A major driver of the link between poor water, sanitation and hygiene (WASH) and child stunting is hypothesised to be a sub-clinical condition of the small intestine termed environmental enteric dysfunction (EED). This systematic review aimed to collate research investigating the association between biomarkers of EED and child linear growth outcomes. A systematic search of literature was conducted to identify articles that contain a measure of a domain of EED and its association with linear growth outcomes published up to 31 December 2024. Data pertaining to the measure of EED and child linear growth, as well as study characteristics, were extracted and tabulated. A total of eighty-one studies comprising 31 996 children were included, which suggested that all EED domains, including intestinal damage and repair, intestinal absorption and permeability, microbial translocation, intestinal inflammation and systemic inflammation, were associated with child linear growth. Nuances in the measurement of association were apparent and impacted the observation of significant associations. This review found that whilst the role of EED in child stunting is relatively well established, there are challenges faced in measuring biomarkers in relation to linear growth with possible ambiguities. These issues are discussed in detail to provide aid in interpretation of existing studies and to inform future studies of this kind.

Sub-Saharan Africa (SSA) is currently undergoing rapid urbanisation, a transition that is closely linked to the adoption of sedentary lifestyles and Westernised dietary habits. This shift has contributed to a substantial rise in obesity and diet-related non-communicable diseases (DR-NCDs), placing a significant strain on already burdened healthcare systems. Among the key modifiable risk factors driving this epidemiological transition are changes in dietary patterns. Western-style diets have been shown to promote inflammation and trigger metabolic and immune dysregulation, factors that underlie the development of DR-NCDs. Conversely, many Tanzanian heritage diets incorporate a diverse array of nutrient-rich foods prepared using techniques that minimise the use of oils, sweeteners and preservatives. These diets predominantly use whole grains, legumes and fruits, foods high in dietary fibre and nutraceuticals. Nutraceuticals are known to have both immunomodulatory and metabolic benefits and could potentially counteract the negative effects associated with Western-style diets. However, the limited scientific documentation of these heritage diets endangers future research into their potential health benefits. This underscores the need for targeted efforts to preserve and promote traditional dietary practices. In this review, we summarise the diversity of heritage diets from four distinct tribes in Northern Tanzania – the Maasai, Chagga, Pare and Hadzabe – who have historically exhibited low rates of DR-NCDs but are now experiencing rapid urbanisation and lifestyle changes. We briefly describe the dietary patterns of these tribes and examine the potential links between the declining usage of traditional dietary practices and the rising prevalence of DR-NCDs in Tanzania.

Frailty is an ageing-related syndrome of physiological decline, heightening vulnerability and increasing risk of adverse health outcomes. Nutritional deficiencies, particularly in vitamins B9, B12 and D, are prevalent among the elderly owing to physiological changes and reduced food intake. Research suggests a correlation between low levels of these vitamins and an elevated risk of frailty. Vitamin B9, crucial for DNA synthesis and cell division, shows potential in frailty prevention, although evidence regarding supplementation remains inconclusive. Similarly, vitamin B12, essential for nerve function and red blood cell formation, presents conflicting findings regarding its impact on frailty prevention. Vitamin D, essential for bone health and muscle function, is linked to frailty risk, yet studies on the efficacy of supplementation yielded mixed results. The mechanisms involving these vitamins, including their roles in DNA methylation and inflammation regulation, highlight the need for further research to clarify their direct impact on frailty prevention. Maintaining optimal levels of vitamins B9, B12 and D may reduce frailty, but older individuals need a complete approach that includes proper nutrition, physical activity and other preventive measures.