Americans are living longer than ever. From 1900 to now, we’ve increased our longevity by over 30 years. But living longer doesn’t necessarily equate to being healthy and having a high quality of life, especially as we age. That means it’s important to focus on both lifespan (number of years lived) and healthspan (number of years with good health). 

Reasons for the increase in longevity have a lot to do with medical advances, including diagnosing, treatments, surgical options and research. While these things may improve quality of life, they often only cure or improve the disease state. This means that ultimately, your quality of life depends on your habits. Though some may think these habits are more important in midlife and older age, the younger you are when you establish healthy habits—even in childhood—the more likely you are to continue them throughout your lifetime. And let’s face it: The more established habits become, the more difficult they are to change. 

Diet plays a large role in how well our bodies and brains function, as well as how quickly they age. Researchers from Australia and the U.S. teamed up to take a closer look at a powerful plant compound—flavonoids—aiming to establish relationships between them and healthy aging. They recently published their findings in The American Journal of Clinical Nutrition. Let’s break them down.

How Was This Study Conducted?

Researchers drew data from two long-term U.S. studies—the Nurses’ Health Study (NHS) and the Health Professionals Follow-up Study (HPFS). The NHS began in 1976 with 121,701 female nurses between the ages of 30 and 55 at baseline; the HPFS included 51,529 male health professionals aged 40 to 75 at baseline and started in 1986. Researchers included 62,743 females and 23,687 males from these studies for this current analysis. 

This study aimed to examine relationships between flavonoid intake and three indicators of healthy aging: frailty levels, physical function and mental health. Flavonoids are plant compounds with antioxidant and anti-inflammatory properties. Foods high in flavonoids include berries, oranges, apples, dark chocolate and tea. For this study, researchers looked at several angles, including a “flavodiet” score based on the number of flavonoid servings per day, flavonoid subclasses and more. To examine flavonoid intakes, researchers used participants’ food frequency questionnaires, which were completed at baseline and every four years. 

Frailty is defined as having three or more of these self-reported criteria: fatigue, poor strength, reduced aerobic capacity (i.e., getting short of breath more easily with activity), five or more chronic illnesses, and 5% or greater loss of body weight. Frailty was determined based on answers to a questionnaire every four years. 

Physical impairment was assessed throughout the study period based on a 10-question survey about physical limitations in performing various moderate and vigorous activities. Participants were given a score, calculated on a 100-point scale. Those scoring under 80 were considered physically impaired. Mental health was assessed using three different scales at various times throughout the study period. Poor mental health was determined based on the scores.

What Did This Study Show?

Because researchers were looking at so many aspects of flavonoids and various factors, many results surfaced from this study. The researchers observed the clearest associations between flavonoids and healthy aging in the Nurses’ Health Study, which included only female participants.

For female participants, those who ate the most flavonoids had a 15% lower risk of developing frailty, a 12% lower risk of developing impaired physical function and a 12% lower risk of developing poor mental health compared to those who ate the least flavonoids. The researchers also broke down those findings for female participants food by food. The findings included that when comparing highest to lowest intakes:

• Tea, red wine, blueberries, apples and oranges were associated with an 11% to 21% lower risk of frailty.
• Red wine, blueberries, apples, strawberries and oranges were associated with 4% to 14% lower risk of physical impairment.
• Apples, strawberries, oranges and grapefruit were associated with 10% to 15% lower risk of poor mental health.

The findings for citrus fruits like oranges and grapefruit also included their juice, so even a morning glass of OJ may have beneficial effects.

There were few strong associations for male participants, but they largely had to do with high amounts of flavonols supporting better mental health with age. For instance, female participants who increased their intake of flavonoid-rich foods by three servings a day were at a lower risk for all three aging outcomes, while male participants only experienced a lower risk for poor mental health.

Researchers aren’t entirely sure why men didn’t show the same level of risk reduction as women. While there may be some sex differences, they surmise that it might also be due to the shorter follow-up time in the male study compared to the female study. Less follow-up time means less data to work with, so more research needs to be done to gain clarity in this area.

One limitation of this study is that it depended on self-reporting on diet, which opens up the possibility of bias and incorrect estimation. The participants of this study were largely white professional men and women, so it is unknown whether the results extend to other populations. 

How Does This Apply to Real Life?

While we often focus on living longer, the same habits contributing to longevity can also help improve quality of life. If this is your goal, this study suggests including plenty of foods rich in flavonoids—and that includes drinks like black tea.

While all tea leaves are loaded with antioxidants, this study primarily considered black tea. But other teas rank right up there, too, including green, hibiscus, oolong, white and rooibos. This study did not note whether the tea was consumed plain or was embellished with sugar or cream, but if you’re going to become a regular tea sipper, we suggest drinking it plain most of the time to avoid consuming too much added sugar and saturated fat. If you want the extra flavoring, consider sweetening your tea with allulose or stevia and using a touch of milk or nondairy milk for creaminess. 

Of course, those recommended flavanol-rich foods also include berries, apples and citrus fruits and juices. Eat the fruits whole or use them in tasty recipes, including smoothies and our Lemon-Blueberry Overnight Oats, Spring Pea Salad with Strawberries or Slow-Cooker Chile-Orange Chicken Tacos. 

Moderate red wine intake was linked to healthier aging in this study. It’s important to emphasize that the benefits were exclusively related to red wine. Plus, research is mixed regarding alcohol and health. If you stick to just one 5-ounce serving with dinner, there is evidence that you might experience health benefits to your heart and brain. Beyond these limits—and for some, with any amount of alcohol—health benefits diminish.

This study didn’t include dark chocolate in the analysis, but that, too, is rich in flavonoids. If you’re looking for creative ways to add dark chocolate to your food lineup, give some of our highly rated recipes a try, including our Crispy Peanut Butter Balls and Chocolate Nut Bark.  

The Bottom Line

This study suggests that eating foods rich in flavonoids may reduce your risk of frailty, physical impairment and poor mental health as you age, especially for women. The foods they found had the greatest influence in these areas are black tea, berries, apples and citrus fruits and juices. Assess how many of these foods you’re currently including in your diet and start by adding a serving each day, gradually increasing over time. 

Other lifestyle areas that influence healthspan include physical activity, stress, sleep and time spent with loved ones. Take a big-picture view of your health and start with any area you feel you’ll have the most success in. This will make it easier to build on that success, as small steps lead to big changes over time.