Published on: May 2, 2018
by Women’s Brain Health Initiative:
Do you drink coffee? Or, maybe the better question is, should you drink coffee? Although the Coffee Association of Canada reports that coffee is the most popular beverage choice amongst adult Canadians over 16 (even more than tap water), many people do not know whether their coffee consumption is beneficial or harmful for their health. In fact, the health effects of coffee are quite controversial amongst the general public and health professionals alike. For years, doctors had warned their patients to avoid drinking coffee because it may increase their risk of heart disease and stunt growth. Experts also worried that coffee had damaging effects on the digestive tract, which could lead to stomach ulcers, heartburn, and other ills.
These concerns emerged from studies conducted decades ago that compared coffee drinkers to non-drinkers on a variety of health measures, including heart problems and mortality. Coffee drinkers, it seemed, were always worse off. However, those studies did not always take into account that high-risk behaviours, such as cigarette smoking and physical inactivity, tended to be more common amongst heavy coffee drinkers.
Recent research reveals that once the proper adjustments are made for confounding factors, coffee drinkers do not appear to have a higher risk for heart disease or cancer than non-drinkers. On the contrary, recent studies have shown that coffee consumption may have health benefits, including protecting against Parkinson’s disease, type 2 diabetes, and liver disease. In June 2016, the World Health Organization announced that regularly drinking coffee may reduce the risk of cancers of the liver and uterine endometrium – a reversal from the organization’s position over 25 years ago, when it cautioned that coffee was possibly carcinogenic to humans.
Interestingly, mostly because of the general public’s concerns around coffee consumption and heart disease, many people, as they age, switch from drinking regular coffee to decaf, while younger individuals (from teenagers to those in their twenties and thirties) drink regular coffee. Dr. Chuanhai Cao of the Byrd Alzheimer’s Center & Research Institute at University of South Florida recommends the exact opposite. “I encourage people 50 and older to start drinking coffee,” he says, while younger people, “if they like the smell of coffee,” should be drinking decaf. As Dr. Cao explains, this is because of coffee’s effects on the immune system and how these cohorts are consuming coffee.
Coffee Boosts Immune System
Recent research suggests that coffee’s effects can translate into immune system boosters. According to research conducted by Dr. Cao and his colleagues, published in the 2011 issue of The Journal of Alzheimer’s Disease, an unidentified component of caffeinated coffee synergizes with caffeine to greatly enhance levels of a growth factor known as granulocyte-colony stimulating factor (GCSF). This protein encourages the bone marrow to release stem cells into the bloodstream, effectively increasing functional immune cells, and to take away the harmful beta-amyloid protein – a prime suspect in Alzheimer’s disease.
In the study, increased GCSF levels as a result of caffeinated coffee intake were linked to enhanced memory performance in mice with Alzheimer’s-like symptoms. Notably, neither decaffeinated coffee nor caffeine alone had this effect. The body works together as a network – blood, brain, and the immune system – and regular coffee appears to activate “the whole system,” explains Dr. Cao. As we age, our immune system’s ability to metabolize the amyloid-beta protein decreases, and therefore it accumulates in the brain and causes “toxicity of the neurons.” By boosting immune function, “caffeine has the ability to suppress amyloid-beta production.” Caffeine easily crosses the blood-brain barrier because its molecule is so small, which is why it perks us up very quickly, but also why it has other effects on the brain itself, like amyloid-beta inhibition.
As we know, one of the biggest risk factors for Alzheimer’s disease is aging. Experts have hypothesized that as our immune systems decline with age, our susceptibility to Alzheimer’s disease and other dementias increases. Since Alzheimer’s disease likely develops for 25 to 30 years before symptoms arise, relying solely upon any kind of drug to counteract the disease will not fix the long-term problem. “Short-term something may work, but long-term, nothing works,” observes Dr. Cao. Accordingly, any kind of treatment for these brain diseases has to be able to address or activate the immune system – the body’s own protective mechanism. This immune system dynamic is why Dr. Cao says that younger people should not consume caffeinated coffee: “When you’re young, your immune system is good so you don’t need to keep boosting or activating it.”
