Leading Edge Magazine March 2001

Vegetables Without Vitamins

Imagine the surprise of going online and discovering that the vitamin and
mineral content of vegetables has drastically dropped.

That's what happened to nutritionist Alex Jack, when he went to check out
the latest US Department of Agriculture food tables. The stunning revelation
came after Jack compared recently published nutrient values with an old USDA
handbook he had lying around. Some of the differences in vitamin and mineral
content were enormous-a 50% drop in the amount of calcium in broccoli, for
example. Watercress down 88% in iron content; cauliflower down 40% in
vitamin C content-all since 1975.

Jack took his findings to the USDA, hoping for a reasonable explanation.
That was two years ago. He's still waiting. So is Organic Gardening
magazine, which published an open letter, seeking an explanation from Dan
Glickman, Secretary of Agriculture. Glickman didn't respond, but USDA
employee, Phyllis E. Johnson did. Johnson (who is head of the Beltsville
area office), suggested to Organic Gardening that the nutrient drain should
be put in context. According to her, the 78% decrease in calcium content of
corn is not significant because no one eats corn for calcium. She further
explains that the problem may not even exist at all; that the apparent
nutrient dips could be due to the testing procedures. For example, "changes
in the public's perception of what the edible portion is may determine what
parts have been analyzed over time." In other words, back when the old food
tables were made up, people may have been eating the cobb too, so they got
more nutrients.

The vitamin drain

We decided to look into this further. Jack had used a 1975 version of the
food tables for his research. We dredged up a 1963 version. After comparing
the nutrient values for over a dozen fruits and vegetables, it was clear
that the nutrient value of many foods has dropped, in some cases
drastically. For example, the amount of vitamin C in sweet peppers has
plummeted from 128 mg to 89 mg. The vitamin A in apples has dropped from 90
mg to 53 mg. The fall-offs seem to be limited mostly to vegetables, and some
fruits.

Some vegetables appear to be gaining vitamins-at least vitamin A. Carrots,
for example, have more of the vitamin now than they did in 1963. Why is a
mystery. But the phenomenon has apparently occurred just in the nick of
time. The National Academy of Sciences has issued an alert that it takes
twice as many vegetables to get the daily requirement of vitamin A as
previously thought. Carrots and pumpkin are exempt from the caveat.

Despite the apparent increase of vitamin A in carrots, most vegetables are
losing their vitamins and minerals. Nearly half the calcium and vitamin A in
broccoli, for example, have disappeared. Collards are not the greens they
used to be. If you're eating them for minerals and vitamin A, be aware that
the vitamin A content has fallen from 6500 IUs to 3800 IUs. Their potassium
has dropped from from 400 mg to 170 mg. Magnesium has fallen sharply-57 mg
to 9. Cauliflower has lost almost half its vitamin C, along with its thiamin
and riboflavin. Most of the calcium in pineapple is gone-from 17 mg (per 100
grams raw) to 7. And the list goes on and on.

The USDA refuses to act

What's the deal on this nutrient drain? We decided to ask USDA ourselves, so
we contacted the head of the USDA Agricultural Research Service, whose job
it is to track the vitamins in food, among other things. Mr. Edward B.
Knipling responded to our inquiry with a restatement of Ms. Johnson's letter
to Organic Gardening magazine. So we pressed for a better answer. Isn't the
agency concerned that Americans may not be getting the vitamins they think
they are? What about the food pyramid? Won't a nutrient drain upset the
pyramid? Already the National Academy of Sciences is telling us our
vegetables don't have as many vitamins as they're supposed to. Will the USDA
double the required servings of vegetables to make up for the vitamin loss?
So far, no answer from the agency.

The question is, what is the nature and extent of the problem? Vegetables
are a major source of nutrition. Without them, humans miss out on important
vitamins, minerals and phytonutrients. Many nutrients (such as folate)
weren't measured in the past. If they are also disappearing, the extent is
unknown. What about more exotic nutrients such as flavonoids, or compounds
like I3C? These aren't tracked by the USDA. Are they disappearing also?

The USDA is apparently unconcerned and not interested in the vitamin drain,
despite its mandate to ensure high quality safe foods. In her letter to
Organic Gardening, Ms. Johnson said that the nutritional content of produce
is not as important as things like appearance and big yield. In other words,
Ms. Johnson espouses the view of commercial growers that food is a product
in the same way that running shoes are a product. Looks are more important
than substance. That view of vegetables and fruits reduces your spinach
salad to pretty roughage, and your chances of meeting RDAs to slim.