Nutritional Pearls: Drink Your Tea

Martha is a 56-year-old woman concerned about her risk of cognitive decline later in life. She follows a relatively healthy diet, but drinks 2 diet colas every morning to “help her wake up.” At her most recent visit, she asks you if there are any simple lifestyle changes she can make to help lessen that risk.  

How would you advise your patient?
(Answer and discussion on next page)

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Answer: Drinking black tea regularly may help your patients avoid cognitive decline later in life.

If I've said it once, I've said it a thousand times: "Instead of soda, drink water, coffee, or tea." A recent study suggests that female carriers of a certain gene might decide that tea is best.

The Research

Researchers in Singapore invited residents that were at least 55 years old from a particular region of Singapore to participate in The Singapore Longitudinal Aging Study. As part of the study, the participants responded to a variety of health and dietary questionnaires and provided blood for additional testing. One of the questionnaires was the MMSE.
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The Mini-Mental State Examination tests different cognitive functions, from orientation, to immediate and short-term memory, to language functioning. It's a quick, cheap, and easy way to test for the presence of cognitive impairment, but it is not a diagnostic tool:  it shows that a problem exists, but not why that problem exists.

Of the 957 participants who received scores of 26 or above on the MMSE (no cognitive impairment), about 30% did not drink tea at the start of the study. The 70% who did were divided into 2 groups: those who drank only black tea and those who drank both green tea and black tea. (Only 1 person drank green tea exclusively.) The tea drinkers were also broken out into groups according to how much tea they customarily drank: Low (less than 1 cup per day but more than 1 cup per week), Medium (1-2 cups per day), and High (3 or more cups per day).

The researchers tested the participants to see if they were carriers of the gene apolipoprotein E4 (Apo-E4), which indicates a greater risk of developing dementia.

Between 3 and 5 years after the start of the study, the authors returned to visit the participants and again administered the MMSE along with their dietary and health questionnaires. Those participants whose scores fell into the realm of cognitive impairment were compared with those whose scores did not.

The Results

Even after taking into account other health and risk factors, those who drank the most tea and maintained that consumption from the start to the end of the study were 47% less likely to experience neurocognitive decline than those who did not drink tea at all.

After separating the participants by gender and whether they carried the Apo-E4 gene, however, the authors discovered that the vast majority of those who benefitted from drinking tea were women: men who drank tea reduced their risk of neurocognitive decline by less than 10%, while women who drank tea reduced their risk by almost 70%. Those men and women who carried the Apo-E4 gene benefitted the most by far: carriers who drank tea reduced their risk by almost 85% compared to 44% for non-carriers.

What’s the “Take-Home”?

The drawbacks of this study include its short duration (10 years or less) and the relatively small number of people who experienced cognitive decline during that period. That said, along with its many other benefits, it does appear that drinking black tea regularly may help your patients avoid cognitive decline later in life.

Note that those who benefitted the most in this study were those who drank tea at the start and the end of the study, which may indicate a much longer-term habit. Advise your patients to choose water, tea, or coffee instead of sodas. Caffeinated, or decaf? The authors of this study didn't seem to have asked, so I would recommend to my patients that they follow their preference.

Reference:

Feng L, Chong MS, Lim WS, et al. Tea consumption reduces the incidence of neurocognitive disorders: Findings from the Singapore longitudinal aging study. J Nutr Health Aging. 2016;20(10):1002-1009.