I remember the days when administering cod liver oil to disgusted schoolchildren was a compulsory daily exercise in post-war Malta. It was considered necessary to give these weaklings some extra nourishment and protection.
While this exercise may or may not have had its desired effect, it is of interest to note that the use of fish oil has now received considerable attention as an adjunct to daily diet, being touted as being of value in providing extra vitamins, and as being beneficial in arthritis, as well as, most recently, in the prevention of metabolic syndrome.
According to the International Diabetes Federation, metabolic syndrome is diagnosed on finding central obesity (with an increased waist circumference), together with two of the following characteristics:
•Raised triglycerides (fatty acids) in the blood
•Reduced ‘good’ cholesterol (known as HDL or high density lipoprotein)
•Raised blood pressure
•Raised fasting blood glucose
Other criteria has been used by the WHO, but in essence the emphasis has been on the association of several factors within the same individual, namely, an abnormality of fat metabolism with a tendency to diabetes and a raised blood pressure.
Metabolic syndrome is a common condition affecting a quarter of the population in some surveys, with higher prevalence in older people where it may affect more than 40 per cent of the population.
While the cause of this condition is still largely unknown, a number of factors have been postulated to explain the high and increasing prevalence.
Among these one could include increased body weight, a genetic tendency which tends to make some families more commonly affected than others, aging, as well as a sedentary lifestyle. In addition, some studies have emphasised the importance of prolonged stress in precipitating this condition.
While efforts to prevent this condition are to be encouraged, there are limits to how far they are successful. Obviously there is little one can do to change our genetic make-up: at least not just yet.
On the other hand, better dietary habits intended to reduce total calorie intake, combined with a regular regimen of exercise, like taking a brisk half-an-hour walk every day, would be expected to be of value, at least in a number of persons.
One study recommended the intake of half a litre of milk a day, which they conclude, halved the risk of metabolic syndrome.
A more recent study coming from the University of Cordoba (Spain) emphasises the role of fat and carbohydrate intake in the production of metabolic syndrome. It is known that high-fat diets promote both weight gain as well as insulin resistance (which is characteristic of Type 2 diabetes).
Likewise, a high carbohydrate diet has the effect of increasing total blood triglycerides and reducing the concentration of HDL (high density lipoprotein, the ‘good’ cholesterol)
In their study, the authors find that a diet containing fish oil (which is rich in unsaturated fatty acids) reduced the blood levels of triglycerides in both normal persons as well as in those with diabetes.
The authors suggest that such diets had an important effect in reducing levels of fats in the blood, particularly after meals.
They emphasise that this effect can be seen in obese persons as well as in those of normal weight and could therefore be helpful in reducing the incidence and complications associated with metabolic syndrome.