Nitrate-rich foods reduce blood pressure

Why NO is a big YES

NONitric Oxide – is a vital chemical messenger which relaxes otherwise constricted and stiff blood vessels, increasing both oxygen and blood flow. So it’s vital for reducing blood pressure and therefore heart health.

Improved blood and oxygen flow is also critical for better brain function as the brain uses 20% of our oxygen intake.

It’s also a way to help in cases of ED – erectile dysfunction. Drugs like sildenafil work in exactly this way – boosting nitric oxide signalling, relaxing arteries and increasing blood flow. And adequate Nitric Oxide is equally important for women, because unhindered blood flow helps sexual arousal in both men and women.

The inside of the arteries produces NO

The interior surface of your arteries is called the endothelium and it produces nitric oxide. When oxidised cholesterol (plaque) builds up there – the condition known as atherosclerosis – you reduce your capacity to produce nitric oxide and your arteries then become rigid, making blood flow more difficult. Your blood pressure rises and that significantly increases your risk of a heart attack, stroke or sexual dysfunction.

Preventing this chain of events is why physicians prescribe nitroglycerin for heart and stroke patients. But beetroot has a similar effect!

The free radical connection

The normal action of Nitric Oxide is impaired by excess free radicals.

Some free radical action is a normal part of metabolism – when food molecules are broken down in the presence of oxygen to create energy.

But there are occasions when oxygen in the body splits into single atoms with unpaired electrons. Electrons need to be in pairs, so these atoms, now called free radicals, scavenge the body to seek out other electrons so they can become a pair. This causes damage to cells, proteins and DNA.

As a consequence, free radical damage is linked to cancer, atherosclerosis, macular degeneration, Alzheimer’s disease, Parkinson’s disease and to ageing generally. Indeed, ageing has been defined as a gradual accumulation of free-radical damage.

Free radicals – and what is called oxidative stress – can be created when we consume high-temperature fried foods and alcohol, when we exercise to excess, or when we are exposed to tobacco smoke, residual pesticides and air pollutants.

A natural solution – anti-oxidants in food

If oxidative stress is the enemy of Nitric Oxide, anti-oxidants are the solution. You need to bathe your blood stream in anti-oxidants to neutralise excess free radicals.  This ensures that your endothelial cells can produce the Nitric Oxide that will, in turn, keep your arteries supple and your blood pressure normal.

You do that with anti-oxidant-rich foods like berry fruits, kale, broccoli and spinach, and nitrate-rich foods like beetroot and leafy green vegetables.

The nitrate in these plants is converted into nitric oxide in the body. Indeed researchers were able to show that drinking 250ml beetroot juice could drop blood pressure in a group of normal BP people by 10 points in just two hours.

Top nitrate foods include:
  • Rocket
  • Rhubarb
  • Lettuce
  • Coriander
  • Beetroot and beetroot greens
  • Spring greens
  • Basil
  • Chard
  • Whole grains

This suggests that a regular mixed salad with rocket, lettuce, coriander, basil and beetroot can be a top blood pressure lowering dish.

Nitrates for boosting athletic performance?

It also suggests that nitrate-rich foods might boost athletic performance. And this seems to be true. A study (referenced below) where cyclists were given beetroot juice before training showed that their energy production became 11% more efficient. For a top athlete that is a huge competitive advantage.

But since it’s an all-natural intervention, don’t expect newspaper headlines along the lines of: ‘Beetroot Doping Scandal Hits Tour de France!!’

Protect your NO

Eating nitrate-rich foods is one important way to lower blood pressure. Another way is to increase your consumption of foods containing the amino acid L-arginine, which can be found in nuts, fruits and dairy.

Nitric oxide only lasts a short time in the body, so the more antioxidant protection we provide it, the longer the effects will last. In fact, surgeons are even coating stents (the mesh tubes that prop open arteries after surgery) with drugs that produce nitric oxide.

You can protect your nitric oxide by consuming anti-oxidant rich foods as outlined above, and by supplementing with anti-oxidant nutrients including vitamins C and E, beta carotene, Co-Q10, lycopene, lutein and selenium.

Exercise for increased NO

When you exercise, your muscles need more oxygen, which is supplied by the blood. As the heart pumps, the lining of the arteries releases nitric oxide into the blood, which relaxes and widens the vessel wall, allowing for more blood to pass through.

