Dark chocolate, the bitter taste is a favorite among lovers of chocolate, tea and coffee. In fact, some of the finest gourmet chocolates worldwide are made primarily from some percentage of unsweetened cacao. But could dark chocolate, in addition to being a tasty treat also serve as a neuroprotective and even cognitive booster?
According to research shared at examine.com, dark chocolate polyphenols have a notable and well-documented effect on blood flow, and a minor but well-documented effect on LDL cholesterol [c]. There is, however, no effect on blood pressure, heart rate, or HDL cholesterol.
Overall, arterial stiffness and blood viscosity may also be reduced. Antioxidant benefits are noted on the mitrochondria (another important part of our energy metabolism). It appears dark chocolate maybe possibly beneficial in numerous disorders including; diabetes, anxiety, dementia.
Supplementing with an extract of cocoa or adding dark chocolate to your diet has been linked to better blood flow and improved insulin sensitivity. Preliminary research suggests (-)-epicatechin may also provide benefits for longevity by increasing blood flow and oxygenation in the brain. Though this effect has not been linked specifically to improved memory or cognitive performance, it may play a protective role especially as aging progresses. Some evidence also suggests (-)-epicatechin can help mitigate the effects of impaired mitochondria.
When (-)-epicatechin is absorbed by the body, it activates an insulin signaling pathway, which causes a mild increase in glucose uptake. Increased glucose uptake means the body is able to take in sugar from the blood more effectively. Supplementing with (-)-epicatechin may also result in an increase in the production of Nitric Oxide, a molecule that widens blood vessels and improves blood flow.
A typical dose of unrefined dark chocolate dilates blood vessels an average of 3% within 25 minutes. This may not sound significant, but due to “flow” physics, the blood flow is actually increased four times as much, or around 12%.
Epicatechin enhances brain blood vessel development, especially after stroke, cancer, or injury. It appears to improve spatial memory, working memory, learning and retention, reduces stress- and depression-related behaviors, and other psychiatric symptoms, probably by modulation of BDNF, dopamine, serotonin, and glutamate:
Epicatechin is also found in green tea, and is heavily studied and highly-regarded. It increases hippocampal BDNF (Brain derived neurotrophic factor) and monoamine levels, improves spatial memory and neurogenesis (new nerve growth), and reduces anxiety- and depression-related behaviors. Among green tea polyphenols, it has received even more attention than the more abundant and well-known EGCG. It appears to be more potent than EGCG (active at lower levels), and to possess a spectrum of effects as interesting and broad, if not broader, than EGCG. Though EGCG has received most of the media attention, epicatechin and catechin are making headlines and rounds in the supplement community.
A preliminary study examining the “follistatin to myostatin ratio” (exposed on examine.com [i]) suggests a role for epicatechin in bodybuilding, muscle growth, and frailty in the elderly. Further studies are needed to determine the level of significance of this effect; as EGCG is known to inhibit testosterone production. It is possible that green tea extract or Japanese green tea consumption may not be ideal for muscular health. Again further studies are needed to draw firm conclusions.
Epicatechin [d], and proanthocyanidins (both found in chocolate) modulate insulin resistance by reducing oxidative stress and endoplasmic stress. Useful in diabetes, they may have utility in other common diseases, where mitochondrial and endoplasmic stress play pivotal and dramatic roles. In regards to mitochondria, many studies exist on both substances, mostly reporting positive effects [f]:
“… both (−)-epicatechin and procyanidin B2 directly influenced mitochondrial functions and the observed effects could help to explain cardiometabolic risk reduction ascribed to the consumption of modest amounts of cocoa products.”
In terms of reducing inflammation (in models of altered glucose metabolism), catechin may be more effective than epicatechin and procyanidin B2, although since both catechin and epicatechin occur in cocoa products, this is not an issue [h]:
“We found that both catechin and epicatechin had a beneficial effect on plasma homocysteine levels and endothelial dysfunction biomarker expression; however, only catechin had a beneficial effect on pro-inflammatory cytokine expression.”
