Clinical studies
Randomized trial of the effects of cholesterol-lowering dietary treatment on psychological function,

https://doi.org/10.1016/S0002-9343(00)00330-2Get rights and content

Abstract

PURPOSE: Epidemiological studies have suggested that cholesterol lowering could affect psychological functioning. This study was designed to test whether cholesterol-lowering diets adversely affect mood and cognitive function.

SUBJECTS AND METHODS: We randomly assigned 176 adults with elevated serum cholesterol levels (>5.2 mM [198 mg/dL]) to either a low-fat diet, a Mediterranean diet, or a waiting-list control. Cholesterol levels, psychological well-being (depression, anxiety, hostility), and cognitive function were assessed at baseline, 6 weeks, and 12 weeks.

RESULTS: Total serum cholesterol levels fell significantly more in the intervention groups (8.2% reduction) than in the control group (P <0.001). All three groups showed a modest improvement in psychological well-being during the 12-week treatment period, but there were no differences among the groups. There were no between-group differences on three measures of cognitive function, but for a fourth measure, which involved the task with the greatest processing load, the two intervention groups did significantly worse (P <0.001) than the control group. The change in performance was correlated with the change in total serum cholesterol level (r = 0.21, P = 0.01).

CONCLUSIONS: Two dietary interventions that successfully lowered serum cholesterol levels had no adverse effect on mood. There was some evidence for a relative impairment in cognitive function in the treated groups in one of four cognitive tests, but additional studies will be required to determine the relevance of this finding.

Section snippets

Participants and design

Adults with mildly or moderately raised serum cholesterol levels were referred by hospital dietetic clinics, hospital physicians, and general practitioners in London and Southeast England. Participants were required to have a serum cholesterol level >5.2 mM (198 mg/dL); no serious illness (except cardiovascular disease, for which cholesterol lowering was indicated); no current or previous (within 3 months) use of lipid-lowering medication; and physician’s permission to participate. In addition,

Results

Of the 176 participants who began treatment, 155 completed the posttreatment assessment and had attended at least four treatment sessions (Figure 1). Participants were generally middle-aged and somewhat overweight (Table 1). Nutrient analyses from the 7-day diaries showed that reported energy intakes were reasonable for adults of this age, as were levels of depression, anxiety, and aggression. There were no significant differences among the three treatment groups in any of the baseline

Discussion

The participants in this study were adults with at least mild hypercholesterolemia by UK criteria. As volunteers who agreed to participate in a relatively demanding study, participants were probably more highly motivated than the population at large, but that is true in most clinical trials. Many of the participants were already following a low-fat diet, and the recorded fat intake at baseline (32% of energy) was lower than the UK average of 39%. The dropout rate was low, partly because

References (36)

  • M.F Muldoon et al.

    Lowering cholesterol concentrations and mortalitya quantitative review of primary prevention trials

    BMJ

    (1990)
  • D Jacobs et al.

    Report of the conference on low blood cholesterolmortality associations

    Circulation

    (1992)
  • M Gallerani et al.

    Serum cholesterol concentrations in parasuicide

    BMJ

    (1995)
  • E Brunner et al.

    Low serum cholesterol and suicide

    Lancet

    (1992)
  • T.E Strandberg et al.

    Serum lipids and depression

    Lancet

    (1993)
  • S.L Brown et al.

    Low cholesterol concentrations and severe depressive symptoms in elderly people

    BMJ

    (1994)
  • M Virkkunen

    Serum cholesterol in antisocial personality

    Neuropsychobiology

    (1979)
  • D.S Freedman et al.

    Plasma lipid levels and psychologic characteristics in men

    Am J Epidemiol

    (1995)
  • Cited by (85)

    • The Effect of Adherence to the Mediterranean Diet on Late-Life Cognitive Disorders: A Systematic Review

      2020, Journal of the American Medical Directors Association
      Citation Excerpt :

      Three of these were cognitive substudies (post-test comparisons),19–21 and another was an RCT based on the data of the PREvencion con Dieta MEditerranea study (PREDIMED).22 The number of the participants assessed by RCTs ranged between 13723 and 127924 (median 447), and the follow-up period ranged between 12 weeks18 and 6.5 years.19–21 The number of participants in the longitudinal studies ranged between 7048 and 28,775,51 and the follow-up period ranged between 243,55 and 26 years.49

    • The association between diet and mood: A systematic review of current literature

      2019, Psychiatry Research
      Citation Excerpt :

      Among 18 studies included, three used DASH (Torres et al., 2008; Torres and Nowson, 2012; Valipour et al., 2017), four MD (Wardle et al., 2000; Hyyppä et al., 2003; McMillan et al., 2011; Lee et al., 2015), four vegetable-based (Beezhold et al., 2010; Beezhold and Johnston, 2012; Beezhold et al., 2015; Olabi et al., 2015), two glycemic load-based (Cheatham et al., 2009; Breymeyer et al., 2016), three ketogenic (McClernon et al., 2007; Lambrechts et al., 2012; IJff et al., 2016), one Paleo (Lee et al., 2017) and one Zone diets (Fontani et al., 2005). Based on the country, eight papers were from United States (McClernon et al., 2007; Cheatham et al., 2009; Beezhold et al., 2010; Beezhold and Johnston, 2012; Beezhold et al., 2015; Olabi et al., 2015; Breymeyer et al., 2016; Lee et al., 2017), four from Australia (Torres et al., 2008; McMillan et al., 2011; Torres and Nowson, 2012; Lee et al., 2015), two from The Netherlands (Lambrechts et al., 2012; IJff et al., 2016) and the others were obtained from United Kingdom (Wardle et al., 2000), Finland (Hyyppä et al., 2003), Italy (Fontani et al., 2005) and Iran (Valipour et al., 2017). Fourteen articles were interventional (Wardle et al., 2000; Hyyppä et al., 2003; Fontani et al., 2005; McClernon et al., 2007; Torres et al., 2008; Cheatham et al., 2009; McMillan et al., 2011; Beezhold and Johnston, 2012; Torres and Nowson, 2012; Lee et al., 2015; Olabi et al., 2015; Breymeyer et al., 2016; IJff et al., 2016; Lee et al., 2017) and four were observational (Beezhold et al., 2010; Lambrechts et al., 2012; Beezhold et al., 2015; Valipour et al., 2017).

    View all citing articles on Scopus

    Supported by a grant from the Biotechnology and Biological Sciences Research Council.

    Access the “Journal Club” discussion of this paper at http://www.elsevier.com/locate/ajmselect/

    View full text