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.
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
Carotenoids Beta-carotene Lycopene Lutein Zeaxanthin Organosulfurs Flavinoids
Phytosterols Alkaloids Tannins Saponins And many, many
others
Here are some pictures of some phytochemicals
para-coumaric acid
Copy right by Michael Davidsonhttp://micro.magnet.fsu.edu/index.htmlOptical microscopy techniques
para-coumaric acid
Saponin
Zeaxanthin
ajoene
Calcium Pectate
Lung cancer and vegetable intake
-0.3
0.2
0.7
1.2
1.7
2.2
2.7
0 100 200 300 400 500
Vegetable intake grams/day
Rel
ativ
e ri
sk
Am Inst for Cancer Research, 1997
Stomach cancer and vegetable intake
-0.3
0.2
0.7
1.2
1.7
2.2
2.7
0 100 200 300 400 500
Vegetable intake grams/day
Rel
ativ
e ri
sk
Am Inst for Cancer Research, 1997
Stomach cancer and fruit intake
0.4
0.6
0.8
1
1.2
1.4
0 100 200 300 400 500
Fruit intake grams/day
Rel
ativ
e ri
sk
Am Inst for Cancer Research, 1997
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
74.479.8
61.2
65.3
55
60
65
70
75
80
US Mean Smokers
Males FemalesMMWR 1997;46:444-51
-13.2 yrs
-14.5 yrs
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
Normalcell
Abnormalcell
Spontaneous or inherited mutation
Carcinogen
Cell proliferation
TumorMetastasis
Repair
Where fruits, vegetables, and whole grains can stop the cancer
process
Normalcell
Abnormalcell
Spontaneous or inherited mutation
Activatedcarcinogen
Cell proliferation
TumorMetastasis
Repair
An Apple a day (with the skin)
0.09
0.29
0.49
0.69
0.89
1.09
0 8 10 11 12 15 19 20 26 30 40 50 75 100
peel
peel+flesh
flesh
concentration
Can
cer
cell
spre
adin
g
Sun, J Agric Food Chem 2002:50:7449
Why not just make a pill that contains
phytochemicals?
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
0.9
0.95
1
1.05
1.1
1.15
1.2
Risk of Death
Placebo
Vitamin A andbeta-carotenesupplement
Lung Cancer Death
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
Lung Cancer Death
Placebo
Vitamin A andbeta-carotenesupplement
Cardiovascular Disease Death
0.8
0.85
0.9
0.95
1
1.05
1.1
1.15
1.2
1.25
1.3
Cardiovascular Disease Death
Placebo
Vitamin A andbeta-carotenesupplement
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 beta-carotene 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
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….
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.