Study shows how exercise makes your brain stronger; Omega-3s work in a similar way 09/01/2016
There’s ample evidence that exercise is powerful brain “food.”
Exercise supports healthy memory and thinking by directly enhancing brain function and helps indirectly by improving overall health.
As Heidi Godman, Executive Editor of Harvard Health Letter wrote, “Exercise is known to reduce insulin resistance, reduce inflammation, and stimulate the release of growth factors – chemicals in the brain that affect the health of brain cells, the growth of new blood vessels in the brain, and even the abundance and survival of new brain cells.”
What isn’t fully understood is exactly how exercise directly alters and improves brain functions.
A new study on mice sheds light on how exercise can directly change how genes function in the brain.
- Clinical and animal studies show that exercise boosts BDNF levels.
- Ketones resulting from low-carb diets boosted BDNF levels in mice.
- Omega-3 DHA boosts BDNF levels in people and animals. (DHA abounds only in fatty fish and in fish or other marine oils — check the label.)
Running rodents make more “Miracle-Gro” for the brain
An intriguing new study comes from scientists at the NYU Langone Medical Center.
It adds evidence of the value of exercise for brain fitness, and suggests new strategies to ward off the brain diseases that come with advancing age.
The NYU team took a close look at the levels of key chemicals in the brain during exercise.
These chemicals are crucial to jump-start the production of a protein called brain-derived neurotrophic factor, or BDNF.
Since the protein’s discovery in the 1980s, BDNF has been called “Miracle-Gro” for the brain, thanks to its role in enhancing memory and the growth of nerve cells.
Previous research showed that BDNF levels in the brains of people with Alzheimer’s disease are, on average, half those of people without healthy brains and intact memories.
A guest column by neurologist David Perlmutter, M.D. — bestselling author of Grain Brain — underscores the critical importance of maintaining healthy BDNF levels as you age (see Growth Hormone for Your Brain – Now without a Prescription.)
Details of the new NYU study
During this new four-week study, researchers compared two groups of mice – half housed in cages with access to exercise wheels, half with no exercise wheels.
During the trial period the mice were left to their own devices, and those with exercise wheels spent a great deal of each day running (up to a mile a day!). Those without wheels lived very sedentary lives.
After the trial period, researchers analyzed brain tissue from both groups of mice, looking specifically at levels of BDNF.
As the NYU researchers had predicted, BDNF levels were much higher in the brains of the mice with access to regular exercise.
The team also examined the gene responsible for creating BDNF, and the animals who were active showed greater gene activity than those who were inactive.
Forced fat-burning yields more Miracle-Gro for the brain
One exciting discovery was that ketones were actively triggering the BDNF gene.
Ketones are chemicals produced in the liver to provide energy when your diet is low in starches and sugars.
On low-carb diets, the body burns stored fat to produce ketones, which take the place of blood sugar as a source of energy — which is why popular low-carb, high-fat/protein diets — like the Atkins or Paleo plans — are called "ketonic" diets.
Apparently, the ketones produced by fat-burning triggered the BDNF gene to produce more of it, thereby potentially enhancing brain function and memory.
According to senior investigator Moses Chao, Ph.D., “We believe that our study shows a precise biological mechanism behind increased BDNF production in mammals due to exercise. Unraveling the mysteries of BDNF is important as we seek more ways to naturally keep mammalian brains healthy, including those of people.”
“Our latest findings suggest how we might boost production of BDNF as studies have confirmed that doing so protects the brain,” said Chao, who notes that studies in people have already linked exercise, increased BDNF levels, and lower rates of dementia.
Boosting BDNF levels with seafood
As Dr. Perlmutter suggests, studies show that you can also influence health BDNF levels with diet, specifically with supplements that contains DHA, an omega-3 fatty acid found in healthy fish fats.
An encouraging 2014 study tested the brain effects of omega-3 fish oil capsules.
The 26-week trial looked at a number of brain functions and benchmarks, before and after volunteers took either a placebo or a 2.2 gram capsule of fish oil.
First, as the researchers reported: “We found a significant increase in executive functions after [taking omega-3 fish oil] compared with placebo.” Executive functions refer to the brain systems that control reasoning, problem solving, planning, execution and working (short-term) memory.
Significantly, the fish oil group’s gains in executive capacity paralleled increases in their blood levels of omega-3s and levels of BDNF.
(For more on that study, see Omega-3s Boosted Healthy Seniors’ Brains.)
An animal study conducted by the same research group found that supplemental omega-3 DHA from fish — one of the two omega-3s critical to human health — raised the levels of six chemicals beneficial to brain health, including BDNF … see Fish Fats Boost Brain Resilience; Fast Food Diet Deepens Brain Damage.
And they found that supplemental omega-3 DHA plus exercise elevated these helpful chemicals even higher, again underscoring the importance of both exercise and diet to brain health.
- Cao W, Duan J, Wang X, Zhong X, Hu Z, Huang F, Wang H, Zhang J, Li F, Zhang J, Luo X, Li CQ. Early enriched environment induces an increased conversion of proBDNF to BDNF in the adult rat's hippocampus. Behav Brain Res. 2014 May 15;265:76-83. doi: 10.1016/j.bbr.2014.02.022. Epub 2014 Feb 22.
- Cardoso HD, Santos Junior EF, de Santana DF, Gonçalves-Pimentel C, Angelim MK, Isaac AR, Lagranha CJ, Guedes RC, Beltrão EI, Morya E, Rodrigues MC, Andrade-da-Costa BL. Omega-3 deficiency and neurodegeneration in the substantia nigra: Involvement of increased nitric oxide production and reduced BDNF expression. Biochim Biophys Acta. 2013 Dec 20;1840(6):1902-1912. doi: 10.1016/j.bbagen.2013.12.023. [Epub ahead of print]
- Godman, Heidi. “Regular Exercise Changes the Brain to Improve Memory, Thinking Skills.” Harvard Health Publications. Harvard Medical School, 09 Apr. 2014. Web. 01 Aug. 2016. Accessed at http://www.health.harvard.edu/blog/ regular-exercise-changes-brain-improve-memory-thinking-skills -201404097110
- Sable P, Kale A, Joshi A, Joshi S. Maternal micronutrient imbalance alters gene expression of BDNF, NGF, TrkB and CREB in the offspring brain at an adult age. Int J Dev Neurosci. 2014 May;34:24-32. doi: 10.1016/j.ijdevneu.2014.01.003. Epub 2014 Jan 22.
- Sleiman SF, Henry J, Al-Haddad R, El Hayek L, Abou Haidar E, Stringer T, Ulja D, Karuppagounder SS, Holson EB, Ratan RR, Ninan I, Chao MV. Exercise promotes the expression of brain derived neurotrophic factor (BDNF) through the action of the ketone body β-hydroxybutyrate. Elife. 2016 Jun 2;5. pii: e15092. doi: 10.7554/eLife.15092. PubMed PMID: 27253067; PubMed Central PMCID: PMC4915811.