As we get older, however, our blood vessels and nitric oxide system become less efficient due to free radical damage, causing our veins and arteries to become less elastic. So maintaining activity and exercise is important for Nitric Oxide health.

There’s a final heart/brain benefit to nitric oxide: in addition to relaxing or vasodilating blood vessels, nitric oxide also displays anti-platelet properties, which helps to prevent inappropriate blood clotting.

 


If you enjoyed this article, please share it with family and friends. You can follow us on Facebook or Twitter for daily headline health tweets.

Visit Us On TwitterVisit Us On FacebookVisit Us On Youtube

CTA Register NewsletterAnd register now for a free monthly e-newsletter on the latest in nutrition and health research.


Dr Paul Clayton designed NutriShield as a comprehensive healthbutton-2 supplement with OPTIMUM levels of essential nutrients. See more detail elsewhere on this site or click on the button.


Dr Paul Clayton’s best-selling book Health Defence is available from most good bookstores.

See the website www.healthdefence.com for excerpts and links to buy direct from the publisher.


See online here for delicious recipes from the Health Defence Cookbook incorporating healthy foods featuring in a Mediterranean Diet. Combined 3 courses strip


REFERENCES

Beetroot juice and exercise: pharmacodynamic and dose-response relationships. Wylie LJ, Kelly J, Bailey SJ, Blackwell JR, Skiba PF, Winyard PG, Jeukendrup AE, Vanhatalo A, Jones AM. J Appl Physiol (1985). 2013 Aug 1;115(3):325-36. doi: 10.1152/japplphysiol.00372.2013. Epub 2013 May 2.

Nitric Oxide: a molecule of the millennium. Shinde UA, Mehta AA, Goyal RK. Indian J Exp Biol 2000 Mar;38(3):201-10.

Discovery concerning nitric oxide as a signaling molecule in the cardiovascular system. Furchgott RF, Ignarro LJ, Murad F. Nobel Prize in Medicine and Physiology 1998.

In vitro effects of a novel class of nitric oxide (NO) donating compounds on isolated human erectile tissue. Seidler M, Uckert S, Waldkirch E, Stief CG, Oelke M, Tsikas D, Sohn M, Jonas U. Eur Urol. 2002 Nov;42(5):523-8

Age-related reduction of NO availability and oxidative stress in humans. Taddei S, Virdis A, Ghiadoni L, Salvetti G, Bernini G, Magagna A, Salvetti A. Hypertension. 2001 Aug;38(2):274-9.

Arginine Metabolism: nitric oxide and beyond. Guoyao WU, Morris SM. Biochem J 1998; 336:1-17

Antioxidants and the bioactivity of endothelium-derived nitric oxide. Tomasian D, Keaney JF, Vita JA. Cardiovasc Res. 2000 Aug 18;47(3):426-35.

Free radicals, antioxidants and functional foods: Impact on human health. V Lobo, A Patil, A Phatak, N Chandra. Pharmacogn Rev. 2010 Jul-Dec; 4(8): 118–126. doi:  10.4103/0973-7847.70902

Beetroot and beet juice – in moderation

Have you seen publicity about beetroot juice? It’s good for all kinds of things, apparently. It improves failing memory, enhances stamina, reduces blood pressure and even acts as a kind of natural male potency enhancer.

Or does it?

Increased athletic performance

exercise-m+f-runners-CThe story was originally kick-started in the mainstream media a few years ago by a trio of scientific papers, all from the University of Exeter, which showed that taking dietary nitrate in the form of beetroot juice increased athletic performance (1, 2, 3).  The performance improvement was significant: the juice boosted stamina and allowed people to exercise for up to 16 per cent longer.

This was not really new work at all, as the basics had already been proven by a team at the Karolinska Institute in Stockholm back in 2007 (4).

The stories were accurate enough, however. Drinking beetroot juice provides a large enough dose of nitrate to alter blood flow and oxygen metabolism in a way that genuinely does enhance physical performance, and many athletes are now bulk-buying this vegetable juice and using it as a form of natural doping!

