Wednesday, March 6, 2013

Watch that salt! It just might be killing you

 

By TABITHA MWANGI [email protected]

The disease patterns in Africa are slowly and steadily shifting from infectious, communicable diseases to non-communicable illnesses more common in high-income nations. Life expectancy in the continent is also rising and our already challenged health systems are feeling the strain as adult diseases become more widespread.

Cardiovascular diseases — which are conditions that affect the heart and blood vessels — are on a steady rise in low and middle income countries.

Dr Anthony Etyang, a consultant physician at the Kilifi District Hospital as well as a clinical scientist at the KEMRI-Wellcome Trust Collaborative programme, is a worried man. Over the years, Dr Etyang has collated published data on causes of admissions and deaths in adults in sub-Saharan Africa, and his findings paint a gruesome picture of the future of Kenya’ health.

In a paper published in the Global Health Action Journal in January this year, Dr Etyang and colleagues reported a definite rise in cardiovascular diseases from less than four cases per 100 admissions in the 1950s to over 20 cases per 100 admissions by 2010.

But, since in their review most of the data came from urban areas, the researchers sought to know what the situation was like in other rural parts of Africa. To achieve the objective, they decided to compile the causes of death from the adult ward at the Kilifi District Hospital for the period betweeb 2007 and 2011.

Again, the findings were heartbreaking; out of the 15,528 admissions, 1,041 were due to heart and blood vessel diseases, which in this case was stroke and heart failure. Despite the fact that heart and blood vessel diseases made up slightly less than seven per cent of all admissions, it was the cause of a sizeable portion of deaths, second only to infectious and parasitic HIV-related diseases.

Out of the 1,543 deaths during the five year period, 224 were due to heart and blood vessel diseases. One out of every five adults admitted at Kilifi District Hospital for cardiovascular diseases died as a result of the illness.

This brings to attention the fact that heart and blood vessel diseases are not necessary ailments afflicting urban populations only.

The main risk factor for heart and blood vessel diseases is untreated high blood pressure or hypertension. But what makes one most at risk of hypertension?

After the age of 55, the risk of developing hypertension is high. According to the World Health Organisation, one out of every three adults worldwide has hypertension. Unfortunately, other than die young, there is not much one can do to avert old age. Nonetheless, there are risk factors that can be somewhat controlled.

The most commonly talked about risk factors, the so called ‘lifestyle changes’, include alcohol, smoking, stress, obesity and lack of exercise. And it is a fact that too much time sitting at the office or in front of the television, coupled with eating fatty, starchy or sugary foods, does increase the risk of these illnesses.

Yet Kilifi is one of the poorest districts in the country. You rarely encounter obesity in both the rural and urban areas. Fast-food shops are rare and red meat is a luxury. The staple foods include maize meal, beans, cassava and green vegetables. And, although Kilifi has huge numbers of boda boda and tuk-tuks, a lot of people still walk to work.

The upshot is simple: there is a far cheaper, deadlier cause of heart and blood vessel diseases in Kenya. The culprit is salt, one of the cheapest items on any shop shelf, with a 500mg packet going for Sh12.

Its effects are global in scale. A Lancet Journal review of 2012, authored by two Egyptian Professors (Mohsin Ibrahim and Albertino Damascero), reported that scientists had found stronger evidence linking high salt intake to heart and blood vessel disease than any other lifestyle risk factor.

This review discussed research conducted in America that found that African-Americans were more susceptible to high blood pressure than Caucasians due to salt sensitivity.

American scientists are not in agreement about race being a contributor to salt sensitivity despite some evidence that there is a gene among African-Americans that causes them to retain the sodium in salt, whereas Caucasians tend to excrete more of it.

In high-income countries, most of the salt is found in processed and mass produced food. In places like Kilifi, the majority of the people cannot afford processed foods and most of the salt that finds its way into the body is added during cooking or after serving.

“If you walk around Kilifi, you will not find obese, lazy, non-exercising people, and although we do not have the data yet, I am convinced that salt plays a major role in the high incidence of cardiovascular diseases here,” says Dr Etyang.

In any restaurant you patronise, salt is provided as free seasoning and, often enough, there are people who will add a pinch to their food without tasting it first. What appears like a harmless habit is slowly damaging the heart and blood vessels of the nation.

The mechanisms by which salt sensitivity causes hypertension are known.

“Think of the last time you ate a really salty dish, like peanuts or something? What did you feel like doing straight away? Most people will say, ‘I felt thirsty and wanted to drink some water’.

This is what happens in the blood. Since we are not great at excreting salt, it stays in the blood and so the body draws water into the blood to keep the balance. Excessive salt leads to excessive water retention in the blood and higher volumes of blood. Higher volumes of blood lead to high blood pressure, which overworks the heart and leads to all the other outcomes of hypertension if not controlled,” says Dr Etyang.

Monitoring the amount of salt consumed will greatly bring down the number of people suffering from high blood pressure. Some of the foods that are known to contain a lot of salt do not even taste salty. Take bread, for example, which has a high salt content. In some countries, like South Africa, citizens have lobbied for salt content of their bread to be lowered as a public health measure.

Preventing hypertension or controlling high blood pressure using drugs is another efficient way of averting cardiovascular diseases.

“Many people have this misguided notion that hypertension is a result of a temporary stress at home or work. Once one is diagnosed with high blood pressure, you need to be aware that there is no cure. However, it can be controlled through a lifetime of treatment and need not lead to cardiovascular disease,” Dr Etyang says.

It is worth repeating that high blood pressure has no symptoms. Often, it is diagnosed when a patient is seeking treatment for a separate ailment. But in the psyche of many Kenyans, a diagnosis of hypertension is linked to stress. So once the crisis that may have resulted in a visit to the hospital passes, the patient assumes that the hypertension is cured and discontinues treatment. This is risky as the crisis, which led to the hospital visit, was actually a godsend that brought to light an underlying condition requiring long-term attention.

Some churches and work places have an annual medical check programme where blood pressure is taken, among other measures. Patients at risk of developing hypertension are advised on diet, exercise, smoking and alcohol consumption risks.

This is also an opportunity to inform about salt intake as a risk factor for heart and blood vessel diseases.

The cost per patient of controlling hypertension with the cheapest drug on the market is about Sh6,000 per year. Although you make no savings from reducing your salt intake, you make a lifetime of savings by cutting down the cost of treatments for hypertension.

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