Phytochemicals
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Chemicals derived from plants
Beneficial Phytochemicals
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Some vitamins
Carotenoids
Anthocyanins
Some drugs
Some herbs
Good phytochemicals to a point
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Caffeine and theophylline
Capsaicin
Active ingredient in St. John’s wort
Not-so-good phytochemicals
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Ma huang/ephedrine (heart and muscle damage)
Chaparral, comfrey and germander (liver damage)
Astragalus (kidney damage)
The Dietary Supplement Health & Education Act of 1994 (DSHEA)
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A law that defines what dietary supplements are and contains provisions
relating to the marketing of these products
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Supplement labels must provide nutrient info, may not make unapproved
health claims, and cannot claim to diagnose or treat specific illnesses
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Can make nonspecific structure-function claims, such as “promotes prostate
health” for saw palmetto (an herb)
The DSHEA’s Definition of a Dietary Supplement
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A product (other than tobacco) that includes vitamins, minerals, herbs,
botanicals, amino acids, and “other dietary substances for human use to
supplement the diet”
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Unlike drugs, dietary supplements can be marketed without proven safety or
effectiveness
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Label must carry disclaimer: “This statement has not been evaluated by the
Food & Drug Administration. This product is not intended to diagnose, treat,
cure, or prevent any disease”
DSHEA deregulated the supplement industry
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FDA has to show that a particular supplement is harmful, BUT it is powerless
(and understaffed) to act unless people die
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Even then, some very harmful supplements are still on the market-e.g., ma
huang
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Still other supplements may not have the quantities of the active ingredient
that they claim to have
Herbal Supplements
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Fall under dietary supplements
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For some herbs, active ingredient is unknown
Do not trust labels-Consumerlab.com
Some herbs can interfere with blood clotting, anesthesia, other drugs (anti-HIV
drugs, oral contraceptives)
Forms of Herbal Preps
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The dried plant part
Water extract
Tinctures--usually alcohol extracts
Purified and dried active compound(s)
Herbs can interact with drugs
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Many interact with coumadin bloodthinners
St. John’s wort interacts with oral contraceptives, protease inhibitors (HIV
drugs), cyclosporine (used in transplant patients)
“Should I be taking a supplement, Dr. Fuller?”
Questions to ask before taking supplements
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Am I trying to make up for my lousy diet?
Is this going to impact any drugs I need to take?
Is there a less expensive alternative?
Some partial answers
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Women of childbearing age should be getting folic acid
Calcium supplements are a good idea for some
Babies who are getting breast milk need vitamin D supplements
Don’t take more than you need
– E.g., iron in men
Nutrition and cancers
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Open to interpretation
What is cancer?
• Characterized by uncontrolled cell growth, lack of differentiation, and ability
to invade local tissues and metastasize (spread to distant sites via blood or
lymphatic system)
• Can strike any tissue at any age
Stages of carcinogenesis
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Initiation
Promotion
Progression
Time from initiation event to actual diagnosis can be decades
Cancer initiators and promoters
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Viruses--human papilloma viruses & cervical cancer
Oncogenes--brca1, brca2
Immune disorders
Tobacco smoke
Ultraviolet light
Dietary Factors & Cancer
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Energy--lifelong Calorie restriction can reduce incidence of cancer--in rodents
Fat--relationship to cancers controversial
Obesity--obese people are more prone to cancer
EtOH-Seems to have synergistic effect (1+1=5) with tobacco for CA’s of
mouth, pharynx, larynx, & esophagus
• Flavonoids-Little solid human evidence
• Carotenoids-High consumption of fruits and vegetables associated with lower
incidence of CA’s, BUT intervention studies with beta-carotene showed
otherwise
Cancer Treatment
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Surgery
Radiation therapy
Chemotherapy
Why do cancer patients go for alternative treatments?
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Conventional therapies aren’t very effective on some cancers
Counter patients’ feelings of helplessness
Belief that “if it’s natural it must be better”
It gives patient something that they can “do” in the face of a life-threatening
disease
6 simple rules for evaluating dietary claims (Lett, 1990)
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Falsifiability
Logic
Comprehensiveness
Honesty
Replicability
Sufficiency