Loffredo L, Perri L, Catasca E, et al. Dark chocolate acutely improves walking autonomy in patients with peripheral artery disease. J Am Heart Assoc. 2014 Jul 2;3(4). pii: e001072.
This was a single blinded, crossover, randomized study.
This study followed 20 patients (14 males and 6 females, mean age: 69±9 y), all of whom had peripheral artery disease (PAD).
Participants were given 40 g chocolate containing either 85% cacao or 35% or less cacao.
Primary Outcome Measures
Subjects were evaluated for mean walking distance (MWD) and maximum walking time (MWT). In addition, various blood markers were measured, including epicatechin, isoprostanes, and nitric oxide‒related indices. All measures were taken at baseline as well as 2 hours after ingestion of the chocolate.
Dark chocolate intake significantly increased MWD (+11%; P<.001), MWT (+15%; P<.001), and mono-nitrogen oxides (NOx) (+57%; P<.001). It also decreased serum isoprostanes (‒23%; P=.01) and sNOX2-dp (‒37%; P<.001). No changes of the above variables were observed after milk chocolate intake. Serum epicatechin and its methylated metabolite significantly increased only after ingestion of dark chocolate.
The idea of practitioners being able to prescribe food to a patient is certainly a great concept, but this study demonstrates the importance of encouraging the consumption of high-quality dark chocolate and not just any form.
In other words, there was a significant improvement in MWD (11%) and MWT (15%), as well as multiple blood indices, in participants consuming the darker chocolate compared with those who consumed milk chocolate. In fact, none of the participants who consumed milk chocolate showed any improvement. The use of a food product with pharmacological benefits in a common condition certainly needs to be studied more. Including chocolate in the diets of people with PAD seems like a simple therapy that would have good compliance.
A number of studies have shown the benefits of dark chocolate consumption in cardiovascular disease; dark chocolate’s high level of antioxidant activity is suspected as the primary reason for its effects.1-4 Certainly, the significant increase in both MWD and MWT from such a small amount of cacao is extremely encouraging, especially considering that more concentrated extracts are available. Also, because the study did not indicate whether the chocolate source was organic, it can be surmised that organic sources, with their typically superior phytonutrient profile, could have even more potent effects on cardiovascular health.
There are upwards of 8 to 12 million people with PAD in the United States.5 A low-cost, appetizing, nonpharmaceutical treatment of PAD would certainly be of great benefit to them. Chocolate is well known to have high levels of polyphenols, which have been found to be protective against oxidative stress and certain types of cancers, as well as cardiovascular diseases.6-9 The idea of practitioners being able to prescribe food to a patient is certainly a great concept, but this study demonstrates the importance of encouraging the consumption of high-quality dark chocolate and not just any form. Further, patients need to be instructed to consume organic forms chocolate, not typical, nonorganic commercial brands. Some speculate that concentrated raw extracts of cocoa may prove to be even more effective. Considering that more than half of the population of the United States has high or high/normal blood pressure, this has huge implications. More research needs to be done to elucidate the best forms of cacao and the ideal concentration.
Of note, this study did not use a placebo, as the non-dark milk chocolate used contained as much as 35% cacao. For future studies, I would recommend including a placebo group with 0% cacao. Using such a placebo would allow researchers to observe a linear effect and better elucidate a dose-dependent response. In addition, various cocoa extracts could be used as there is evidence that raw cocoa and/or organic forms may have even greater benefits.
- Monahan KD. Effect of cocoa/chocolate ingestion on brachial artery flow-mediated dilation and its relevance to cardiovascular health and disease in humans. Arch Biochem Biophys. 2012;527(2):90-94.
- Monahan KD, Feehan RP, Kunselman AR, Preston AG, Miller DL, Lott ME. Dose-dependent increases in flow-mediated dilation following acute cocoa ingestion in healthy older adults. J Appl Physiol. 2011;111(6):1568-1574.
- Balzer J, Rassaf T, Heiss C, et al. Sustained benefits in vascular function through flavanol-containing cocoa in medicated diabetic patients a double-masked, randomized, controlled trial. J Am Coll Cardiol. 2008;51(22):2141-2149.
- Farouque HM, Leung M, Hope SA, et al. Acute and chronic effects of flavanol-rich cocoa on vascular function in subjects with coronary artery disease: a randomized double-blind placebo-controlled study. Clin Sci (Lond). 2006;111(1):71-80.
- Al Mahameed A. Peripheral arterial disease. Available at: http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/cardiology/peripheral-arterial-disease/. Accessed January 5, 2015.
- Meng CC, Jalil AM, Ismail A. Phenolic and theobromine contents of commercial dark, milk and white chocolates on the Malaysian market. Molecules. 2009;14(1):200-209.
- Andujar I, Recio MC, Giner RM, Ríos JL. Cocoa polyphenols and their potential benefits for human health. Oxid Med Cell Longev. 2012;2012:906252. Epub 2012 Oct 24.
- Stoner GD, Muhktar H. Polyphenols as cancer chemopreventive agents. J Cell Biochem Suppl. 1995;22:169-180.
- Galleano M, Oteiza PI, Fraga CG. Cocoa, chocolate and cardiovascular disease. J Cardiovasc Pharmacol. 2009;54(6):483-490.