Just like the debate around coffee, dark chocolate has elicited mixed responses regarding its impact on human health. But if you would like to feel a little less guilty the next time you indulge, researchers have some good news. 

Two new studies have suggested that eating certain types of dark chocolate can reduce stress, improve mood, and have a positive effect on memory and immunity. Dr. Lee S. Berk, the lead researcher of both studies, is the associate dean of research affairs for Loma Linda’s School of Allied Health Professions in California. The findings were presented at the Experimental Biology 2018 meeting in San Diego on April 23-24.

Only certain types of dark chocolate? Which ones do they mean?

The chocolate products we consume are made from seeds that are derived from the cacao tree. The study attributed numerous health benefits to dark chocolate which contains a high concentration of cacao (at a minimum, 70 percent cacao).

Flavonoids, found in cacao, are powerful antioxidants as well as anti-inflammatory agents. According to numerous studies, they can protect the human brain and provide cardiovascular benefits.

So what sets the new research apart from previous studies?

"For years, we have looked at the influence of dark chocolate on neurological functions from the standpoint of sugar content — the more sugar, the happier we are," Dr. Berk explained. The new research suggested it's not just sugar but also cacao that plays a role in helping people reap health benefits from chocolate consumption.

"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. These studies show us that the higher the concentration of cacao, the more positive the impact on cognition, memory, mood, immunity and other beneficial effects," he added.

As per the findings of the two studies, what can people take away?

The first study, which was an experimental trial, looked at how 70 percent cacao chocolate consumption influenced gene expression in human beings. It was found that the chocolate could boost the immune system by upregulating pathways involved in T-cell activation as well as the genes involved in neural signaling and sensory perception. 

In the second study, the researchers analyzed brain activity and measured the electroencephalography (EEG) response in people who consumed 48 grams of dark chocolate containing 70 percent cacao. The results showed an "enhanced neuroplasticity for behavioral and brain benefits" which meant that it could improve memory and learning abilities.

However, this does not mean you should stock up the refrigerator with a regular supply of chocolate bars. Moderation of intake is important while also ensuring a low concentration of sugar.

"Eating excessive amounts of chocolate is not recommended because many chocolate products are high in calories from sugar and fat and could lead to weight gain and other metabolic problems," explained Dr. Elizabeth Mostofsky, instructor in the Department of Epidemiology at Harvard Chan School in Boston. "But moderate intake of chocolate with high cocoa content may be a healthy choice."