Prof. Dr. Werner Seebauer is Dean of Studies – Association of German Preventologists, Head of Preventive Medicine Department of Institute of Transcultural Health Sciences (European University Viadrina) and Head of Preventive Medicine – NESA (The New European Surgical Academy).
Since 2000, prof. dr. Werner Seebauer worked only in preventive medicine, after ten years spent at the Frankfurt University Hospital. He is also involved in the medical professionals training for nutrition and prevention.
MediHelp International, together with LAMP Insurance, and in collaboration with NESA has created the NESAcard based on the wish to offer access to high standards medical services to patients all over Europe.
This way, MediHelp contributes to the medical science development and is actively involved in the international social responsibility advocacy.
Dietary Nitrate, which is converted to nitrosamines in the gastrointestinal tract can increase some disease risks. But you can reduce nitrate by selecting appropriate salads that contain less nitrate and compensate (“detox”) the nitrosamine endogenous production via a nutrient rich diet. Some food contains nitrate (examples in the article); this nitrate can be transformed in the human gastrointestinal tract (in the digestive tract) to nitrosamines; nitrosamines are pollutants that can increase disease risks, such as cancer.
So it is important to reduce the nitrates in the food and to improve the detoxification.
Salad, vegetables and groundwater can provide nitrate. They are the main sources of dietary nitrates. Relatively high nitrate levels can be found mainly in leafy and root vegetables such as beetroot, radish, radish, lettuce, lamb's lettuce, spinach and chard, and especially rucola.
Which vegetable and salad varieties show higher nitrate levels?
Rucola leaves often showed nitrate levels of more than 4,500 mg / kg measured e.g. in Bavaria. This is followed by lamb's lettuce at circa 2100 mg / kg, lettuce and radish at 2000 mg / kg, beetroot or radish at around 1800 mg / kg and spinach at circa 1300 mg / kg.
The nitrate levels are low (about 50-150 mg / kg), for example, with peppers, cucumbers, cauliflower and potatoes; and even lower for onions, brussels sprouts, asparagus, tomatoes, which did not contain significant amounts.
Consuming more than 25 g of rucola leaves per day exceed the tolerable daily intake by addition to the average consumption of all other usual food groups that supply nitrate.
But even without rucola you can achieve higher values. If you eat a lot of vegetables and salads, the daily tolerable levels, as assessed by the WHO, can be significantly exceeded!
One should not follow the approved agriculture limit values of the EU Commission but try to reduce the nitrate sources by taking certain measures into account.
In agriculture, there are plenty of nitrates in the manure, which represents a source of risk for humans through the pollution of groundwater, this varies greatly from region to region and is highest in areas where many big animal farms exist.
Nitrate is also used as a food additive (E 520, E251 and E252) e.g. in meat and fish products and possibly in cheese. Higher values for nitrate and nitrite from food supply processed meat products (especially raw sausage, and raw ham such as bacon, etc.). Canned meat contains nitrate and nitrite pickling salt. You can identify that by the food additive E numbers in the European Union (E 249, E250, E521 or E 252).
The concentration of nitrosamines in pickle products has been significantly reduced by changes in manufacturing and processing processes in recent decades. Nevertheless, this poses a risk if these products are highly heated. If nitrate-containing meat (e.g. bacon) is fried very crispy and loses water content, significantly more nitrosamines are formed. Especially under high and prolonged heat (longer about 180 ° C and seared) nitrosamines are formed.
Recipes that contain hams, but are not fried too much, such as Toast Hawaii or ham pizza, provide relatively lower levels of nitrosamines. The warning not to heat cured meat with cheese today is relativized and not seen as such a high source of risk. Nevertheless, such dishes should not be on the menu too often. Fresh fish has higher levels of nitrosamines (8 μg / kg) than smoked fish, but smoked fish or meat raises other carcinogenic pollutants, which is why it is not preferable.
You should not miss out on salad and vegetables!
Although some salads and vegetables may contain more nitrate, you should not give them up. The vitamin C and the phytochemicals (e.g. polyphenols such as flavonoids) can reduce the nitrosamine synthesis from the nitrate.
Most likely, the effects of health-promoting ingredients in vegetables outweigh the disadvantages of increased nitrate intake. And reducing lettuce and vegetables potentially creates many other higher disease risks; conversely, many risks of chronic diseases are reduced when plenty of vegetables and salads are consumed.
Of course, it is good to take care to reduce some nitrate sources in potentially nitrate-rich lettuce and vegetables. This can be achieved through the selection and more advantageous processing processes.
- Salads should not just be composed of one leaf type; especially not only from rucola or lamb's lettuce.
