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Nitrates and nitrites are found in chemicals like sodium nitrate and potassium nitrate. These are used as preservatives, preventing harmful bacterial growth in certain foods like bacon and other cured meats.
Nitrates occur naturally in plants and can have cardiovascular (heart) health benefits. Dietary nitrate is absorbed in the gastrointestinal (GI) tract and much of it is excreted in the urine. The salivary glands play a significant role in reabsorbing the nitrate from the body and concentrating it. Bacteria in the back of the mouth converts nitrate to nitrite, which is absorbed in the stomach and small intestine and is distributed to the rest of the body.
This article will talk about what foods have nitrates in them, whether it is naturally occurring or an additive, and how this can affect your overall health.
Where Are Nitrates Found?
Nitrates are found naturally in some vegetables. They are also added to processed foods to enhance flavor and preserve color.
Naturally in Vegetables
There are some plants that naturally contain high concentrations of nitrates, including:
- • Leafy vegetables such as rucola, lettuce, spinach, and chard
- • Beets and beetroot
- • Carrots
- • Celery
- • Radishes
- • Rhubarb
Leafy vegetables have the highest levels of nitrates. Nitrate and nitrite levels are lower, on average, in pickled vegetables compared to fresh ones.
Processed Foods
There are high levels of nitrates added to many processed meats. These additives serve multiple purposes, including preservation, giving them salty flavor, and, in some cases, preserving the color (such as with red meat). These meats include:
- • Bacon
- • Jerky (beef, turkey, other meats)
- • Canned poultry products
- • Ham
- • Hot dogs
- • Pork loins
- • Sausage
Water
Nitrates can be found in drinking water. You cannot see, smell, or taste nitrates, so water levels must be tested via one of two methods: the cadmium reduction method and the nitrate electrode. These are generally performed by your local Department of Health, but those with private water sources (e.g., a well) need to have their water tested by a professional.
Nitrates enter the water system because of runoff from fertilization, wastewater, and landfills. It should not be in your water system; however, if you have well water with a disintegrating or poorly-built well, it can leak into your drinking water.
Bottled water may have nitrates. The U.S. Food and Drug Administration (FDA) states that the maximum allowable concentration for total nitrate and nitrite (as nitrogen) is 10 milligrams per deciliter (mg/dL). If the bottle exceeds this amount, the label must state "Contains Excessive Nitrate."
Benefits of Nitrates
Nitrates found naturally in vegetables may help through the effects of nitric oxide, a type of vasodilator (meaning it helps blood vessels relax and open). Nitric oxide plays a role in cardiovascular health by improving blood pressure, heart function, and exercise performance.
A 2021 diet study followed people who reported their dietary intake over time. Eating 1 cup of nitrate-rich vegetables per day was associated with a reduced risk of cardiovascular disease in that population. The study also showed that people who consume moderate to high amounts of nitrate-rich vegetables showed these specific benefits:
- • A 15% lower risk of heart failure
- • A 12% lower risk of heart disease
- • A 17% lower risk of stroke
It is unclear if eating naturally-occurring nitrates help offset symptoms of cognitive decline—a hallmark symptom of Alzheimer's disease — although research is ongoing. Factors include age and health of the patient and how far along they are in disease progression. Further study is needed to evaluate the benefit of eating healthy nitrates for cognitive benefits.
Dietary nitrate supplementation can improve endurance and sprint-type exercises in athletes. It can also benefit weight lifters by supporting skeletal health, building muscle, and increasing overall performance.
Risks of Consuming Nitrates
Ingesting dietary nitrates added to foods for preservation, flavor, and color may also lead to certain conditions and health issues, although these risks can be mitigated by eating organic nitrates found in vegetables. However, pinpointing the exact cause (e.g., environmental, lifestyle factors, genetics) of these conditions can be challenging.
Conditions associated with high levels of nitrate consumption include:
- High blood pressure: Eating a diet high in processed foods can affect your blood pressure, which can lead to heart disease.