This compound is also found in blueberries (one of the most brain healthy of the superfruits), and is generally regarded as highly protective. It’s also healthy as a longevity agent, according to longitudinal studies which report:
“Further analysis showed that compared to consistently infrequent tea drinkers, subjects who reported frequent tea drinking at both age 60 and at baseline survey had a 10% reduction in mortality…”
The jury is still out as far as agreement among the experts as far as the degree to which catechin is the main contributor to longevity, and the degree to which other polyphenols, theanine, and caffeine contribute to longevity. EGCG also makes contributions to longevity (at least in insect models, by reducing stress; this same mechanism may help humans, because the elderly have a reduced capacity for handling stress).
Theanine has potential life-enhancing properties in humans though has currently only been established in an insect model:
“We here aimed to test whether pharmaceutical concentrations of L-theanine, a putative anti-cancer, anti-obesity, blood pressure-lowering, and neuroprotective compound contained in green tea (Camellia sinensis), are capable of extending lifespan in a nematodal model organism for aging processes, the roundworm Caenorhabditis elegans… L-theanine extends C. elegans lifespan when applied at concentrations of 100 nM, as well as 1 and 10 micromolar.”
And caffeine as well (again by increasing tolerance to stress, which plays a role in many neurodegenerative and chronic diseases of the elderly):
“… chronic caffeine consumption may generally enhance resistance to proteotoxic stress and may be relevant to assessing risk and developing treatments for human diseases like Alzheimer’s and Huntington’s disease. Future work addressing the relevant targets of caffeine in models of aging and healthspan will help to clarify the underlying mechanisms and potentially identify new molecular targets for disease intervention.”
Other Conditions (Depression, Anxiety)
As already mentioned in our article on “Ginkgo, Ginseng, and Green Tea”, compounds in chocolate are great for memory, even in young, healthy volunteers. They also display benefits for attention (again already covered) and mood.
The evidence for depression is strongest and most coherent, while that for anxiety and more serious conditions is mixed. Epicatechin appears able to mitigate and cause anxiety, it mitigates through hippocampal BDNF and serotonin [j], and causes through up-regulating GluR2 [k].
According to examine.com, 60g of 50% dark chocolate is sufficient, or 150mg epicatechin. Some studies report a “bell-curve” or “biphasic trend” to epicatechin’s effects, with above 200mg reporting less effect than 50mg. So in this case, it is important to not fall into the trap of always thinking more is better. This is an especially important factor to consider if you both eat chocolate and drink tea, as contributions from both add up to the daily total.
But other sources have chimed in with concerns that to improve taste, certain processors of chocolate make it an established manufacturing protocol to remove much, if not all, of the “bitters” from their dark chocolate. Therefore product choice is an important factor in deciding quality. And it hardly needs stating that milk and white chocolate provide only negligible quantities of epicatechin and catechin.
Among dark chocolates, a bitter product is generally better, and without laboratory tests, a consumer may fall back on his own tastes to decide on the quality of the product. Indicators of potentially bad quality include chocolate advertised as 72% which is sweet, has a flat or Earthy taste, and is either too brittle and waxy or too soft and malleable. Generally the product more pleasing to the tastebuds is better for the brain.
Due to its phenylethylamine content, excessive chocolate consumption may reduce survival of dopaminergic neurons [a]. This is not a problem with tea, which does not contain PEA. It also appears compounds in chocolate (epicatechin and catechin) and tea (EGCG, theanine) are able to mitigate, prevent, or even reverse PEA-induced dopaminergic degeneration.
But Jeanne Calment, the only person to reach age 122, swore by olive oil and chocolate. The olive oil she rubbed restlessly onto her entire skin, the chocolate she ate daily in amounts totaling two kilos weekly (imagine four Trader Joe’s Pound Plus Bars every week!).
Going just by her data point as a case study, and the fact that she remained sharp and cognizant until her death, it would seem dark chocolate is fine to indulge in. But she could always have carried a beneficial mutation, or other disposition against dopaminergic degeneration.
So it remains to see whether large consumption of chocolate is good, bad, or mostly neutral to cognitive health. On the whole, with regard to any supplement, or in all things, moderation is recommended.
[a] Contribution of ß-phenethylamine, a component of chocolate and wine, to dopaminergic neurodegeneration: implications for the pathogenesis of Parkinson’s disease.
[b] Dark Chocolate’s Surprising Effects on Eyes.