What can Annona muricata fruit juice do to the gut microbiome of healthy Nigerian children under-five, and those with acute watery diarrhoea?
Showcasing probiotic, prebiotic and related research from African scientists - Part 2.
By Benedictta Chinweoke Okeke-Nwolisa
Annona muricata (soursop) fruit
Soursop is the fruit of Annona muricata, a broad leaf, flowering, evergreen tree belonging to the Genus, Annona; Family, Annonaceae. The exact origin of this tree is unknown; it is believed to be native to the tropical regions of South America and the Caribbean and is widely propagated. The edible part of the soursop fruit is the pulp (mesocarp) which is white in colour. With an aroma similar to pineapple, the flavor of the fruit has been described as a combination of strawberries and apple, and sour citrus flavour, contrasting with an underlying creamy texture reminiscent of coconut or banana.
Annonamuricata (soursop) grows in most parts of West Africa, especially Nigeria, yet health authorities have not seriously considered its utility. WHO/FAO reported in 2004 that some tropical fruits are under-utilized and noted very low consumption trends among low/middle income nations
Can soursop have clinical utility in children with watery diarrhoea?
Diarrhoea has been an important health problem and is in fact responsible for substantial morbidity and mortality among children and adults in both developing and developed countries. Diarrhoea has also been reported to be more frequent among those under 5 years of age, where it accounts for a reasonable percentage of death due to dehydration, hypovolaemia, acidosis, haemoconcentration and loss of electrolytes. Acute gastroenteritis (AGE) or acute watery diarrhoea remains a major cause of morbidity and mortality among young children worldwide. It accounts for approximately 1.34 million deaths annually in children younger than five years. The human gastrointestinal tract (GIT) is a reservoir of the largest community of commensals in the body, and hence recent research on diarrhoea must take into account this community. Gut microbiota plays a crucial role in health and disease through maintaining several physiological processes such as food digestion, immunity and metabolism. Consequently, alteration of the structure and function of gut microbiota has been linked to several human disorders, including infections by pathogenic bacteria, autoimmune disorders, obesity, and gastrointestinal disorders such as inflammatory bowel disease.
Annona muricata (soursop) is commonly found in rural areas, readily available and relatively cheap in Nigeria, but consumption is sporadic as a snack. The moisture content of the fruit is over 70%. The nutritional composition of soursop includes carbohydrates, glucose; proteins; lipids; ash; fiber, and citrate. The epicarp, mesocarp and juice of both contain potassium, sodium, iron, magnesium, calcium, chloride and bicarbonate. Carbonate is present in the fruit juices. The juices also contain phosphorus, zinc and copper.
Key :
Units: µg = micrograms; mg = milligrams; IU = International Units
DV = Daily values (Nutrition Facts in US)
Percentages are roughly approximated using US recommendations for adults.
Source: United States Department of Agriculture, USDA Nutrients Database .
In recent times, two studies from Prof. Ifeoma Enweani, in our faculty have investigated the use of soursop fruit juice as complementary to Oral rehydration salt (ORS) in the dietary management of acute watery diarrhoea, especially among children under-five. This is justifiable based on the findings that the nutritional composition of soursop is relatively similar to that of the standard ORS. The ORS when properly prepared and administered, provides adequate quantities of electrolytes to correct the deficits associated with acute diarrhoea. But there are some setbacks associated with ORS usage in the management of diarrhoea in Nigerian children. First, there is a high chance of mothers and health workers carrying out wrong dilution. The children’s caregivers and health workers, especially in the rural areas, depend largely on the use of teaspoons for the measurement of sugar and salt; and beer bottles for water measurement when mixing ORS in their homes. Some of the caregivers also keep the ORS for too long (>24 h). In addition, most children dislike the taste and they have to be forced to drink the ORS. These shortcomings reduce the chances of caregivers particularly in the rural areas achieving rehydration for the children during diarrhoea fluid loss. Soursop appears to overcome these shortcomings and could potentially be considered as a complementary way of replacing electrolyte loss during diarrhoea episodes.
Replenishment of specific deficiencies in vitamins and mineral salts is also advisable and some nutrients such as glucose provides energy. The presence of potassium in the juice is important in view of the large potassium losses associated with acute diarrhoea, especially in infants. The function of the citrate or bicarbonate is to correct the base- deficit acidosis. The absorption of sodium and water in the small intestine is directly related to the absorption of glucose. This is true irrespective of the cause of diarrhoea and forms the physiological basis of oral rehydration therapy (ORT) - using oral rehydration salts/ solution (ORS).
Diarrhoea can also lead to substantial losses of micronutrients e.g. zinc and copper, which could impair tissue repair and compromise the immune response. Since the soursop fruit juice has been discovered to contain higher levels of electrolytes and nutrients than the recommended WHO/ UNICEF standard for ORS, it is highly recommended that it should be administered to children who are suffering from acute diarrhea as a dietary complement to standard ORS because of its nutritional composition in order to correct any form of electrolyte loss. In addition, soursop is considered to have phytochemicals such as tannins, alkaloids, etc which have been reported to have anti-diarrhoeal effects in laboratory animals. Previous studies recommended the use of soursop fruit juice and the use of various other home remedies for the treatment of diarrhoea abound in literature: soup, rice water, yoghurt drink, unsweetened fresh juice, and resistant starch. These may offer hope for the management of acute watery diarrhea, and with more scientific study, we may be able to assess which ones are the most effective.
