In a recent study published in The Journal of Nutrition, researchers examine the associations between variety/quantity of fruit and vegetable (FV) intake and mortality in older Chinese adults.
Study: Quantity and variety in fruit and vegetable consumption and mortality in older Chinese: a 15-year follow-up of a prospective cohort study. Image Credit: Natalia Lisovskaya / Shutterstock.com
The health benefits of FV intake
Epidemiologic evidence suggests an association between higher FV consumption and lower risks of cancer, cardiovascular disease (CVD), and all-cause mortality. Dietary recommendations have repeatedly emphasized the significance of increasing the intake of FVs. Consumption of different FVs has been recommended for adequate intake of fiber and vitamins.
Although associations between a higher variety of FV consumption and reduced risks of cancer, obesity, and diabetes have been reported, the independent role of FV variety and quantity remains unclear, as people who consume a variety of FVs may also have higher intake and vice versa. For example, one study demonstrated that absolute quantity, rather than the variety of FV intake, was associated with a reduced risk of coronary heart disease.
About the study
In the present study, researchers examine how the variety and quantity of FV intake impacts mortality in older adults in China. To this end, data from the population-based Guangzhou Biobank cohort study (GBCS) between 2003 and 2008 was used.
Baseline data were collected through interviews. Subjects from the first and second phases were included in the study.
The primary exposure was FV intake, which was assessed using a 300-item food frequency questionnaire (FFQ) that spanned 66 and 30 types of vegetables and fruits, respectively. Participants were asked to indicate food items, portion size, and intake frequency every week. Results from the questionnaire were compared with approximate estimations for total energy, potassium, and sodium intake.
Fruit/vegetable juices were excluded from the analysis, as the older population in China rarely consumes these products. Variety in FV consumption reflected the number of unique items consumed in the past week.
FVs were categorized based on the color of the edible part, including red/purple, white, green, and orange/yellow. The primary outcome was mortality from all causes, CVD and cancer.
Multivariate Cox regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals of mortality associated with FV intake quantity and variety. One model was crude, whereas the second model was adjusted for age and sex, and the third model was adjusted for lifestyle factors, socioeconomic status, comorbidities, and other dietary factors.
Overall, 19,597 participants with an average age of 62.7 were included in the current study, 71.6% of whom were female. During follow-up, 4,385 deaths were recorded, with 1,678 due to CVD, 1,450 due to cancer, and 1,257 from other causes. The average quantity of FV intake was 2,508 g/week, with ten types of FVs consumed every week.
Subjects in the highest quintile of FV intake quantity were more likely to be male, current drinkers, never smokers, older, and have a lower education/family income but higher body mass index (BMI) and physical activity. These individuals also reported a higher intake of cereal grains. Furthermore, CVD prevalence was higher in this group; however, diabetes prevalence was lower.
In contrast, participants in the highest quintile of the FV intake variety were younger and had higher education/family income but lower physical activity and cereal grain intake. No association of FV intake quantity was reported with all-cause, CVD, or cancer mortality. In the adjusted model, greater FV intake variety was associated with a reduced risk of mortality from all causes and CVD but not cancer.
Increasing FV intake variety by one type was associated with a 3% reduction in all-cause and CVD mortality risks. In sensitivity analyses, excluding deaths recorded in the first three years or for using aspirin/other medicines for CVD did not alter these results. Notably, the association between FV variety and all-cause mortality was more potent in individuals with diabetes.
No association was reported between FV intake quantity and all-cause, CVD, or cancer mortality by FV color groups. However, a significant dose-response inverse association was observed between variety in green vegetable intake and all-cause or CVD mortality. Likewise, a similar dose-response inverse association was evident between variety in red/purple FVs and all-cause or cancer mortality.
Greater variety in the intake of FVs was associated with a reduced risk of mortality from all causes and CVD among older Chinese adults. These findings suggest that an increase in the variety of FVs, mainly green, white, and red/purple FVs, may provide beneficial health effects for older adults.
- Sun, C., Zhang, W. S., Jiang, C. Q., et al. (2023). Quantity and variety in fruit and vegetable consumption and mortality in older Chinese: a 15-year follow-up of a prospective cohort study. The Journal of Nutrition. doi:10.1016/j.tjnut.2023.03.021