Study: Exercise, Vitamins Failed to Prevent Cognitive Decline in Older People

To keep their minds sharp, older people are often advised to take vitamins or other dietary supplements and to engage in regular exercise.

Two studies in JAMA show those practices had no effect on cognitive function.

Kaycee Sink, MD, MAS of the Wake Forest School of Medicine in Winston-Salem, NC and colleagues looked at whether a 24-month physical activity program would make participants mentally sharper.

Emely Chew, MD, of the National Eye Institute/National Institutes of Health in Bethesda, MD and colleagues looked at whether several popular nutrients—including certain vitamins-- improved cognitive function

In the Wake Forest study, 1, 635 people ages 70 to 89 were randomly assigned to either a moderate-intensity physical activity program or a health education program where the only exercise was stretching upper extremities. All were sedentary adults who were at risk for mobility disability but able to walk about a quarter mile.

The exercise program involved walking, resistance training and flexibility exercises.

At the end of the study period, the participants were assessed for mild cognitive impairment and dementia.

Overall, the group in the exercise program had slightly higher rates of these mental conditions (13.2%) than did the group of older people who were in the health education program.

In one positive finding, the researchers said that the people over 80 who were in the exercise group did score better on the executive function composite testing than their peers in the health-education group. So did people in that age group who were in poorer physical condition at the start of the study.

The authors said the findings did not rule out the possibility that both interventions helped maintain whatever level of cognitive function participants had when they entered the study.

“Cognitive function remained stable over 2 years for all participants,” they noted.

In the nutrients study, participants in a study of age-related macular degeneration were also tested for cognitive impairment. The participants’ average age was 73.

The researchers wanted see whether participants who consumed omega-3 long-chain polyunsaturated fatty acids, lutein supplements, or both did better than patients who got placebo.

All participants also got varying combinations of vitamin C, vitamin E, beta carotene and zinc.

In all, 3,501 participants had the cognitive testing as a follow-up to the eye study.

The people who got the supplements did not score any better than those who got placebo.

The authors speculate that the supplements were started too late in the aging process to have an effect.

“The process of cognitive decline may occur over decades, thus a short-term supplementation given too late in the disease may not be effective,” they wrote. It is also possible instead of supplements, people should eat those foods that contain the targeted nutrient.

In an editorial discussing the two studies, Sudeep Gill, MD, MSc, and Dallas Seitz, MD, PhD, of Queen’s University in Ontario, Canada wrote that physicians should still encourage patients to engage in physical activity throughout their lives. They also said Mediterranean or other heart healthy diets are likely to help prevent cognitive decline.

“These [study]results should not lead to nihilism involving lifestyle factors in older adults,” they wrote.