TRADITIONAL African foods like leafy vegetables and small grains, along with edible insects and legumes, contain bioactive compounds that may reduce chronic inflammation and oxidative stress driving the progression of diabetes.

Dr Tendaiishe Berejena and Dr Florence Malongane of the University of South Africa reviewed 46 studies conducted between 2010 and 2023 examining the role of African indigenous food groups in preventing and managing type 2 diabetes mellitus.

The review indicated that indigenous African foods rich in anti-inflammatory and antioxidant compounds could play a significant role in preventing and managing type 2 diabetes, a disease that is rising rapidly across the continent.

In the review published by The Conversation, it was affirmed that in 2021 alone, diabetes and related kidney disease caused more than two million deaths. Type 2 diabetes is a long-term metabolic condition that affects millions of adults worldwide. The global number of people living with diabetes rose dramatically from 200m in 1990 to 830m in 2022, they said. 

The burden has increased rapidly in low- and middle-income countries, including many in sub-Saharan Africa, where inflammation as a natural immune response helping the body fight infection and heals injury is diminished. 

Inflammation becomes chronic it can damage healthy tissues and blood vessels, disrupt glucose and fat metabolism, weaken immune responses and increase the risk of long-term illnesses such as type 2 diabetes, the researchers noted.

Traditional African diets — historically rich in fibre, polyphenols and antioxidants — may offer affordable, culturally relevant dietary strategies to address this escalating public health challenge, they said, pointing at cereals, legumes, fruits, vegetables, milk and poultry.

There is limited red meat consumption and notable use of edible insects, they said in a keynote finding, stressing the use of okra leaves, nightshade, amaranth and cowpeas as underutilized and often dismissed as food for poor people.

Over time, dietary patterns have shifted towards Western-style diets high in sugar, salt and unhealthy fats, significantly increasing the risk of obesity and type 2 diabetes across the continent, the study noted.

The review highlights how returning to indigenous food systems may help mitigate chronic inflammation and improve metabolic health, they particularly suggested, listing “edible insects” as including caterpillars, ants, crickets and locusts.

They were found to contain bioactive compounds such as peptides, chitin and polyphenols, substances exhibiting antioxidant and anti-inflammatory properties, with caterpillars, for example being shown in some studies to possess two to five times the antioxidant capacity of orange juice or olive oil. 

Locust-derived peptides may inhibit enzymes involved in breaking down sugars and fats, potentially reducing risks associated with fatty liver disease, diabetes and cardiovascular conditions, they said.

African leafy vegetables such as cowpea leaves, nightshade, amaranth, okra leaves and jute mallow demonstrated promising blood sugar-lowering and anti-inflammatory effects, while one study found that patients with type 2 diabetes who consumed blackjack (Bidens pilosa) experienced reductions in fasting blood glucose levels. 

Jute mallow was shown to help regulate inflammatory responses by influencing nitric oxide production, while wild bitter gourd reduced pro-inflammatory cytokines, indigenous small grains such as finger millet and sorghum being naturally high in fibre, which slows glucose absorption and improves blood sugar regulation, they said.

Finger millet was shown in animal studies to lower fasting blood sugar levels. Sorghum contains antioxidant compounds including luteolin and quercetin, which may help reduce inflammation and improve insulin sensitivity, while red pericarp sorghum varieties have demonstrated anti-inflammatory effects in diabetic models, they said.

Baobab fruit powder and prickly pear were identified as potentially effective in moderating blood sugar levels by blocking specific digestive enzymes, while wild medlar exhibited enzyme-inhibiting properties in laboratory studies, suggesting potential affordability and accessibility for diabetic patients.

Cassava contains compounds that reduce the breakdown and absorption of dietary starch, which may help regulate blood sugar levels, while yams and their extracts were associated with lower fasting glucose and insulin levels, reduced body fat and improved lipid profiles.

Fermented yam products showed potential in strengthening antioxidant defences and reducing inflammatory mediators, with ‘Livingstone potatoes’ demonstrating promising effects in improving liver and kidney health, plus regulating glucose metabolism in laboratory studies.

Legumes such as cowpea, bambara nuts, soybean and mung beans were found to support insulin production and reduce blood sugar spikes, as bambara nuts displayed particularly high antioxidant capacity — even higher than orange peels in laboratory comparisons. 

Soybeans and mung beans improved glucose tolerance and cholesterol levels, while the fibre content in cowpea and bambara nuts contributed to better blood sugar control, they specified.

Incorporating indigenous African foods into medically tailored diets could provide a cost-effective approach to managing diabetes, particularly in marginalised communities facing rising healthcare costs, they suggested.

Beyond individual health benefits, revitalising indigenous food systems could enhance food security, promote sustainable agriculture and preserve cultural heritage, even as more clinical trials are required to validate laboratory and animal findings before firm dietary guidelines can be established, they added.