Cocoa, Chocolate And Health

Chunks of dark chocolate piled up on a white background. An example of confectionary.
Dark chocolate is extremely healthy. Image by adamr, c/o FreeDigitalPhotos.

It’s always pleasing to read in the press about all the benefits of eating chocolate (usually dark chocolate by the way) or drinking cocoa. Yet again, another bar found its way into our body following a long walk through the glades in the Forest of Dean and we welcomed the soothing effects to counter the ache in our muscles.

Certainly, it’s worth commenting on what scientific information is out there to support these benefits. The amount of research into the health benefits of cocoa and chocolate generally has accelerated in the last twenty years (Cooper et al., 2008). There is a continual ‘feed’ linking chocolate in the diet mainly to a reduction in cardiovascular risks such as high blood pressure (hypertension) and heart disease. 

The latest studies also show that consuming dark chocolate reduces stress and inflammation. It can also improve memory, our immunity and even mood. One benefit is linked to the key ingredient in dark chocolate: cocoa.

There are many benefits it seems to ingesting cocoa, because it contains flavonoids and polyphenols. These are the key groups of compounds which are thought now to be closely associated with chocolate’s benefits. Much of the research concerns the consumption of dark chocolate but we must not forget other forms of chocolate such as milk or white which by association and through the presence of cocoa also have these beneficial compounds. 

As this post proceeds, I intend to add more data based on the many and varied studies associated with the benefits of cocoa and chocolate.

The Nutritional Composition Of Dark Chocolate

The vitamin and mineral profile of a dark chocolate bar containing 85% cacao solids which is a typical plain and dark chocolate bar sold by retailers (see nutritiondata.self.com);

 Recommended Daily Allowance
Per Ounce
 Recommended Daily Allowance
Per 100g
Minerals  
Calcium – 3% RDA Calcium – 11% RDA
Magnesium – 30% RDA Magnesium – 106% RDA
Potassium – 10% RDA Potassium – 37% RDA
Manganese – 46% RDA Manganese – 163% RDA 
Copper – 45% RDA Copper – 160% RDA
Iron – 19% RDA Iron – 65% RDA
Phosphorus – 18% RDA Phosphorus – 62% RDA
Zinc – 11% RDA Zinc – 38% RDA
Selenium – 5% RDA Selenium – 17% RDA
Vitamins  
Riboflavin (B2) – 3% RDA Riboflavin (B2) – 14% RDA
Niacin (B3) – 3% RDA Niacin (B3) – 9% RDA

 

By Boians Cho Joo Jung. Courtesy of Freedigitalphotos.net
A chocolate splash. Photo by Boians Cho Joo Jung.
Courtesy of Freedigitalphotos.net

The most recent exciting news about chocolate comes from a meta-analysis (a review on the current statistical evidence from a number of research papers), which states that chocolate is essentially good for you (Buitrago-Lopez et al., 2011) !

In particular, reducing cardiovascular problems, and improving skin and brain health. The excitement prompts a number of pithy provisos. There are better alternatives to protection from cardiovascular disease (CVD). Chocolate bars contain fats and sugars which could lead to obesity and type 2 diabetes, but the investigation into chocolate derived polyphenols is beginning to reveal some useful nutritional benefits. It might simply be because of the reduction in stress or encouraging occasions in marketing terms to promote relaxation and pleasure.

Some of the thinking has been clouded by the presence of sugar in chocolate. It was thought sugar had profound effect on our neurological functions. The more sugar we consumed the happer we were.

Epicatechin and other proanthocyanidins are found in a number of plant foods but also chocolate and is believed to help reduce CVD by its antioxidant benefit or reduce inflammation. Indeed, the quantity of such compounds is higher than red wine and some fruit (Vinson et al. 1999) on a weight basis.

Let’s look in more detail at the benefits:-

Lowering Cholesterol

SA large number of studies involving chocolate and cocoa focus on reducing the risk factors associated with heart disease. One of the key ones is influencing the levels of HDL (high density lipoprotein) and LDL (low density lipoprotein) cholesterol.

One well controlled study looked at how cocoa powder significantly decreased oxidized LDL in the blood of a population of men. It also increased the levels of HDL and lowered the total LDL of those men who presented with high cholesterol levels (Baba et al., 2007). 

Studies show that moderate amounts of dark chocolate lower low density lipoprotein -cholesterol (LDL-cholesterol). This is the bad cholesterol simply put and also raises the levels of high-density lipoprotein cholesterol (HDL-cholesterol). The improvement in ratios of these two types of cholesterol is associated with a reduction in the risk of cardiovascular disease and stroke. We delve into the benefits a bit more fully in the next section.

Heart (Cardiovascular) Health Benefits

The evidence for chocolate benefits is not always clear, unfortunately. There has been a great welter of research on chocolate, cocoa and other related products and formats which has been built mainly on the properties of the flavan-3-ols and catechins (Engler & Engler, 2006; Corti, et al., 2009; Desch et al., 2010).

