HEALTH:Produce has been losing vitamins and minerals over the past half-century

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HEALTH:Produce has been losing vitamins and minerals over the past half-century

 

By Deborah K. Rich, Special to The Chronicle Saturday, March 25, 2006

 

The fruits and vegetables that our parents ate when they were growing up were

more nutritious than the ones we'll serve our children tonight. On average, the

produce we grow in the United States has lower levels of several vitamins and

minerals today than it did 50 to 60 years ago. By growing or buying and eating

organic produce, however, we can make up much of the difference. Organically

grown fruits and vegetables are proving to have higher levels of antioxidants,

vitamins and minerals than their conventionally grown counterparts.

Donald R. Davis, a research associate with the Biochemical Institute at the

University of Texas, Austin, recently analyzed data gathered by the USDA in 1950

and 1999 on the nutrient content of 43 fruit and vegetable crops. He found that

six out of 13 nutrients had declined in these crops over the 50-year period (the

seven other nutrients showed no significant, reliable changes). Three minerals,

phosphorous, iron and calcium, declined between 9 percent and 16 percent.

Protein declined 6 percent. Riboflavin declined 38 percent and ascorbic acid (a

precursor

of vitamin C) declined 15 percent.

A study of the mineral content of fruits and vegetables grown in Britain between

1930 and 1980 shows similar decreases in nutrient density. The British study

found significantly lower levels of calcium, magnesium, copper and sodium in

vegetables, and of magnesium, iron, copper and potassium in fruit.

The report concludes that the declines indicate " that a nutritional problem

associated with the quality of food has developed over those 50 years. "

The decline in our produce's nutritional value corresponds to the period of

increasing industrialization of our farming systems. As we have substituted

chemical fertilizers, pesticides and monoculture farming for the natural cycling

of nutrients and on-farm biodiversity, we have lessened the nutritional value of

our produce. Integrated

well-established organic farming systems can counter the decline.

Good science comparing the nutritional value of organic and conventional foods

is accumulating rapidly. It isn't uncommon for researchers to find that the

higher nutrient levels in organic produce completely offset the

declines Davis found in conventional produce. " What all our data shows, " says

Charles Benbrook, chief scientist at the Organic Center and a former executive

director of the Board on Agriculture of the National Academy of Sciences, " is

that whenever there's been a valid comparison between conventional and organic,

organic is virtually never lower than conventional and, in a significant number

of cases, it's higher.

Sometimes it's significantly higher in several important nutrients. "

For example, Virginia Worthington, a clinical nutritionist who earned her

doctorate in nutrition at Johns Hopkins, published a review in 2001 of 41

studies comparing the nutritional value of organic and conventional produce.

After tallying the data across all the studies, Worthington concluded that

organic produce had on average 27 percent

more vitamin C, 21.1 percent more iron, 29.3 percent more magnesium and 13.6

percent more phosphorous than conventional produce.

Benbrook released a review in 2005 of the research comparing antioxidant levels

in conventional and organic foods. In humans, antioxidants reduce damage to

cells and DNA from free radicals (molecules generated by

metabolic processes within the body), and thereby promote cardiovascular health,

inhibit the reproduction of cancerous cells, slow the aging process in the brain

and nervous systems, and lessen the risk and/or severity of Alzheimer's,

Parkinson's and Huntington's diseases. Benbrook found that in 85 percent of the

comparable data points, produce from organic farms had higher levels of

antioxidants than did produce from conventional farms. On average, antioxidant

levels in organic produce were 30 percent higher.

Earlier this year, a Swedish team of scientists demonstrated that extracts from

organically grown strawberries slowed the proliferation of colon and breast

cancer cells to a significantly greater degree than extracts from conventional

strawberries did. The levels of all the antioxidants analyzed by the team were

higher in the organic

strawberries than in the conventional.

" As someone that has been involved with science and science policy for my whole

life, " says Benbrook, " I think the scientific case has been made for organic

produce. The case has been made firmly enough so that it is appropriate and,

indeed, irresponsible at this point not to tell consumers straight up that

choosing organic fruits and vegetables probably delivers nutritional benefits

because of the higher levels of antioxidants and vitamins and minerals. "

 

To read the full and extensive article go to

http://sfgate.com/cgi-bin/article.cgi?f=/c/a/2006/03/25/HOG3BHSDPG1.DTL

 

 

Caroline Collard

 

World's first fully certified organic skin, body, oral and health care products

www.happyandhealthy.org.uk

 

 

 

 

 

 

 

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