Table 1 Characteristics of type 2 diabetes and hypertension studies included in the review

Masilela 2020 [46]

Cross-sectional

South Africa, (Mpumalanga)

157

24 males

133 females

Age categories:

≤ 49 years

50–59 years

≥ 60 years

Fruits and vegetables frequency of consumption (e.g., 1–3 times/week)

Fast food

Fasting blood samples were collected to measure:

HbA1c levels

Galbete

2018 [48]

Cross-sectional

Ghana, (Ashanti)

2362

Rural: 942

Urban: 1420

Rural:

365 males

577 females

Urban:

409 males

1011 females

Mean age: 46.2 ± 11.0 years

Rural mean age:46.8 years

Urban mean age: 45.3 years

“Roots, tubers and plantain” dietary pattern: refined cereals, fruits, nuts/seeds, roots/tubers/plantain, fermented maize products, legumes, palm oil and condiments.

“Mixed” dietary pattern

“Rice, pasta, meat and fish” dietary pattern

Fasting blood samples were collected to measure:

Glucose levels

Chikowore 2017 [49]

Cohort

South Africa, (North West)

2010

Rural:

347 males

659 females

Urban:

399 males

605 females

Age range:

35 to 60 years

“Magnesium, phosphorus and plant protein” pattern

“Starch, dietary fibre and B vitamin” pattern

“Thiamine, zinc and plant protein” pattern

“Thiamine, starch and folate” pattern

“Fat and animal protein” pattern

“Retinol and vitamin B12” pattern

“Beta carotene and vitamin C” pattern

Fasting blood samples were collected to measure:

Glucose levels

HbA1c levels

Kimani 2019 [44]

Cross-sectional

Kenya, (Nairobi)

229

102 males

127 females

Age categories:

18–25 years

26–35 years

36–45 years

46–55 years

56–65 years

≥ 66 years

Fruits and vegetables frequency of consumption (e.g., daily)

Fast food and meals high in animal fat

Blood pressure readings were taken. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) classification was used.

Rush

2018 [42]

Cross-sectional

Zambia, (Western Province)

261

Urban:131

Rural: 130

92 males

169 females

Urban mean age: 39.40 ± 14.39 years

Rural mean age: 54.13 ± 17.56 years

Fruit and vegetable frequency of consumption (e.g., average number of days/week)

–

Blood pressure readings were taken. The 2014 Clinical Practice Guidelines for the Management of Hypertension in the Community was used.

Katalambula 2017 [43]

Cross-sectional

Tanzania, (Arusha)

549

233 males

316 females

Mean age:

40.70 ± 12.07 years

‘Healthy’ dietary pattern: carbohydrate rich foods, vegetable, fruits, and spices.

‘Complex carbohydrate’ dietary pattern: sweets, roots, tubers, and legumes.

‘Western’ dietary pattern

Blood pressure readings were taken. The JNC 7 classification was used to define hypertension.