It was reported back in 2002, that consuming a dark chocolate bar or a cocoa powder drink reduced low density lipoprotein oxidation but not a number of other markers of inflammation such as C-reactive protein (CRP) (Mathur et al., 2002). One human intervention study looked at the feeding of plain, dark chocolate to 12 healthy volunteers, which increased both their total antioxidant capacity and epicatechin content in blood plasma (Serafini et al., 2003). They conjectured that twice as much milk chocolate might need to be eaten as plain chocolate because of their relative antioxidant contents, and that milk itself could inhibit in vivo antioxidant activity and absorption into the blood of epicatechin. Their valid point was that other dietary ingredients could impair absorption although it would be worth identifying factors which significantly improved uptake.

Eating chocolate ! Photo by imagerymajestic. Courtesy: FreeDigitalPhotos.net
Eating chocolate ! Photo by imagerymajestic. Courtesy: FreeDigitalPhotos.net

A larger study compared consumption of 75 g daily of white, dark and dark chocolate enriched with cocoa powder (Mursu et al., 2004) in 45 subjects. They showed that dark chocolate promoted a rise in high density lipid (HDL) cholesterol and a reduction in a marker for lipid peroxidation. They didn’t however see changes in other important markers such as antioxidant capacity in blood plasma. An elegant study demonstrated dark chocolate consumption reduced blood pressure (hypertension), insulin resistance and endothelium-dependent vasodilation (Grassi et al., 2005).

The reduction of blood pressure was picked up in an epidemiological study of 470 elderly men over 15 years as part of the Zutphen Elderly Study (Buijsse et al., 2006) which estimated dietary intake of cocoa but which also considered other cofactors such as reduced calorie intake, lower BMI (body mass index) and higher physical activity. They reasoned that a cocoa intake of 4.2g (ca. 10 g dark chocolate/day) was just enough to significantly reduce blood pressure. A study conducted by the University Hospital of Cologne demonstrated that with a consumption level of 6.3 g (30 kcal)/day of dark chocolate for a year in a randomised controlled study showed similar reductive effects on blood pressure especially in those with what is termed above-optimal levels of blood pressure (Taubert et al., 2007a). Subsequently, the group from Cologne wrote a meta-analysis of research into cocoa, and effectively confirmed its potency in the reduction of hypertension (Taubert et al., 2007b).

Stroke – A Reduction In Risk

A recent study from the Karolinska Institute, Sweden claims to have demonstrated that regular ingestion of chocolate can decrease the risk of stroke especially in men. This complements similar findings for women in a similar study (Larsson et al., 2011) .   In this decade-long study assessing the dietary habits of 37,000 men, it appears that a group which ate the most chocolate had reduced their risk of stroke by 17% compared to a group who did not eat it.  The study group aged from 50 to 75 kept a diary on their food intake. The top quartile (25%) in terms of chocolate intake had a lower rate of stroke compared to the quartile eating the least chocolate.  Other factors needed to be taken into consideration, so other elements of diet, weight, smoking etc. were considered. Even on this basis, there was a 17% lower risk of stroke (Larsson, S.C. et al., 2012)

Inflammation

Cocoa also has a possible benefit in reducing joint inflammation when it was shown in a rat study to reduce markers associated with arthritis. In the investigation, rats were fed diets enriched with 5 or 10% cocoa and then adjuvant arthritis was induced by injection of a dead Mycobacterium suspension into their hind paws (plethysmometry). Although there was no statistically significant reduction in the swelling of the inflamed hind paws, there was a tendency to do so. What was noticeable however, was a reduction in certain biomarkers such as blood levels of T-helper (TH) lymphocytes and prostaglandin E2 which is generated during inflammation (Ramos-Romero et al., 2011). A human study has also demonstrated that consumption of 40 g of polyphenol-rich cocoa powder led to a significant reduction in the inflammation marker protein NF-kappaB (Vasquez-Agell et al., 2011).

Dark Chocolate And Cocoa Helps Improve Our Mood

The taste of chocolate is probably adored by everybody, not just for its silkiness and warmth of flavour, but also with enjoyment. We know chocolate contains interesting compounds classed as methylxanthines such as theobromine as well as small amounts of caffeine.

Theobromine is very interesting ! It affects the Central Nervous System but unlike caffeine helps us to relax, producing a mildy soporific and contented effect. It also appears to heighten our perceptions, making us more alert but not agitated. Caffeine is known for mobilising blood lipids for energy consumption whereas theobromine does not create such an impact and the combination helpfully reduces the less appealing aspects of caffeine (Martínez-Pinilla et al., 2015).

