Do Nitrates and Nitrites Help or Harm?

Nitrates have a bad rap. Conventional wisdom and the media say to steer clear of these dangerous, carcinogenic compounds, and keep eyes peeled for labels boasting “nitrate-free.” But not all foods with nitrates come with a label, and not all nitrates can be considered bad. Nitrates and nitrites are obtained in the diet from vegetables, fruits and processed meats, and the source of these compounds determines if they help or harm.

Vegetables and fruits account for about 80% of dietary nitrate intake and these compounds have been linked to potential health benefits. Nitrates are naturally found in certain fruits and vegetables including celery, cauliflower, radishes, beets, spinach, cabbage, carrots, broccoli and bananas. Plants obtain these compounds from soil, water and nitrogen in the atmosphere. When nitrate (NO₃) is consumed from plants, it is converted in the body to nitrite (NO₂), nitric oxide (NO) and other nitrogen-containing compounds. These compounds dilate blood vessels, decrease clot formation and prevent plaque buildup in arteries, thereby lowering blood pressure and supporting heart health

A 2009 paper from the American Journal of Clinical Nutrition highlighted the benefits of nitrates from fruits and vegetables for cardiovascular health, specifically protection against coronary heart disease, stroke and hypertension. In a 2015 study from Washington University, patients with heart failure saw a 35% to 50% increase in breath nitric oxide, a potential marker of muscle function, along with an 11% increase in muscle power after drinking nitrate-rich beet juice.

Dietary nitrates from plants may be particularly beneficial to athletes. A 2015 paper by researchers from the UK reviewed the current research on nitrates and exercise performance, citing a study from Exeter University in which athletes saw a 16% improvement in high-intensity exercise tolerance when they drank about two cups of nitrate-containing beetroot juice for six days. Nitrates may help by decreasing the amount of oxygen and respiratory activity required for exercise by supporting muscle energy metabolism and recovery. Norwegian researchers also found a benefit of nitrate-rich beet juice for mountain climbers in a 2015 study. When blood vessels normally contract at high altitudes, the nitrates in the beet juice allowed blood vessels to relax and return to normal function.

Nitrates and nitrites found in processed meats have different effects in the body. These compounds are added as preservatives to help develop flavor, maintain color and prevent bacterial growth. The salt sodium nitrate does this job well, but most meat producers use synthetic sodium nitrite to skip the step of chemical reduction. However, when meat is heated above 266°F, sodium nitrite reacts with other compounds in the meat and generates nitrosamines, compounds that are carcinogenic to animals. Though vitamin C can also be added to meat to prevent this reaction from happening, the fat content in meat may offset this effect. A number of studies reviewed in the World Journal of Gastroenterology support a positive association between processed meat intake and stomach cancer risk.

In a very recent report from the World Health Organization, 22 experts from ten different countries reviewed over 800 studies that investigated associations between eating red or processed meats and developing cancer. The evidence showed a probable link between eating red and processed meats such as bacon and hot dogs and developing colorectal, pancreatic and prostate cancers, leading experts to classify these foods as probably carcinogenic to humans.

Though you likely won’t find any nitrites in your Thanksgiving turkey—they are not added to fresh meats—check labels on processed deli turkey to ensure it is nitrate-free and avoid any red or processed meats like hot dogs, which have been linked to increased risk of certain cancers, COPD and early risk of death. Get your nitrates the natural way by eating lots of vegetables and fruits, which offer the whole package of nutrition, another possible reason they do not produce carcinogens.

For a healthy dinner idea, try our Turkey Tostados with Cranberry Chili Dressing, made with nitrate-free leftover turkey and DOLE® Very Veggie Salad Blend. 

Published November 1, 2015