Whole Fruits and Fruit Fiber Emerging Health Effects

Abstract

Less than 10% of most Western populations consume adequate levels of whole fruits and dietary fiber with typical intake being about half of the recommended levels. Evidence of the beneficial health effects of consuming adequate levels of whole fruits has been steadily growing, especially regarding their bioactive fiber prebiotic effects and role in improved weight control, wellness and healthy aging. The primary aim of this narrative review article is to examine the increasing number of health benefits which are associated with the adequate intake of whole fruits, especially fruit fiber, throughout the human lifecycle. These potential health benefits include: protecting colonic gastrointestinal health (e.g., constipation, irritable bowel syndrome, inflammatory bowel diseases, and diverticular disease); promoting long-term weight management; reducing risk of cardiovascular disease, type 2 diabetes and metabolic syndrome; defending against colorectal and lung cancers; improving odds of successful aging; reducing the severity of asthma and chronic obstructive pulmonary disease; enhancing psychological well-being and lowering the risk of depression; contributing to higher bone mineral density in children and adults; reducing risk of seborrheic dermatitis; and helping to attenuate autism spectrum disorder severity. Low whole fruit intake represents a potentially more serious global population health threat than previously recognized, especially in light of the emerging research on whole fruit and fruit fiber health benefits.

Keywords: asthma; bone mineral density; cancer; cardiovascular disease; depression; diabetes; gastrointestinal health; metabolic syndrome; prebiotic effects; psychological well-being; successful aging; weight management.

Figure 1

Recommended daily dietary fiber intake by age and gender [18].

Figure 2

Correlations between daily servings of fruit intake and the microbiota abundance of beneficial Bacteroides and Bacteroidetes in children [51].

Figure 3

Risks of Crohn’s disease in children for fruit and total fiber intake [82].

Figure 4

Associations between a daily serving of specific non-juice fruits and vegetables and weight change in US men and women over 4 years from the Nurses’ Health Studies and Health Professionals Follow-up Study (pooled data; multivariate adjusted; *excludes French fries and potato chips) [96].

Figure 5

Change in body mass index (BMI) and weight associated with level of fiber intake from The Nurses’ Health Study (74,091 women; age 50 years; 12 years) [104].

Figure 6

Effect of dietary energy density associated with various levels of fat and fiber intake on body weight in overweight and obese pre-diabetic adults over 3 years in an intensive dietary and exercise program (fiber range 10.9 to 15.6 g/1000 kcal and fat range from <30 to >36.9% energy) [119].

Figure 7

Mean energy intake at ad-libitum dinner after a late afternoon 65 kcal pre-dinner snack of mixed berries vs. confectionary sweets (p < 0.001) [143].

Figure 8

Association between the number of fruit servings/day and excessive vascular age from pooled estimates of World Health Organization (WHO) and US National Health and Nutrition Examination Survey (NHANES) data among adults aged 30–74 years (p = 0.038) [156].

Figure 9

Progression of intima-media thickness (IMT) in the common carotid-artery by quintile of fiber intake among 500 participants in the Los Angeles Atherosclerosis Study [157].

Figure 10

Effect of fiber and fat on total and LDL-cholesterol in a crossover Randomized Controlled Trial (RCT) of 45 overweight or obese adults over 5 weeks (based on 2100 kcal/diets; total fat 34% of energy for all diets except 24% for the low-fat diet; protein approx. 16% of energy for all diets; saturated fat energy 13% for the American diet, 7% for the low-fat diet and 6% for the two moderate fat diets with healthy vegetable oil vs. 1 avocado. Values with different superscript letters (a and b) are significantly different (p < 0.05) [169].

Figure 11

Change in the risk of hypertension associated with fruit consumption from pooled Nurses’ Health Study, Nurses’ Health Study II, and Health Professional Follow-up Study data [175].

Figure 12

Association between the number of fruit or vegetable servings and hypertension risk in a cohort of middle-aged and older Koreans [182].

Figure 13

Effect of 3 servings per week of fruit varieties on type 2 diabetes (diabetes) risk from pooled data from US men and women in the Nurses’ Health Studies and the Health Professionals Follow-up Study [208].

Figure 14

Association between fruit and fruit fiber intake on insulin sensitivity measures in 40 normal-weight young women with low to normal TNF-α values [214].

Figure 15

Mean postprandial plasma glucose levels after eating whole apples, applesauce, and apple juice (applesauce and apple juice plasma glucose significantly fell below whole apple levels after 75 to 180 min [p < 0.05]) [221].

Figure 16

Mean postprandial serum insulin levels after eating whole apples, applesauce, and apple juice with serum insulin significantly increased for apple juice above whole apples and applesauce after 10 to 40 min (p < 0.01]) [221].

Figure 17

Odds ratio for Metabolic Syndrome by categories of fiber sources of intake (median) at baseline examination from the Tehran Lipid and Glucose Study (multivariate adjusted; total fiber (g) = 10.2, 14.1, and 21.6; fruit fiber (g) = 1.2, 2.7 and 5.2; vegetable fiber (g) = 1.2, 2.6 and 5.9; and cereal fiber (g) = 1.6, 3.2 and 4.5) [252].

Figure 18

Non-linear dose-response effect of increasing intake of fruits and vegetables on colorectal cancer (CRC) risk from meta-analysis of cohort studies [260].

Figure 19

Effects of a healthy dietary pattern (DP) stratified by energy intake level, and the Western DP on the odds for successful aging (multivariate adjusted) [279].

Figure 20

Effect of key dietary pattern food items associated with the odds of successful aging (all p-trend across quintile groups = 0.001) [281].

Figure 21

Association of fruit intake with mortality risk for a composite of European, American, Japanese and Chinese adults (mean age 50 years over 7.4 years; multivariate adjusted) [4].

Figure 22

Association between the number of servings of fruits and vegetables/day and increases in life satisfaction (p < 0.001) [329].

Figure 23

Odds ratio for depressive symptoms with fruit and vegetable fiber intake compared to cereal fiber (fruit and vegetable fiber tertiles = 1.5 g, 2.5 g and 4.0 g) [336].