By Rachel Johnson, Ph.D, M.P.H., R.D., "Inflammatory Foods,"January/February 2008
As a nutrition professor, I thought I was up to speed on which healthy habits can help you prevent heart disease—until a few years ago when my University of Vermont colleague Paula Fives-Taylor, Ph.D., rattled my thinking. In a riveting lecture, this professor of microbiology and molecular genetics explained that something as simple as flossing your teeth regularly could make a big difference in reducing heart disease risk. (That’s when my jaw dropped.) Since flossing keeps plaque-forming bacteria from invading gum tissue, she explained, it helps prevent the body’s immune system from launching into defense mode—a process known as inflammation. Inflammation, she added, was now understood to be both a warning sign and a trigger for a number of medical conditions including heart disease.
Fives-Taylor was onto something. Today, inflammation is so widely linked to heart disease, many physicians routinely order tests for a key marker of inflammation, C-reactive protein (CRP), as readily as they do cholesterol tests.
It seems counterintuitive, but inflammation begins with the body’s way of defending itself against harm. We’ve all experienced it as part of the normal healing process after a scrape or cut. Waves of immune cells rush to the injury, combatting threatening pathogens and sometimes causing heat, redness and swelling. But the new thinking is that serious health problems begin when inflammation overstays its welcome, persisting in a chronic, low-grade state in which some immune cells remain activated even though they’re not needed.
We used to think heart disease resulted from deposits of fatty plaques in our arteries, like the buildup of rust in a water pipe. But we now know that heart attacks rarely happen simply due to this buildup. Far from being mere “pipes,” arteries are active participants in the progress of heart disease, both attracting and harboring cells that release inflammatory substances. The result is a fatty plaque that forms within the artery walls and is a target for yet more inflammatory damage. According to my friend Penny Kris-Etherton, Ph.D., R.D., distinguished professor of nutrition at Penn State, “inflammation plays a key role in weakening arterial plaque, causing the deposits to rupture—which can lead to sudden coronary death, heart attack or stroke.”
Anything you can do to lower your level of inflammation, then, can go a long way toward reducing your risk for heart disease. Your doctor may recommend a daily dose of aspirin, the original anti-inflammatory drug. Also, since body fat is itself a source of inflammation, losing extra pounds can help—as can increasing your fitness level. And exciting research is showing that what we eat can make a difference too.
Numerous studies show that individual foods and nutrients can either stoke or subdue the inflammatory process. The foods that inflame aren’t new villains: they are saturated fats and trans-fatty acids, along with high-glycemic-index carbohydrates like refined starches and sweets, which the body quickly converts to glucose.
It’s old news that saturated fats and trans fats increase LDL (“bad” cholesterol) in the blood, but we now know that too much LDL can start a cascade of inflammatory events. When it accumulates in artery walls excessively, LDL undergoes chemical changes, including oxidization; the body interprets these changes as “danger” and responds by drawing inflammatory compounds into arteries. This process ultimately results in both the buildup of plaque and chronic inflammation.
The anti-inflammatory prescription, then, begins with avoiding anything that increases LDL, and it’s a familiar refrain: Limit intake of full-fat animal products and read labels to avoid common trans-fat sources like commercial cakes, cookies, crackers, pies and breads. Focus on getting more omega-3 fats, which the body converts to substances that decrease inflammation. And, since elevated blood sugar can stoke some of the chemical changes that render LDL more dangerous, it makes sense to limit your intake of refined grains and other high-glycemic-index carbohydrates like white bread and potatoes.
Instead, try to get more of what I call “inflammation soothers”: foods that inhibit LDL and help prevent reactions that spark inflammation. The list is long and includes foods high in healthy mono-unsaturated and omega-3 fats (like extra-virgin olive oil and canola oil, fatty fish, nuts and seeds—particularly omega-3-rich walnuts and flaxseed), along with antioxidant-rich fruits and vegetables. (A few surprising “extras” like red wine, cocoa and turmeric have shown promising anti-inflammatory activity in some studies.) Whole grains and legumes are also key. And phytosterols, cholesterol-lowering plant compounds that are turning up in some brands of low-fat yogurt, orange juice, butterlike spreads and granola bars, also may help reduce inflammation.
But rather than just concentrating on individual foods, Kris-Etherton and other experts recommend focusing on an overall dietary pattern that combines these foods for additive and/or synergistic effects. The renowned Mediterranean Diet pattern, rich in plant foods and seasoned with olive oil, is one of many healthy models that fit this description.
Of course, lowering LDL cholesterol remains the cornerstone of reducing your risk of heart disease. But it’s clear that inflammation plays an important role, too, and soothing the flames of inflammation is within our power.
So lose weight if you need to, take a daily aspirin if prescribed and make sensible food choices. As you can see, there’s plenty of common ground between anti-inflammatory eating and healthy eating in general. You’ve undoubtedly heard this advice before, but now there are new reasons to act on it.
Oh, and don’t forget to floss.