An arterial relaxant

Beet juice may also have medical applications. Nitrate is metabolised in the body to nitric oxide (NO), a powerful messenger compound with multiple effects in the body including the relaxation of arteries. The changes in arterial behaviour which occur when nitrates are ingested would be expected to reduce the symptoms of intermittent claudication, a painful cramping of the calf muscles that is a consequence of peripheral vascular disease and often diabetes.

Nitrates would also be predicted to reduce blood pressure, which makes beetroot juice a potential treatment for hypertension. I am not aware of any studies yet on intermittent claudication, but at least two reports find that beetroot juice (5) and inorganic nitrate (6) do indeed lower blood pressure. These two studies were both in healthy volunteers but they certainly suggest that beetroot juice could be an alternative or adjunct to anti-hypertensive drugs.

There are no scientific reports of the use of beet juice as a sexual enhancer, but as its mechanism of action on blood flow is in some ways similar to that of Viagra, there has been a lot of speculation (fuelled, no doubt, by the companies that make beet juice), that this fashionable new drink could be a kind of sex aid.

Brain food?

To add to the media hysteria, a trial also demonstrated that beetroot juice increases blood flow in certain key areas of the brain (7).  A major feature of nitrate’s ability to increase blood flow is that it acts preferentially in conditions of low oxygen, allowing nitrate to increase blood flow precisely in the areas where it is needed most.

In this study, the high nitrate diet did not alter total cerebral blood flow, but did lead to increased regional blood flow in the frontal lobe white matter – the areas of the brain commonly associated with degeneration that leads to dementia and other cognitive problems. The scientists who did this study at North Carolina’s Wake Forest University claimed that this improvement in blood flow might improve mental function in the elderly.

roasted-vegetables-wth-cracked-wheat-salad

Enjoy beetroot in Health Defence Cookbook recipe “Roasted vegetables with cracked wheat salad”

But danger of too much nitrate

So should we all be drinking daily beet juice for breakfast? I’m afraid that the answer is almost certainly NO. This is because in the longer term, too much nitrate is not good for us.

You’ll know that nitrates are often added to processed meats like bacon, ham, sausages and hot dogs, as they add a pink colour and function as preservatives to help prevent the growth of harmful bacteria. Unfortunately these processed meats are strongly linked to increased cancer risk of the digestive tract.

Moreover, despite the above research suggesting that nitrates could be used to help the ageing brain, there is a good deal of evidence that high dietary nitrate levels will increase the risk of developing Alzheimer’s.

High levels of dietary nitrate lead to raised levels of nitric oxide synthesis, and this, if sustained, causes a condition known as nitrosative stress. This has been strongly implicated as a cause of protein malfolding, a form of protein denaturation that occurs in the brains of Alzheimer’s patients (8, 9, 10). In fact, compounds that block nitrosative stress in the brain have been shown to slow and reverse the damage caused by Alzheimer’s in pre-clinical models (11).

Moderation in all things

The lesson of all this is moderation in all things, including natural things.

That includes l-arginine, a natural amino acid used by some to treat the vascular problem intermittent claudication (mentioned above), and to enhance male sexual function. As this compound is another potent source of nitric oxide, it also increases nitrosative stress (12), and will therefore, like beet juice, increase the risk of Alzheimer’s if used heavily.

Just as worryingly, l-arginine is widely used to treat the symptoms of vascular disease yet it has been implicated in increased death rates after heart attacks (13). The counter-arguments made by arginine sales-persons are not convincing, and certainly not enough to ignore the principle of due diligence.

By all means eat more beetroot in your healthy Mediterranean-style diet, but beware of too much concentrated beet juice.

Indeed, beware of ANY high-dose single-nutrient concentrates or supplements. As with foods, a wide range of nutrient supplements in moderate amounts is hugely preferable to an excessive intake of just one.

 


If you enjoyed this article, please share it with family and friends (see buttons below).

CTA Register NewsletterAnd register now for a free e-newsletter on the latest in nutrition and health research.

You can follow us on www.facebook.com/nutrishield or www.twitter.com/colinrose40 for daily headline health tweets.


Dr Paul Clayton designed NutriShield as a comprehensive healthbutton-2 supplement with OPTIMUM levels of essential nutrients. See more detail elsewhere on this site or click on the button.

Health Defence bookDr Paul Clayton’s best-selling book Health Defence is available from most good bookstores. See the website www.healthdefence.com for excerpts and links to buy direct from the publisher.

