Keeping Brains Healthy
Science spotlights everyday nutrients that can counter the slide into inflammation.
By Hara Estroff Marano published July 6, 2021 - last reviewed on July 6, 2021
Like cars, houses, and waistlines, brains need regular upkeep. And as with the others, the older they get, the more crucial maintenance is for everyday performance.
Left to their own devices, over time brains get neglectful of cellular housekeeping in many ways. As they age, populations of brain cells lose efficiency in clearing out their damaged brethren, foreign agents, and the slag cast off from energy burned to help you remember where you left the car keys. The accumulation of debris impairs the brain’s efficiency.
Trouble is, such negligence also sets off inflammatory processes that appear to be a key factor in mental aging. Maintaining a vibrant brain at any time, but especially with age, relies on subduing inflammatory factors.
Crucial to age-related changes in cognition are the microglia, a type of myeloid cell in the brain. Less celebrated than the high-voltage neurons, they serve a number of backstage functions. In addition to being the brain’s housekeepers, they are its immune sentinels, alerting the central nervous system to trouble and becoming its first line of defense. Microglia activate protective inflammatory processes that jump-start the response to foreign invasion. They also promote repair of brain tissue.
According to a recent report in the journal Nature, the microglia malfunction with age, turn traitorous, and actually set off chronic inflammation. All because time leads them to overproduce an inflammatory hormone that catapults them into inflammatory overdrive.
When that hormone (prostaglandin E2) is blocked in myeloid cells, they regain their youthful kick. In animal studies, doing so actually reverses age-related mental decline. “If you adjust the immune system, you can de-age the brain,” observes the study’s lead author, Katrin Andreasson, M.D., neurologist and neuroscientist at Stanford University.
Aging is not an outlier. A mound of research implicates inflammatory activation of the immune system as a largely underground process that also drives the behavioral and psychological changes seen in many psychiatric disorders, including depression and anxiety, and even fatigue. Studies have found increased levels of inflammatory compounds in brain areas linked to depression, such as the hippocampus, even before the onset of clinical symptoms.
The role of stealth inflammation in compromising brain operations highlights the need for everyday action to keep the process under control. Enter curcuminoids, bioactive compounds in turmeric, the culinary spice that gives curry its color and has been a mainstay of traditional medicine for centuries.
Modern medicine is exploring curcumin as a way to maintain brain health and stave off neurodegenerative disease because the agent displays a dazzling array of biological effects
—anti-inflammatory, antioxidant, neuroprotective, and chemoprotective properties, due to its ability to modulate numerous signaling molecules. Curcumin compounds are known to cross the blood-brain barrier and exert neuroprotective effects.
Animal studies consistently show benefits of curcumin in reversing cognitive decline at the behavioral as well as the molecular level. Although the few clinical studies that have been done show mixed results, there’s some evidence that curcumin may be best at maintaining cognitive function. Reaping its therapeutic value may hinge on consuming it with a fat-containing meal.
Perhaps most significant, in a recent laboratory study in China using cultured rat cells, curcumin blocked a specific cascade of inflammatory action in microglia. It inhibited the release of a protein known to kindle inflammation and lead to tissue damage associated with memory impairment. A number of inflammatory cascades are believed to play a role in Alzheimer’s disease.
Evidence continues to mount that long-chain polyunsaturated omega-3 fats, primarily found in fatty fish, also protect the brain in a wide range of ways. For starters, omega-3s, particularly the omega-3 fat DHA (docosahexaenoic acid), are a major constituent of nerve cell membranes, through which all cell functions transpire.
A low concentration of omega-3s in cellular membranes stiffens the membrane, reducing the ability of nerve cells to take in fuel for all their high-level activities. In particular, it limits the energy available for nerve transmission and communication at synapses. Another major consequence is reduced production of nerve growth factor for neuroplasticity, growth, and repair.
But omega-3s are also important anti-inflammatory agents, a role that arises primarily from occupying nerve cell membranes at the expense of their biochemical competitors, omega-6 fatty acids. Many inflammatory molecules arise from omega-6 fatty acids; they are, for example, readily oxidized to produce pro-inflammatory cytokines. Omega-3s also break down into resolvins, active metabolites so named because they facilitate the resolution phase of acute inflammation.
Despite the role of omega-3s in maintaining brain health, most of the world’s population is deficient in them, studies show, largely because of the rising consumption of cooking oils loaded with omega-6s. The more the evidence implicates inflammation as an undercover thief of brain health, the greater the need for the everyday protection that comes from nutrients, whether consumed in food or concentrated in supplements.
Tapping the Alpha Talents of Omega-3s
- Studies suggest that intake of marine omega-3s was 660—14,250 mg/day during the Paleolithic era, compared with 100—200 mg/day today.
- Intake of omega-3s has plummeted due to rising consumption of omega-6s found in soybean, corn, and safflower oils; the latter two have an omega-6 to omega-3 ratio of more than 60:1.
- The ratio of omega-6 fats to omega-3 fats has increased from around 4:1 in our hunter-gatherer ancestors to 20:1 today.
- Omega-3 fatty acids are especially critical during the third trimester of pregnancy, when they get incorporated into the developing neuronal and retinal tissues of the fetus.
- The International Society for the Study of Fatty Acids and Lipids recommends that pregnant and lactating women consume 300 mg/day of DHA; average intake is only about 25 percent of that.
- Having twins increases the maternal need for omega-3 fatty acids.
- DHA is essential for the genesis of glial cells, including microglia, as well as for the formation of synapses and for electrical and chemical/neurotransmitter signaling in the brain.
- Studies show that supplements containing the omega-3 fat EPA, eicosapentaenoic acid, are effective in curbing depression.