If your daily diet doesn't include a serving of citrus fruit, it should. And for reasons that go beyond vitamin C.
According to a study published online last week in the journal Stroke, eating more oranges and grapefruit may help reduce stroke risk thanks to their flavonoid content.
Flavonoids are bioactive compounds in fruits, vegetables, nuts, dried beans and lentils, cocoa, tea and red wine. Flavonoids can be categorized into several classes; the ones found in citrus fruit are called flavanones.
The study analyzed 14 years of data from the U.S. Nurses' Health Study involving 69,622 healthy women who reported their food intake every four years.
Over the course of the study 1803 strokes occurred, half of them ischemic strokes (caused when a blood clot interrupts blood flow topart of the brain).
Total flavonoid intake did not alter the risk of stroke but total flavanone intake did. Women who consumed the most flavanones were 19 per cent less likely to suffer a blood-clot related stroke compared to their peers whose diet contained the least.
Flavanone intake was not related to hemorrhagic stroke, the type caused by uncontrolled bleeding in the brain.
The vast majority – 95 per cent – of flavanones came from oranges, grapefruit and their juices. Women in the top flavanone category consumed at least 63 milligrams a day – an amount found in 1 pink grapefruit, 1 large orange or 1 cup of orange juice made from frozen concentrate.
While vitamin C has often been cited as a cardio-protective component in citrus fruit, in this study vitamin C was not linked with a lower risk of stroke suggesting that flavanones play an important role.
Flavanones in oranges and grapefruit have been shown to protect brain cells, strengthen and tone blood vessels and reduce inflammation. Recently naringenin, the predominant flavanone in grapefruit, was found to be the most potent anti-inflammatory flavonoid tested.
Although this study was conducted on women, the researchers suspect the findings should also apply to men.
There are other reasons to add citrus fruit to your diet. A citrus fruit rich diet has been associated with a lower risk of digestive tract cancers, lung cancer, colon cancer and pancreatic cancer. Citrus fruit is also though to help protect from cataract, macular degeneration and cognitive impairment.
In addition to flavanones, citrus fruit contains generous amounts of vitamin C, folate, potassium and thiamin as well as some vitamin A, calcium, magnesium and fibre. Pink and red grapefruit also contain lycopene, a phytochemical thought to guard against prostate cancer.
Aim to have at least one citrus fruit each day to boost your intake of flavanones and important nutrients. Choose whole fruits more often than juice because they contain more flavanones and fibre and less sugar.
(Note: Substances in grapefruit interfere with how your body absorbs and breaks down certain drugs. Certain medications used to treat high blood pressure, high cholesterol, migraines, depression, anxiety, sleep disorders, and impotence don't mix with grapefruit or grapefruit juice. Seville oranges and tangelos may have similar effects. If uncertain, consult your doctor or pharmacist.)
Ten ways to enjoy citrus:
•Add orange segments or ½ cup of 100 per cent orange juice to a breakfast smoothie.
• Enjoy half a grapefruit with your morning meal.
• Mix orange slices with low-fat yogurt for a midday snack.
• Toss citrus fruit segments into green and spinach salads. (The vitamin C in citrus will enhance your body's ability to absorb iron from leafy greens.)
• Use freshly squeezed citrus juice in vinaigrettes and other salad dressings.
• Top low-fat cottage cheese with orange or grapefruit segments and toasted walnuts for a light lunch. Drizzle freshly squeezed orange juice.
• Place thinly sliced lemons, peel and all, underneath and around fish before baking. Baking softens the lemon so it can be eaten too.
• Toss cooked brown rice or quinoa with chickpeas, scallions, lime juice and lime zest for a tasty side dish.
• Sauté sliced cooked beets with freshly squeezed orange juice and orange zest for a vegetable dish.
• Combine diced grapefruit with cilantro, chopped red peppers and red onion for a fruit salsa to serve with chicken or fish.
Leslie Beck, a Toronto-based dietitian at the Medcan Clinic, is on CTV's Canada AM every Wednesday. Her website is lesliebeck.com.