A number of studies have shown that physical activity can have positive effects on the brain, particularly in later life. New research has found that it may be possible to bolster these effects, simply by drinking beetroot juice before exercising.
Researchers found that older adults who consumed beetroot juice prior to engaging in moderately intense exercise demonstrated greater connectivity in brain regions associated with motor function, compared with adults who did not drink beetroot juice before exercising.
The research team - including co-author W. Jack Rejeski of the Department of Health and Exercise Science at Wake Forest University in Winston-Salem, NC - says that the increased brain connectivity seen among the adults who drank beetroot juice was comparable to the connectivity seen in younger adults.
Rejeski and colleagues recently reported their findings in the Journals of Gerontology: Series A.
Beetroot - often referred to as "beet" - is a root vegetable best known for dominating plates of food with its bright purple juice. In recent years, beetroot has gained popularity for its potential health benefits, which include reduced blood pressure and increased exercise performance.
Such benefits have been attributed to the high nitrate content in beetroot. When consumed, nitrates are converted into nitric oxide, which studies have shown can lower blood pressure and increase blood flow to the brain.
Studies have demonstrated that exercise alone can benefit the brain. For their study, Rejeski and team set out to investigate whether beetroot juice might boost the brain benefits of physical activity.
The study comprised 26 participants, aged 55 years and older, who had high blood pressure. None of the participants engaged in regular exercise, and they were taking up to two medications to help lower their blood pressure.
All subjects were required to engage in 50 minutes of moderately intense exercise on a treadmill three times per week for 6 weeks. One hour before each session, half of the participants consumed a beetroot juice supplement containing 560 milligrams of nitrate, while the remaining participants consumed a placebo low in nitrates.
At the end of the 6 weeks, the researchers measured participants' brain functioning using MRI.
The team found that subjects who consumed the beetroot juice supplement prior to exercising demonstrated a structurally stronger somatomotor cortex - a brain region that helps to control body movement - compared with participants who consumed the placebo.
Furthermore, subjects who drank the beetroot juice supplement also showed greater connectivity between the somatomotor cortex and the insular cortex, a brain region associated with motor control, cognitive functioning, emotion, and other brain functions. Such connectivity is usually seen in the brains of younger individuals, the team notes.
The researchers explain that the somatomotor cortex receives and processes signals from the muscles. As such, physical activity should strengthen this process.
They suggest that beetroot juice strengthens the somatomotor cortex further through its nitrate content; its conversion into nitric oxide boosts the delivery of oxygen to the brain.
"Nitric oxide is a really powerful molecule. It goes to the areas of the body which are hypoxic, or needing oxygen, and the brain is a heavy feeder of oxygen in your body," says Rejeski.
While further research is required to replicate their results, the researchers believe that their study suggests that what we eat in later life may play an important role in brain health and mobility.
"We knew, going in, that a number of studies had shown that exercise has positive effects on the brain. But what we showed in this brief training study of hypertensive older adults was that, as compared to exercise alone, adding a beetroot juice supplement to exercise resulted in brain connectivity that closely resembles what you see in younger adults."
W. Jack Rejeski