Our brains inevitably shrink in size as we age, but several factors can speed up this process, according to researchers at the University of California, Davis.
Recent studies have shown that only the human brain shrinks in size. We may have to pay to live longer, but scientists believe there are several things that contribute to brain size shrinking.
Chronic back pain
Chronic back pain can cause an 11 percent loss in brain volume. In 2004, researchers at Northwestern University identified a link between chronic back pain and gray matter thinning. In other words, the researchers explained that the loss of brain density is related to the duration of pain, implying that for every year of chronic pain, there is 1.3 cc of gray matter.
Alcohol can cause the brain to shrink. In 2008, researchers found that the hippocampus, the region of the brain responsible for memory, spatial tasks, and other functions, was 10 percent smaller in those who drank and still preferred wine over beer.
Internet addiction can also cause the brain to shrink. In the June issue of Scientific American, a Chinese study was published in which 18 students with Internet addiction underwent brain scans. It was found that in several areas of the brain, these students experienced a reduction in volume from 10 to 20 percent.
Lack of sleep
In 2010, a study found a link between chronic sleep deprivation and loss of brain density. Brain scans have shown that chronic insomnia can reduce gray matter density in areas that regulate the brain's ability to make decisions and rest. However, there is one caveat: Researchers cannot yet determine for sure whether insomnia precedes gray matter loss or vice versa.
One controversial 2008 study found that malnutrition, especially when vitamin B12 is lacking, which comes from meat and milk, does not work well for the brain. The researchers concluded that those on a meat-free diet were 6 times more likely to have brain contractions, as the main sources of vitamin B12 are meat, liver, fish and milk.
Lack of sunlight
The 2007 study was conducted in mice, but as with many studies, the results apply to humans as well. Ohio State University researchers argue that if the human brain also shrinks in size without exposure to sunlight, this could be evidence of the depression people experience when daylight levels are reduced.
This can be a very sensitive, controversial issue for advocates of the medical use of marijuana, but it's worth noting that a 2008 study that conducted brain scans found that the hippocampus and amygdala were smaller in those who regularly smoked marijuana, and namely, at least 5 marijuana cigarettes a day.
When this research surfaced, it played into the hands of some religious skeptics. However, the researchers explained that accelerated brain shrinkage was observed in both those who went through a breakthrough religious experience and those who did not belong to any religious group. It's all about the stress experienced by a person belonging to a religious minority.