Políticas Organizacionales

Plant-based diets are shown to significantly alter the gut composition, and a large food item consumed in a plant-based diet is fruit. Fruit is currently the second most popular food item in the US, and by sales alone, berries, apples, bananas, grapes, and citrus rank in the top five highest grossing fruits, with berry sales ranking the highest at $3.02 billion.105 _{Compared to other berries, strawberry consumption is much greater with an} estimated per capita annual consumption of 7.9 pounds per year.106 _{With increased} accessibility and per capita consumption, high levels of vitamins, minerals, and antioxidants, fruit has the potential to be an effective approach to improving health, specifically through the gut.

Gut health has been associated with the concept of the ‘three P’s which include

probiotics, prebiotics, and polyphenols.107 _{As such, research has investigated the effect} of berries and berry polyphenols on the gut as they have received attention as

antioxidants with properties to prevent chronic disease.108 _{The gut bacteria convert} polyphenols into active and bioavailable metabolites, suggesting that variations in the gut microbiota can affect polyphenol activity108 _{and thus, may have short and long-term} impacts on human health.

2.2.6.1 Previous work: polyphenols and gut health

While relatively low in polyphenols compared to strawberries, several studies have assessed the potential for non-berry consumer fruits to modulate the gut microbiota. Shinohara et al. found that consumption of two apples per day increased Lactobacillus and Streptococcus while C. perfringens and Enterobacteriaceae decreased.13 _Oranges and bananas have also been identified as a fruit with the ability to beneficially alter the gut microbiota. In a SHIME (Simulator of the Human Intestinal Microbial Ecosystem) vessel, Duque et. al. found that fresh orange juice significantly increased commensal bacteria species (from genera Lactobacillus, Enterococcus, Bifidobacterium, and Clostridium)while reducing Enterobacteria.14 _{Mitsou et al. assessed the impact of} bananas on the gut microbiota and found that 60 days of banana consumption resulted in a non-significant increase in Bifidobacterium levels in the banana group.15

In addition to whole non-berry fruit, two studies have investigated the influence of red wine polyphenols on the human gut. Queipo-Ortuno et al. had 10 healthy men consume 272 ml a day of red wine (797.86 mg gallic acid equivalents [GAE] of total phenols), de- alcoholized red wine (733.02 GAE of total phenols), or gin, each for 20 days.9 _{Red wine} polyphenols significantly increased Proteobacteria, Fusobacteria, Firmicutes, and Bacteroidetes, while the de-alcoholized red wine increased Fusobacteria but

significantly decreased Firmicutes and Bacteroidetes. The authors concluded that red wine polyphenols exhibit a prebiotic effect. Moreover, changes in cholesterol and C- reactive protein concentrations were linked to changes in Bifidobacterium numbers.9

found that red wine and de-alcoholized red wine, consumed for 30 days each, significantly increased the number of Bifidobacterium and Lactobacillus while

decreasing Bacteroides, E. coli, and Enterobacter spp.10 _{The polyphenols also improved} various metabolic markers. The authors concluded that the changes in the MetS

participants’ gut microbiota could be responsible for the improvement in the MetS markers.10

Polyphenols in the form of fruit extracts can also impact the gut microbiota. Molan et al. assigned thirty healthy men and women to consume blackcurrant extract powder with lactoferrin and lutein or to consume only blackcurrant extract powder in capsule form four times per day for two weeks.11 _{Both forms of blackcurrant significantly increased} Bifidobacterium and Lactobacilli population sizes while Clostridium spp. and Bacteriodes spp. decreased significantly. The authors concluded that blackcurrant powder can act as a prebiotic.11 _{Similarly, in a controlled trial, Li et al. instructed 20 normal weight healthy} male and females to consume a daily dose of 1000 mg of pomegranate extract (680 mg GAE of total phenols), equivalent to 8 oz of pomegranate juice, for 4 weeks.12

Consumption of pomegranate extract significantly increased Actinobacteria with a significant decrease in Firmicutes. The authors proposed that these results may have implications in weight maintenance and insulin resistance by changing the ratio of Firmicutes to Bacteroidetes.12

Numerous studies have investigated the effect of whole berries on the composition of the gut microbiota. Specifically, red berries have been analyzed in several controlled diet intervention trials. Vendrame et al. investigated the daily consumption of a wild

blueberry (WB) freeze-dried powder drink in a RCT, crossover, diet intervention.16 Twenty male volunteers with at least one risk factor for CVD consumed a 250 mL WB drink (25g of WB freeze-dried powder; 375 mg anthocyanins) or a placebo drink for 6 weeks. Blueberry polyphenols significantly increased Bifidobacterium spp. after the blueberry treatment with increased Lactobacillus acidophilus after both treatments.16 In another diet intervention, Ige et al. assigned four female volunteers to consume 600 ml of blueberry puree per day for 29 days.17 _{Before stool analysis, the samples were} incubated for Lactobacillus spp. and Enterobacteriaceae spp. The authors found that consumption of blueberry puree resulted in new strains of Lactobacillus bacteria while other Lactobacillus strains resisted the anti-oxidant properties of the blueberry.17 In addition to blueberries, raspberries have also been targeted as a fruit rich in

polyphenols with the potential to impart health benefits through the gut. In a free-living diet intervention trial, Gill et al. instructed 10 male participants to consume 200 g of raspberry puree (296 mg gallic acid equivalents) per day for 4 days.18 _{Following stool} sample analysis, it was observed that the raspberry supplementation resulted in small, yet insignificant changes to the microbiota composition.18

In addition to assessing the impact of single fruits on the gut microbiota composition, one researcher investigated the synergistic effect of a combination of whole red berries on the gut. Puupponen-Pimia et al. assigned 32 male and female participants with MetS to consume either 300 g of fresh berries (70.7 mg anthocyanins) comprised of 100 g

berry consumption for 8 weeks.19 _{Participants maintained their habitual diet but} restricted consumption of berries to 80 g/day. Stool samples were collected during five separate laboratory visits and were analyzed for microbial diversity. Results showed that 4 subjects in the berry group saw insignificant changes to their bacterial profile while 13 participants saw no change. Further, no significant differences in diversity of

predominant bacterial populations were seen between groups.19

Compared to the top fruits consumed in the US, as reviewed in the studies above, berries, including strawberries, contain a wide spectrum of beneficial ingredients, and combined with their affordability and accessibility, give them the potential to improve health through the gut.