The Dash Diet (Dietary Approaches to Stop Hypertension), which was developed in the USA has been used successfully all over the world and South Africa is no exception.
A study conducted by Prof Karen Charlton and her team in 2007 at the University of Cape Town and the Medical Research Council in Cape Town, achieved promising results with a group of 80 black patients suffering from mild to moderate hypertension who were receiving antihypertensive treatment, just by changing six food items in their diets for a period of eight weeks.
High incidence of hypertension
South Africans in general, and our black population in particular, are very prone to hypertension or high blood pressure. It is estimated that 24,4% of adult black South Africans suffer from hypertension and that this disease tends to be poorly managed due to a variety of factors. Consequently strokes and cerebral accidents are also common in this population.
Two major dietary factors that can influence hypertension are salt or sodium intake (which increases blood pressure) and potassium intake (which decreases blood pressure). The WHO recommend a sodium to potassium ratio in the diet of 1. In our black population the sodium intake is very high (up to 8 gram per day - compared to the recommended maximum of 6 gram per day), while potassium intake is very low (50-60 mmol/day). It is, therefore, understandable that South African black people struggle to achieve the sodium to potassium ratio of 1 as recommended by the WHO.
The Dash Diet has provided sound scientific evidence that eating plenty of fruit, vegetables and wholegrains together with moderate quantities of low-fat or fat-free dairy products, can improve potassium, magnesium and calcium intakes, while reducing sodium intake to acceptable levels to reduce blood pressure.
While more affluent members of our society can easily apply the principles of the Dash Diet, the less economically advantage sectors of our population tend to have low intakes of fruit, vegetables and dairy products because of outright poverty and consequent food insecurity.
The researchers, therefore, had to devise another plan to reduce the sodium intake and increase the potassium intake of their 80 black subjects. What they decided to do was to reduce sodium intake while increasing intakes of potassium, magnesium and calcium in commonly consumed foods.
Prof Charlton’s team provided bread, margarine, stock cubes, soup mix and a flavour enhancer with a lower sodium or salt content, and a 500 ml serving per day of maas (unflavoured sour milk) to 40 study participants for a period of eight weeks.
The 40 control subjects were given the same diet with a ‘normal’ salt content and 500 ml of artificially sweetened cold drink per day for the same period.
After eight weeks, the average systolic blood pressure of the test subjects was 6.2 mm Hg lower than that of the control subjects. Other blood pressure results such as average systolic and diastolic bp measured by a 24-hour ambulatory blood pressure monitor were on average up to 4.5 mm Hg lower for the test group.
In the test group the sodium intake remained unchanged, while in the control group it increased by nearly 1 gram per day. The protective nutrient intakes improved dramatically; for example calcium intake nearly doubled, potassium intake increased by nearly 900 mg per day and magnesium intake increased by 84 mg per day in the study group. Keep in mind that these improvements in potassium, calcium and magnesium intakes were achieved without using mineral supplements.
Prof Charlton and her team (2007) concluded that their study demonstrated a public health intervention that “can achieve a clinically significant reduction in systolic BP in moderately hypertensive subjects on treatment living in a low-income community setting in South Africa through the dietary manipulation of seven commonly consumed processed foods".
This study not only showed that even poor communities with few resources can make dietary changes that can improve their blood pressure, but that diets can be changed by making just a few adjustments.
If you suffer from hypertension and would like to try out the Dash diet, click here.
Please keep in mind that if you find it difficult to work out this diet for yourself that you can contact a dietician to assist you to achieve the best results. Visit the Association for Dietetics in SA website to find a dietician in your area.
(References: Charlton KE et al (2007). A food-based dietary strategy lowers blood pressure in a low-socio-economic setting: a randomised study in South Africa. Public Health Nutrition, Vol 11(12):1397-1406.)
- (Dr IV van Heerden, DietDoc, March 2010)
Any questions? Ask DietDoc
The Dash diet
Menu plan for Dash diet
Hypertension and diet