- Many studies have shown that nitrates benefit cardiovascular health. Other studies suggest that it may increase the risk of cancer.
- Researchers conducted an analysis of studies examining the benefits and risks of dietary nitrates.
- More research is needed to better understand these associations.
Nitrates are compounds made of nitrogen and oxygen atoms. They are mostly found in vegetables, meat and drinking water.
In the year In 1976, two studies found that nitrates can form N-nitrosamines, which are highly carcinogenic in laboratory animals and linked to cancer in humans. These studies and others are based on guidelines governing the use of nitrates.
However, other studies have shown that vegetables with nitrate content can prevent cardiovascular diseases.
Studies also suggest that some nitrate sources can inhibit N-nitrosamine production. one
Further research on the health effects of nitrates may lead to the development of healthy diets and prevention strategies for various conditions.
Recently, a team led by researchers at Edith Cowan University in Australia reviewed studies examining the health benefits and harms of dietary nitrates.
They concluded that there is insufficient evidence to suggest that nitrates in food and water are carcinogenic and that more research is needed to understand the extent of the damage.
“About 80% of our dietary nitrate intake comes from vegetables,” said Dr. Kelly Johnson-Arbor, interim executive director of the National Capital Poison Center, who was not involved in the study. Medical News Today.
“When dietary sources of nitrate are consumed, the nitrate is absorbed by the salivary glands and converted to nitrite. From here, nitrite is taken into the blood and converted to nitric oxide. “Nitric oxide plays a key role in many functions in the human body, including blood pressure control and heart health,” she added.
The study was published in Trends in food science and technology.
Current guidelines suggest a nitrate intake of 0-3.7 milligrams per kilogram (mg/kg) of body weight – or 260 milligrams (mg) for an adult weighing 70 kilograms.
Plants are the main sources of nitrates. Leafy greens such as arugula, Chinese spinach, and collard greens contain the highest levels of nitrates at over 2,500 mg/kg. Fruits such as nectarines and peaches have a low nitrate content of less than 25 mg/kg.
Nitrates are found in small amounts in animal-based food products. Most animal-based products such as red meat, poultry and fish contain less than 50 mg/kg. Dairy products contain low levels, skimmed milk contains less than 0.5 mg/kg.
Processed meat products
As Dr. Johnson-Arbor said MNT: “Nitrates and nitrites are added to processed meats to reduce bacterial contamination and prevent foodborne illnesses such as botulism. This process is called ‘curing’. Because cured meats contain nitrates, many people choose not to eat ham, bologna, bacon, or other processed meats to avoid nitrates and reduce their risk of cancer.
“Some people choose to eat ‘uncured’ or ‘naturally cured’ meat products instead. These meat products are cured with celery or other vegetable juices instead of nitrates and salt. However, because vegetables are a good source of nitrates, ‘naturally cured’ or ‘uncured’ meats still contain high levels of nitrates, and the health benefits of eating those products are minimal.
– Dr. Kelly Johnson-Arbor
Nitrates are found in both surface and groundwater. The World Health Organization (WHO) has guideline values for nitrates in drinking water.
According to the 2021 European Commission report, 14% of groundwater monitoring stations have more than 50 mg/L, but most of them contain more than 25 mg/L or nitrates.
Several comprehensive reviews have found that dietary nitrates improve cardiovascular function and health and reduce the long-term risk of cardiovascular disease. Most of these studies have examined the effects of nitrate intake from plant sources.
In addition, the amount of dietary nitrite can increase the amount of nitric oxide, a molecule involved in the control of the central nervous system and the cardiovascular system, affecting both cognitive and brain functions.
The researchers note that nitric oxide inhibits the phosphorylation of the protein tau, which may be important since Alzheimer’s disease is associated with:
Seven of 12 clinical trials reported that dietary nitrate from beetroot juice was associated with improved cognitive function and cerebral blood flow. Four studies, however, found that nitrate had no effect on cognitive function.
Research shows that nitrates taken as supplements or from dietary sources include:
Few trials have explored the direct effects of nitrates on type 2 diabetes. However, one trial using beetroot powder as a dietary nitrate source found no effect on glucose or insulin measurements.
“Dietary nitrates in fruits/vegetables have healthy cardiovascular effects by opening blood vessels, as well as antioxidants and anti-inflammatory compounds, and may inhibit the formation of harmful N-nitrosamines, which are linked to cancer,” Senior Clinical Dietitian at UCLA Medical Center and Dana Ellis Huness, an assistant professor at the UCLA Fielding School of Public Health in Los Angeles, who was not involved in the study. MNT.
Foods are among the lowest sources of carcinogenic N-nitrosamines. The highest levels include tobacco products – over 16,000 micrograms per kilogram (μg/kg) – and some personal care products over 1,500 μg/kg.
Foods typically contain levels of N-nitrosamines between 0 and 373 μg/kg. They include:
- Meat products
- Fish products
- Canned vegetables
- Packaged, processed plant-based food products
- Beverages including alcoholic beverages
- Animal products
Increasing the cooking temperature by frying, baking, and grilling foods promotes the formation of various N-nitrosamines.
A meta-analysis found that higher dietary nitrates were associated with an increased risk of colorectal cancer. However, a meta-analysis conducted prior to 2016 found no association.
Another study found that high levels of nitrates may reduce the risk of stomach cancer. Meanwhile, other studies have found no association between dietary nitrate intake from vegetables and the following foods.
Some studies, however, have suggested that nitrates from processed meats increase the risk of bladder cancer.
The effects of drinking water with nitrates on cancer risk are mixed. A meta-analysis found that high consumption was not associated with gastric and colorectal cancer, but another study found that it was associated with colon cancer and not other cancers.
Dr. Hunes noted that some of the biggest limitations in the current analysis are that the diet studies are currently too short to show long-term effects or significant changes. In real life, she explains, people often have different diets than research suggests.
When asked who should increase and who should decrease nitrate levels, Dr. Johnson-Arbor said there is no “one size fits all” approach and that the risks and benefits must be balanced according to individual characteristics.
“People with dementia, heart disease, diabetes or other risk factors may benefit. [the] “People who are at high risk for cancer may want to avoid exposure to high levels of nitrates,” she told us.
“However, as stated in this article, the relationship between nitrate consumption and human cancer is not accurate, and more research is needed to summarize the relationship between nitrate consumption and human cancer,” he said.