Heart health, down to a tiny molecule

Everyone knows exercise and a healthy diet are good for people, but Dr Louis Ignarro's Nobel Prize-winning research is among the first to explain this scientifically.

Dr Ignarro, an American, was in Singapore last week to give talks to cardiologists, and also gave tips to stay healthy.

Q: You shared the 1998 Nobel Prize in Medicine for research on nitric oxide's role in cardiovascular health. What does the molecule have to do with exercise and eating healthy food?

If you're healthy, the body produces nitric oxide at a steady level to keep your veins and arteries healthy.

The molecule widens veins and arteries to improve blood flow, and more blood and oxygen are delivered to muscles.

When its levels go down due to age, sickness or disease, the body loses the protection. Unhealthy arteries can lead to strokes, heart attacks, heart failure, you name it.

Drugs like Nebivolol boost nitric oxide production to lower blood pressure safely, reducing cardiovascular events.

The harder you exercise, the faster the heart rate, the more nitric oxide you produce. Foods like fish and olive oil also give the body materials to produce nitric oxide.

Q: But not bacon. Why are foods like bacon and fatty pork bad for health?

They contain saturated fats, which markedly reduces the amount of nitric oxide in the body. Saturated fats come mainly from animal sources, including meat and dairy products.

When you eat saturated fats, they are metabolised into smaller molecules and create oxidative stress, which destroys nitric oxide.

If you have someone in a chair and measure his nitric oxide production, you will see that two strips of bacon or a little fatty pork will make his nitric oxide go down and stay down for eight hours.

It's a shame. I love bacon and eat it. You can eat it, but you can't eat it every day.

Q: Some studies suggest that too much nitric oxide may be linked to diseases like arthritis. Is it possible to have too much nitric oxide?

No, it's not possible. All the sceptics have looked for that, but no one has found anything significant. I have not seen significant evidence to show the possibility of over-producing nitric oxide, except in endotoxic patients, who have bacteria in the blood that can be toxic.

You're not taking in the oxide, it's not like you're walking around with a gas tank and breathing it in.

When you exercise or fuel your body with materials like fish, you're asking your body to make as much nitric oxide as possible, but the body will never make too much.

The problem is usually when you get old and sick, your body makes too little.

Q: You ran your first marathon when you were 64 years old and you still cycle 240km every week. How important is exercise to reducing cardiovascular disease?

In the United States, about 70 per cent of people suffer from cardiovascular disease, and half of them will die of it.

But among people who are athletes or who work out all the time, the incidence is significantly less. That tells you cardiovascular disease is largely preventable and avoidable with a healthy lifestyle.

I can't run any more because I hurt my knees, but now I bike. The body is not particular when it comes to producing nitric oxide as long as the heart rate increases, so you can run, cycle, swim.

My only regret is that my best marathon time was 4hr 3min, when I was 68 years old. All I ever wanted was to get 3hr 59min 59sec, but it never happened. I cried.

Q: You've spent years in both academia and industry. What advice do you have for young scientists?

After I got my PhD, I went into the drug industry for five years. I helped to develop drugs like an anti-inflammatory drug to treat arthritis, and I really liked that. But the companies wanted me to focus on their drugs, whereas I wanted to do other things, so we parted on very peaceful, friendly terms.

But the industry experience gave me a purpose even after I left. When I joined the academic world, I thought, I'm going to focus on drugs society needs, and how I can help to do research that will allow pharmaceutical companies to develop those drugs.

Q: You were eight years old when you asked your parents for a chemistry set. Why were you already interested in science at that age?

I had all these questions: Why is water wet and sand dry? Also, if you're eight and you mix one clear solution with another clear solution and it turns purple, you're going to get all excited. These things capture kids' attention.

zengkun@sph.com.sg

This article was published on April 27 in The Straits Times.

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