Can soursop impact the gut microbiota of children in health and disease?
Annona muricata (soursop)fresh fruit juice aseptically prepared and packed in sterile screw-capped containers for administration to children under-five with acute watery diarrhoea and their apparently healthy counterparts.
The gut microbiota of healthy children is dynamic and undergoes rapid changes, which are affected by multiple factors including mode of birth delivery, development process, diet, and use of antibiotics. The gastrointestinal tract (GIT) microbiome in children is largely colonized by bacteria belonging to Bacteroidetes, Firmicutes and Proteobacteria phyla. Facultative bacteria such as Escherichia coli (E. coli), Enterococcus, α-hemolytic Streptococci, and Staphylococcus species have been found to colonize the anaerobic GIT of infants during their first days after birth, followed by colonization of anaerobic bacteria including Bacteroides, Bifidobacterium, and Clostridium species, due to the presence of anaerobic conditions and human milk oligosaccharides. Typically, the healthy gut microbiota is composed of only a minor proportion of bacteria from the Proteobacteria phylum, and thus, high abundance of these bacteria is often a sign of an imbalanced microbiome. The GIT is also a common site of infections in children younger than 5 years. Acute gastroenteritis (AGE) leads to around 1.34 million deaths annually, or nearly 15% of all child fatalities. Viral infections remain the leading cause of AGE in children, particularly noroviruses (NoV) and rotaviruses (RV). NoV is a group of RNA viruses that are responsible for about one fifth of AGE cases globally. Annually, these viruses lead to around 200 million cases in children less than 5 years old, and result in about 50,000 fatalities. RV is also one of the main viral agents of AGE worldwide. Despite the availability of rotavirus vaccine (RVV), this virus is the most common cause of diarrhea related deaths in children, contributing to 215,000 deaths in young children every year, particularly in low-income countries. Gut microbiota plays a critical role in immune response and pathogenesis of GIT infection especially in young children. Accordingly, several studies have investigated the correlation between intestinal microbiota composition and immune response to RVV. Further, immune tolerance to gut microbiota is an essential component of mucosal immunity. Loss of this immune tolerance has been reported as a consequence of GIT infection, where immune response to commensals parallels the immune response to pathogenic microorganisms. Virally-infected infant’s exhibit altered gut microbiota after infection, which may put them at higher risk of developing health complications. More recently, it was reported that children with severe viral AGE, particularly patients infected with RV, have decreased intestinal microbiota diversity compared to healthy controls. The use of antibiotics following viral infections has also been linked to gut microbiota alteration in children. Nonetheless, the current data concerning the contribution of gut microbiota in the development, complications, and pathogenesis of AGE is still limited, which underscores the need for more investigations, using 16S rRNA sequencing and metabolic functional capabilities. To address the paucity of data, my study is investigating both the possible probiotic/prebiotic effect(s) of soursop fruit juice and the gut microbiota of children under-five with watery diarrhea or acute gastroenteritis (AGE) in Nigeria. The research will help to assess if soursop fruit juice will have any effect on the relative abundances of the gut microbes of both the diarrhoeic children under-five and that of their apparently healthy counterparts by comparing the relative abundances of these microorganisms pre- and post-administration of soursop fruit juice. To find this out, we will employ next generation sequencing (NGS) techniques under the guidance of my supervisor-Dr. Kingsley Anukam. We intend to expand this study using fermented soursop fruit juice of two types: one would be produced spontaneously and the other would be produced using a well characterized bacterium, Lactiplantibacillus plantarium CNEI-KCA4 (NCBI Gene bank Accession number# CP053571). Part of the study expansion will encompass metabolomics and transcriptomics if we are funded, as Nigeria has a poor track-record in funding post-graduate research. We encourage any interested parties in the ISAPP community to reach out to us, as we seek assistance and advice about funding agencies and industrial collaborators. In conclusion, soursop (Annona muricata) fruit juice holds promise as a useful intervention tool in the management of acute watery diarrhea or acute gastroenteritis (AGE), especially among children under-five in developing countries like Nigeria. Considering its nutritional and phytochemical composition, as well as its potential probiotic and prebiotic nature, we hope for positive results in our study.
Benedictta Chinweoke Okeke-Nwolisa
Benedictta Chinweoke Okeke-Nwolisa is a PhD student in the Department of Medical Laboratory Science, Faculty of Health Sciences and Technology, College of Health Sciences, Nnamdi Azikiwe University, Nnewi Campus, Nnewi, Anambra State, Nigeria. Benedictta is being supervised by Dr. Kingsley C Anukam and Prof. Ifeoma B Enweani.
Benedictta can be contacted at bc.okeke-nwolisa@unizik.edu.ng while Dr. Kingsley Anukam may be reached at kc.anukam@unizik.edu.ng