natural or man-made chemicals? adapted from a presentation by penny le couteur, the fraser...
TRANSCRIPT
Natural or Man-made Chemicals?
Adapted from a presentation by Penny Le Couteur,
The Fraser Institute, Vancouver, Canada
“All substances are poisonous,there is none which is not a poison; the right dose differentiates a poison from a remedy.”
Paracelsus circa 1538
The great myth
“Natural is good;
man-made is bad”
It may be natural but you’ll be just as dead!
The seven most deadly chemical compounds
LD50 /mg/kg
Botulinum toxin A 3 x 10-8
Tetanus toxin A 5 x 10-6
Diphtheria toxin 3 x 10-4
Dioxin * 3 x 10-2
Muscarine 2 x 10-1
Bufotoxin 4 x 10-1
Sarin * 4 x 10-1
LD50 = The lethal dose of a compound for 50% of animals exposed
* Synthetic
The best chemists can do
O
O Cl
Cl
Cl
Cl
(Dioxin)
2,3,7,8-tetrachlorodibenzo-p-dioxin
Viktor YushchenkoPresident of the Ukraine
July 2004 December 2004
Muscarine - from mushrooms
OCH2
H3C
HO
N
CH3
CH3
CH3
Cl
Bufotoxin – from the common toad
O
CH3
OH
O
CH3
O C
O
CH3
O
C
(CH2)6O C
O
NH CH
COOH
CH2 CH2 CH2 NH C
NH
NH2
The next ten …. (most deadly)
* Synthetic
LD50/ mg/kg
Strychine 5 x 10-1
Soman * 6 x 10-1
Tabun * 6 x 10-1
Tubocurarine chloride 7 x 10-1
Rotenone 3
Isoflurophate * 4
Parathion * 4
Aflatoxin B1 10
Sodium cyanide * 15
Solanine 42
Vitamin C
O O
OHHO
CH
CH2OH
HO
Ascorbic acid
Other variations of “natural is good; man-made is bad”
• Synthetic chemicals were not around as man evolved so we haven’t had time to become
resistant to them as we have to naturally occurring compounds.
• Synthetic chemicals bioaccumulate in our bodies.
Chemicals in food: Advertisements from “organic food”
stores
“We read the labels so you don’t have to. We want you to concentrate on how good the food tastes and not worry about words that you can’t
pronounce”
Chemicals in food: Advertisements from “organic
food” stores
“We keep the chemicals out of your food”
Chemicals in food: Advertisements from “organic
food” stores
“We think your food tastes better
without the flavour of preservatives”
Chemicals used to preserve food
Chemical Use
Ascorbic acid Antioxidant/antimicrobial
BHA Antioxidant
Calcium propionate Mold inhibitor
EDTA Antioxidant
Sodium benzoate Microbial inhibitor
BHT Antioxidant
Sodium nitrite Microbial inhibitor in meat
Sorbic acid Mold inhibitor in cheese
BHA= butylated hydroxyanisole BHT = butylated hydroxytoluene EDTA = ethylenediaminetetraacetic acid
Sodium nitrite
Risk: Cancer from nitrosaminesBenefit: Prevents botulism in meats
NO2- + HCl HNO2
+ Cl-
HNO2 + (CH3)2NH (CH3)2NNO + H2O
Natural toxins in food
Chemical Food source Hazard
Allyl isothiocyanate Brown mustard, horseradish, garlic
Tumours
Benzo(α)pyrene BBQ/smoked meats Stomach cancers
Cyanides Bitter almonds, cashews, lima beans
General toxicity
Nitrosoamines Cooked bacon Cancer
Estragole Basil, fennel, tarragon
Tumours
Glycyrrhizic acid Liquorice Hypertension/heart
Hydrazines Raw mushrooms Cancer
Natural toxins in food –part 2
Chemical Food source Hazard
Myristicin Nutmeg, parsley, dill, carrots, celery, pepper
Hallucinations/liver damage/death
Oxalic acid Rhubarb, spinach Kidney damage/death
Saxitoxin Shellfish Paralysis/death
Symphatine Comfrey plant Tumours
Tannins & tannic acid
Black tea, coffee, cocoa Cancers/ throat & mouth
Tetrodotoxin Puffer fish Paralysis/death
Don’t worry, it’s organic•Organic farming is a multi-dollar industry that relies on the public’s perception that organic food is more healthy.
•There is little evidence to suggest that organic fruit and vegetables are any healthier than conventional produce.
•Some forms of organic farming may introduce natural toxins into consumers’ food.
Chemistry World, June 2004
Science writer John Emsley quotes
• We come into this world with a wonderful built-in detoxifying system that protects us against thousands of natural toxins every day.
• Cancer (from synthetic chemicals) is a risk, but the risk may be so low as to be worth ignoring.
Cosmetics•Cinnamon•Citrus•Angelica•Almond extract•Clove•Bergamot •Cornstarch•Fennel•Geranium•Lavender•Lemon balm•Lime•Papaya•Peppermint•Rose•Thyme•Witch hazel•Wintergreen
Should DDT be banned everywhere?
CH
CCl3
ClCl