Researchers at Loma Linda University Adventist Health Sciences Center in Southern California studied how consumption of dark chocolate with a high concentration of cacao -- at least 70 percent, with the rest organic cane sugar -- has positive effects. The two studies were presented Tuesday at the Experimental Biology 2018 annual meeting in San Diego.
In the past, research has shown that cacao is a major source of flavonoids. Because they are extremely potent antioxidants and anti-inflammatory agents, flavonoids benefit brain and cardiovascular health, the researchers said.
"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. Lee S. Berk, associate dean of research affairs at Loma Linda and principal investigator on both studies, said in a press release. "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."
He noted the higher the concentration of cacao, the more positive the impact on cognition, memory, mood, immunity and other beneficial effects.
One study was how dark chocolate affects human gene expression, including immune response, neural signaling and sensory perception.
The other study examined how cacao enhances neuroplasticity for behavioral and brain health benefits. They recorded the electroencephalography, or EEG, response to consuming 48 grams of dark chocolate after a 30 minute and two hours. They noted beneficial gamma frequency, as well, during the EEGs.
Beck said additional research in a large study is needed to determine the significance of these effects for immune cells and the brain. They also want to study the cause-and-effect brain-behavior relationship with cacao at a high concentration.
In 2017, researchers reported that consuming moderate amounts of dark chocolate lowered the risk of atrial fibrillation, or AF, a common type of irregular heartbeat. Researchers at Harvard School of Public Health and in Denmark studied 55,502 men and women who participated in the Danish Diet, Cancer and Health Study, which recruited participants from December 1993 to May 1997.
In 2014, research also concluded that dark chocolate helps loosen up stiff arteries and prevents white blood cells from sticking to thickening artery walls -- two primary causes of atherosclerosis. For that study, researchers in The Netherlands monitored 44 middle-aged, overweight men who ate 70 grams of dark chocolate per day over two to four weeks.