Even though this study was conducted using mice, the scientists revealed that they have collected clinical evidence of the ability of caffeine/coffee to provide humans with protection against Alzheimer’s disease. Other studies involving human subjects have also supported the inverse relationship between caffeine consumption and reduced risk of dementia, including the results of the Canadian Study of Health and Aging, published in 2002. This study analyzed the data of 4,615 subjects (aged 65 and older) and looked at risk factors for developing Alzheimer’s disease, such as physical activity, wine consumption, and history of depression, in addition to coffee intake. More recently, research published in The Journals of Gerontology: Series A in 2016 sought to investigate the relationship between caffeine intake and incidence of cognitive impairment or probable dementia in women aged 65 and older from The Women’s Health Initiative Memory Study (a randomized, controlled clinical trial of postmenopausal hormone therapy that tracked nearly 6,500 women over the course of ten years). The researchers found that the participants who self-reported drinking more than 261 milligrams of caffeine (one average cup of coffee has 94.8 milligrams) were less likely to develop incident dementia. The authors warned, however, that the results were not enough to establish a direct link between higher caffeine consumption and lower incidence of cognitive impairment and dementia.
A study published in the Journal of Alzheimer’s Disease in 2016 also reported that coffee consumption was significantly associated with a lower risk of dementia. The researchers examined 13,137 Japanese subjects over the age of 65 for nearly six years. Interestingly, the researchers found that the “significant inverse association was more remarkable among women, non-smokers, and non-drinkers.”
Research published in The Journal of Nutrition in 2014 found that higher caffeine intake “may benefit cognition acutely and even prevent age-related declines in certain cognitive domains, including global cognition, verbal memory, and attention.” For this study, researchers used data from the Baltimore Longitudinal Study of Aging, which is the longest running scientific study of human aging in the U.S., according to the National Institute of Aging’s website.
Coffee as Herbal Medicine
According to Dr. Cao, coffee is not just a beverage, it is also a “herbal medicine.” As is the case with any herbal medicines, the appropriate dosage at the right time is critical. “A lot of people wake up and drink a cup of coffee. That’s a bad habit. You have to eat food first and then drink coffee,” says Dr. Cao. On an empty stomach, the caffeine “gets into the bloodstream in a short time and accelerates your metabolism rate,” which may be the cause of the abnormal response experienced by some coffee drinkers. Consuming coffee in the late afternoon is also problematic because it interferes with the function of melatonin in the brain, which regulates sleep. How much coffee is good for you depends upon your metabolism rate. Generally speaking, on average, two eight-ounce cups of regular coffee works for most people, notes Dr. Cao. However, this amount will also depend on the strength of the coffee. Dr. Cao and his colleagues are currently working on a standardized coffee formulation so that people will know exactly how much to consume.
Moderation is Key
Overall, there appears to be little evidence of health risks and some promising evidence of health benefits for adults consuming moderate amounts of coffee. However, some groups, including people with hypertension, may be more vulnerable to the adverse effects of caffeine. As with most things in life, moderation seems to be paramount. Consuming coffee in reasonable amounts just might be one of the easiest things you can do to help protect your brain health.
Coffee Consumption and Depression
In addition to the correlation between coffee and Alzheimer’s disease and other forms of dementia, recent research has suggested that an individual’s coffee consumption may alter his or her risk of depression. In one large longitudinal study out of the Harvard School of Public Health, published in the Archives of Internal Medicine, the researchers found that depression risk decreased with increased caffeinated coffee consumption amongst women (mean age, 63 years old). This finding was consistent with earlier observations that suicide risk is lower amongst individuals with higher consumption of coffee. Decaffeinated coffee was not associated with depression risk.
In light of the fact that the World Health Organization reports that depression is twice as common in women than men, there is an important gendered component to finding solutions to this disorder. The researchers concluded that further investigations are needed to confirm their findings and to determine whether usual caffeinated coffee consumption may contribute to prevention or treatment of depression.
Effects of Caffeine in the “Oldest-Old”
Research published in 2016 in Alzheimer Disease & Associated Disorders examined the data of nearly 600 people aged 90 and over (who did not have dementia at the commencement of the study) to query how lifestyle factors influence the health of this segment of the population. The researchers found that caffeine consumption was one of the few lifestyle factors that may be related to a reduced risk of incident dementia. Participants who consumed 200 milligrams or more per day of caffeine had a 34% lower risk compared with those who consumed less than 50 milligrams per day.
Although cause and effect could not be determined, the authors concluded that their findings could represent a substantial reduction in dementia incidence and warrant further study in other very old individuals. Additionally, like many of the studies that investigate the relationship between coffee consumption and dementia, the authors of the study emphasized that because therapeutic regimens are currently limited, “modification of lifestyle behaviours may offer the only means for disease control.”
Source: MIND OVER MATTER V.6
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