Why Some Nitrates Are Healthy While Others Are Harmful
- Nitrate-rich plant foods are a valuable part of your diet as they help promote heart health. Meanwhile, the nitrates in cured and processed meats such as bacon and hot dogs are known to be carcinogenic
- Nitrites from plants turn into beneficial NO due to the presence of antioxidants such as vitamin C and polyphenols
- NO is a soluble gas, and while it’s a free radical, it’s also an important biological signaling molecule that supports normal endothelial function and protects your mitochondria
- Dietary nitrates are converted into nitrites by oral bacteria. The nitrites are then converted into either nitric oxide (NO) or N-nitroso compounds when reacting with your stomach acid
- Nitrites from processed meat turn into carcinogenic N-nitroso compounds such as nitrosamines due to the presence of proteins and heme in the meat. Nitrates are also more prone to converting into carcinogenic nitrosamines when heated
By Dr. Mercola
Nitrate-rich plant foods are a valuable part of your diet as they help promote heart health. Meanwhile, the nitrates in cured and processed meats such as bacon and hotdogs are known to be carcinogenic. So, what’s the deal? Why are plant-based nitrates healthy and animal-based nitrates harmful? The answer to that question has to do with biochemistry — how the nitrates are processed in your body based on cofactors found in their source.
Plant- Versus Animal-Based Nitrates
In a recent Nutrition Action article on this topic, Gunter Kuhnle, professor of food and nutritional sciences at the University of Reading, U.K., explains the core differences between plant- and animal-based nitrates:1
“When you eat nitrates, they are converted to nitrites by bacteria in your mouth. Once the nitrites reach the stomach’s acid, they can turn into either nitric oxide [NO] or N-nitroso compounds. N-nitroso compounds like nitrosamines are carcinogenic. What makes processed meats so ideal for forming N-nitroso compounds is that they have a combination of nitrite and proteins from the meat. And the meat’s heme seems to help convert them into N-nitroso compounds.”
Nitrates are also more prone to converting into carcinogenic nitrosamines when heated. According to a review of more than 7,000 clinical studies, the World Cancer Research Fund concluded there’s no safe lower limit for processed meats2 and that they should be avoided altogether to minimize your cancer risk.
Plants, on the other hand, contain antioxidants (such as vitamin C and polyphenols) that impede the formation of harmful nitrosamines. The presence of these compounds help to ensure that the nitrites are converted into beneficial NO once they reach your stomach rather than harmful N-nitroso compounds.3 Most plant foods are also not cooked or fried at high temperatures, which further minimizes the chances that harmful substances will be produced.
The Benefits of Nitric Oxide
NO is a soluble gas, and while it’s a free radical, it’s also an important biological signaling molecule that supports normal endothelial function and protects your mitochondria — the little “power stations” in your cells that produce a majority of your body’s energy in the form of ATP. NO is a potent vasodilator, helping relax and widen the diameter of your blood vessels, thereby allowing a greater volume of blood to flow through.
Healthy blood flow in turn helps your body function optimally, carrying oxygen and nutrients to your tissues and organs while removing waste material and carbon dioxide. Importantly, NO infuses into areas that are hypoxic, meaning in need of oxygen, and both your heart and brain4,5 are heavy oxygen users.
NO has actually been shown to improve brain neuroplasticity by improving oxygenation of the somatomotor cortex (a brain area that is often affected in the early stages of dementia).6,7 As for your heart, cardiologist Dr. Stephen Sinatra explains the importance of NO, saying:8
“Adequate NO production is the first step in a chain reaction that promotes healthy cardiovascular function, while insufficient NO triggers a cascade of destruction that eventually results in heart disease… NO promotes healthy dilation of the veins and arteries so blood can move throughout your body. Plus, it prevents red blood cells from sticking together to create dangerous clots and blockages.”
Nitrate-Rich Foods Offer Potent Benefits
While NO is continually produced from the amino acid L-arginine inside your cells, you can also boost your body’s NO production by eating certain NO-boosting foods and/or performing high-intensity exercises such as the Nitric Oxide Dump (see demonstration below). Research9 shows a nitrate-rich diet can be a powerful strategy for the treatment of prehypertension and hypertension (high blood pressure), and as such helps protect against heart attacks.
In conventional medicine, nitrates are used to treat angina and congestive heart failure, and research shows a glass of beetroot juice has the same effect as prescription nitrates.10 Raw beets — which are high in nitrates — have been shown to lower blood pressure by an average of four to five points within a few hours.11
Another study12 found drinking 8 ounces of beet juice per day lowered blood pressure by an average of nearly eight points after the first week, which is more than most blood pressure medications. Raw beets have also been shown to boost stamina during exercise by as much as 16 percent,13 courtesy of increased NO production.
