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Playing their familiar 'Will this kill you or cure you?' food quiz, todays offering from @MailOnline is.... 
Harmful Ham , From #Wiltshire "Supermarkets' hams SEVEN times more cancer-causing nitrites as others" https://mol.im/a/8548197 Is your ham salad a health risk? <thread>
Harmful Ham , From #Wiltshire "Supermarkets' hams SEVEN times more cancer-causing nitrites as others" https://mol.im/a/8548197 Is your ham salad a health risk? <thread>
What's a typical portion of that risky #Wiltshire ham? Let's say half a typical 130g vacuum pack of four slices - a 65g serving. Choosing the highest level of nitrite measured in this type of ham (77mg/kg), the average serving delivers *5mg* of nitrite. Is this a real risk?
Nitrites are classified as 'possible carcinogens' by @IARCWHO https://publications.iarc.fr/564 , because nitrites + protein may form nitrosamines - but it's by no means guaranteed. 90% of the 300 nitrosamines identified are recognised as potentially carcinogenic to mammals.
In 2017, the European Food Safety Authority @EFSA_EU published guidance on dietary nitrite and nitrate https://www.efsa.europa.eu/sites/default/files/corporate_publications/files/nitrates-nitrites-170614.pdf
An 'Acceptable Daily Intake (ADI) for nitrite of 0.07 mg/kg body weight/day was considered "sufficiently protective of public health"
An 'Acceptable Daily Intake (ADI) for nitrite of 0.07 mg/kg body weight/day was considered "sufficiently protective of public health"
With an EFSA ADI (Acceptable Daily Intake) of 0.07mg/kg/d, a 65kg person could consume 4.6mg and an 85kg person 5.9mg of nitrite and still be within the 'safe' level of nitrite intake. So that highest nitrite portion of #Wiltshire ham containing 5mg of nitrite is absolutely safe
There's several caveats when it comes to whether dietary or endogenously produced nitrites form those risky nitrosamines. Nitrite amount, type of protein, the presence or absence of other nutrients or foods, and your stomach 'milieu' all influence whether nitrosamines will form.
When it comes to overall nitrite load, we can't ignore dietary nitrates because our body has a nifty way of making them into nitrites, too. Because nitrites make nitric oxide, to aid blood vessel stretch forl blood pressure control, and aid immunity, too https://academic.oup.com/nutritionreviews/article-abstract/77/8/584/5509465?redirectedFrom=fulltext
Nitrites travelling along our digestive system are 'sourced' from dietary nitrites - but also, cleverly, from dietary nitrates. Sources of dietary nitrates include the same 'cured' meats as nitrites. But additionally, from vegetable choices https://onlinelibrary.wiley.com/doi/abs/10.1002/jsfa.2351
Dietary nitrates are pretty well absorbed into our body, where they travel around in our blood, eventually reaching the salivary glands. Nitrates secreted in saliva are converted into nitrites by the action of mouth bacteria - particularly S mutans - the main tooth decay bacteria
Nitrites from food or mouth bacteria production are swallowed then absorbed - the nitrite being used for blood pressure benefits and immune functions, too. Using mouthwash regularly reduces bacterial numbers and nitrite formation, losing the BP benefits https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3605573/#:~:text=Oral%20nitrate%2Dreducing%20capacity%20and,pressure%20increased%20by%202%E2%80%933%20.
So... nitrites are essential for health -especially when it comes to blood pressure and immune function. Too high an intake is associated with potential risk, But enjoying #Wiltshire ham, or preferably lower nitrite-containing ham once or twice a week just isn't going to kill you
Just to clarify - mouthwash reduces mouth bacteria numbers, including Strep mutans. So the mouth conversion of nitrates to nitrites is much reduced. But nitrites in food sources remain unaffected by your level of dental hygiene
