Chapter 6 Thinking About Fruits and Vegetables in a Very Different Way

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Chapter 6 Thinking About Fruits and Vegetables
in a Very Different Way
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• In all things of nature there is something of the
  marvelous
• Aristotle

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• 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
  100s of different phytochemicals
• Different fruits and vegetables have different
  phytochemicals. Eating a variety is the best way
  to get all of them.

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Common Phytochemicals

• Carotenoids
• Beta-carotene
• Lycopene
• Lutein
• Zeaxanthin
• Organosulfurs
• Flavinoids

• Phytosterols
• Alkaloids
• Tannins
• Saponins
• And many, many others

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• Here are some pictures of some phytochemicals

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Copy right by Michael Davidson http//micro.magnet
.fsu.edu/index.html Optical microscopy techniques
para-coumaric acid
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para-coumaric acid
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Saponin
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Zeaxanthin
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ajoene
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Calcium Pectate
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Lung cancer and vegetable intake
Relative risk
Vegetable intake grams/day
Am Inst for Cancer Research, 1997
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Stomach cancer and vegetable intake
Relative risk
Vegetable intake grams/day
Am Inst for Cancer Research, 1997
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Stomach cancer and fruit intake
Relative risk
Fruit intake grams/day
Am Inst for Cancer Research, 1997
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• So why are fruits and vegetables so important?

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Free Radicals are oxygen atoms that are missing
an electron
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Where do free radicals come from?

• Most are produced by our own bodies
• UV light
• burned food
• toxic chemicals
• Industrial
• automobile pollution
• unknown sources

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Cigarette Smoke

• One puff of smoke contains
• 100,000,000,000,000,000
• free radical species
• Tobacco is responsible for 31 of all cancers

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If you are a smoker your life will be shortened
by 13 years on average
-14.5 yrs
-13.2 yrs
MMWR 199746444-51
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• 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

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• Each cell gets 10,000 free radical attacks every
  day

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How do we protect our selves?

• Eat more fruits, vegetables, and whole grains.
• Some phytochemicals are also anti-free radicals
  (antioxidants). They have the ability to donate
  an electron to a free radical with out harming
  itself. Its kind of like having a spare
  electron.

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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

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What we should be eating if we want the health
benefits
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• 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

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• 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

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• When the people who consumed the most fruits and
  vegetables were compared to those who ate the
  least, they had half the cancer risk.

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The Cancer Process
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Spontaneous or inherited mutation
Abnormal cell
Normal cell
Repair
Carcinogen
Tumor
Metastasis
Cell proliferation
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Where fruits, vegetables, and whole grains can
stop the cancer process
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Spontaneous or inherited mutation
Abnormal cell
Normal cell
Repair
Activated carcinogen
Tumor
Metastasis
Cell proliferation
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An Apple a day (with the skin)
peel flesh
flesh
Cancer cell spreading
peel
concentration
Sun, J Agric Food Chem 2002507449
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Why not just make a pill that contains
phytochemicals?

• The pill will never contain all the same
  phytochemicals because we still dont even know
  what they are
• Phytochemicals dont 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

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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)
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Risk of Death
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Lung Cancer Death
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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.

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In other studies

• Long term supplementation with beta-carotene had
  no effect on preventing cancers or cardiovascular
  disease

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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

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Vitamin E

• Long-term supplementation with Vitamin E revealed
  no prevention of CVD, stroke, or cancers

Blot, 1993 Stephens, 1996
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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 wouldnt do any harm

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Points to Remember

• Americans get suckered in to supplement makers
  claims. Dont 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.

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Continued.

• 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.