It's well known that a diet rich in fruits and vegetables can help lower the risk of developing coronary heart disease and stroke thanks to its fibre, potassium and magnesium content.
But there's another reason to boost your intake of these cardio-protective foods: flavonoids.
According to a new study published online in the American Journal of Clinical Nutrition, men and women whose diets contained the most flavonoids were significantly less likely to die from heart disease or stroke. What's more, even a modest intake of these natural compounds offered protection.
Flavonoids are bioactive compounds in fruits, vegetables, nuts, dried beans and lentils, cocoa, tea and red wine. Flavonoids can be categorized into several classes, each class found in certain foods and having specific health properties.
Lab studies have revealed that flavonoids have a number of positive effects on blood vessels.
Some – but not all – studies conducted in people have linked a high intake of flavonoids to protection against heart disease. Yet many of these studies were small and investigated only one or two classes of flavonoids.
In the current study, researchers from the American Cancer Society and Tufts University in Boston explored the relationship between intake of total flavonoids and seven classes of flavonoids and the risk of dying from cardiovascular disease.
The study followed 98,469 healthy men and women, average age 69, for seven years. The researchers accounted for cardiovascular risk factors such as history of high blood pressure or high cholesterol, family history of heart attack, body weight, physical activity and smoking status.
Men and women who consumed the most – versus the least – flavonoids were 18 per cent less likely to die from cardiovascular disease.
Five flavonoid classes – called anthocyanidins, flavanols, flavones, flavonols and proanthocyanidins – were each linked to a lower risk of cardiovascular death.
Flavonoids, in particular flavones, offered substantial protection from fatal heart attack especially among women. Men and women whose diets provided the most had a 25-per-cent lower risk of dying from heart attack. Among women, the risk was reduced by 40 per cent.
Men with the highest intake of total flavonoids were also 37 per cent less likely die from stroke.
Those in the top flavonoid category consumed, on average, 515 milligrams of flavonoids a day, an intake that can be achieved by eating 10 daily servings of flavonoid-rich foods.
Protective effects also occurred with a modest intake – 150 to 300 milligrams of flavonoids daily – suggesting that eating a relatively small amount of flavonoid-rich foods (three to six servings a day) guards against cardiovascular death.
Flavonoids may protect the heart in a number of ways. They act as antioxidants, decrease inflammation and inhibit the formation of blood clots. They're also thought to help regulate blood pressure by keeping arteries relaxed.
While flavonoid-rich foods do appear to boost heart health, other dietary measures are important too.
Limiting foods rich in saturated (animal) fat and emphasizing unsaturated fats in vegetable oils, avocado, nuts and seeds can help lower LDL (bad) cholesterol and reduce inflammation.
A daily intake of 500 to 1,000 milligrams of omega-3 fatty acids from fish oil – called DHA and EPA – can make the blood less likely to form clots, reduce inflammation and protect against irregular heartbeats that cause sudden cardiac death. (Eating six ounces of salmon provides roughly 500 milligrams of DHA and EPA combined.)
If you have high LDL cholesterol in your blood, consuming foods such as oats, oat bran, psyllium-enriched breakfast cereals, flaxseed and barley on a daily basis – foods rich in soluble fibre – can help lower cholesterol.
A regular intake of whole grains, nuts, dried beans and lentils, and, of course, fruits and vegetables also guard against heart disease by lowering blood pressure, reducing LDL cholesterol and maintaining blood-sugar levels.
Keeping your daily sodium intake under 2,300 milligrams can keep blood pressure in check. (Adults require 1,200 to 1,500 milligrams of sodium a day.)
To reduce your sodium intake, limit how often you eat restaurant meals. Reduce processed meats such as bologna, ham, sausage, hot dogs, bacon and deli meats. Rely less on convenience foods such as canned soups, frozen dinners and packaged rice and pasta mixes.
Regular exercise is also essential. People who are regularly active are less likely to succumb to heart disease and 20 to 30 per cent less likely to die from the disease compared to their sedentary peers.
Physical activity can lower blood fats (triglycerides), increase HDL (good) cholesterol, reduce blood pressure, maintain a normal blood sugar and help manage stress.
To help lower the risk of heart disease, aim for 30 minutes of moderate-intensity exercise on most days of the week. Research suggests you need to burn at least 1,000 calories each week from exercise to reap its cardio-protective effects.
Leslie Beck, a Toronto-based dietitian at the Medcan Clinic, is on CTV's Canada AM every Wednesday. Her website is lesliebeck.com.