Usual intake of flavonoids is inversely associated with metabolic syndrome in African American and white males but not females in Baltimore City, Maryland, U.S.A.

Authors: Sebastian, Rhonda; KUCZMARSKI, MARIE - National Institute On Aging (NIA, NIH); Goldman, Joseph; Moshfegh, Alanna; ZONDERMAN, ALAN - National Institute On Aging (NIA, NIH); EVANS, MICHELE - National Institute On Aging (NIA, NIH)

Submitted to: Nutrients
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/2/2022
Publication Date: 5/4/2022
Citation: Sebastian, R.S., Kuczmarski, M.T.F., Goldman, J.D., Moshfegh, A.J., Zonderman, A.B., Evans, M.K. 2022. Usual intake of flavonoids is inversely associated with metabolic syndrome in African American and white males but not females in Baltimore City, Maryland, USA. Nutrients. 14(9):1924. https://doi.org/10.3390/nu14091924.
DOI: https://doi.org/10.3390/nu14091924

Interpretive Summary: Several unfavorable conditions increase a person's risk of heart disease and diabetes. These conditions are a large waist, high blood pressure, high blood glucose, high triglycerides, and low high-density lipoprotein (HDL) cholesterol. When people have three or more of these conditions, they have what is called metabolic syndrome (MetS). Flavonoids are compounds found in many plant foods, like fruits and vegetables. Flavonoids may protect against the development of MetS and its risk factors. It takes MetS a long time to develop. For that reason, it makes sense to estimate the long-term average, or "usual," intake of flavonoids. In this study, we estimated usual total flavonoids intake in a population of African American and White men and women. Then we determined whether that intake was associated with MetS and its risk factors. We analyzed data from 1,837 adults in the Healthy Aging in Neighborhoods of Diversity across the Life Span study. Among all men together, those with higher total flavonoid intake were 32% less likely to have MetS than those with lower intake. Similarly, for all men together and both racial groups separately, those with higher total flavonoid intake were less likely to have low HDL cholesterol and high glucose compared to those with lower intakes. However, among both African American and White women separately, but not among all women grouped together, those at the higher level of flavonoid intake were 30-31% more likely to have high glucose. Future research studying relationships between flavonoid intake and health outcomes should do so using usual flavonoid intake.

Technical Abstract: Individuals are considered to have metabolic syndrome (MetS) when three or more of following risk factors are present: central obesity, elevated blood pressure, elevated blood glucose, elevated triglycerides, and reduced high-density lipoprotein (HDL) cholesterol. Flavonoids are plant compounds that have favorable effects in various body systems and may protect against MetS. Most investigations of flavonoid-MetS associations have used short-term rather than long-term average, or "usual," dietary intake methods. This study's objectives were to estimate usual total flavonoids intake in a racially diverse population of U.S. adults and determine whether that intake was associated with MetS and its risk factors. Healthy Aging in Neighborhoods of Diversity across the Life Span study data (1,837 adults) were analyzed by sex and by race within sex. Usual total flavonoids intake and linkages between intake and health outcomes were estimated using the NCI Method. Among all men together, but not by race, odds of MetS were 32% lower at the 75th percentile of usual total flavonoid intake (239.3 mg/d) than at the 25th percentile (64.6 mg/d; OR = 0.68; 95% CI = 0.53, 0.87). For all men and both racial groups, odds of reduced HDL cholesterol and elevated glucose were inversely related to flavonoid intake. Among both African American and White women but not all women collectively, odds of elevated glucose were 30-31% higher at the 75th than at the 25th percentile of flavonoid intake. Future research in other populations should apply usual intake methods to maximize the validity of associations between flavonoid intake and MetS.