| LE 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?
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“90% of women and 71% of men get
less than the RDA for vitamin B6.” Dietary vitamin B-6 intake
and food sources in the US population: NHANES II, 1976-1980.
Kant AK, et al. 1990.
“Men with the lowest amount of
vitamin C have a 62% increased risk of cancer and a 57%
increased risk of dying from any cause.“ Vitamin C status and
mortality in US adults. Loria CM, et al. Am J Clin Nutr
72:139-45, 2000.
“Lutein and zeaxanthin reduce the
incidence of cataract by 22%.” A prospective study of
carotenoid and vitamin A intakes and risk of cataract
extraction in US women. Chasan-Taber L, et al. Am J
Clin Nutr 70:509-16, 1999.
“People with low levels of
retinol, beta-carotene, vitamin E and selenium are more likely
to get cancer.” Serum retinol, beta-carotene, vitamin E and
selenium as related to subsequent cancer of specific sites.
Comstock GW, et al. Am J Epidemiol 135:115-21,
1992.
“Supplemental vitamin D reduces
the risk of colon cancer by half compared to dietary vitamin D
which reduces it 12%.” Calcium, vitamin D, and dairy foods and
the occurrence of colon cancer in men. Kearney J, et
al. Am J Epidemiol 143:907-17, 1996.
“The area of China with the
lowest micronutrient intake has the highest rate of cancer.
Supplementation with vitamin E, selenium and beta-carotene
lowers the rate.” Vitamin/mineral supplementation and cancer
risk: internationaal chemoprevention trials. Blot WJ.
Proc Soc Exp Biol Med 216:291-6, 1997.
“American children have
inadequate levels of vitamin E.“ Vitamin E status of US
children. Bendich A. J Am Coll Nutr 11:441-4, 1992.
“Flavonoids protect against
stroke.” Dietary flavnoids, antioxidant vitamins, and
incidence of stroke: the Zutphen study. Keli SO, et al.
Arch Intern Med 156:637-42,
1996. | |
What’s for dinner
The USDA advises
that we should be eating 3 to 5 servings of vegetables plus 2 to 4
servings of fruit a day to maintain health. (A serving is one cup of
something raw and leafy or one-half a cup of something either not leafy or
cooked-or 3/4 cup of vegetable juice). That is potentially 9 cups of
vegetables and fruit a day. That’s a lot of lettuce. Are people doing
this?
Harry Balzer is vice president of NPD Group, a firm that
gathers information on the eating habits of Americans. His data says no
way. According to him, the preferred American meal is one-dish, already
prepared. Unless a vegetable can be squirted out of a bottle, it’s a
nonentity. Why? We’re in a hurry. Vegetables are considered side dishes,
and Americans don’t have time for such frivolity. The decline is
relentless. Within the last 15 years, the percentage of all dinners
including a vegetable (other than salad or potatoes) dropped 10%. It’s now
41%.
This raises a big question. If people are not eating their
vegetables, how are they getting their vitamins? The answer is they’re
not. Study-after-study show that Americans don’t meet the RDAs for many
nutrients. That’s not good considering that RDAs are probably too low to
keep most people in optimal health to begin with.
Americans know
what they should be eating. They’re just not doing it. And they’re not
likely to. According to Balzer, for example, pizza is one of America’s
favorite meals. It fulfills, he says, the American ideal of being easy and
fast, liked by old and young, and easy to clean up. If you blot it with a
paper towel, throw on some pineapple, and use your imagination, it even
seems to fit with the food pyramid. What else are people eating? Bread,
doughnuts, pasta, cheese, beef and milk. Without fortified cereal,
Americans would not come close to meeting RDAs.
Yes, but what about
the produce section? Isn’t it filled with resealable bags full of
wholesome, scrubbed little carrots, prewashed salad greens and spinach?
Somebody must be buying them, or they wouldn’t be there, right? According
to Balzer, those puppies are highly successful, raking in a billion
dollars in sales ($100M is considered successful for a new food product).
But the fact that people are buying them doesn’t mean they’re eating them.
The reality is that onions are most-often served vegetable in America.
Tomatoes (including ketchup) are second.
