

less expensive food. But now it appears there’s a hidden long-term

cost — 

lowered food quality.

For example, a study of phosphorous fertilizer on raspberries found that

applying high levels of phosphorus caused the yield to double and

concentrations of phosphorus to increase in the plants, but meanwhile levels of

eight

other minerals declined by 20 to 55 percent!

The other force at work is what Davis calls the genetic dilution

effect — 

the decline in nutrient concentration that results when plant breeders

develop high-yielding varieties without a primary focus on broad nutrient

content. That’s what the studies of wheat, corn and broccoli confirm.

In fruits, vegetables and grains, usually 80 to 90 percent of the dry

weight yield is carbohydrates — sugars and starches (the last things we

need

more of in the American diet). Davis says that when breeders (and growers)

specifically choose varieties for high yields, they are selecting mostly for

the highest amounts of carbohydrates.

“These studies suggest to me that genetic dilution effects may be common

when selective breeding successfully increases crop yield,†Davis says. USDA

data indicate that yields have increased an average of 1.8 fold for 24

vegetables and 1.3 fold for six fruits over the past 30 years.

What can we do?

Vegetables and fruits are our richest sources of many vitamins and

minerals. It seems likely that those of us who grow food gardens (or shop at

farmers markets) will get more nutrient-dense foods if we grow (or pay a premium

for) older, lower-yielding heirloom varieties. Odds are good that heirloom

varieties may be more nutritious than current supermarket fare. Plus, using

organic methods such as moderate amounts of slow-release fertilizers

should help us get maximum nutrition from our homegrown produce. And most

important of all, Davis points out that the nutrient declines in processed

foods

are much deeper and broader than the declines in fresh, whole foods.

You can review the full study by requesting **Declining Fruit and

Vegetable Nutrient Composition,** HortScience, 2009; 44:15, at your local

library.