From a biochemical standpoint, caffeine and theobromine block adenosine receptors and inhibit phosphodiesterases. The extent of this inhibition by theobromine has produced some interesting effects. The interference with the action of other neurotransmitters especially in the brain is important. Serotonin, which is a recognised mood improver in the brain increases in concentration because chocolate contains this compound. It also contains significant quantities of the amino-acid tyrosine which is often used as a supplement by body builders and serious athletes. Tyrosine is also a major component of neuropteptides and can be converted to dopamine like compounds which raise mood levels (Nehlig, 2013).

One of the most interesting benefits chocolate has is helping to alleviate the effects of various mood and mental –health related issues such as depression. It’s not entirely clear yet how this benefit will be exploited but there are exciting associations with reducing the impact of Parkinson’s and Alzheimer’s.

Curbs Cravings

Research has shown that dark chocolate reduce our craving for food. It has a high satiety value which means it makes you feel full for a longer time. The reason: cocoa is full of monounsaturated fatty acids (MUFAs) and these boost metabolism and burn fat.

Keeps Weight In Check

If you can control your food hunger and cravings then you wont binge. Dark chocolate is used as part of weight loss plans because of this effect. In 2012, the University of California looked at the diets of 1,000 US citizens. Those who ate dark chocolate just a few times every week were on average a bit slimmer than those just eating it from time to time or occasionally. Whilst dark chocolate has many calories its ingredients helped to promote weight loss rather than  weight gain. The interpretation is still ongoing.

Dark Chocolate And Gene Expression

A research study conducted as the Loma Linda University in California, USA found that chocolate influenced levels of gene expression.

The findings were presented at the Experimental Biology 2018 meeting in San Diego, USA.

Lead investigator Lee S. Berk reported that:-

“This is the first time that we have looked at the impact of large amounts of cacao in doses as small as a regular-sized chocolate bar in humans over short or long periods of time, and are encouraged by the findings.”

The reason for the excitement was that if dark chocolate consumption affects gene expression it is implied to affect the regulation of biochemical activities like cellular immune response, neural signalling, and sensory perception. The scientists reported that chocolate might influence a phenomenon involved in brain hyperplasticity. Cacao consumption up-regulates multiple intracellular signalling pathways involved in T-cell activation, cellular immune response and genes involved in neural signalling and sensory perception. Brain hyperplasticity is implicated in activities such as neural signalling and sensory perception.

To understand the role of sensory, the team assessed the electroencephalography (EEG) response to consuming 48 g of dark chocolate (70 percent cacao) after an acute period of time (30 minutes) and after a chronic period of time (120 minutes), on modulating brain frequencies between the range of 0-40Hz, specifically beneficial gamma frequency range of 25-40Hz.

Berk also commented:- “These studies show us that higher the concentration of cacao, the more positive the impact on cognition, memory, mood, immunity and other beneficial effects.”

Further investigation is required before more comprehensive conclusions can be drawn. They want to look at the affect on immune cells and the brain in a larger study population.

Issues With Eating Dark Chocolate

Are there negatives to eating chocolate bars ? Yes, weight gain and diabetes would be two issues because of calorie content and the challenge made to our blood sugar levels. Many health professionals caution on eating chocolate to excess in the belief that it will actively reduce risks to heart health and rightly so – a balanced diet is very important. It’s probably for another post because this is about the benefits of chocolate, especially the componentry in it. I’d be interested to hear from others about the concerns on the more negative aspects of eating chocolate.  . 

Summary

Although this post is by no means complete and will be added to with more rigorous assessment, I have a fascinating geographical postscript. In Panama, the Kuna Indians living on the San Blas Islands have a low prevalence of cardiovascular type diseases, low type 2 diabetes and show little age-related increases in blood pressure. They are habitual drinkers of their own cocoa beverage. They lose this benefit when they move away to other parts of Panama or change their diet because they do not take their cocoa drink (McCullough et al., 2006).

References.

Baba, S., Natsume, M., Yasuda, A., Nakamura, Y., Tamura, T., Osakabe, N., … & Kondo, K. (2007). Plasma LDL and HDL cholesterol and oxidized LDL concentrations are altered in normo-and hypercholesterolemic humans after intake of different levels of cocoa powder. The Journal of Nutrition137(6), pp. 1436-1441 (Article).

