Oily fish, liquid wax esters and keriorrhoea – a review

Keriorrhoea is the involuntarily passing of orange oil per rectum. One of us (PMB) had the misfortune to experience this symptom, together with considerable gastrointestinal disturbances for a prolonged period of time after consumption of a deep sea fish, orange roughy, which is rich in liquid wax esters (LWEs). This paper presents a summary of available evidence concerned with the physiology and pathology of ingestion of LWEs, which can enter the human diet in substantial amounts from consumption of several species of deep-sea fish. LWEs are poorly digested and absorbed by the human body. They generally cause keriorrhoea when ingested deliberately or accidentally. Jojoba oil, which is a plant LWE, together with certain nutritional products (e.g. olestra) and medical (e.g. Orlistat) which are not LWEs may mimic the effects of LWEs, and cause similar gastrointestinal disturbances. This paper discusses the potential effects of LWEs as components of gastrointestinal micelles, and predicts that the orange oil which is leaked from a bout of keriorrhoea may contain considerable volumes of triacylglycerols (TAGs).

The pH of very dilute solutions of weak acids – a calculation involving the application of numerical skills to the solution of a cubic equation

This paper presents the solution to a calculation of the pH of a very dilute solution of a weak acid, taking into account the effect of the hydroxonium ions generated from the ionization of the acid on the ionization of water, also a very weak acid. To be solved successfully, this calculation involves the concepts of conservation of charge, pH, equilibria and the application of the general solution to a cubic equation. Such an exercise requires the application of skills in algebra, and can provide a core of understanding that can prepare advanced students for many different sorts of calculations that represent real-life problems in the chemical sciences. A programme is presented in C++ which enables the work of students to be individualized so that each student in a class can work through a slightly different pH calculation, in such a way that a class supervisor can quickly check each student’s result for accuracy. This exercise is presented as a potential means of enabling students to undertake and master similar types of calculations involving the application of complex algebra to problems related to equilibria and solution dynamics.

The pH of very dilute solutions of strong acids – a calculation for a medical or biomedical class involving the application of simple numerical skills

This paper presents the solution to a calculation of the pH of a very dilute solution of a strong acid or base, taking into account the effect of the hydronium or hydroxyl ions generated from the ionisation of the strong acid or base on the ionisation of water, as a second very weak acid. To be solved successfully, this calculation involves the concepts of conservation of charge, pH and the application of the general solution to a quadratic equation. Such an exercise involves the application of skills in basic numeracy, and can provide a core of understanding that can prepare students for many different sorts of calculations that represent reallife problems in the medical and biological sciences. A programme is presented in C++ which enables the work of students to be individualised so that each student in a class can work through a slightly different pH calculation, in such a way that a class supervisor can quickly check each student’s result for accuracy. This exercise is presented as a potential means of enabling students to undertake and master similar types of calculations involving simple or more complex equilibria.

Lactose tolerance and intolerance in Malaysians

This review explores the digestibility of lactose by Malaysians, and the value of milk and other milk-derived products as sources of appropriate nutrition for Malaysians. Increased calcium intake through consumption of milk is an effective mechanism for increasing calcium uptake from the diet and thereby minimising the risk of development of osteoporosis in later life. Detailed information about rates of lactose intolerance, and adaptation to dietary lactose and its consequences for Malaysians, will help in the formulation of dietary advice, and improve commerial food manufaturing practice and Government policy directed to the minimization of rates of osteoporosis, which presents a substantial morbidity risk to elderly female Asians in particular.