Assessment of the Impact of early nutrition on cardiovascular risk in 3 to 9 month-old infants , a cross-sectional cohort study.

Background

Sub-Saharan Africa (SSA) is experiencing a growing burden of cardiovascular diseases, which are among the leading causes of death both globally and in the region (Yuyun et al. 2020). Emerging evidence suggests that risk factors for CVDs may have their origin in the in utero and early infancy periods of life. Environmental and nutritional influences determine epigenetic modifications, influencing the risk for CVDs later in life (Gomez-Verjan et al. 2020). The first 1,000 days of life, spanning from conception to a child’s second birthday, represent a critical window for shaping metabolic and cardiovascular health. During this period, rapid growth and development lay the foundation for vital organ function, metabolic pathways, and immune system maturation, all of which influence the risk of non-communicable diseases (NCDs), including CVDs (Likhar and Patil, 2022). Early feeding practices such as EBF and optimal times for introducing complementary foods are, therefore, important determinants of the child’s nutritional status and long-term cardiovascular health (Gispert-Llauradó et al. 2025).

Breast milk, the gold standard for infant nutrition, provides an optimal balance of micronutrients and macronutrients for supporting the growth and health of the infant and maintaining a healthy microbiota (Arguelles-Lopez et al. 2025). Breastmilk components enhance immune function and reduce the risk of obesity, insulin resistance, and other CVD risk factors (Magalhães et al. 2025).

The World Health Organization (WHO) recommends EBF for the first six months of life, followed by the introduction of nutritious complementary foods (WHO, 2025). However, only 37% of the global maternal population adheres to these guidelines. In SSA, great disparities exist in the prevalence of EBF in the first six months: in Tanzania, EBF rates are relatively high at 58% and only 32% in South Africa. To mitigate this low EBF, South Africa developed the Infant and Child Feeding Policy (2013), which aims to promote optimal nutrition by advocating for early initiation of breastfeeding, EBF for six months, and continued breastfeeding up to two years. Even though nursing mothers may be aware of these guidelines, health, socioeconomic and cultural pressures may lead to the early introduction of complementary feeds (Amzat et al. 2024; Scarpa et al. 2022; SADoH, 2013).

The rising burden of CVD in SSA underscores the urgency of addressing early nutritional risk factors. The prevalence of hypertension is also on the rise in the pediatric population in these two countries and is reported in children as young as six (Matjuda et al. 2020; Said et al. 2025). The drivers of this early onset of raised blood pressure in children in the SSA population are yet unclear. Furthermore, there is a paucity of evidence on how early nutrition might influence specific CVD risk markers, such as blood pressure and endothelial function, during the first 3-9 months of life. Importantly, comparative studies between SSA populations with differing feeding practices are limited. A comparative study on infant feeding practices between South Africa and Tanzania would therefore offer a valuable insight into how geographical, cultural, and normative factors shape cardiovascular outcomes in the region.

This study aims to investigate the relationship between infant feeding practices, nutritional status, and early markers of CVD risk in infants aged 3–9 months in South Africa and Tanzania.

Materials

Ethical clearance for this study has been obtained from the Walter Sisulu University Human Research, Ethics and Biosafety Committee with approval number: 216/2024. Written informed consent will be obtained from the mothers or caregivers of all participating infants (Nkeh-Chungag, 2025).

On the day of testing, a complete medical examination will be performed by a clinician to ensure that children meet the inclusion criteria.

Study design

This will be a cross-sectional study using a convenience sampling technique based on parental consent as a prerequisite. Participants will be recruited as shown in Figure 1 from vaccination clinics.

Figure 1. Summary of participant recruitment plan.

Inclusion criteria:

• • Infants who are 3-9-month-old.

• • Infants must be of African ancestry.

• • Infants must be healthy and not on any therapy.

Exclusion criteria:

• • Infants younger or older than 3-9-month-old.

• • Infants who are not of African ancestry.

Discussion

This study aims to investigate infant feeding practices and their relationship with cardiovascular disease risk. Early nutrition and feeding practices greatly influence the growth, development, and long-term health outcomes of infants. The WHO recommends EBF for the first six months of life, followed by the introduction of complementary foods with continued breastfeeding for up to two years. Globally, however, adherence to these guidelines varies due to socioeconomic, cultural, and healthcare-related factors (Moret-Tatay et al. 2025).

Globally, only 48% of infants are breastfed exclusively for the first six months, as reported by UNICEF (2023). Breastfeeding rates are generally lower in high-income countries associated with aggressive formula marketing, maternal employment, and limited parental leave policies. On the other hand, higher breastfeeding rates are reported in low- and middle-income countries, particularly in SSA, though EBF rates may be low. In South Africa, EBF rates are as low as 32%, compared to 58% in Tanzania. The constraints of work contribute significantly to the early cessation of breastfeeding. These practices reflect a complex interplay of cultural norms, economic constraints, and limited access to nutrition education, which collectively influence the child’s feeding habits and food preferences.

The theory of the developmental origins of health and disease supports the fact that early-life nutrition may play a pivotal role in shaping a child’s susceptibility to chronic diseases, such as CVDs (Gomez-Verjan et al. 2020). Breastfeeding provides adequate nutrition, especially in the first six months of life, and is widely recognized for its protective effects, reducing obesity risk, improving cholesterol profiles, and lowering blood pressure in later life (Zhou et al. 2024; Masi and Stewart, 2024).

In contrast, formula feeding is associated with rapid weight gain, higher LDL cholesterol levels, and increased CVD risk. Complementary feeding practices, particularly the timing and quality of introduced foods, also influence cardiovascular outcomes (Capra et al. 2024). For example, the early introduction of protein-poor foods, such as maize porridge and starchy staples readily available in SSA, contributes to stunting, underweight status, and micronutrient deficiencies, predisposing children to metabolic disorders and CVD.

In South Africa, the consumption of energy-dense, nutrient-poor foods has been linked to higher inflammation markers in infants, a precursor to cardiovascular risk (Ebrahim and Manji, 2025). Similarly, in Tanzania, high-fat complementary feeding by nine months increases BMI-for-age Z-scores, indicating an elevated risk of obesity and related metabolic conditions (Muhimbula and Issa-Zacharia, 2010). These findings are important indicators of the potential long-term implications of suboptimal feeding practices, particularly in contexts where cultural norms and economic constraints drive the early introduction of the most affordable foods, which are generally low in protein.

In conclusion, this study will provide information on the nutritional content of homemade infant foods, which is essential for health promotion outreach to the community. By comparing these two populations, the research seeks to elucidate how variations in EBF adherence, timing of complementary food introduction, and dietary quality influence cardiovascular health. The findings could provide insights into the high prevalence of hypertension and other CVD risk factors in children of African ancestry and inform evidence-based interventions to reduce the long-term burden of CVD in SSA.

Status of the study

Data collection has begun in South Africa; research personnel are still undergoing training on data collection process.

Study status

Data collection has started in the Mthatha site – South Africa while it is still scheduled to start by the 20 September 2025 in the Dar es Salaam study site.