Assessment of the association of plant-based diets with cardiovascular disease risk profile in Africa: a systematic review and meta-analysis protocol

Assessment of the association between plant-based dietary exposures and cardiovascular disease risk profile in sub-Saharan Africa: a systematic review

Background

Studies have investigated dietary attributes associated with cardiovascular disease (CVD) risk in Africa. However, there has been no effort to critically assess the existing evidence. This systematic review examined available evidence on the association between plant-based dietary exposures and CVD risk profile in Africa. PROSPERO registration number: CRD42020159862.

Methods

We conducted a literature search for observational studies reporting on plant-based dietary exposures in relation to CVD risk profile in African populations. PubMed-Medline, Scopus, EBSCOhost, and African Journals Online platforms were searched up to 19 March 2021. Titles and abstracts of the identified records were screened independently by two investigators. The quality of the studies was also assessed independently.

Results

Of 458 entries identified, 15 studies published between 2002 and 2020 were included in this review. These studies originated from 12 sub-Saharan Africa (SSA) countries. Sample sizes ranged from 110 to 2362, age from 18 to 80 years; and majority of participants were females (66.0%). In all, four plant-based dietary exposures were identified across SSA. Sixty percent of the studies reported a significant association between a plant-based dietary exposure with at least one CVD risk factor such as hypertension, diabetes mellitus, dyslipidaemia, overweight/obesity, and metabolic syndrome.

Conclusions

The few available studies suggest that there may be a protective effect of plant-based dietary exposures on CVD risk profile in the African setting. Nonetheless, more elaborated studies are still needed to address plant-based diet (PBD) adherence in relation with CVD risk in African populations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12724-w.

A review of dietary phytochemicals and their relation to oxidative stress and human diseases

Phytochemicals refer to active substances in plant-based diets. Phytochemicals found in for example fruits, vegetables, grains and seed oils are considered relatively safe for consumption due to mammal-plant co-evolution and adaptation. A number of human diseases are related to oxidative stress caused by for example chemical environmental contaminants in air, water and food; while also lifestyle including smoking and lack of exercise and dietary preferences are important factors for disease development in humans. Here we explore the dietary sources of antioxidant phytochemicals that have beneficial effects on oxidative stress, cardiovascular and neurological diseases as well as cancer. Plant-based diets usually contain phenolic acids, flavonoids and carotenoids, which have strong antioxidant properties, and therefore remove the excess of active oxygen in the body, and protect cells from damage, reducing the risk of cardiovascular and Alzheimer's disease. In most cases, obesity is related to diet and inactivity and plant-based diets change lipid composition and metabolism, which reduce obesity related hazards. Cruciferous and Allium vegetables are rich in organic sulphides that can act on the metabolism of carcinogens and therefore used as anti-cancer and suppressing agents while dietary fibres and plant sterols may improve intestinal health and prevent intestinal diseases. Thus, we recommend a diet rich in fruits, vegetables, and grains as its content of phytochemicals may have the potential to prevent or improve a broad sweep of various diseases.