European Journal of Clinical Nutrition (2018) 72:894–903
https://doi.org/10.1038/s41430-018-0123-0
ARTICLE
Interventions and public health nutrition
Effect of individualised dietary advice for weight loss supplemented
with walnuts on blood pressure: the HealthTrack study
Rhoda N. Ndanuko
1
●
Linda C. Tapsell
1
●
Karen E. Charlton
1
●
Elizabeth P. Neale
1
●
Marijka J. Batterham
2
Received: 31 May 2017 / Revised: 24 January 2018 / Accepted: 31 January 2018 / Published online: 20 March 2018
© Macmillan Publishers Limited, part of Springer Nature 2018
Abstract
Background/objectives In addition to weight-loss, healthy dietary patterns and lower sodium intakes can help reduce blood
pressure (BP), but individualised dietary advice may be necessary to achieve these effects. This study aimed to examine the
impact of individualised dietary advice on BP in the intensive phase of a weight-loss trial.
Subjects/methods Secondary analysis of baseline and 3-month data from the HealthTrack randomised controlled trial (n =
211). Participants were randomly assigned to one of three dietary advice groups: general advice (control), individualised
advice (intervention group, I), or intervention group supplemented with 30 g walnuts/day (IW). Resting BP and 24-h urine
sodium and potassium were measured. Dietary intake was evaluated through diet history interviews.
Results Unadjusted SBP reduced significantly in all groups (IW and I groups P < 0.001; control group P = 0.002) and DBP
in IW and I groups (P < 0.001). Compared to controls, the reductions in BP were 3–4 mmHg greater in the I and IW groups,
but this only reached significance for DBP in the I group (−3.3 mmHg; P = 0.041). After controlling for age, sex, medi-
cation, weight-loss, physical activity and smoking, only the IW group showed a significant association between SBP
reduction and increased urinary potassium (β = −0.101, P = 0.044), decreased sodium:potassium ratio (β = 2.446, P =
0.037) and increased consumption of seed and nut products and dishes (β = −0.108, P = 0.034).
Conclusions Dietary patterns with distinctive foods and lower sodium:potassium ratios may enhance the effects of weight-
loss on BP. The patterns were best achieved with individualised dietary advice and food supplements.
Introduction
Hypertension or high blood pressure (BP) is a major risk
factor for cardiovascular disease and the leading risk factor
for total burden of disease and mortality worldwide [1].
Lowering systolic BP (SBP) by 10 mmHg or diastolic BP
(DBP) by 5 mmHg through the use of BP-lowering medi-
cation has been shown to reduce the incidence of coronary
heart disease events and stroke by 25 and 30% respectively
[2].
Different lifestyle approaches have been recommended
to lower BP. These include weight loss, regular physical
activity, reducing dietary sodium intake and consuming a
healthy diet [3]. Previously, dietary trials for BP-lowering
have primarily focused on interventions that result in
reductions in sodium intake, either with or without a con-
comitant increase in potassium intake. A systematic review
of these trials shows that reducing dietary salt to 4.4 g/day
(1716 mg sodium/day) leads to an estimated reduction of
5.0 and 3.0 mmHg in SBP and DBP, respectively, in
hypertensive subjects and 2.0 and 1.0 mmHg, respectively,
in normotensive subjects [4]. On the other hand, a meta-
regression has shown an increase in potassium intake by
44 mmol/day (1716 mg/day) to be associated with a
reduction of 2.4 and 1.6 mmHg in SBP and DBP, respec-
tively [5]. However, the urinary sodium-to-potassium (Na:
K) ratio may be more strongly associated with BP than
urinary sodium or potassium alone [6], and may be more
indicative of total diet.
Given that weight loss itself helps to reduce BP [7],
adding knowledge of healthful food patterns to that of
energy restriction may be beneficial in managing obesity
and its related disorders such as hypertension. The rela-
tionship between obesity and hypertension is well
* Rhoda N. Ndanuko
rnn954@uowmail.edu.au
1
School of Medicine, University of Wollongong, Northfields
Avenue, Wollongong, NSW 2522, Australia
2
Statistical Consulting Service, School of Mathematics and Applied
Statistics, University of Wollongong, Northfields Avenue,
Wollongong, NSW 2522, Australia
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