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Caffeine May Temporarily Shrink Your Brain

Caffeine May Temporarily Shrink Your Brain

If you drink coffee or energy drinks, you may want to examine other lifestyle factors

A recent placebo-controlled study has found daily caffeine consumption can significantly reduce the volume of gray matter in the human brain. The researchers stress these findings do not imply caffeine negatively impacts the brain but instead suggest the chemical may prompt a temporary neural plasticity, or change in brain structure, that warrants further investigation.

The brain and central nervous system are largely composed of both gray and white matter. Gray matter consists of neural cell bodies and nerve synapses, while white matter is primarily the bundles and pathways that connect those neural cells.

Prior research has indicated caffeine consumption may be associated with short term reductions in gray matter volume. But other research has also suggested caffeine may confer beneficial neuroprotective effects, slowing the cognitive decline associated with diseases such as Alzheimer’s and Parkinson’s.

The focus of this new study was to specifically investigate the effects of caffeine on gray matter volume in young and healthy subjects. One compelling question the researchers wanted to clarify was whether the influence of caffeine on gray matter was a result of the drug’s effect on sleep, as it has been shown that sleep deprivation or disruption can lead to temporary reductions in gray matter.

Twenty subjects were recruited and tasked with two blinded 10-day programs. One period involved taking three tablets of caffeine each day and the other period involved placebo tablets. At the end of each program the participants' gray matter volume was measured through magnetic resonance, and slow-wave sleep activity was measured by electroencephalogram.

The results indicated significant reductions in gray matter after 10 days of caffeine. Grey matter reductions were not seen after 10 days of placebo. And even more importantly, the study found no difference in slow-wave sleep activity between the placebo and caffeine periods. This suggests the gray matter reductions detected are not related to sleep disruptions but perhaps a unique feature of caffeine.

The effect of caffeine on the brain was particularly impactful in the right medial temporal lobe. This area of the brain includes the hippocampus and is responsible for processes such as memory formation and spatial cognition.

Carolin Reichert, an author on the new study from the University of Basel, notes these caffeine-induced gray matter changes seem to recover quite quickly after caffeine consumption is ceased.

“The changes in brain morphology seem to be temporary, but systematic comparisons between coffee drinkers and those who usually consume little or no caffeine have so far been lacking," says Reichert.

Reichert is also cautious to note this study does not imply caffeine consumption damages cognitive functioning. In fact, there has been a notable volume of recent research pointing to the contrary, showing caffeine seems to be somewhat neuroprotective, slowing cognitive decline in older subjects at high risk of conditions such as Alzheimer’s and Parkinson’s.

It is hypothesized these incongruent outcomes may be due to the new research’s focus on young healthy subjects compared to prior work looking at older subjects already displaying some degree of neurodegeneration or cognitive decline.

The new study was published in the journal Cerebral Cortex.


Aside from fundamental lifestyle parameters such as adequate sleep and consistent physical activity, several nutrients have been shown to preserve brain volume and support neurological function. Chief among these dietary factors is docosahexaenoic acid (DHA). Indeed, some researchers believe that the human brain only grew to its current size after DHA rich seafood was added to the diet in significant quantities (1). DHA is one of the most prevalent building blocks in the human brain.

Several studies indicate that adequate consumption of DHA helps to preserve gray matter in the brain (2,3).

Healthy levels of DHA are also required for the following neurological activities:

  • Neuroplasticity:The brain’s ability to create and re-wire connections between neurons; especially important during learning and after injury.
  • Neurogenesis:The growth and development of neurons.
  • Neurite Outgrowth:More projections from neurons.
  • Synaptogenesis:The formation of new synapses between neurons.
  • Membrane Fluidity:Less resistance in the membrane (important for proper functioning).
  • Membrane Protein Function:A change in enzyme activities that improves the transmission of visual signals.

DHA can also increase blood flow to the brain during thinking because it decreases blood vessel constriction3 and affects gene transcription. Essentially, DHA enhances neurotransmission efficiency.

Vitamin D exhibits functional attributes that may prove neuroprotective through antioxidative mechanisms, neuronal calcium regulation, immunomodulation, enhanced nerve conduction and detoxification mechanisms. Compelling evidence supports a beneficial role for the active form of vitamin D in the developing brain as well as in adult brain function (4). 


Lifestyle factors play important roles in preserving brain health. These include sleep, exercise, and diet. Dietary factors that particularly support brain health include omega-3 fatty acids, particularly DHA, and immune modulating vitamin D.

Alaskan cod liver oil is an excellent source of both of these critical nutrients. In fact, Alaskan cod liver oil has one of the highest natural vitamin D levels of any food.

  • Harris WS, Pottala JV, Vasan RS, Larson MG, Robins SJ. Changes in erythrocyte membrane trans and marine fatty acids between 1999 and 2006 in older Americans. J Nutr 2012;142:1297-1303. [PubMed]
  • University of Pittsburgh Schools of the Health Sciences. "Omega-3 Boosts Grey Matter, May Explain Improved Moods." ScienceDaily. ScienceDaily, 7 March 2007.
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