Nov. 10 (UPI) -- Vitamin D, omega-3 supplements and exercising regularly -- either alone or in combination -- won't necessarily lower blood pressure, improve cognitive function or reduce risk for bone fractures in older adults, a study published Tuesday by JAMA found.
Vitamin D and omega-3 fatty acids may help reduce the risk for infections in some older adults, however, the researchers said.
For example, older adults who take 800 international units -- or 20 micrograms -- per day of vitamin D lowered risk for infections by 5%, but they had a 3% higher risk for suffering a fracture than those not taking the supplement, the data showed.
Those who take 1 gram a day of an omega-3 fatty acid supplement day had an 11% lower risk for developing an infection, but an 18% higher risk for suffering a broken bone.
And older adults in a strength-training exercise program with three, 30-minute sessions weekly had a 4% higher risk for infection and a 6% higher risk for fractures, the data showed.
All three health interventions had negligible effects on study participants' blood pressure -- dropping average readings by one or two points -- and cognitive function performance, based on several commonly used measures, the researchers said.
"The results suggest that additional vitamin D and omega 3 intake in active 70-plus adults without previous illnesses carries no benefit for the risk of non-vertebral fractures, or for muscle and memory function. However, we suspect a connection with infections," study co-author Dr. Heike A. Bischoff-Ferrari told UPI.
In addition, "certain groups could still benefit from omega-3 fatty acids and vitamin D with regard to infections and systolic blood pressure reduction," said Bischoff-Ferrari, a professor of geriatrics and aging research at University Hospital Zurich in Switzerland.
Vitamin D has been linked with improved immune system and bone health, while omega-3 fatty acids may have added benefits for heart health as well as brain function, according to the National Institutes of Health.
The National Institute on Aging also recommends regular physical exercise for older adults to improve both physical and mental health.
For this study, part of the DO-Health project, a research initiative designed to support healthy aging among European seniors, the authors enrolled 2,157 adults age 70 and older from five European countries.
Study participants were divided into eight groups, with some receiving vitamin D, others receiving omega-3 and still others participating in an exercise program, or various combinations of all three, according to the researchers.
Some study participants also served as controls, meaning they received none of the three study interventions, the researchers said.
All 2,157 participants were tracked for an average of approximately three years, and 25 died during the study period. They were roughly evenly divided among all eight groups, according to the researchers.
"It is important to clarify that our results do not invalidate the overwhelming evidence of a benefit of exercise on health," Bischoff-Ferrari said.
"Our exercise intervention was a simple home strength exercise program, which likely was not challenging enough in our unexpectedly active study population, where over 80% already engaged moderate to high intensity exercise," she said.