Cardiovascular Journal of Africa: Vol 25 No 6 (November/December 2014)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 25, No 6, November/December 2014

AFRICA

299

Town Department of Medicine used their specialised metabolic

unit to give a high-fat diet to subjects with an initially low blood

cholesterol level (Fig. 1).

12,13

A butter load of 100 grams given

daily increased blood cholesterol by proximately 40% within five

days. The addition of large amounts of olive oil to the butter

load restored cholesterol levels to their prior low levels (Fig. 1).

Therefore the type of fat diet affected blood cholesterol levels.

The decisive further link between circulating cholesterol

values and coronary heart disease came from the Framingham

study, which found that higher blood cholesterol values were

associated with increased cardiovascular and total mortality

rates.

Over time, the emphasis on selection of drug therapy via

statins has shifted to the blood level of low-density lipoprotein

(LDL) cholesterol.

In South Africa in 2000, high blood cholesterol levels have

been estimated to have caused 24 144 deaths (95% CI: 22 404–25

286) or 4.6% of all deaths.

Studies in the Cape Peninsula and

in the South African Indian population support links between

lipid abnormalities and coronary heart diseases.

18,19

Severely

obese South African white women have greatly reduced values

for serum high-density lipoprotein (HDL) cholesterol or ‘good’

cholesterol, rather than high levels of LDL cholesterol.

Lipids in diabetes: the role of statins

The ideal approach to nip diabetes in the bud is by testing HbA

values in those with the metabolic syndrome or obesity, and then

to go for weight loss induced by combined diet and exercise.

In those with established type 2 diabetes (DM2), a population

study in Hong Kong suggested that statin therapy attenuated

the associated increased cancer risk.

For diabetes, in a large

study with 215 725 person-years of follow up, statin use before

the diagnosis of diabetes reduced diabetic retinopathy (hazard

ratio 0.60, 95% CI: 0.54–0.66;

< 0.0001), diabetic neuropathy

(HR 0.66, 95% CI: 0.57–0.75;

< 0.0001), and gangrene of the

foot (HR 0.88, 95% CI: 0.80–0.97;

= 0.010).

Regarding the

general adult population, statins are recommended as first-line

therapy in those up to and including 75 years of age, who have

clinical atherosclerotic cardiovascular disease (ASCVD) (Table 4

in Stone

et al

Exercise versus drugs

In studies on the secondary prevention of coronary heart

disease and pre-diabetes, randomised trials on exercise

interventions suggest that exercise and many drug interventions

are often potentially similar in terms of their mortality benefits,

rehabilitation after stroke, treatment of heart failure, and

prevention of diabetes.

This important observation reinforces

the essential role of exercise in any programme aimed at overall

cardiovascular health (Table 1).

Banting first linked diet to mortality

Banting in his pamphlet

in 1869 emphasised the role of diet

in weight loss, stating that: ‘The dietary is the principle point in

Fig 1.

A historical study in Cape Town. The effect of dietary fats on blood lipid levels and their relation to ischaemic heart disease,

neutralised by the effect of added olive oil. Note the rapid rise in serum cholesterol levels with the provision of the high-butter

diet. All values were obtained in the Metabolic Unit, University of Cape Town, South Africa. From Bronte-Stewart.