Flavonoids are types of polyphenol compounds. They are classified into six main subclasses based on chemical structure: anthocyanidins, flavan-3-ols, flavonols, flavones, flavanones, and isoflavones. The flavonoid content of fruits and vegetables likely plays a role in the benefits of these foods, including decreased risk of all-cause mortality, cardiovascular disease, and cancer. The below study focuses on flavonoid intake, mortality outcomes, and lifestyle variables including alcohol intake and smoking.
Journal: Nature Communications
This 4-year prospective cohort study involved over 56,000 individuals ages 50-65 years in the greater area of Copenhagen and Aarhus, Denmark. This Danish Diet, Cancer, and Health cohort study is an associated cohort of the European Prospective Investigation into Nutrition and Cancer (EPIC). To learn more about findings on polyphenol intake and thyroid cancer risk from the EPIC cohort, check out our July Science Nook. In the present study, 192-item food frequency questionnaires were completed at baseline. Flavonoid intake was studied as related to the main outcomes of mortality, cardiovascular (CVD)-related mortality, and cancer-related mortality.
The authors found:
1. An inverse association between moderate habitual intake of flavonoids and all-cause, CVD-, and cancer-related mortality
2. For CVD-related mortality, this association plateaued beyond intakes of 500 mg/day of total flavonoids
3. For cancer-related mortality, this association plateaued beyond intakes of 1000 mg/day of total flavonoids
4. Inverse associations of flavonoid intake and mortality outcomes were stronger and more linear in smokers than non-smokers, as well as in heavy alcohol consumers than low-moderate alcohol consumers
For the Patient and Caregiver
In this population, the authors write that tea, chocolate, wine, apples, and pears were likely the main food sources of flavonoids. They also outline: “one cup of tea, one apple, one orange, 100 grams of blueberries, and 100 grams of broccoli would provide most of the flavonoid subclasses and over 500 mg of total flavonoids” [i]. This is beneficial information as it demonstrates the maximum amount of flavonoid intake to achieve the most benefit for decreasing CVD-related mortality is realistic within one day of consumption, and double this for maximum benefit for decreasing cancer-related mortality may be doable as well.
For the Healthcare Team
This research supports encouragement of flavonoid intake to patients. It may be particularly beneficial to speak about the benefits to smokers and those who are heavy alcohol drinkers (>20 g/day), while also encouraging these individuals to decrease alcohol intake and provide support methods to quit smoking. The authors also found the inverse association of flavonoid intake and risk of mortality to be weaker in obese participants compared to normal or overweight participants. This may present an additional ground to support weight loss when appropriate.
[i] Bondonno NP, Dalgaard F, Kyro C, Murray K, Bondonno CP, Lewis JR, Croft KD…Hodgson JM . (2019). Flavonoid intake is associated with lower mortality in the Danish diet cancer and health cohort. Nature Communications. doi: 10.1038/s41467-019-11622-x