What's really going on when you down those "Sausage McMuffins® with Egg" and two hash browns or the American favorite, a Big Mac® with fries? Real and present danger.

It all centers on endothelial health. Your endothelium-the largest organ in the body-is a thin, one-cell layer lining the interior of your entire vascular tree and a dynamic interface between the blood and body.

Back when I was in medical school, the endothelium was thought to be like a Teflon lining of the arterial system, relatively ignored and certainly not factored into vascular health or disease prevention.

But that concept has all changed in the last few years. We've learned it is much, much more than that. In fact, the Mayo Clinic released a paper in 2003 defining endothelial dysfunction as the "ultimate risk" among all the cardiovascular risk factors.

A highly active endocrine organ with one trillion cells, the endothelium produces hormones that cause blood vessels to dilate and constrict.

Endothelial cells secrete substances-like the vitally important messenger molecule, nitric oxide, needed for a number of physiological processes-for critical functions: regulate homeostasis, keep blood moving smoothly, control blood pressure, ensure vascular tone as well as maintain inflammatory processes, oxidation and even coagulation.

If you could spread your endothelium out on the ground, it would encompass six tennis courts!

And if you were to lump it all together in one mass, it would be larger than your liver and equal to five hearts.

An enormously important organ. So when your endothelium functions well, life is good. But when it doesn't, that brings on vascular dysfunction, which is the precursor to a litany of health issues: heart attack, stroke, dementia, Alzheimer's, hypertension, angina, erectile dysfunction, diabetes/diabetic foot, renal failure, among others.

Genetics, aging (men over 55, women over 65), diabetes, smoking, obesity, inactivity, stress, sleep apnea, poor nutrition and other unhealthy conditions are some of the cardiovascular risk factors that can damage the endothelium- causing it to decrease its protective secretions, like the nitric oxide mentioned earlier.

Back to that Mac. Let's zero in on the last risk factor, poor nutrition. Check out the effect on your body in the four-hour period after eating a high-fat meal (like a Sausage McMuffin® with Egg/two hash browns or Big Mac® with fries): 70% drop in blood flow (arteries constrict/less elasticity), 125% hike in triglycerides, 50% jump in leukocytes (white blood cells) and 125% rise in IL-8 (inflammatory markers).

The negative response is due to the impact high-saturated fat foods have on the endothelium.

Two major problems exist in today's approach to cardiovascular health:

Problem 1: Our inability to accurately assess an individual's cardiovascular risk, like the Churchill/Fixx example below.

Are you a Winston Churchill or a Jim Fixx? Winston Churchill was overweight, not fit, a heavy smoker and allegedly a heavy drinker. He lived to 91. Yet, looking at him, you probably would have tagged him as a high risk for heart disease. Well, guess what? Churchill didn't have heart disease.

On the other hand, famed runner/author of the 70s Jim Fixx lived a healthy lifestyle, was lean, didn't smoke or drink and died at 52 from a sudden cardiac arrest.

It's said that his autopsy showed atherosclerosis-byproduct of endothelial dysfunction-resulted in 95% blockage of one coronary artery, 85% of another and 50% of yet another.

Problem 2: Our inability to adequately monitor the arterial system's response to treatments.

And that's what my new endothelial testing is all about.

A great example is "Meet the Press" host/NBC Washington Bureau Chief Tim Russert, who died at 58. Known to have heart disease, Tim was a patient at a high-end, traditional cardiology clinic, where he was treated with the current standard of care: Statins, aspirin and ace inhibitors to reach his target lipid profile. Yet, he died of a massive heart attack at his desk.

What happened? He wasn't treated aggressively with exercise, diet and hormone optimization despite being diagnosed with metabolic syndrome, nor were his very sensitive endothelial biomarkers monitored. These markers would have produced easy-to-see information to keep him focused on the right medical protocols and lifestyle modifications to avoid a premature death. In fact, monitoring early warnings and making the right protocol changes would have reversed his heart disease.

The current risk factors doctors look at for heart disease work well for large populations and long-term predictions-but not for individuals or short-term predictions.