- Colorectal cancer: Eating meats (with nitrate additives) that are cooked at very high temperatures increase the risk of colorectal cancer. The correlation between eating a high meat diet to colorectal cancer is well known.
- Gastric cancer: High or moderate nitrate intake of dietary nitrates is associated with a higher risk of gastric cancer (stomach cancer) Studies are ongoing to further understand the connection.
- Methemoglobinemia: Also known as blue baby syndrome, this condition occurs in babies under 6-months old due to the over-consumption and absorption of nitrates.
Minimizing Risks
There are ways to reduce the risk of the health conditions of food additives containing nitrates:
- • Eat lots of fresh fruits and vegetables.
- • Limit processed foods such as beef jerky and hot dogs.
- • Researchers observed a decrease in blood pressure in older adults drinking beet juice.
- • Dietary nitrate supplements are being studied to see if they have the potential to improve conditions like stroke, heart attack, and hypertension (high blood pressure), and alleviate gastric ulcers. Always check with your healthcare provider before starting a new supplement.
Summary
Depending on the source, nitrates can help or hinder your health. One way to support overall health is to eat lots of whole foods, fresh fruits, and vegetables, which can benefit your cardiovascular health and blood flow to the brain and the rest of your body. Eating a healthy diet can minimize chronic illness and the onset of certain diseases like colorectal and gastric cancer.
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Nitrate Summary
Nitrate (NO3-) is a small molecule produced in the body to limited amounts (as a byproduct of nitric oxide) and is obtainable via consumption of vegetables, particularly beetroot and other low-calorie tuber vegetables such as turnips and leafy green vegetables such as spinach or rocket (arugula). It appears to be a potent regulator of blood flow and vasodilatation via its metabolite nitric oxide, and has greater relative affinity for areas of the body with poor oxygenation as the conversion of nitrite (NO2-, a metabolite of nitrate) to nitric oxide is undergone by deoxygenated blood.
In regards to cardiovascular health, it appears to reduce blood pressure in instances where blood pressure is raised. This appears to occur in people with hypertension and can occur in otherwise healthy persons undergoing exercise with little effect on resting blood pressure in healthy persons. It may exert endothelial protective effects, and is thought to be a link between vegetable intake and cardiovascular health.
It appears to enhance exercise performance secondary to reducing the oxygen cost of exercise (and thus prolonging time to exhaustion, thought to be due to increased mitochondrial efficiency). There is little to no effect on acute power output, but seems to reduce the rate of fatigue seen with continued muscle contractions and as such seems to have most benefit in exercises ranging from 1 minutes up to 10 minutes and as such exerts most benefit during anaerobic cardiovascular exercise or muscular endurance events (sports requiring anaerobic intervals such as hockey or rugby, some benefit to rowing and crossfit-type exercises) but although it does have benefit to prolonged cardiovascular exercise (5km jogs or 10km cycling events) the magnitude of effect appears to be lesser.
Due to interactions with nitric oxide, it appears to also be kidney protective and may help to regulate blood flow during the aging process (which is associated with reduced nitrate levels in circulation); the anti-aging effects, however, are preliminary at this moment in time. Due to endogenous production of nitrate and some disease states with lower circulating nitrate (cardiovascular diseases and aging) nitrate may have pseudovitamin-like properties but more evidence is required to support this claim.
Nitrate has the potential to form carcinogenic nitrosamines, although the practical significance of this in living systems is not known (epidemiological survey research has failed to show a significant link after controlling for other confounds, but some nitrosamines themselves are proven carcinogenic; practical relevance of nitrates and subsequently forming nitrosamines following supplemental or vegetable intake in a mixed diet is not really known). Although the carcinogenic potential cannot be ruled out at this time, it cannot be supported reliably either.
Source
Note 1: Antioxidant Capacity, Nitrite and Nitrate Content in Beetroot-Based Dietary Supplements
Note 2: Leafy Vegetable Nitrite and Nitrate Content: Potential Health Effects