When I’m at a dinner party and people find out I’m a doctor, generally at least one person in the room will ask me for medical advice. Usually, it’s about a mysterious lump or a harmless rash. Or sometimes someone will tell me they’re convinced they have a deadly disease. While many of us in medicine are focused on diseases, most doctors don’t pay the same attention to health.

A friend once said to me, “Health is the ultimate negative idea. You don’t think about it until you lose it.”

True, we tend to take our health for granted until we’re in serious pain or discomfort. Well, it’s time to change how we approach our health so we can live our best lives.

So, what is health? And what does it really mean to be healthy?

Most of us think of health as “the absence of disease.” This is not only a murky definition, but it’s also inaccurate. In reality, diseases creep up on us long before the symptoms show. Health is way more than not being sick.

Here’s what’s important to know: health is achieved when the body is able to protect itself against imbalances, breakdowns and foreign invaders. The human body has evolved powerful defense systems that help it maintain optimal physical, mental and emotional states.

At the Angiogenesis Foundation, a nonprofit I founded in 1994, we’ve identified five crucial defense systems in the body that are the key to protecting our health. They are:

• Our body’s ability to maintain good circulation. (This is called angiogenesis. Check out my TED Talk)

• Our ability to regenerate. (Yes, people can regenerate tissues and organs. It’s not just salamanders and starfish anymore!)

• Our immune system. (How efficiently our body fights infection and cancer)

• Our ability to repair our DNA. (This system helps slow damage from aging)

• Our microbiome. (Our bacterial ‘selves’ are made of good microbes that keep us healthy)

Each of these five systems must work in proper balance within the body. That’s when we feel our best and are truly healthy. And when this balance gets out of whack, our health falls off track.

So, what can we do to boost our body’s health defenses?

Let’s start with these four evening rituals for better health:

Dim the Lights.

Sleep is the cornerstone of our health, but most of us don’t get enough or as high quality sleep as we should. Here’s a tip for a good night’s rest: dim the lights before bedtime to optimize your brain’s release of the sleep hormone melatonin. It turns out not only does melatonin control our body’s clock, but it also does double duty as a cancer-fighter by rightsizing our circulation and keeping blood vessels from feeding cancer cells. A study of 116 healthy people showed that exposure to bright room light in the evening delayed the release of melatonin by the brain’s pineal gland and shortened the duration of melatonin release by 90 minutes. This means when you keep the lights bright before bed your body is not receiving melatonin’s protective benefits. You want to keep your melatonin surging to its optimal level throughout the night for good sleep and cancer protection. Proper sleep is also critical to maintaining your immune system’s defenses. So power down your electronic devices and dim the lights before going to bed.

Hot Cocoa Warms the Heart.

Hot cocoa is a comfort for many folks, especially in cold weather. Amazingly, chocolate has been used in beverages since the Aztecs dating as far back as 1900 B.C.E. Cacao, the main ingredient in chocolate, has bioactive polyphenols that promote heart health in many ways. Recently, cacao has even been shown to increase the number of stem cells in our bloodstream. A clinical study showed people who consumed a daily cup of hot cocoa made with dark chocolate increased the number of stem cells circulating in their bloodstream, improved their blood flow, and decreased their blood pressure.It’s been shown that more stem cells in the blood leads to a healthier heart and even improves survival from heart disease. So, indulge in some hot (dark) chocolate for your ticker.

Floss Every Night.

Brushing your teeth may be a reflex, but flossing is an extra step that can keep your body healthy. According to the American Dental Association, 60 percent of people don’t floss daily, while 20% never floss. Flossing removes harmful bacteria that are caught in the hidden crevices of your teeth and gums. These bad bacteria in your mouth actually provoke inflammation throughout your body — an effect that can damage the blood vessels in your heart and raise the risk of a heart attack. In fact, a study of 942 people who were at risk for heart attacks showed that those who had better oral hygiene, including flossing, had an 80% lower risk of having and dying from a heart attack or stroke. So, take the extra few minutes to floss — it will be heartfelt.

Take a Probiotic.

Speaking of bacteria, not all bugs are bad. In fact some bacteria are great for our health! One of the most exciting scientific discoveries I’ve seen in recent years about healthy bacteria revolves around one called Lactobaccillus reuteri. This is a gut bacteria that is naturally passed from mom to baby through breastfeeding. It turns out L. reuteri doesn’t just help our gut health, but it also boosts the immune system. In laboratory research conducted at MIT, researchers found another amazing benefit: L. reuteri trims abdominal fat and even keeps animals eating a high fat Western diet slim. So, look for a probiotic supplement containing L. reuteri for better immunity and even a slimmer waistline.

Making these four easy steps a part of your evening ritual can boost your body’s defense systems. You’ll wake up a healthier person and in better shape to deliver the productivity your busy life demands over the long haul. If we take our health more seriously on the front end, we can avert suffering on the tail end of our lives. Disease prevention is the key investment we can all make for a better life — for ourselves and our families.