According to one study,
less than one-third of Americans get the minimum five servings of fruits
and vegetables a day, let alone the recommended nine. According to
Balzer’s data, the percentage of Americans who buy healthy groceries is
about 10%. The other 90% relies on ketchup, onions, fat-free snacks, ice
cream, cheese and Sweet Tarts™ as their source of nutrition. Now we find
out that even if a person accidentally eats a vegetable, it may not
contain the nutrients it’s supposed to. What can a person do?
Vitamin supplements work
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"...the nutritional content of produce is
not as important as things like appearance and big yield. In
other words, the view of commercial growers is that food is a
product in the same way that running shoes are a product.
Looks are more important than
substance." | |
Supplements have proven their worth in scientific studies. Cancer,
heart attacks, bone loss, stroke and macular degeneration-most any
degenerative disease you can think of can either be prevented by, or
ameliorated by, the right nutrients given in supplement form. Over the
long term, the benefits can really add up. For example, nurses who took
multi-vitamins containing folic acid for fifteen years slashed their risk
of colon cancer by 75%. Folate from food didn’t work as well. No one knows
why, although bioavailability problems may be to blame. It’s estimated
that about 90% of the population gets less folate per day than necessary
for health (400 micrograms).
In the same study, nurses who took
multi-vitamins containing vitamin B6 reduced their risk of heart disease
by 30%. The more B6 they took, the lower the risk. Could a high potency,
high quality supplement reduce risk even more? We don’t know, but a study
from Norway shows that a combination of vitamin B6 and folate reduces
homocysteine 32% within five weeks in healthy individuals. This has the
potential to significantly lower the risk of heart attack and stroke.
Other studies show that for every decade of life, plasma concentrations of
B6 decrease, and that people who take supplements have a much greater
chance of meeting RDAs than those who don’t.
There are good
reasons to take supplements. The bioavailability of the nutrients in
supplements (assuming you buy high-quality) is 100% compared to food which
is very unpredictible when it comes to bioavailability. Nutrient content
also appears unpredictible. If the vitamin drain is confirmed, it will
mean that people cannot count on vegetables and fruit to be the packages
of concentrated nutrients they’re supposed to be. In a time when most
people aren’t coming close to getting five, let alone nine, servings of
fruits and vegetables, it seems pointless to ask them to eat more to get
the same nutrients.
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.
The USDA can be accessed at
http://www.lef.org/magazine/mag2001/www.usda.gov.
The food tables are available online.
The folks who do the food
testing are in the Agricultural Research Service which can be accessed at
http://www.lef.org/magazine/mag2001/www.ars.usda.gov.
*1963 values have been set at 100%
References
Cleveland LE,
et al. 2000. Dietary intake of whole grains. J
Am Coll Nutr 19 (3 Suppl):331S-38S.
Composition of Foods
(Raw, Processed, Prepared): Agriculture Handbook No. 8. USDA Agricultural
Research Service. 1963.
Cuskelly GJ, et al. 1996. Effect of
increasing dietary folate on red-cell folate: implications for prevention
of neural tube defects. Lancet
347:657-9.
Giovannucci E, et al. 1998. Multivitamin use, folate and
colon cancer in women in the nurses’ health study. Ann Intern Med 129:517-24.
Manore MM, et
al. 1989. Plasma pyridoxal 5’-phosphate concentration and dietary vitamin
B-6 intake in free-living, low-income elderly people. Am J Clin Nutr 50:339-45.
Mansoor MA, et
al. 1999. Plasma total homocysteine response to oral doses of folic acid
and pyridoxine hydrochloride (vitamin B6) in healthy individuals. Oral
doses of vitamin B6 reduce concentrations of serum folate. Scand J Clin Lab Invest 59:139-46.
NPD
Group, Inc. has a website at www.npd.com. Highlights from the 15th Annual
Report on Eating Patterns in America are available online.
Organic
Gardening’s letter to Dan Glickman, and the response of Phyllis E. Johnson
of the USDA - see www.organicgardening.com.
Rimm EB, et al. 1998.
Folate and Vitamin B6 from diet and supplements in relation to risk of
coronary heart disease among women. JAMA
279:359-64.
Rose CS, et al. 1976. Age differences in vitamin B6
status of 617 men. Am J Clin Nutr
29:847-53.
Subar AF, et al. 1998. Dietary sources of nutrients
among US adults, 1989 to 1991. J Am Diet
Assoc 98:537-47.
Subar AF, et al. 1989. Folate intake and
food sources in the US population. Am J Clin
Nutr 50:508-16.
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