See online here for delicious recipes from the Health Defence Cookbook  incorporating healthy foods featuring in a Mediterranean Diet. Combined 3 courses strip


REFERENCES

1. Bailey SJ, Winyard P, Vanhatalo A, Blackwell JR, Dimenna FJ, Wilkerson DP, Tarr J, Benjamin N, Jones AM. Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans. J Appl Physiol. 2009 Oct;107(4):1144-55

2. Bailey SJ, Fulford J, Vanhatalo A, Winyard PG, Blackwell JR, DiMenna FJ, Wilkerson DP, Benjamin N, Jones AM. Dietary nitrate supplementation enhances muscle contractile efficiency during knee-extensor exercise in humans. J Appl Physiol. 2010 Jul;109(1):135-48.

3. Vanhatalo A, Bailey SJ, Blackwell JR, DiMenna FJ, Pavey TG, Wilkerson DP, Benjamin N, Winyard PG, Jones AM. Acute and chronic effects of dietary nitrate supplementation on blood pressure and the physiological responses to moderate-intensity and incremental exercise. Am J Physiol Regul Integr Comp Physiol. 2010 Oct;299(4):R1121-31

4. Larsen FJ, Weitzberg E, Lundberg JO, Ekblom B. Effects of dietary nitrate on oxygen cost during exercise. Acta Physiol (Oxf). 2007 Sep;191(1):59-66.

5. Webb AJ, Patel N, Loukogeorgakis S, Okorie M, Aboud Z, Misra S, Rashid R, Miall P, Deanfield J, Benjamin N, MacAllister R, Hobbs AJ, Ahluwalia A. Acute blood pressure lowering, vasoprotective, and antiplatelet properties of dietary nitrate via bioconversion to nitrite. Hypertension. 2008 Mar;51(3):784-90.

6. Kapil V, Milsom AB, Okorie M, Maleki-Toyserkani S, Akram F, Rehman F, Arghandawi S, Pearl V, Benjamin N, Loukogeorgakis S, Macallister R, Hobbs AJ, Webb AJ, Ahluwalia A. Inorganic nitrate supplementation lowers blood pressure in humans: role for nitrite-derived NO. Hypertension. 2010 Aug;56(2):274-81.

7. Presley TD, Morgan AR, Bechtold E, Clodfelter W, Dove RW, Jennings JM, et al. Acute effect of a high nitrate diet on brain perfusion in older adults. Nitric Oxide 2010 Oct 15, Published online ahead of print

8. Dildar K, Sinem F, Gökhan E, Orhan Y, Filiz M. Serum nitrosative stress levels are increased in Alzheimer disease but not in vascular dementia. Alzheimer Dis Assoc Disord. 2010 Apr-Jun;24(2):194-7.

9. Gu Z, Nakamura T, Lipton SA. Redox reactions induced by nitrosative stress mediate protein misfolding and mitochondrial dysfunction in neurodegenerative diseases. Mol Neurobiol. 2010 Jun;41(2-3):55-72. Epub 2010 Mar 25. Review

10. Nakamura T, Lipton SA. S-Nitrosylation of Critical Protein Thiols Mediates Protein Misfolding and Mitochondrial Dysfunction in Neurodegenerative Diseases. Antioxid Redox Signal. 2010 Sep 2. Epublished ahead of print.

11. Dumont M, Wille E, Calingasan NY, Nathan C, Flint Beal M, Lin MT. N-iminoethyl-L-lysine improves memory and reduces amyloid pathology in a transgenic mouse model of amyloid deposition. Neurochem Int. 2010 Jan;56(2):345-51.

12. Huang H-S, Ma M-C, Chen J. Chronic L-arginine administration increases oxidative and nitrosative stress in rat hyperoxaluric kidneys and excessive crystal deposition. Am J Physiol Renal Physiol 295: F388-F396, 2008

13. Schulman SP, Becker LC, Kass DA, Champion HC, Terrin ML, Forman S, Ernst KV, Kelemen MD, Townsend SN, Capriotti A, Hare JM, Gerstenblith G. L-arginine therapy in acute myocardial infarction: the Vascular Interaction With Age in Myocardial Infarction (VINTAGE MI) randomized clinical trial. JAMA 2006 Jan 4;295(1):58-64.