Buijsse, B., Feskens, E.J.M., Kok, F.J., Kromhout, D.(2006) Cocoa intake, blood pressure, and cardiovascular mortality: the Zutphen Elderly Study. Arch. Intern. Med. 166 pp. 411–7

Buijsse, B., Weikert, C., Drogan, D., Bergmann, M., & Boeing, H. (2010). Chocolate consumption in relation to blood pressure and risk of cardiovascular disease in German adults. European Heart Journal, 31(13), pp.1616-1623 (Article)
Buitrago-Lopez, A., Sanderson, J., Johnson, L., Warnakula, S., Wood, A., Di Angelantonio, E. Franco, O.H. (2011) Brit. Med. J 343: d4488 ( http://doi: 10.1136/bmj.d4488)
Cooper, K. A., Donovan, J. L., Waterhouse, A. L., & Williamson, G. (2008). Cocoa and health: a decade of research. British Journal of Nutrition, 99(1), pp. 1-11 (Article)

Corti, R., Flammer A.J., Hollenberg N.K., Luscher T.F. (2009) Cocoa and cardiovascular health. Circulation 119  pp. 1433-1441 (Article)
Desch, S., Schmidt J., Kobler D.; et al. (2010) Effect of cocoa products on blood pressure: systematic review and meta-analysis. Am J Hypertens. 23 pp. 97-103
Engler, M.B., Engler M.M. (2006) The emerging role of flavonoid-rich cocoa and chocolate in cardiovascular health and disease. Nutr. Rev. 64 pp. 109-118
Grassi, D, Necozione S, Lippi C, et al.(2005) Cocoa reduces blood pressure and insulin resistance and improves endothelium-dependent vasodilation in hypertensives. Hypertension. 46, pp. 398-405

Hooper, L., Kay, C., Abdelhamid, A., Kroon, P. A., Cohn, J. S., Rimm, E. B., & Cassidy, A. (2012). Effects of chocolate, cocoa, and flavan-3-ols on cardiovascular health: a systematic review and meta-analysis of randomized trials. The American Journal of Clinical Nutrition95(3), pp. 740-751 (Article).
Larsson, S.C., Virtamo, J. Wolk, A. (2011) Chocolate consumption and risk of stroke in women. J Amer, Coll. Cardiol. 58 (17) pp. 1828-9
_________________________(2012) Chocolate consumption and risk of stroke. A prospective cohort of men and meta-analysis. Neurology  79 pp. 1223-1229

Martínez-Pinilla, E., Oñatibia-Astibia. A., Franco. R. (2015) The relevance of theobromine for the beneficial effects of cocoa consumption. Frontiers in Pharmacology. 6:30. doi:10.3389/fphar.2015.00030 (Article).
Mathur, S., Devaraj, S., Grundy, S.M., Jialal, I. (2002) Cocoa products decrease low density lipoprotein oxidative susceptibility but do not affect biomarkers of inflammation in humans. J. Nutr. 132, pp. 3663–3667.
McCullough, M.L., Chevaux, K., Jackson, L., Preston, M., Martinez, G., Schmitz, H.H., Coletti, C., Campos, H., Hollenberg, N.K. (2006) Hypertension, the Kuna, and the epidemiology of flavanols. J. Cardiovasc Pharmacol. 47 S103–9
Mursu, J., Voutilainen, S., Nurmi, T., Rissanen, T.H., Virtanen, J.K., Kaikkonen, J., Nyyssonen, K., Salonen, J.T. (2004) Dark chocolate consumption increases HDL cholesterol concentration and chocolate fatty acids may inhibit lipid peroxidation in healthy humans. Free Radic Biol Med. 37 pp. 1351–135

Nehlig, A. (2013) The neuroprotective effects of cocoa flavanol and its influence on cognitive performance. British Journal of Clinical Pharmacology. 75(3) pp. 716-727. doi:10.1111/j.1365-2125.2012.04378.x. (Article). 

References R-Z

Ramos-Romero, S., Perez-Cano, F.J., Castellote, C., Castell, M., Franch, A. (2011) Effect of cocoa-enriched diets on lymphocytes involved in adjuvant arthritis in rats. Br. J. Nutr. doi: 10.1017/S0007114511003035
Serafini, M.; Bugianesi, R.; Maiani, G.; Valtuena, S.; De Santis, S.; Crozier, A. (2003) Plasma antioxidants from chocolate. Nature 424, p.1013.
Taubert, D., Roesen, R., Lehmann, C., Jung, N., Schömig, E. (2007a) Effects of low habitual cocoa intake on blood pressure and bioactive nitric oxide. JAMA. 298 pp. 49–60
_______., _______., Schömig, E. (2007b) Effect of cocoa and tea intake on blood pressure: A meta-analysis. Archive Int. Medicine 167 (7) pp. 626-634
Vazquez-Agell, M., Urpi-Sardi, M., Sacanella, E., Camino-Lopez, S. et al., (2011) Cocoa consumption reduces NF-kappaB activation in peripheral blood mononuclear cells in humans. Nutr. Metab. Cardiovasc. Disease doi: 10.1016/j.numecd.2011.03.015
Vinson, J. A., Jang, J., Dabbagh, Y. A., Serry, M. M. & Cai, S. (1995) Plant polyphenols exhibit lipoprotein-bound antioxidant activity using an in vitro oxidation model for heart disease. J. Agric. Food Chem. 43 pp. 2798-2799.

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