Yes, in the sense that dose makes poison. Too much is never good.
No. In the sense of nitrates and nitrites in meat products are currently the main culprits this is senseless campaigning based on faulty logic and jumping to conclusions. Fish and vegetables contribute just so much more to all kinds of diets. Nitrite is more poisonous than nitrate and so adding that to by choice to any type of food seems highly questionable. But for the industry it is also quite more effective.
Nitrate and nitrite in meat and sausages serves primarily three functions:
- taste (adding more 'zing' than table salt
- microbial growth control (both substances are poisonous after all; remember the dose, though)
- a smooth spectrum between aesthetics and outright fraud: it preserves the (by now) expected colours – or simulates a lengthy 'natural ageing' process when in reality the produce was turbo-cured
From a public health perspective "taste" is debatable preference (I do prefer nitrate to be not in it, some want exactly that). The colour of many traditional meat products would be quite dull greys and the avoidance advice of "red meat" very easy to follow if these salts were banned. Only very few meat products keep or attain the red often now expected by traditional curing processes (eg Italian Parma ham is not allowed to contain nitrate.
That leaves the microbial prevention aspect as the only true advantage from a food chemistry and public health standpoint as a real and undeniable plus.
Both chemicals are quite harmful to children and people already having organic problems, like kidney trouble. Both are also used as medical drugs with very useful applications.
The chemistry and food chemistry of these compounds is very complex and thousands of compounds are formed during, growth, harvest, processing, cooking, eating, digestion and even pharmaco-dynamically. We just have a large number of tiny windows into that. Complicated by the fact that humans are coctivores and lab-rats are usually not. Many cancers in rats can be caused by substances that humans effectively control and eliminate without any harm in usual doses.
Using the epidemiological results of "processed meat correlates with cancer" and "nitro-meat is the bogey-man" to "meat is the new tobacco" is unreasonable. Italian ham is red meat and devoid of added nitrate or nitrite. Are there any studies comparing incidence of cancer in American nitro-ham eaters to Italian parma-lovers that manage to control for confounding factors? Of course not. Are there links from compulsive salad eaters to higher risks of cancer, as salad from fertilised fields is usually very high in nitrates? No.
But campaigners just know that "meat is bad".
For a link from the small increase in cancer rates in meat eaters to the nitrates in meat, we find no conclusive evidence.
But the current focus in the debate on cured meat is a crusade of zealots. Deliberatly adding these salts during manufacturing may seem and probably is superfluous. But these substances occur in other foods, even in much higher concentrations, and even contributing more to a typical dietary intake than "processed meat". They are even formed in the human body and also in there are N-nitroso-compounds formed.
Roila R, Branciari R, Staccini B, Ranucci D, Miraglia D, Altissimi MS, Mercuri ML, Haouet NM: "Contribution of vegetables and cured meat to dietary nitrate and nitrite intake in Italian population: Safe level for cured meat and controversial role of vegetables", Ital J Food Saf. 2018 Sep 26; 7(3): 7692.
Published online 2018 Nov 7. doi: 10.4081/ijfs.2018.7692 PMCID: PMC6240834
mean NO3 mg/kg mean NO2 mg/kg
Spinach 2036 8
Radish 3817 –
Bacon 178 7.7
Cured ham 21 –
The content of nitrate and nitrite is actually much worse for example in spinach, soy, beets, salads and all kinds of fish. As the physiological fates of nitrates and nitrites forming N-nitroso compounds as the main cancerogenic concern is by far not fully understood. Nitrate from veggies forming nitrosamines is also of significant concern. Even the otherwise often lauded DASH-diet is:
The DASH diet is rich in fruits, vegetables, whole grains, and low-fat dairy foods; includes meat, fish, poultry, nuts, and beans; and is limited in sugar-sweetened foods and beverages, red meat, and added fats.
Any yet, following this diet leads to increased exposure to dietary nitrates and nitrites.
Pietro Santamaria: "Nitrate in vegetables: toxicity, content, intake and EC regulation", Journal of the Science of Food and Agriculture J Sci Food Agric 86:10–17 (2006) DOI: 10.1002/jsfa.2351:
Nevertheless, no official method has been published in EU legislation and nitrate levels in vegetables are generally assayed by modifying the protocols used for other foods.
Limits to maximum levels of nitrate for trade in other vegetables are set in some European countries (Table 6). For potato, several countries have put forward the proposal of ‘guidelines’ for nitrate content (in Germany, for instance, only tubers with less than 200 mg kg−1 fresh matter (fm) are accepted), while in Poland there is a maximum limit of 183 mg kg−1 fm.73
Rocket and other Italian export vegetable (e.g. potato) sales contracts include very strict clauses, for instance with Switzerland and Germany. Namely, nitrate content for rocket is required not to exceed 2.5 – 4.0 g kg−1 fm, which is a very strict threshold that is difficult to respect on account of the high accumulation of nitrate in rocket, even when reduced amounts of nitrate are used in its cultivation.
Although current epidemiological data provide conflicting evidence regarding the potential long-term health risks of nitrate levels encountered in the diet, it is widely accepted that the reduction of dietary nitrate is a desirable preventive measure. The maximum allowable nitrate levels in vegetables should not exceed levels that reflect good agricultural practices.
A reduction in nitrate content can, however, represent added value for vegetable products (already rich in carotenoids, vitamins C and E, selenium, dietary fibre, plant sterols, glucosinolates and indoles, isothiocyanates, flavonoids, phenols, etc.).
Norman G. Hord & Melissa N. Conley: "Regulation of Dietary Nitrate and Nitrite: Balancing Essential Physiological Roles with Potential Health Risks", p 153–162 (DOI 10.1007/978-3-319-46189-2_12) in: Nathan S. Bryan & Joseph Loscalzo (Eds): "Nitrite and Nitrate in Human Health and Disease", Nutrition and Health, Humana Press: Cham 22017.
