The health benefits of dark chocolate are well known, the cacao within it being a bountiful source of antioxidants that can protect against aging and disease. Two small new studies have sought to build on this knowledge by exploring how particular concentrations of cacao can boost cognitive function along with endocrine and cardiovascular health, finding that the darker the chocolate the brighter the results.

The study was carried out by researchers from California's Loma Linda University, and is claimed to be the first to look at the immediate health benefits of highly concentrated cacao when consumed in typical amounts.

"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," said Lee S. Berk, researcher in psychoneuroimmunology and food science at Loma Linda University and principal investigator on both studies. "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 first of the studies involved five subjects who were made to avoid all other high-antioxidant foods for 48 hours beforehand. They were then fed 48 g (1.7 oz) of dark chocolate heavy in cacao – a 70 percent concentration – daily over a period of eight days.

Their immune response and gene expression were then analyzed through blood samples and total RNA assays, both in the hours following and one week later, with the researchers keeping an eye out for pro- and anti-inflammatory cytokines. The researchers observed heightened T cell activation, cellular immune response and stimulation of genes associated with neural signaling and sensory perception, which are in turn linked with hyperplasticity – a state where the brain is believed to be more receptive to muscle memory and learning new skills.

The second study saw five healthy subjects again given 48 g of 70 percent cacao dark chocolate. Their brain activity was then monitored by placing electrodes at nine different scalp locations and measuring the electroencephalography response 30 minutes and 120 minutes after consumption. The team observed heightened activity and neuroplasticity in regions associated with behavioral and brain health.

"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," says Berk.

From here, the team plans to carry out further studies involving larger groups of participants to learn more about how the high concentrations of cacao play into brain-behaviour.

The two studies were published in the FASEB Journal here and here.