The caveat with beets is they’re high in sugar, which is why I recommend them only in limited amounts or in fermented form. Fermenting your beets rather than eating them raw gives you all the health-boosting benefits of raw beets without the concerns of high sugar content, as the beneficial bacteria created during fermentation consume most of the naturally occurring sugars.
The Hazards of Nitrosamines
While NO has potent health benefits, the same cannot be said for the nitrosamines formed when nitrites from processed meats react with gastric acid in your stomach.
Again, the reason meat-based nitrites don’t boost NO production but rather turn into harmful N-nitroso compounds has to do with the presence of proteins and heme14 (an iron-containing compound that makes up part of the hemoglobin molecule in blood) and the absence of antioxidant compounds. The evidence against processed meats — including bacon, ham, pastrami, salami, pepperoni, chorizo, hot dogs, sausages, hamburgers and more — is fairly extensive. For example:
•Studies have linked processed meats like sausages, hot dogs and sandwich meats to an increased risk of cancer, male infertility and early death.
•A 2007 analysis15 by the World Cancer Research Fund found eating just 1.8 ounces of processed meat per day — about one sausage or two to three slices of bacon — was found to raise your likelihood of bowel cancer by 20 percent.
•The American Institute for Cancer Research16 recommends avoiding processed meats entirely to minimize your risk of bowel cancer, and explicitly warns that “there is no safe threshold” for eating processed meats. They also recommend limiting red meat a maximum of 18 ounces per week, to avoid raising your risk for colorectal cancer.
•After reviewing some 800 studies, the International Agency for Research on Cancer (IARC), which is part of the World Health Organization, concluded that processed meat can cause colorectal cancer in humans,17,18 and has classified processed meat as a Group 1 carcinogen, right next to tobacco and asbestos. The agency estimates a daily serving of 1.8 ounces of processed meat can increase your risk for colorectal cancer by 18 percent. Higher amounts may raise your risk even higher.
(Keep in mind the IARC’s classifications of carcinogens are based on strength of evidence, not degree of risk, so this does not mean processed meats are as hazardous as smoking and asbestos exposure. It simply means the strength of the evidence is the same.)
•A British study19 published in January this year, which evaluated data from more than 262,000 women, found eating just 9 grams of bacon per day significantly raises a woman’s risk for breast cancer later in life.
Nitrate-Free Bacon Is a Safer Alternative
While the presence of saturated fat is not a valid reason to shun bacon, the presence of nitrates is of real concern. Still, bacon can be a healthy addition to your diet, in small amounts, provided you take certain precautions. First, make sure your bacon comes from organic pasture-raised pigs, as this will reduce the risk of pathogenic contaminations20 that factory farmed pigs are prone to. Second, make sure it’s free of added nitrates. The easiest way is to check the label, but the color of the meat can also be a powerful tipoff.
As noted in The Guardian,21 “The pinkness of bacon — or cooked ham, or salami — is a sign that it has been treated with chemicals, more specifically with nitrates and nitrites.” The article includes commentary from French journalist Guillaume Coudray, author of the book “Cochonneries,” which loosely translates into “junk food,” but also means “piggeries.”
In his book, Coudray argues that it’s really the addition of nitrates that creates the problem, and the processed meat industry could easily make these foods far less hazardous. As reported by The Guardian:
“’Pure insane crazy madness’ is how Coudray described the continuing use of nitrates and nitrites in processed meats … The madness, in his view, is that it is possible to make bacon and ham in ways that would be less carcinogenic. The most basic way to cure any meat is to salt it — either with a dry salt rub or a wet brine — and to wait for time to do the rest.
Coudray notes that ham and bacon manufacturers claim this old-fashioned way of curing isn’t safe. But the real reason they reject it is cost: it takes much longer for processed meats to develop their flavor this way, which cuts into profits … The health risk of bacon is largely to do with two food additives: potassium nitrate (also known as saltpetre) and sodium nitrite.
It is these that give salamis, bacons and cooked hams their alluring pink color … when otherwise it would be a murky greyish brown … It is this nitrite that allows the bacteria responsible for cured flavor to emerge quicker, by inhibiting the growth of other bacteria … It is the use of these chemicals that is widely believed to be the reason why ‘processed meat’ is much more carcinogenic than unprocessed meat.”
