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SA JOURNAL OF DIABETES & VASCULAR DISEASE
REVIEW
VOLUME 12 NUMBER 1 • JULY 2015
5
Lifestyle and diet
LIONEL H OPIE
Correspondence to: Lionel H Opie
Hatter Institute for Cardiovascular Research in Africa, Groote Schuur Hospi-
tal and Medical School, University of Cape Town, Cape Town, South Africa
e-mail:
Lionel.Opie@uct.ac.zaPreviously published in
Cardiovasc J Afr
2014;
25
(6): 298–301
S Afr J Diabetes Vasc Dis
2015;
12
: 5–7
Abstract
Currently, there is widespread interest in many different diets.
The best-known diets include the New Atkins diet in the USA,
the Dukan diet in France, and in South Africa the Noakes diet.
Two different approaches have emerged, one focusing on a life-
long healthy lifestyle and the other emphasising weight loss.
These are in fact complementary aims, as will be reviewed and
reconciled. Furthermore, besides the dietary approach, there is
a valid case for added drug therapy for selected lipid disorders
with the use of statins. In addition, new drugs are emerging
that in the future might eventually considerably reduce the
negative health impact of coronary artery disease.
Keywords:
diet, cardiovascular risk, Noakes diet, Banting diet,
Mediterranean diet
Lifestyle is life-long
Lifestyle is life-long in its health implications.
1
Although diet is
only one of the five components of a healthy lifestyle,
2
diet has
recently come to the fore.
3
When considering overall health, the
most important are non-smoking and regular exercise, followed
by body weight and diet, in order of importance (Table 1). These
proposals are based on a series of important studies on over
100 000 US health professionals over 10 to 25 years, which defined
the contribution to health of four major lifestyle factors, only one of
which is diet (Table 1).
2,4,5
While there are many diets to choose from, the majority focusing
on weight loss, few diets have had scientifically solid outcome
studies to prove that the diet in question actually improves health
and increases life span. An exception is the Mediterranean diet, so
called because of the very low incidence of heart attacks observed
by Ancel Keys in the Mediterranean islands of Corfu and Crete,
thus leading to the concept that the Mediterranean diet is an ideal
diet,
1,6,7
also protecting against heart failure.
8
Palaeolithic, the oldest diet
What is the paleolithic diet? Mankind evolved over hundreds of
millions of years, therefore the paleolithic diet must have been the
standard diet that also evolved over that time. Studies on the teeth
of the paleolithic man, as found in East Africa (also in its congener
from South Africa), showed that the dental bones and teeth had
adapted to process large quantities of low-quality vegetation rather
than hard objects.
9
The paleolithic diet is now recognised as a
nutritional pattern based on the ancient diet of wild plants and
animals that our ancestors consumed over 10 000 years ago.
In the Kitava dietary study on isolated tribes in Papua, New
Guinea, who even recently ate a pre-Westernised diet of 55 to
65% animal foods and 35 to 45% plant foods, these societies had
no incidence of stroke, heart disease, diabetes or hypertension.
10
The diet consisted mainly of fish, grass-fed pasture-raised meats,
vegetables, fruits, roots, spices and nuts. There was no restriction
on calories or on the foods to be cooked.
Although the Mediterranean diet overlaps with the palaeolithic
diet in terms of fibre, antioxidants, saturated fat and mono-
unsaturated fat, the paleolithic diet improved glucose tolerance
more than did the Mediterranean diet.
10
Furthermore, this diet
is more food satiating than a Mediterranean-like diet in persons
with ischaemic heart disease.
11
Therefore the paleolithic diet both
preceded the Mediterranean diet and was apparently better, so it
may be that ‘the simpler, the better’.
Diet and lipids
Moving on in history, it was the early Cape Town studies that
made the link between fat in the diet and blood cholesterol values.
Nearly 60 years ago, Professor John Brock and Brian Bronte-Stuart
from Groote Schuur and the University of Cape 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.
15
Over time,
Table 1.
The ‘big-five’ components of the healthy lifestyle, with
contributions of the various components to give protection from risk
of death, with and the proposed mechanisms of action. Note that the
missing 21% is probably stress related. From Opie,
1
page 33.
Lifestyle: ‘big five’
Reduced all-cause
death risk (%)
Mechanism
Non-smoking
28
Protects arteries
Exercise 30 min or
more daily
17
Slows the heart rate,
lowers BP
Ideal weight
14
Less toxic chemicals
released from fat cells
Ideal diet
13
High unsaturated
fatty acids, high veg-
etables and fruit, low
red meat
Modest alcohol
7
Red wine preferred,
contains melatonin
All five
79
Remaining 21% may
be stress related