Download Chapter 6 Thinking of fruits and vegetables in a very different way

Chapter 6
Thinking About Fruits and
Vegetables in a Very Different Way
In all things of nature there is
something of the marvelous
Aristotle

As impressive as the benefits of
whole grains are, the benefits of
eating fruits and vegetables are
even greater.

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
Fruits and vegetables are the real
phytochemical power houses.
One serving of vegetables or fruits can
have 100’s of different phytochemicals
Different fruits and vegetables have
different phytochemicals. Eating a
variety is the best way to get all of them.
Common Phytochemicals

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

Carotenoids
Beta-carotene
Lycopene
Lutein
Zeaxanthin
Organosulfurs
Flavinoids

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Phytosterols
Alkaloids
Tannins
Saponins
And many, many
others

Here are some pictures of some
phytochemicals
para-coumaric acid
Copy right by Michael Davidson
http://micro.magnet.fsu.edu/index.html
Optical microscopy techniques
para-coumaric acid
Saponin
Zeaxanthin
ajoene
Calcium Pectate
Lung cancer and vegetable intake
2.7
Relative risk
2.2
1.7
1.2
0.7
0.2
-0.3
0
100
200
300
400
500
Vegetable intake grams/day
Am Inst for Cancer Research, 19
Stomach cancer and vegetable
intake
2.7
Relative risk
2.2
1.7
1.2
0.7
0.2
-0.3
0
100
200
300
400
500
Vegetable intake grams/day
Am Inst for Cancer Research, 19
Stomach cancer and fruit intake
Relative risk
1.4
1.2
1
0.8
0.6
0.4
0
100
200
300
400
500
Fruit intake grams/day
Am Inst for Cancer Research, 19

So why are fruits and vegetables so
important?
Free Radicals are oxygen atoms
that are missing an electron
Where do free radicals come from?
Most are produced by our own bodies
 UV light
 burned food
 toxic chemicals
 Industrial
 automobile pollution
 unknown sources

Cigarette Smoke
One puff of smoke contains:
100,000,000,000,000,000
free radical species
Tobacco is responsible for 31% of all
cancers
If you are a smoker your life will be
shortened by 13 years on average
80
79.8
74.4
75
70
65.3
65
61.2
-14.5 yrs
60
-13.2 yrs
55
US Mean
Smokers
Males
Females
MMWR 1997;46:444-51
If one free radical steals an electron
from a strand of DNA, a mutation or
cancer has started.
 Most of these abnormal cells are
destroyed by our own bodies.
 It only takes one to slip through our
defenses for a cancer to take over

 Each
cell gets 10,000 free
radical attacks every day
How do we protect our
selves?
Eat more fruits, vegetables, and whole
grains.
Some phytochemicals are also anti-free
radicals (anti–oxidants). They have the
ability to donate an electron to a free
radical with out harming itself. It’s kind
of like having a spare electron.
The Typical American (Western)
Diet: What most Americans Eat
Red meat
 Processed meat
 Butter
 Potatoes
 Refined grains
 High fat dairy foods

There are few phytochemicals here
What we should be eating if
we want the health benefits

In 2001, 553,768 Americans died of
cancer. Of these deaths, 387,637
(70%) could have been prevented
with good nutrition, physical activity,
and avoiding tobacco

Over 230 different studies have
evaluated the impact of fruits and
vegetables on cancer. Fruits and
vegetables help prevent cancers of
the stomach, esophagus, lung, oral
cavity, pharynx, endometrium,
pancreas, and colon

When the people who consumed
the most fruits and vegetables were
compared to those who ate the
least, they had half the cancer risk.
The Cancer Process
Spontaneous or
inherited mutation
Abnormal
cell
Normal
cell
Repair
Carcinogen
Metastasis
Tumor
Cell proliferation
Where fruits, vegetables, and whole
grains can stop the cancer process
Spontaneous or
inherited mutation
Abnormal
cell
Normal
cell
Repair
Activated
carcinogen
Metastasis
Tumor
Cell proliferation
An Apple a day (with the skin)
Cancer cell spreading
1.09
0.89
0.69
peel
+flesh
0.49
flesh
peel
0.29
0.09
0
8
10
11
12
15
19
20
26
30
40
50
75 100
concentration
Sun, J Agric Food Chem 2002:50:7449
Why not just make a pill that
contains phytochemicals?
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The pill will never contain all the same
phytochemicals because we still don’t even
know what they are
Phytochemicals don’t work all by themselves.
They need the other chemicals with them.
The phytochemicals only appear to work when
they are in their natural food, not a pill
The dosages may be too high
Some of the pills are very
dangerous
Randomized clinical trial with 18,000
smokers and former smokers
 30 mg of beta-carotene plus vitamin A
 Followed for 4 years
 Studied terminated 2 years early

Omenn, N Engl J Med,1996, 334:(18)
Risk of Death
1.2
1.15
Placebo
1.1
1.05
Vitamin A and
beta-carotene
supplement
1
0.95
0.9
Risk of Death
Lung Cancer Death
1.5
1.4
1.3
Placebo
1.2
1.1
Vitamin A and
beta-carotene
supplement
1
0.9
0.8
Lung Cancer Death
Cardiovascular Disease
Death
1.3
1.25
1.2
1.15
Placebo
1.1
1.05
Vitamin A and
beta-carotene
supplement
1
0.95
0.9
0.85
0.8
Cardiovascular Disease Death
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In this and in many other studies the
supplements actually increased risk
Risk of many supplements are unknown
Supplement claims are unregulated. They
can say what ever they want.
Consumers tend to believe the marketing
hype of supplement makers.
No pill can compare with the benefits of eating
whole foods.
In other studies:

Long term supplementation with betacarotene had no effect on preventing
cancers or cardiovascular disease
What about Vitamin C?
500 mg of Vitamin C every day for
3 weeks caused more DNA
damage than the placebo group
 Vitamin C has no effect on cancer,
cardiovascular disease

Vitamin E

Long-term supplementation with
Vitamin E revealed no prevention of
CVD, stroke, or cancers
Blot, 1993; Stephens, 1996
What about a one-a-day
vitamin?
Some experts say there is no harm
in this, but neither is there any
evidence that it improves health
 If you are not going to eat a good
diet, a one-a-day vitamin probably
wouldn’t do any harm

Points to Remember
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Americans get suckered in to supplement
makers claims. Don’t get suckered in.
Our understanding of the functions of
phytochemicals and free radicals is very
limited.
Everyday the DNA in our cells gets attached
10,000 times by free radicals. Phytochemicals
can neutralize free radicals and help prevent
cancer.
Continued….
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Eating at least five or more servings of fruits
and/or vegetables everyday provides
significant protection against many cancers
and other diseases; even more servings per
day is better.
Whole foods are incredibly complex. Scientists
are just beginning to figure out how our bodies
use everything that is in the food we eat.
Consuming individual phytochemicals in
supplements is not recommended; eat whole
foods.