In 1998 the Nobel Prize in Medicine went to three scientists for showing that a gas, nitric oxide, is a signalling molecule in the cardiovascular system.1 It was a strange finding. Gases are supposed to be pollutants, not messengers. But nitric oxide, one nitrogen atom and one oxygen atom, turned out to be the signal your blood vessels use to relax. Twenty-five years later it is still almost unknown outside research labs. Medical training spends very little time on it, because there is no drug called "nitric oxide" to prescribe. Which is a pity, because it does more for you than most things you can name.
What it does
- It opens your arteries. Nitric oxide diffuses from the vessel lining into the muscle of the artery wall and tells it to relax. A relaxed artery is wider, and a wider artery carries more blood at lower pressure.2 This is the mechanism blood pressure runs on.
- It delivers everything. Oxygen, nutrients and hormones reach your organs by blood flow, and waste leaves the same way. Nitric oxide regulates that flow to every tissue you have.
- It keeps blood flowing smoothly. It discourages platelets from clumping and calms inflammation in the vessel wall, two of the processes behind clots and plaque.3
- It carries messages in the brain. Nitric oxide is a neurotransmitter, involved in how neurons connect and in memory.4
- It helps your immune system fight. Immune cells produce nitric oxide to signal and to attack bacteria, viruses and damaged cells.5
- It affects blood sugar. Low nitric oxide availability is linked to insulin resistance.6
- It powers exercise and recovery. More blood flow means more oxygen to working muscle and faster clearance afterwards.
- It drives sexual function. Erection is a nitric oxide event. The drugs that treat erectile dysfunction work by protecting the nitric oxide signal.7
Nitric oxide lasts a few seconds in the bloodstream. Its effect lasts a lifetime.
Why you have less of it than you did
Your body makes nitric oxide in the lining of your blood vessels, the endothelium. That production falls with age: by roughly 10 to 12 percent a decade, so that at 40 you make about half of what you did at 20, and by 65 or older perhaps 15 percent.8 Older adults show
measurably lower nitric oxide availability and more oxidative stress in their arteries.9 Smoking, alcohol, a sedentary life and diabetes all speed the decline. Your blood pressure doesn't fall to match. Less nitric oxide, less opening, higher pressure. Most readings start to climb in exactly the decade production halves.
The signs of low nitric oxide
They are easy to blame on something else: loss of energy, a rising blood pressure reading, poorer sexual function, worse exercise capacity, foggier memory, insulin resistance. Up to half the adult population over 40 may have reduced nitric oxide availability,8 and most of them attribute the symptoms to age.
The good news: one pathway doesn't age
Your cells' own production declines, but there is a second route. Nitrate from leafy greens andbeets is converted, through bacteria on your tongue and acid in your stomach, into nitrite and then nitric oxide.10 This pathway works at any age, which means nitric oxide can be brought back toward healthy levels in people whose own production has fallen. In a randomised trial,about 400mg of dietary nitrate a day lowered systolic pressure by around 8 mmHg in hypertensive adults over four weeks.11
Movement, slow breathing, sleep, less smoke and less alcohol all help you keep the nitric oxide you make. Antioxidants help it survive long enough to work. That is the whole of the Core3 model in one paragraph, and it is also, more or less, what the Nobel committee was pointing at.