- US and European Union regulatory limits on nitrates in drinking water are necessary to limit environmental pollution known as eutrophication.
- Health concerns of excessive nitrate and nitrite consumption have driven regulatory actions due to perceived risk of methemoglobinemia in infants and gastrointestinal cancer risk in adults.
- The World Health Organization’s Acceptable Daily Intake recommendations for nitrate can be exceeded by normal daily intakes of single foods and recommended dietary patterns, such as the DASH diet.
- Inconsistent positions on the health risks and bene ts of foods containing nitrates and nitrites by the International Agency for Research on Cancer (IARC) and the European Food Safety Authority (EFSA) may contribute to confusion for consumers; regulators must take the opportunity to clarify and expand upon these positions in order to provide coherent dietary guidance.
- The established vasoprotective, blood pressure lowering, and antiplatelet aggregation properties of nitrite alone, or of nitrite originating from dietary nitrate, requires a new regulatory paradigm that incorporates the concepts of physiological deficiency, sufficiency, and excess.
- There is a need to engage an independent panel of experts from academia, industry, and governmental and non-governmental sectors to undertake the first comprehensive, systematic review of the potential health risks and bene ts of food sources of nitrates and nitrites.
- U.S. Institute of Medicine’s Dietary Reference Intake paradigm may be a useful guide to the development of coherent dietary nitrate and nitrite intake recommendations.
It may well be that "nitrite" for example reacts differently when added to meat and then further processed or heated and then gets ingested as compared to occurring naturally and very finely dispersed in a vegetable.
Ronald B. Pegg & Fereidoon Shahid: "Nitrite Curing Of Meat. The N-Nitrosamine Problem and Nitrite Alternatives", Food & Nutrition Press: Trumbull, 2000.
Nitrite is a very reactive entity that can act as an oxidizing, reducing and nitrosating agent. It can be converted to various forms such as nitrate, nitric oxide, dinitrogen trioxide and nitrous acid. When added to meat, evidence of its reactiveness comes not only from well-recognized changes in the color, flavor and shelf-life of meat products, as previously discussed, but also because a significant portion of that added disappears. Once processing of cured meat products is complete, less than 50% of the nitrite added can be analyzed chemically (Cassens et al. 1974)
When addressing the fate of nitrite, clarification in terminology is necessary. Research studies have shown that nitrite can react with proteins, lipids, pigments and other constituents of meat, but a portion of it remains unreacted in the free form (i.e.,NO,. and HNO,). This unreacted nitrite is often referred to as free or residual nitrite, whereas nitrite that has reacted with constituents of the meat matrix is termed bound nitrite. Residual nitrite is the quantity of nitrite that can be detected by present analytical methodology, but the accuracy of the assay is questionable (Goutefongea et al. 1977). Conventionally, nitrosyl refers to NO which is liganded to a metal ion such as the ferrous ion of the heme moiety in myoglobin; thus, NOMb is termed as a nitrosylheme complex. Nitroso refers to NO which has reacted with a non-metal constituent (e.g., C - NO, S - NO); a N-nitrosamine is a classic example of N-nitrosation. Nitroso-nitrite derivatives are referred to as nitrosites while nitroso-nitro derivatives are pseudonitrosites.
Despite all of its desirable effects, nitrite can react, under certain conditions, with amines and amino acids in meat producing N-nitrosamines in some thermally processed cured products. N-Nitrosodimethylamine (NDMA) and N-nitrosopyrrolidine (NPYR) are key examples of such reaction products and have been found to be carcinogenic, mutagenic and teratogenic in experimental animals. Because of their possible link to the incidence of various cancers in man, considerable attention has been focused on the presence of N-nitrosamines in nitrite cured meat products (Magee and Barnes 1967; Gray and Randall 1979; Newberne 1979; Preussmann and Stewart 1984; Preussmann and Eisenbrand
1984; Sen 1986). Greater than 90% of the more than 300 N-nitroso compounds that have been tested in animal species including higher primates caused cancer (Preussmann and Stewart 1984; Tricker and Preussmann 1991), but no known case of human cancer has ever been shown to result from exposure to N-nitroso compounds.
For most cured meat products in Canada, nitrite levels have been reduced to a maximum allowable level of 200 mg/kg, except for bacon which was lowered even further to 120 mg/kg, and addition of sodium ascorbate, a N-nitrosamine blocking agent, is required at a minimum level of 500 mg/kg (Canadian Food and Drugs Act and Regulations 1981). Such actions have resulted in a decrease in the concentration of volatile N-nitrosamines (e.g., NDMA and NPYR) detected in thermally processed products, but not their total elimination. However, in the case of fish and seafood, reduced nitrite addition levels do not work as well at curbing N-nitrosamine formation. In order for N-nitrosamines to form, a nitrosating agent and an amine or its precursor, are required. Compared to meat, fish has substantially higher levels of amines and thus the likelihood of N-nitrosamine formation in smoked and cured fish products is greater.
Current science suggests that adding beer and pure ascorbic acids to a meal of highly processed red meat effectively reduces the amount of nitrates and nitrites absorbed and cancerogenic substances formed compared to an organic spinach salad with 'healthy fish' and no alcohol.
Can that be the basis for scientific nutritional advice? That would seem quite counter-intuitive.
Any call to immediate action for reduction of nitrate in meat – lower than current guidelines – that goes beyond 'give us more money to better research this better' and instead calls for immediate bans and 'eat less meat' looks more like well published hysteria than anything resembling reason. Singling out a single ingredient in an otherwise normal human diet has always been just wrong, it will continue to be that way.