CHAPTER ONE
INTRODUCTION
Sodium chloride (NaCl) is a prototypical stimulant that elicits salty taste. Sodium chloride is a commonly used food ingredient which provides many technological functions such as Flavor enhancement, preservation and texture modification (Hutton, 2002). Sodium (Na) also performs a number of vital roles in the body including maintaining the volume of extracellular fluid, osmotic pressure, acid-base balance and transmission of nerves impulses (Geerling and Loewy, 2008).
Unlike other essential minerals such as calcium, we do not have large stores of sodium in the body and need to constantly replenish sodium via the diet (Reddy and Marth, 1991). While sodium is essential for normal human body functioning, current sodium intakes far exceed recommendation for good health (Brown and Tzoulaki, 2009). This is a problem because there is a strong positive relationship between sodium intake and raised blood pressure.
Raised blood pressure is a major cause of cardiovascular diseases, responsible for 62% of stroke and 49% of coronary heart disease (He and MacGregor, 2010). Excess sodium consumption has also been linked to numerous other negative health effects including gastric cancer (Tsugane et al., 2004), decreased bone mineral density (Devine et al., 2000) and obesity (He et al., 2008).
In general attempts to reduce dietary sodium intake through sodium restricted diets have shown short term success but have lacked long term sustainability and practicality for large populations due to high level of sodium in processed foods and the significant contribution of processed foods to our diet (James et al., 1987). Also, a reduction of sodium chloride in foods is accompanied by a loss of palatability of those foods (Mattes, 2007). The ideal solution would be to reduce the concentration of sodium in the food while retaining optimum saltiness for palatability. One strategy to reduce sodium is to replace with potassium salts, and while potassium chloride elicits weak saltiness at higher concentrations it also elicits metallic and bitter taste limiting its utility in foods (Ainsworth and Plunkett, 2007).
However, minimizing those ‘off-flavors’ means potassium could be an effective salt taste replacer. Arguably, the human diet has undergone more significant changes in the past 50 years than in the past 10 million years (Cordian et al., 2005). One of such modification is the molar ratio consumption of sodium to potassium. Historically, hominid diet contains high potassium and low sodium concentration due to a diet consisting largely of fruit, vegetables and whole grains (Cordian et al., 2005). Our evolutionary forbears had a need to consume sodium, and the sodium was a scarce dietary element, we developed an appetitive response to sodium via salt taste (Mela, 2006). Although the taste mechanism for sodium has not changed, the food supply has developed to suit our appetitive desire and the modern western diet contains a high proportion of processed food with high levels of sodium, which is inherently appealing to humans (Mattes, 2001).
Moreover, fruit and vegetables are the major source of dietary potassium but they are not much consumed in the diet. High consumption of processed food has resulted in a decrease intake of potassium and increase intake of sodium which has much negative health effect including raise blood pressure, obesity and decreased mineral density etc. In recognition of the risks posed by the excessive consumption of sodium, a new daily consumption limit of less than 5g/day (<87mmole per day) has been set for high risk groups, including adults of black African origin. Therefore, this research is aimed at estimating the daily salt intake of healthy ambulant Nigerian adults.
The high risk of hypertension and its related complications in both developed and developing countries has been attributed to the sociological, political and economic changes and the associated alterations in people’s lifestyles (Ukoh et al., 2004). This research is aimed to investigate what is known from previous studies relating to the relationship between hypertension and:
- Risk factors including age, gender, genetics, diet, and weight, alcohol, smoking, lack of activity and co- morbidity
- Mediating factors including economic factor, stress or personality and medication
- Management of hypertension through life style modification
- Complimentary therapy: foot reflexology and foot message