Tools for Practice


#175 Chocolate: Can anything this tasty be good for us?


CLINICAL QUESTION
Is chocolate consumption linked to health concerns like cardiovascular disease?

BOTTOM LINE
Chocolate consumption is associated with no change or a small reduction in cardiovascular disease in cohort studies. Evidence is too weak to recommend chocolate consumption for health benefits. Surrogate marker changes are minimal and perhaps unreliable. Chocolate likely increases acne lesions in susceptible individuals.  


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EVIDENCE
Six systematic reviews:1-6 Each with 5-9 observational studies (mostly prospective cohort) and 75,408-157,809 adults. Comparing highest chocolate consumption versus little to no consumption, after 8-16 years:  
  • Cardiovascular disease: Relative Risk (RR) 0.63 (95% Confidence Interval (CI), 0.44-0.90).1 
  • Myocardial infarction and angina: RR 0.90 (95% CI, 0.82-0.97).3 
  • Stroke: RR 0.81 (95% CI, 0.73–0.90).4 
  • Heart failure (admission or death): RR 0.81 (95% CI, 0.66-1.01).5 
  • Issues: Overall mortality not reported, individual study results varied considerably,1,2,5 and poor assessment of potential bias.2-6 
    • Non-randomized so imbalanced groups: Chocolate eaters generally younger, lower BMI, active, etcetera (healthy).2,4,5 Although researchers adjust for these factors, it is suboptimal.  
    • Unclear if dark or milk chocolate1-5 but possibly ~90% milk.4   
    • Consumption measurement varied considerably but ‘highest’ often >50 grams/week or ≥1-2 servings/week.1-5 
  • Cardiovascular risk factors:  
      • Blood pressure (BP): Three systematic reviews (10-20 Randomized Controlled Trials (RCTs), 297-856 patients).7-9 
        • Statistically significantly reduced 2.8-4.5 mmHg systolic and 2.0-2.7 mmHg diastolic.7-9   
        • Blood pressure reductions less if normotensive, studied longer or if comparator included cocoa product (example, dark versus milk chocolate).7 
      • Lipids: Two systematic reviews (8-10 RCTs, 215-320 patients).10,11
        • LDL reduced 0.15 mmol/L but other lipid parameters not statistically different.   
      • Issues: Short-term studies (mean 4.4 weeks),7 study BP results varied considerably.7     
    • Adverse events: Chocolate 5% versus 1% (gastrointestinal, bad taste, headache, jitteriness but numbers small).7 
Context:   
  • Dark chocolate is 50-85% cocoa and milk chocolate is 20-30%.7 
    • Cocoa contains flavanols: A proposed but unproven source of health benefits.  
  • Other health issues: 
    • Depression: Not clinically assessed.12   
    • Migraine: No reliable association.13 
    • Acne: Two RCTs (13 and 54 acne patients): Increase of 4-5 lesions 2-3 days after chocolate ingestion.14,15   
  • Observational studies suggest chocolate consumption associated with lower risk of being overweight/obese, albeit likely confounding bias.16 
November 21, 2016

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Author(s):

  • G. Michael Allan MD CCFP
  • Mary Anne Zupancic MSc

1. Buitrago-Lopez A, Sanderson J, Johnson L, et al. BMJ. 2011; 343:d4488.

2. Kwok CS, Boekholdt SM, Lentjes MA, et al. Heart. 2015; 101(16):1279-87.

3. Larsson SC, Åkesson A, Gigante B, et al. Heart. 2016; 102(13):1017-22.

4. Larsson SC, Virtamo J, Wolk A. Neurology. 2012; 79(12):1223-9.

5. Kwok CS, Loke YK, Welch AA, et al. Nutr Metab Cardiovasc Dis. 2016; 26(8):722-34.

6. Khawaja O, Gaziano JM, Djoussé L. Curr Atheroscler Rep. 2011; 13(6):447-52.

7. Ried K, Sullivan TR, Fakler P, et al. Cochrane Database Syst Rev. 2012; (8):CD008893.

8. Desch S, Schmidt J, Kobler D, et al. Am J Hypertens. 2010; 23(1):97-103.

9. Ried K, Sullivan T, Fakler P, et al. BMC Med. 2010; 8:39.

10. Tokede OA, Gaziano JM, Djoussé L. Eur J Clin Nutr. 2011; 65(8):879-86.

11. Jia L, Liu X, Bai YY, et al. Am J Clin Nutr. 2010; 92(1):218-25.

12. Scholey A, Owen L. Nutr Rev. 2013; 71(10):665-81.

13. Lippi G, Mattiuzzi C, Cervellin G. Acta Biomed. 2014; 85:216-21.

14. Caperton C, Block S, Viera M, et al. J Clin Aesthet Dermatol. 2014; 7:19-23.

15. Delost GR, Delost ME, Lloyd J. J Am Acad Dermatol. 2016; 75:220-2.

16. Gasser CE, Mensah FK, Russell M, et al. Am J Clin Nutr. 2016; 103:1344-56.

Authors do not have any conflicts of interest to declare.