- To reduce the nitrate content in salads and vegetables, you should prefer fresh goods, especially in leafy and some root vegetables, harvested in sunny bright months (winter grown in greenhouses contains higher values and legislators tolerate higher limits for nitrate)
- For leafy vegetables, remove stalks, stems and large leaf ribs, as well as outer bracts. That can reduce nitrate levels.
- Amestecați salata din diferite tipuri de salată cu frunze; folosiți frunzele tinere cu tulpini mai mici și alegeți nu numai salată verde cu frunze, ci și legume rădăcinoase (morcovi etc.), roșii, măsline, ardei, varză și leguminoase (de exemplu, mazăre, linte, fasole) pentru salate.
Mix salad from different lettuce leaves; use young salad leaves with smaller stems and choose not only leafy lettuce but also root vegetables (carrots, etc.), tomatoes, olives, pepper, cabbage and legumes (e.g. shell peas, lentils, beans) for the salads.
The more varied the salad ingredients are the better!
Additional point: Salads with less contamination surface (iceberg lettuce or radicchio) also have less heavy metal pollution through the air. This is important also in the context of nitrosamines.
- Blanching and cooking vegetables and spinach reduce the nitrate level by about 40 to 80% when cooking water is not consumed. (Source Bavarian State Office for Health and Food Safety)
- Young spinach has thinner stems and thus contains less nitrate.
- In the case of sausage products that have been cured for longer periods of time, the nitrate content is no longer so high these days, but the heating of such meat products results in higher levels of nitrosamines and other pollutants. This is also important with fish products.
Especially raw sausage (bacon, etc.) should rather not be heated harder or longer. The crispier it has become the more nitrosamines and other carcinogenic pollutants are produced.
Warming up nitrate-containing foods can increase the nitrite content and thus nitrosamine formation.
This is known for spinach, but this may also apply to other nitrate-rich vegetables and fish.
Precautions can reduce the increased nitrite formation in spinach:
- Wrap the spinach in a damp kitchen towel and store it in the fridge. In this way he stays good for two days.
- If you are freezing fresh spinach, wash it thoroughly first and remove the stems. Freeze spinach in portions. When defrosting, you should let the spinach thaw slowly in the refrigerator, before you continue processing it quickly.
- To heat, put the spinach in a pot and heat briefly over a medium heat until it collapses. Refine it with spices and bulbous plants (onions, garlic). By blanching, you can reduce the nitrate content of the spinach while deep frying increases the level.
- Cool the leftovers of the spinach meal as quickly as possible (e.g. in a glass bowl in an ice water bath), cover it in a glass box and put in the fridge in the lowest compartment (coolest compartment). Cold temperature reduces nitrite formation significant.
- If you want to eat warmed up spinach again, you should eat it at the latest after one to a maximum of two days, because even in the refrigerator with increasing time still relevant nitrite could be produced.
- Heat the spinach to above 70 ° C for at least two minutes to eat it again.
Some more information
Nitrosamines are considered carcinogens for a variety of cancers, and they also increase the risk for type 2 diabetes. The pollutants produced from highly heated meat products, such as nitrosamines (from nitrates and nitrites added to meats as a preservative), increase various cancer risks and can also reduce insulin production and promote insulin resistance with impaired sugar metabolism. In humans, the extent of cancer risks posed by nitrosamines has not been fully established. But as they have proven in many animal species to be powerful carcinogens, there are many indications suggesting that they can also lead to cancer of various organs in humans.
In addition to the sources of nitrosamine from the environment and food, endogenous production in the body also plays a role; and the dosage, type of contamination and exposure duration play essential roles, as with all pollutants.
It should be emphasized that the largest amounts of nitrosamines do not come from food.
The highest health risk sources for nitrosamines arise by smoking - including secondhand smoke!
Smoking 20 cigarettes a day may increase the exposure to nitrosamines more than 20-fold, which corresponds to a multiple of the potential sources of food. Even the highest food sources, such as e.g. rucola leaves provide only a fraction of that.
According to studies by the Harvard School of Public Health, the smoke or its toxic substances (nitrosamines and formaldehyde, etc.) deposited on floor or where else in the house dust is a carcinogenic risk over the skin too - especially for children. Overall, the nitrosamines from smoke and tobacco smoke have been shown to be potent carcinogens for lung cancer.
- Also, latex and synthetic rubber products (balloons, pacifiers, etc.) can provide nitrosamines, which can be absorbed through the skin. Baby and children's toys should not contain such nitrosamines (especially those that they can put into the mouth).
- Some cosmetics are also sources of nitrosamines.
- Spices can contain considerable amounts of nitrosamines through the drying process (especially pepper with up to 29 μg nitrosamine / kg), but you consume relatively small amounts of it.
- About the malt drying processes, beer contained higher levels of nitrosamine earlier in the '70s. Today’s beer is no longer a significant source of nitrosamine due to changes in beer production methods.