By Dr. Mercola
Your diet is an important, if not crucial, factor for the maintenance of a healthy heart well into old age. Healthy dietary fats top the list of heart-healthy foods, of course, but aside from that, a nitrate-rich diet can go a long way toward protecting your heart.
Nitrates should not be confused with nitrites, found in bacon, hot dogs, ham and other less-than-healthy cured meats. Nitrites can convert into potentially dangerous nitrosamines, especially if heated, which is why processed meats are best avoided. In fact, after examining over 7,000 clinical studies, the World Cancer Research Fund concluded there's no safe lower limit for processed meats.1 They should be avoided altogether.
On the other hand, many vegetables contain naturally occurring nitrates. When consumed, the bacteria in your mouth convert these nitrates to nitrites, but since vegetables are also rich in antioxidants, these nitrites do not pose a health hazard. More importantly, your body transforms the nitrates in vegetables into nitric oxide (NO),2 a soluble gas continually produced from the amino acid L-arginine inside your cells.
Nitrate-Rich Foods Boost Nitric Oxide Production
NO is a gas and free radical that is an important biological signaling molecule that supports normal endothelial function and protects the little powerhouses inside your cells, your mitochondria. Acting as a potent vasodilator, NO also helps relax and widen the diameter of your blood vessels, allowing a greater volume of blood to flow through.
Healthy blood flow helps your body function at its best, as your blood carries oxygen and nutrients to your heart, brain and other organs. It nourishes and oxygenizes your immune system and muscles, and helps keep your heart beating. It also carries away waste material and carbon dioxide.
As noted in research3 presented by Dr. Michael Greger above, a diet high in nitrate is a natural strategy recommended for the treatment of prehypertension and hypertension (high blood pressure), "and to protect individuals at risk of adverse vascular events," i.e., heart attacks. Indeed, raw beets — which are high in nitrates — have been shown to lower blood pressure by an average of four to five points within a matter of hours.4
Some studies have shown a glass of beet juice can lower systolic blood pressure by more than eight points5 — far more than most blood pressure medications. 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.6
NO Promotes Healthy Heart and Brain Function
In one recent study,7,8,9,10 patients diagnosed with high blood pressure who drank beet juice an hour before exercise, three times a week for six weeks, experienced increased tissue oxygenation and blood flow. It also improved brain neuroplasticity by improving oxygenation of the somatomotor cortex (a brain area that is often affected in the early stages of dementia).
As noted by study co-author W. Jack Rejeski, a health and exercise science professor at Wake Forest University in North Carolina, NO is a vital biomolecule that "goes to the areas of the body which are hypoxic, or needing oxygen, and the brain is a heavy feeder of oxygen in your body."11,12 Your heart, too, requires NO and oxygen for optimal function. As noted by cardiologist Dr. Stephen Sinatra:13
"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."
Which Foods Contain the Most Nitrates?
As noted by Greger in the featured video, leafy greens top the list of nitrate-rich foods. Beets, which are a root vegetable, are well-known for their high nitrate content, but leafy greens contain even more nitrates per serving. In fact, beets barely made it onto the top 10 list, which is as follows:
1. Arugula, 480 mg of nitrates per 100 grams
2. Rhubarb, 281 mg
3. Cilantro, 247 mg
4. Butter leaf lettuce, 200 mg
5. Spring greens like mesclun mix, 188 mg
6. Basil, 183 mg
7. Beet greens, 177 mg
8. Oak leaf lettuce, 155 mg
9. Swiss chard, 151 mg
10. Red beets, 110 mg
Arugula, in the No. 1 spot, contains more nitrates than any other vegetable, and by a wide margin too — 480 mg per 100 grams. The second-highest source, rhubarb, contains about 280 mg per 100 grams, which is about the same amount found in a 100-gram serving of beet root juice, whereas 100 grams of whole red beets provide a mere 110 mg of nitrates.
