5 foods containing potentially heart-healthy polyphenols
February 12, 2016
There isn’t much dispute about the health benefits of apples. After all, “an apple a day keeps the doctor away,” right? But what about red wine and chocolate?
As it turns out, chemical compounds called polyphenols are found in all three. And, while the jury is still out, there is some evidence that polyphenols may help protect people from a variety of diseases.
Polyphenols occur naturally and are found mostly in fruits, vegetables, cereals, dry legumes, chocolate, some beverages, and spices. They have antioxidant properties and protect plants from ultraviolet radiation.
The word “antioxidant” can make people feel good, but the reality of whether antioxidants provide health benefits is much more complex. Some preliminary research suggests that diets rich in foods containing polyphenols could potentially offer some protection from the development of cancer, heart disease, diabetes, osteoporosis, and neurodegenerative disease, but we must weigh initial findings such as these with clinical results.
We’ve seen numerous instances in which changes in a biomarker, such as cholesterol levels, do not necessarily translate into clinical benefit. So far, no clinical studies to track changes in disease burden and patient longevity have not been conducted to evaluate the true benefit of antioxidants.
Several studies have focused on polyphenols over the past 20 years. When it comes to heart disease, some research suggests that polyphenols may improve the function of the inner lining of the blood vessels, increase protective HDL cholesterol (the good cholesterol), and promote anti-platelet and anti-inflammatory activity.
Below is what preliminary research suggests – and what we truly know – about the health benefits of five polyphenol-rich foods:
- Red wine
- Olive oil
Both the skin and flesh of apples contain polyphenols. Researchers have tried to determine which parts of the apple affect cholesterol levels, but we don’t have a concrete answer yet.
One randomized, placebo-controlled study indicated that the polyphenols in apples may result in a health benefit. Specifically, the study suggested that a diet supplemented with apple polyphenol extract resulted in lower cholesterol.
However, a more recent study leads us to believe that the soluble fiber in apples may be driving cholesterol benefits. The study compared eating whole apples (which contain polyphenols and soluble fiber) to drinking apple juice (which contains only polyphenols). Researchers found that eating the apples significantly reduced total cholesterol but drinking the juice did not.
These two studies are not “apples-to-apples,” though. In the initial study, the polyphenols were more concentrated than in the more recent study. That difference may have impacted the results.
Also, one would have to drink an enormous amount of juice to see any relevant antioxidant activity. The amount of sugar and calories in the juice would most likely offset any potential antioxidant benefit.
Bottom Line: Whether it’s the soluble fiber or a combination of soluble fiber and polyphenols doing the good work, apples contain both potentially protective substances. They’re convenient, filling, and a delicious, sweet treat – one of nature’s great “fast foods.”
Red wine and dark grape juice contain a specific kind of polyphenol called resveratrol. Researchers have discovered that resveratrol:
- Decreases inflammation
- Stimulates the production of nitric oxide, which,
- Signals the arteries to expand, easing blood flow
You may have heard that red wine is good for your heart, and it’s true, when consumed in moderation. Red wine is one of the components of the heart-healthy Mediterranean diet. Similar to apple juice, one would likely have to consume several bottles of wine to experience antioxidant benefits from resveratrol – and drinking that much alcohol is in no way heart-healthy.
Bottom Line: If you drink, do so in moderation. If you are on medication, drink only after discussing it with your doctor. Moderate alcohol consumption is defined as one drink per day for women and two per day for men. One drink equals a 5-ounce glass of wine, a 12-ounce beer, or 1.5 ounces of liquor.
Several studies have examined whether chocolate provides heart-healthy benefits. One large observational study has linked eating milk chocolate or dark chocolate in moderation to a lower risk of heart disease and stroke.
Milk chocolate and dark chocolate contain flavonoids, a kind of polyphenol that is associated with heart health. But dark chocolate contains much more flavonoids than milk chocolate.
Some research suggests that eating small amounts of dark chocolate that is 70 percent or higher in cocoa reduces blood pressure and LDL cholesterol and also improves cognition. Again, a clinical study to track changes in patient health and longevity over time would be necessary to determine any true benefits of flavonoids found in chocolate.
Bottom Line: Just because chocolate may have some health benefits doesn’t mean it’s OK to have a candy bar every day. Most experts recommend no more than 1 ounce per day of chocolate, which averages 170 calories.
Extra-virgin olive oil is the least processed form of olive oil and has the highest concentration of polyphenols. It is produced by natural extraction from the olive fruit.
Olive oil is another staple of the Mediterranean diet. There is strong evidence that olive oil consumed in appropriate amounts helps prevent heart disease, strokes, metabolic syndrome, and some cancers. The proven health benefits from olive oil are due to the “healthy fats” it contains, and not necessarily due to the presence of polyphenols. More research is needed to determine the link between improved health, olive oil, and polyphenols.
It’s common to find olive oil products labeled as “extra-virgin” that are actually diluted with cheaper vegetable oils, which limit or eliminate the health benefits. Always check labels to ensure the olive oil is certified by the USDA, the North American Olive Oil Association, or the California Olive Oil Council.
Olive oil doesn’t stay good forever. It’s best to use it up within one year to receive the health benefits. Light causes the oil to deteriorate, so choose a brand that uses a dark bottle.
Bottom Line: It is well established that olive oil offers many health benefits, but it’s important to understand that not all olive oil is created equal.
Turmeric is a plant-based spice found in mustard and curry powder. Research is underway about curcumin, the pigment in turmeric that give it its vibrant yellow color, to determine if it has an effect on heart disease.
Preliminary findings suggest that turmeric may lower total cholesterol and increase beneficial HDL cholesterol. Another study involving post-menopausal women suggests that turmeric may improve how the blood vessel lining functions. Our blood vessels’ performance worsens as we age and is associated with cardiovascular-related disease.
Bottom Line: There have been no clinical studies to determine the actual antioxidant benefits of turmeric. While there is insufficient research to recommend it as a dietary supplement, consider adding this spice to your diet for flavor and color. In fact, here’s a recipe you could try!
Roasted Turmeric Cauliflower and Broccoli
Makes: 8 servings
- 1 medium head cauliflower
- 1 medium bunch of broccoli
- 4 or more cloves of garlic (optional)
- 1 Tablespoon olive oil
- 1 teaspoon turmeric
- ¼ teaspoon Kosher salt
Preheat oven to 350°F. Wash and cut cauliflower and broccoli to slightly larger than bite-size. Peel and press cloves of garlic. Toss vegetables and garlic in bowl with oil. Sprinkle with turmeric and salt, and toss well. Spread on cookie tray . Bake for 30 to 45 minutes (depending on how tender you prefer your vegetables), turning several times to brown all sides.
Nutrition facts per serving: Calories: 61, Total Fat: 2.1 g, Saturated Fat: 0.4 g, Sodium: 107 mg, Total Carbohydrate: 9.1 g, Dietary Fiber: 3.4 g, Sugar: 2.7 g, Protein: 3.5 g, Vitamin A: 9%, Vitamin C: 171%, Calcium: 5%, Iron: 5%