Medical Minutes
Wine drinking may help protect against cataracts
People who consume alcohol moderately appear less likely to develop cataracts that require surgery. Wine consumption showed the strongest protective effect, suggesting that antioxidants which are abundant in red wine may play a role in cataract prevention. However, people who drank daily or nearly daily had about a 6% higher risk of cataract surgery compared with people who consumed alcohol moderately. The new research was published in Ophthalmology, the journal of the American Academy of Ophthalmology.
A research team from NIHR Moorfields Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust in London, England conducted the study because previous studies on cataracts and alcohol consumption were limited in their design and offered mixed results. Some studies showed an increased risk from heavy drinking, some suggested a reduced risk from low to moderate drinking and some data showed no link at all between alcohol and cataracts.
A cataract is a clouding of the eye’s normally clear lens. Most cataracts develop slowly and don’t affect vision early on. However, cataracts eventually make it more difficult to read, drive a car or see people’s faces. An ophthalmologist surgically removes the cloudy lens and replaces it with an artificial lens. Cataract surgery is highly effective and one of the most common procedures performed in all of medicine. Three million Americans undergo cataract surgery each year.
This study, the largest of its kind, tracked 490,000 volunteers in the U.K. who agreed to give detailed information about their health and lifestyle. After taking into account factors already known to affect cataracts (age, sex, ethnicity, social deprivation, weight, smoking and diabetes) the researchers found that people who consumed about 6.5 standard glasses of wine per week (which is within the current guidelines for safe alcohol intake in both the U.S. and U.K.) were less likely to undergo cataract surgery.
Wine drinkers benefited the most compared with those who abstained and those who drank other types of alcohol, showing a 23% reduction in cataract surgery in one study group and a 14% reduction in the other study group. However, the researchers note that their study does not establish causation, only a strong association between alcohol consumption and cataracts.
The study’s findings are consistent with what is already suggested about the health benefits of red wine and with previous studies that found diets rich in antioxidants may prevent the onset of cataracts. Grape skin is loaded with healthful antioxidants, resveratrol and flavonoids. These powerful plant compounds and antioxidants are found in higher concentrations in red wine than in white. Both red and white wine have higher concentrations of these compounds than beer.
“Cataract development may be due to gradual damage from oxidative stress during aging,” explained Dr. Sharon Chua, who is the lead study author. “The fact that our findings were particularly evident in wine drinkers may suggest a protective role of polyphenol antioxidants, which are especially abundant in red wine.”
Boosting brain power with exercise
It’s not just your legs and heart getting a workout when you walk briskly. Exercise affects your brain as well. A new study by researchers at UT Southwestern in Dallas, Texas, shows that when older adults with mild memory loss followed an exercise program for a year, the blood flow to their brains increased. The results were published in the Journal of Alzheimer’s Disease. “This is part of a growing body of evidence linking exercise with brain health,” said study leader Rong Zhang, PhD, who is a professor of neurology at UTSW. “We’ve
shown for the first time in a randomized trial in these older adults that exercise gets more blood flowing to your brain.”
As many as one-fifth of people age 65 and older have some level of mild cognitive impairment (MCI). This is slight changes to the brain that affect memory, decision-making, or reasoning skills. In many cases, MCI progresses to dementia, including Alzheimer’s disease.
Scientists have previously shown that lower than usual levels of blood flow to the brain, and stiffer blood vessels leading to the brain, are associated with MCI and dementia. Studies have also suggested that regular aerobic exercise may help improve cognition and memory in healthy older adults. However, scientists have not established whether there is a direct link between exercise, stiffer blood vessels, and brain blood flow.
In the study, 70 men and women aged 55 to 80 who had been diagnosed with MCI were followed. Participants underwent cognitive exams, fitness tests, and brain magnetic resonance imaging (MRI) scans. Then they were randomly assigned to either follow a moderate aerobic exercise program or a stretching program for one year. The exercise program involved three to five exercise sessions a week, each with 30 to 40 minutes of moderate exercise such as a brisk walk.
In both programs, exercise physiologists supervised participants for the first four to six weeks, then had the patients record their exercises and wear a heart rate monitor during exercise. Forty-eight study participants (29 in the stretching group and 19 in the aerobic exercise group) completed the full year of training and returned for follow-up tests. Among them, those who performed aerobic exercise showed decreased stiffness of blood vessels in their neck and increased overall blood flow to the brain. The more their oxygen consumption (one marker of aerobic fitness) increased, the greater the changes to the blood vessel stiffness and brain blood flow. Changes in these measurements were not found among people who followed the stretching program.
While the study didn’t find any significant changes in memory or other cognitive function, the researchers say that may be because of the small size or short length of the trial. Changes to blood flow could precede changes to cognition, according to the investigators. They’re already carrying out a larger two-year study that further investigates the link between exercise and cognitive decline.
A hidden health benefit from coffee
Drinking a strong coffee half an hour before exercising increases fat-burning, according to a new Spanish study. Scientists from the Department of Physiology of the University of Granada in Spain have shown that caffeine (about 3 mg/kg, the equivalent of a strong coffee) ingested half an hour before aerobic exercise significantly increases the rate of fat-burning. They also found that if the exercise is performed in the afternoon, the effects of the caffeine are more marked than in the morning.
In their study, published in the Journal of the International Society of Sports Nutrition, the researchers aimed to determine whether caffeine actually does increase oxidation or “burning” of fat during exercise. Despite the fact that its consumption in the form of supplements is very common, the scientific evidence for its beneficial claims is scarce.
“The recommendation to exercise on an empty stomach in the morning to increase fat oxidation is commonplace. However, this recommendation may be lacking a scientific basis, as it is unknown whether this increase is due to exercising in the morning or due to going without food for a longer period of time,” explained the lead author of this research, Francisco José Amaro-Gahete of the UGR’s Department of Physiology.
A total of 15 men (average age 32 years) participated in the research, completing an exercise test four times at seven-day intervals. Subjects ingested 3 mg/kg of caffeine or a placebo at 8 a.m. and 5 p.m. (each subject completed the tests in all four conditions in a random order). The conditions prior to each exercise test (hours elapsed since last meal, physical exercise, or consumption of stimulant substances) were strictly standardized, and fat oxidation during exercise was calculated accordingly.
The results of the study showed that acute caffeine ingestion 30 minutes before performing an aerobic exercise test increased maximum fat oxidation during exercise regardless of the time of day, according to the authors. These results also showed that caffeine increases fat oxidation during morning exercise in a similar way to that observed without caffeine intake in the afternoon. The findings of this study suggest that the combination of acute caffeine intake and aerobic exercise performed at moderate intensity in the afternoon provides the optimal scenario for people seeking to increase fat-burning during physical exercise.
John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute. He can be reached at medicalminutes@gmail.com.
John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute.
