Whether the safety of our food is improvingis an open question, but radical changes in the food indu

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Poisonous Food
Whether the safety of our food is improvingis
an open question, but radical changes in the food
industry since the Second World War have
multiplied the potential hazards (or sources of
risk). Dr Geoff Spreigel Technical Director of
Sainsburys supermarkets UK.
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Poisonous Food

• Consumption has moved further away from
  production
• People shop less often
• Food supply is more global
• National regulations vary in effectiveness
• Eating out and convenience food markets have
  grown
• Demand for more natural and added value foods has
  increased with reductions in the use of
  preservatives, salt, acidity and heat treatment

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Poisonous Food

• My favourite Bacon quote
• Mens thoughts are much according to their
  inclination, their discourse and speeches
  according to their learning and infused opinion,
  but their deeds after they have been accustomed.
• Francis Bacon ca. 1610

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Poisonous Food

• Custom dictates what we eat
• Why Jews and Muslims dont eat pork?
• WWII foods supplies of gherkins to British
  soldiers
• Scientists must be careful with their advice
• Explain properly the benefits of technical or
  scientific knowledge
• Explain clearly the limitations

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Poisonous Food

• Acrylamide discovered in baked and fried starchy
  foods by Swedes, confirmed by UK in 2002.
• Acrylamide may cause cancer
• Or maybe not
• Evidence from laboratory trials
• Scandinavian study compares cancer frequency
  with upper and lower consumption of acrylamide.
  L A Mucci, P W Dickman, G Steineck, H-O Adami,
  and K Augustsson British Journal of Cancer (2003)
  88, 84 -89

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Poisonous Food

• Screening a new food, unless classified as GRAS,
  can cost gt2m
• Principle for toxins is that they should be
  present lt1 of the level that causes biological
  effect
• Sir Walter Raliegh potato - solanine

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Poisonous Food

• 1928 John Hopkins Hosp US identifies substance in
  cabbage that causes goitre in Rabbits.
• 1,5 vinyl-2 thio-oxazolidine complexes iodine out
  of the diet.
• Tazmania 1955

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Poisonous Food

• Rhubarb is poisonous
• Contains oxalic acid that complexes calcium
• So does spinach
• WWI UK government ministry of health advice to
  eat rhubarb leaves as source of healthy green
  vegetables

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Poisonous Food

• And then there are parsnips (and celery and
  parsley)
• Roots and leaves contain psoralens
• Psoralens are potent carcinogens
• Ivie W, et al, (1981) Science 213, p909

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Poisonous Food

• From work by Sebrell in 1930 onions cause anaemia
  in dogs and horses.
• Horseradish contains b-phenylisothiocyanate
• Nutmeg and Mace contain a number of neurotoxins
  and carcinogens myristicin, saffrole, eugenol
• See http//www.erowid.org/plants/nutmeg/nutmeg_fa
  q.shtml for an interesting collection of articles

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Poisonous Food
Spot the similarities
B
A

• A atropine
• B ecstasy
• C myristicin

C
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Poisonous Food

• Favism caused by broad beans in certain
  susceptible populations.
• X-linked recessive hereditary disease (i.e. males
  get it females carry it). Sufferers lack
  glucose-6-phosphate dehydrogenase enzyme.
• Broad beans (or pollen) cause haemolytic anaemia
  because the add oxidative stress as the beans
  contain vicine, divicine, convicine and
  isouramil.
• G-6PD deficiency protects against malaria
• Affects Sardinians, American Jews and Blacks 1/10
  children die.

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Poisonous Food

• Strawberries contain coumarin (blood clot
  inhibitor)
• Cheeses, red wine, chocolate and many other foods
  contain tyramine
• Tyramine raises blood pressure if it is not
  metabolised by mono-amine oxidase
• So a good meal of cheese, redwine, polished off
  with strawberries dipped in chocolate could kill
  you if you are on certain types of
  antidepressants (monoamine oxidase inhibitors)

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Poisonous Food

• Contamination, accidental or deliberate
• Fungal toxins Aspergillus flavus afflatoxins,
  Fusarium fucotoxins
• Mid 1970s afflatoxins on peanuts and corn
  estimated to be responsible for 2000 cases of
  cancer per year in USA when FDA allowed levels
  were reduced from 20 to 15 ppb.
• 20 ppb carcinogen in rats (but not mice) reversed
  by DDT!
• Jukes T, (1978) Nature 271, p 499

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Poisonous Food

• So why was the use of diethylstibestrol (DES) to
  fatten cattle banned?
• Fear of DES causing rare vaginal cancer in female
  offspring.
• Cost to industry 500 million at 1970 prices in
  extra feed etc.
• Chance of lt 1 cancer arising in 133 years in the
  whole US population

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Poisonous Food

• Cooking adds flavour
• Oleander
• BBQs flame grilled addition of benzpyrenes
• Mercury for dinner?

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Poisonous Food

• Which drink contains more sugar
• Sprite or Orange juice?

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Poisonous Food

• A return to Bacon
• Debate over use of nitrites to maintain bacon
  colour and as preservative.
• Nitrites and caffeine make nitrosamines in
  stomach
• But 66 of nitrites in stomach come from nitrates
  from healthy green vegetables
• And Vitamin C inhibits nitrosamine formation
• So drink orange juice
• But what about all that sugar?

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Poisonous Food

• The only safe food is sawdust and Bran Thomas
  Jukes (US nutritional scientist)
• It is high time to accept the fact that nothing
  whatsoever is completely safe Craddock (UK
  toxicologist) bran is post stone age, no time
  to adapt to it and sawdust contains known
  carcinogens.

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Poisonous Food

• Useful web sites
• www.foundation.org.uk
• www.food.gov.uk
• www.fda.gov
• http//vm.cfsan.fda.gov/list.html
• http//www.nih.gov/