Cocoa and chocolate products have been used as medicine in many cultures for centuries for their health benefits. Many of these benefits are from flavonoids, which act as antioxidants, help lower blood pressure, and balance certain hormones in the body.﻿﻿ Dark chocolate contains a large number of antioxidants, far more than milk or white chocolate, which do not confer the same health benefits.

Health Benefits of Dark Chocolate

Here's what research says about the potential health benefits of eating dark chocolate.

Cardiovascular Benefits

According to a 2012 review, there have been at least 42 short-term clinical studies that found positive effects of cocoa intake on factors related to cardiovascular disease, including improvements in flow-mediated dilatation, reductions in diastolic blood pressure and mean arterial pressure, and small effects on LDL and HDL cholesterol.﻿﻿

These studies involved varying doses of cocoa at least once per day. The review draws on in vitro studies supporting that flavanols could be the reason for these improvements, because of their effects on endothelial and platelet function, inflammation, glucose transport, and angiotensin-converting enzyme activity, more clinical research is needed to confirm these effects.

A 2017 review of the effects of cocoa flavanols on blood pressure did not find a significant difference betweeen flavanol-free chocolate and chocolate containing 1218 mg of flavanols on lowered blood pressure.﻿﻿

A 2009 population-based study followed 1169 non-diabetic patients that had been hospitalized after an acute myocardial infarction and found that self-reported chocolate consumption twice a week correlated with a 66 percent reduction in cardiac mortality over the next 8 years as compared with those who did not report eating chocolate.﻿﻿

Cognition, Stress, and Mood

Most people who eat chocolate do so for the benefits doing so has on their mood. According to a 2013 review, it is unclear with the effects of chocolate on mood are due to the pharmacological effects of such constituents as polyphenols or whether they have to do with the interplay between pleasurable sensory experience and reward.﻿﻿

The effects of chocolate on mood could be due to its effects on endorphins and serotonin, or it could be due to the caffeine and theobromine stimulant constituents. Three of the eight studies which met the criteria for inclusion in the review indicated some sort of improved cognition. Two others didn't indicate any benefits but did demonstrate significant changes in patterns of brain activation.

One study found that men who took 50g of flavanol-rich dark chocolate were protected from the physical effects of psychosocial stress.﻿﻿ A 2013 in vitro study also found that cocoa polyphenols triggered neuroprotective effects in an Alzheimer's disease model via a BDNF signaling pathway, which has also been implicated in research related to posttraumatic stress and fear extinction learning.﻿﻿

Possible Side Effects of Eating Chocolate

Consuming cocoa can lead to digestive issues, skin reactions, constipation, and migraine headaches in some people.﻿﻿ There are also side effects related to the caffeine, including increased anxiety, loss of sleep, faster heartbeat, and increased frequency of urination.

High doses of caffeine during pregnancy are associated with low birth weight and premature delivery,﻿﻿ however low-dose caffeine and the other ingredients of cocoa supplements are generally pretty safe. One study even found positive effects on mood for mother and baby.﻿﻿ It's best to speak with your doctor and make sure the product you choose is safe for you.

Interactions

Cocoa may interfere with the effects of adenosine and dipyridamole﻿﻿ and should not be taken 24 hours before a cardiac stress test.

Estrogens can slow down the metabolism of caffeine and may increase the likelihood of side effects from cocoa.﻿﻿

The caffeine in cocoa increases lithium metabolism﻿﻿ and so consistency in the amount of cocoa taken each day is important to limit lithium side effects.

Taking caffeine along with asthma medications or depression medication﻿﻿ can lead to overstimulation.

Cocoa can raise blood sugar and should be taken with caution by those with diabetes.﻿﻿

Dosage and Preparation

50 to 200 mg of flavanols per day have been shown to be enough to yield positive results,﻿﻿ however many studies showing a high degree of benefit have used dosages as high as 400 and 500 mg. The bioavailability and activity of cocoa flavanols need more research and improved methods for assessing the quantity and success of absorption by the body in various products. The flavanol content of supplements and cocoa products varies a lot and many do not list the flavanol content on the label for this reason.

It is generally understood that a whole foods approach to nutrition is best because the complexities of the way constituents interact to confer the health benefits of a food are not entirely known and sometimes just taking supplements does not confer the same degree of benefit. About 3 dark chocolate bars would be required however to hit the 500 mg flavanol content that can be found in some supplements, and even more milk chocolate would be needed, at which point the poor nutrient density, i.e. calorie count to nutrient content ratio, of the ingredients might outweigh the benefits.

A good approach would be to start with a low supplement dose or perhaps 1 dark chocolate bar a day and to discuss with your doctor whether raising the amount would be the most effective way to achieve the desired effects on cardiovascular and mental health.

Tips for Choosing a Cocoa Brand

Before picking a cocoa supplement brand, consult ConsumerLab.com. This resource has found that some products contain toxic heavy metals. The best scoring product was CocoaVia powder, which contains 250 mg of cocoa flavanols per serving and was not found to contain any contaminants.

This desired amount of flavanols can also be found in dark chocolate bars and other chocolate products, however, these products will also be high in calories. If you do seek out chocolate as a source of cocoa flavanols, look for pure dark chocolate or dark chocolate with nuts, orange peel or other flavorings. Avoid anything with caramel, nougat or other fillings, which nutritionally are just adding sugar and fat.