Research has shown that the more vegetables you eat, the lower your risk of heart disease, with different types of vegetables protecting your heart through different mechanisms. Leafy greens, for example, have high amounts of nitrates that naturally boost your nitric oxide (NO) level.1 Cruciferous veggies, on the other hand, lower your risk of stroke and heart attack by promoting more supple neck arteries and preventing the buildup of arterial plaque.
In fermented cabbage, it's the fiber content that helps lower blood pressure and improve blood sugar control, thereby lowering your risk of heart problems. Phytonutrients in sauerkraut also help promote easy blood flow and flexible blood vessels, and veggies rich in magnesium and quercetin also provide important heart benefits. Following is a summary of some of the top vegetable types for maintaining healthy heart function well into old age.
Nitrate-Rich Veggies Boost Heart Health and Lower Risk of Heart Attack
NO is an important biological signaling molecule that supports normal endothelial function and protects your mitochondria. A potent vasodilator, it also helps relax and widen your blood vessels, which improves blood flow. A recent study published in The American Journal of Clinical Nutrition,2 which followed nearly 1,230 seniors for 15 years, found that the higher an individual's vegetable nitrate intake, the lower their risk for atherosclerotic vascular disease (ASVD) and all-cause mortality.
According to the authors, "These results support the concept that nitrate-rich vegetables may reduce the risk of age-related ASVD mortality." Research3 has also shown a diet high in vegetable nitrates helps prevent and treat prehypertension and hypertension (high blood pressure), and protects against heart attacks, courtesy of their NO-boosting power.
Vegetable nitrates should not be confused with the nitrates found in processed meats such as bacon, hot dogs, ham and other cured meats. Dietary nitrates can convert into either NO or nitrosamines, the latter of which are carcinogenic and should be avoided as much as possible.4 Vegetable nitrates turn into beneficial NO while the nitrates in processed meats are primarily converted into harmful nitrosamines.
To learn more about the biochemical underpinnings creating these radical differences, see "Why Some Nitrates Are Healthy While Others Are Harmful." The top 10 nitrate-rich foods that can help boost your heart health include:
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
Surprise! Watermelon Also Boosts NO Production
Watermelon is a popular summer delicacy, and it will also improve NO production thanks to L-citrulline. However, it is important to understand that watermelon is high in net carbs and consuming large amounts of it on a regular basis will likely worsen insulin resistance and increase your risk of heart disease.
Watermelon also has lycopene, a carotenoid antioxidant that gives fruits and vegetables like tomatoes and watermelon their pink or red color. Its antioxidant activity has long been suggested to be more powerful than that of other carotenoids, such as beta-carotene, and research suggests it may significantly reduce your risk of stroke.
A study5 that followed men in their mid-40s to mid-50s for more than 12 years found those with the highest blood levels of lycopene were 55 percent less likely to have a stroke than those with the lowest levels. Other antioxidants, including alpha carotene, beta-carotene, vitamin E and vitamin A, showed no such benefit. L-citrulline, meanwhile, is a precursor of L-arginine, the substrate for nitric oxide synthase in the production of NO. As explained in a 2006 study:6
"Supplemental administration L-arginine has been shown to be effective in improving NO production and cardiovascular function in cardiovascular diseases associated with endothelial dysfunction, such as hypertension, heart failure, atherosclerosis, diabetic vascular disease and ischemia-reperfusion injury, but the beneficial actions do not endure with chronic therapy.
Substantial intestinal and hepatic metabolism of L-arginine … makes oral delivery very ineffective … In contrast, L-citrulline is not metabolized in the intestine or liver … L-citrulline entering the kidney, vascular endothelium and other tissues can be readily converted to L-arginine, thus raising plasma and tissue levels of L-arginine and enhancing NO production."