Other foods high in nitrates include the following.14,15,16 (While garlic is low in nitrates, it helps boost NO production by increasing NOS, which converts L-arginine to NO in the presence of cofactors such as vitamins B2 and B3.17)
|Source||Mg of nitrates per 100 grams|
70 to 95 mg
92 to 195 mg
70 to 95 mg
24 to 387 mg
43 to 161 mg
16 to 136 mg
25 to 42 mg
100 to 250 mg
100 to 250 mg
50 to 100 mg
20 to 50 mg
20 to 50 mg
Less than 20 mg
Less than 20 mg
Less than 20 mg
Nitrate-Rich Foods Protect Against Heart Disease
Previous research has shown that the more vegetables and fresh fruits you eat, the lower your risk of heart disease, with leafy greens being the most protective. As noted by Greger, the reason for this is likely their NO-boosting nitrates. This was confirmed in a May 2017 study published in The American Journal of Clinical Nutrition.18
In this study, nearly 1,230 Australian seniors without atherosclerotic vascular disease (ASVD) or diabetes were followed for 15 years. A food-frequency questionnaire was used to evaluate food intake, while nitrate intake was calculated using a comprehensive food database. As expected, the higher an individual's vegetable nitrate intake, the lower their risk for both ASVD and all-cause mortality. According to the authors:
"Nitrate intake from vegetables was inversely associated with ASVD mortality independent of lifestyle and cardiovascular disease risk factors in this population of older adult women without prevalent ASVD or diabetes. These results support the concept that nitrate-rich vegetables may reduce the risk of age-related ASVD mortality."
Leafy Greens and Sports Performance
Most competitive athletes understand the value of NO, and the wise ones take advantage of Mother Nature's bounty. While research19,20 has shown nitrate supplements can boost sports performance and enhance fast-twitch muscle fibers, you can get the same results using whole foods. For example, research shows raw beets can increase exercise stamina by as much as 16 percent,21 an effect attributed to increased NO.
In another study,22 nine patients diagnosed with heart failure who experienced loss of muscle strength and reduced ability to exercise were found to benefit from beet juice. The patients were given 140 milliliters (mL) — about two-thirds of a cup — of concentrated beet juice, followed by testing, which found an almost instantaneous increase in their muscle capacity by an average of 13 percent.
There's one important caveat though: Avoid using mouthwashes or chewing gum, as this actually prevents the NO conversion from occurring.23 The reason for this is because the nitrate is converted into nitrite in your saliva by friendly bacteria. That nitrite is then converted into NO in other places in your body.
More Information About NO
NO24 — not to be confused with nitrous oxide, commonly known as laughing gas, a chemical compound with the formula N2O25 — serves as a signaling or messenger molecule in every cell of your body. Hence, it's involved in a wide variety of physiological and pathological processes. As mentioned, it causes arteries and bronchioles to expand, but it's also needed for communication between brain cells, and causes immune cells to kill bacteria and cancer cells.
Now, your body loses about 10 percent of its ability to make NO for every decade of life, which is why eating a nitrate-rich diet is so important. NO is further synthesized by nitric oxide synthase (NOS). There are three isoforms of the NOS enzyme:
- Endothelial (eNOS): a calcium-dependent signaling molecule that produces low levels of gas as a cell signaling molecule
- Neuronal (nNOS): a calcium-dependent signaling molecule that produces low levels of gas as a cell signaling molecule
- Inducible (immune system) (iNOS): calcium independent; produces large amounts of gas, which can be cytotoxic
Problematically, when fluoride is present (such as when you're drinking fluoridated water), the fluoride converts NO into the toxic and destructive nitric acid. As noted in "Pharmacology for Anesthetists 3,"26 "[NO] will react with fluorine, chlorine and bromine to form the XNO species, known as the nitrosyl halides, such as nitrosyl chloride." Hence, avoiding fluoridated water and other halide sources, such as brominated flour, is important to optimize your health and avoid damaging interactions.
Exercise Also Boosts NO Production
Aside from eating a nitrate-rich diet, one efficient way to increase NO production is a series of callisthenic exercises. I'm using a modified version of a routine originally developed by Dr. Zach Bush. You'll find a quick demonstration of my "Nitric Oxide Dump" routine in the video above. This routine takes about three to four minutes and is ideally done three times a day, at least two hours apart.