Healthy Nitrate Sources — Fresh Veggies
Hopefully, you can now appreciate the difference between nitrates from plants versus those from processed meats. A nitrate-rich diet is indeed a boon to your health, but only when the nitrates come from the plant kingdom. Here’s a list of the Top 10 most nitrate-rich ones to add to your diet.22,23,24 Eating garlic also helps boost NO production. While low in nitrates, garlic increases nitric oxide synthase, which converts L-arginine to NO in the presence of cofactors such as vitamins B2 and B3.25
- Arugula, 480 mg of nitrates per 100 grams
- Rhubarb, 281 mg
- Cilantro, 247 mg
- Butter leaf lettuce, 200 mg
- Spring greens like mesclun mix, 188 mg
- Basil, 183 mg
- Beet greens, 177 mg
- Oak leaf lettuce, 155 mg
- Swiss chard, 151 mg
- Red beets, 110 mg
Three-Minute Exercise to Boost NO Production
As mentioned earlier, high-intensity exercise will also trigger NO production in your body and, ideally, you’d both eat nitrate-rich veggies and exercise. The Nitric Oxide Dump exercise, developed by Dr. Zach Bush and demonstrated in the video above, will help:
- Improve blood flow by relaxing and widening your arteries, thinning your blood and decreasing its viscosity. The latter also decreases platelet aggregation, which will discourage the development of blood clots that may cause a heart attack or stroke
- Lower your blood pressure
- Boost your mitochondrial health
- Slow down age-related muscle decline
- Improve immune function
Your body stores NO in the lining of your blood vessels (the endothelium). It’s produced inside your endothelial cells from the amino acid L-arginine, and acts as an important signaling molecule throughout your body. When you exercise and your muscles ache, it’s because you’ve run out of oxygen, which your body compensates for by releasing NO (to dilate your blood vessels making it easier for oxygen to be delivered).
This process fuels muscle development, but here’s the secret that’s not widely known: When you exercise, it takes only about 90 seconds for your blood vessels to run out of stored nitric oxide and begin the process of making more. “So working each major muscle group out for 90 seconds,” says Bush, “gives you the most efficient workout to tone and build muscles.”26 Indeed, the key to harnessing your body’s NO-generating powers is to engage in short bursts of high-intensity activity.
You also want to wait at least two hours between sessions because that’s how long it takes for NO to synthesize for subsequent release. “Your body has the ability to regenerate nitric oxide every couple of hours, giving you the opportunity to release it multiple times a day,” Bush says. “What that means is the most effective way to increase your muscle function is to work out very briefly every few hours.”27
Increasing NO Is an Important ‘Antiaging’ Strategy
Your body loses about 10 percent of its ability to produce NO for every decade of life, which is why it’s important to take steps to increase your NO production, especially as you age. One way to do this is by eating nitrate-rich plant foods such as arugula and beets, as the plant-based nitrates are converted into NO in your body.
Just remember that nitrates from processed meats will not have this effect. On the contrary, processed meats will encourage the creation of carcinogenic substances — again because of the combination of a lack of antioxidants and the presence of proteins and heme, which triggers the creation of N-nitroso compounds rather than NO. This is an important distinction, so don’t get confused.
Beyond diet and high-intensity exercises such as the Nitric Oxide Dump, you can also increase NO by getting sensible sun exposure on large portions of your body, as NO is released into your bloodstream when UVA from sunlight touches your skin.28,29 Certain supplements, like olive extract and bitter melon, as well as acupuncture,30 may also enhance your body’s generation of NO, as may using a sauna31 or even taking a hot bath.32
- 1 Nutrition Action March 5, 2018
- 2 World Cancer Research Fund, Limit Red Meat and Avoid Processed Meat
- 3 Essentialstuff.org April 28, 2014
- 4 New York Daily News April 20, 2017
- 5 Express.co.uk April 20, 2017
- 6 Journals of Gerontology November 9, 2016, glw219
- 7 Neuroscience News April 19, 2017
- 8 DrSinatra.com February 20, 2015
- 9 Hypertension 2008 Mar;51(3):784-90
- 10 Bodyecology.com What Can Nitrates in Beet Juice Do For You?
- 11 Nutr J. 2012 Dec 11;11:106
- 12 Hypertension 65: 320, 2015
- 13 J Appl Physiol (1985). 2009 Oct;107(4):1144-55
- 14 Wired October 27, 2015
- 15 World Cancer Research Fund: Food Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective November 2007
- 16 American Institute for Cancer Research, Processed Meat Brochure (PDF)
- 17 Scientific American October 26, 2015
- 18 The Atlantic October 26, 2015
- 19 NHS Choices January 3, 2018
- 20 MedicineNet.com October 5, 2015
- 21 The Guardian March 1, 2018
- 22 Morning Steel, Nitric Oxide Foods
- 23 Anabolic Men, Nitric Oxide Foods
- 24 Livestrong, Fruits and Vegetables High in Nitrates
- 25 The Drs Wolfson, 10 Foods to Boost Nitric Oxide
- 26, 27 Zachbushmd.com The Four Minute Workout
- 28 J Invest Dermatol. 2014 Jul;134(7):1839-1846.
- 29 Circ Res. 2009 Nov 6;105(10):1031-40.
- 30 Anesth Analg. 2007 Feb;104(2):301-7.
- 31 Journal of Cardiac Failure October 2004, Volume 10, Issue 5, Supplement Page S188
- 32 Med Hypotheses. 2009 Jul;73(1):103-5.