Boost Your Brain Health Naturally

Brain Health

Story at-a-glance

  • Vitamin D deficiency is associated with a substantially increased risk of dementia and Alzheimer’s disease
  • The carotenoids lutein and zeaxanthin, found in dark leafy greens, may promote cognitive function in old age by enhancing neural efficiency
  • Among people with Alzheimer’s disease, those who drank milk containing probiotics experienced significant improvements in cognitive function


This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.

By Dr. Mercola

Ninety-three percent of Americans believe maintaining brain health is very or extremely important, according to an AARP survey; however, few are aware of the many holistic approaches available to do so.1

Contrary to popular belief, your brain doesn't have to slow down or become unreliable with age, and there are steps within your control that can influence your memory, cognition and more.

Your lifestyle, from vitamin D to vegetables, may make the difference between staying mentally sharp in old age or starting to lose your edge. Even if you're already living your "golden years," simple healthy choices can prompt brain changes for the better.

In fact, while it was once believed that brain cells (neurons) were produced only during a certain period of development, it's now known that neurogenesis (the growth of new brain cells) continues into adulthood.

" … [N]ew neurons are integrated into functional circuits, and the ongoing neuronal turnover is significant for some functions," researchers wrote in "Brain Aging: Models, Methods and Mechanisms."2

Exactly what influences the rate of neurogenesis is still being explored, but if you want to support your brain health as much as possible, here's what you should know.

Vitamin D Deficiency Is Linked to Dementia

Strong links between low levels of vitamin D in Alzheimer's patients and poor outcomes on cognitive tests have been revealed. It's thought that optimal vitamin D levels may protect brain cells by increasing the effectiveness of the glial cells in restoring damaged neurons.

In addition, vitamin D may be beneficial for brain health because it has anti-inflammatory and immune-boosting properties and has even been found to clear amyloid plaques in the brain, which is a hallmark of Alzheimer's disease.

Its neuroprotective effects are so strong that the risk of cognitive impairment was up to four times greater in elderly people with severe vitamin D deficiency compared to those with adequate levels.3

In 2014, a study of more than 1,650 elderly adults, described as the "most robust" of its kind, also found that vitamin D deficiency is associated with a substantially increased risk of dementia and Alzheimer's disease.4

Do You Know Your Vitamin D Level?

Fortunately, the solution is both simple and inexpensive — optimize your vitamin D. The first step is to find out your level, which can be done via a blood test. For optimal health, you need a vitamin D level of at least 40 to 60 ng/ml (a more ideal level may be 50 to 70 ng/ml).

If you're outside of the optimal range, you can fix it by getting sensible sun exposure or taking a vitamin D3 supplement.

While sunlight is the ideal way to optimize your vitamin D, winter and work prevent more than 90 percent of those reading this from achieving ideal levels without supplementation. As a general guideline, research by Grassroots Health suggests adults need about 8,000 IUs per day to achieve a serum level of 40 ng/ml.

If you do opt for a vitamin D supplement, please remember that you also need to boost your intake of vitamin K2 through food and/or a supplement, as well as get your levels tested to be sure you're safely within the therapeutic range.

Carotenoids in Veggies Improve Cognition

Carotenoids are antioxidant compounds found in certain vegetables. Most often associated with orange produce like sweet potatoes and carrots, some carotenoids, namely lutein and zeaxanthin, are also found in dark green vegetables like kale and spinach.

Lutein and zeaxanthin, in turn, are most known for the role they play in vision health, such as reducing the risk of age-related macular degeneration. However, accumulating evidence suggests they play a powerful role in cognitive health as well.

One recent study, the first of its kind, found lutein and zeaxanthin may promote cognitive function in old age by enhancing neural efficiency.5

In the study of 43 older adults, participants were asked to learn pairs of unrelated words while undergoing functional magnetic resonance imaging (fMRI). Higher levels of the two carotenoids were associated with lower brain activity during memory tasks, which suggests they did not have to work as hard to complete them.

Cutter Lindbergh, a doctoral candidate in the psychology department of the Franklin College of Arts and Sciences at the University of Georgia, said in a press release:6

"There's a natural deterioration process that occurs in the brain as people age, but the brain is great at compensating for that. One way it compensates is by calling on more brain power to get a job done so it can maintain the same level of cognitive performance.

On the surface, it looked like everyone was doing the same thing and recalling the same words, but when you pop the hood and look at what's actually going on in the brain, there are significant differences related to their carotenoid levels."

The take-home message here is that improving your diet by eating more lutein- and zeaxanthin-rich foods may help protect your aging brain. Following is a list of lutein-rich foods. Most of these also contain zeaxanthin, albeit in lesser quantities than lutein.

Lutein Content of Foods

Food Milligram (mg)/serving

Kale (raw)

Mg/serving: 26.5 / 1 cup

Kale (cooked)

Mg/serving: 23.7 / 1 cup

Spinach (cooked)

Mg/serving: 20.4 / 1 cup

Collards (cooked)

Mg/serving: 14.6 / 1 cup

Turnip greens (cooked)

Mg/serving: 12.2 / 1 cup

Green peas (cooked)

Mg/serving: 4.1 / 1 cup

Spinach (raw)

Mg/serving: 3.7 / 1 cup

Broccoli (raw)

Mg/serving: 1.3 / 1 cup

Romaine lettuce (raw)

Mg/serving: 1.1 / 1 cup

Green beans (cooked)

Mg/serving: 0.9 / 1 cup

Broccoli (cooked)

Mg/serving: 0.8 / 1/2 cup

Papaya (raw)

Mg/serving: 0.3 / 1 large


Mg/serving: 0.2 / 1 large

Orange (raw)

Mg/serving: 0.2 / 1 large

U.S. Department of Agriculture, Agricultural Research Service, USDA Nutrient Data Laboratory. 2005. USDA National Nutrient Database for Standard Reference, Release 20 (2007), Nutrient Data Laboratory Home Page

Probiotics for Your Brain

You're probably familiar with the importance of probiotics for gut health. Lesser known is that certain beneficial bacteria strains also have a marked, positive effect on your brain, and consuming such bacteria in your diet may benefit your brain function.

In a study by University of California (UCLA) scientists, women who regularly consumed beneficial bacteria via yogurt experienced changes in multiple areas of their brain, including those related to sensory processing, cognition and emotion.7

Also revealing, in a study by John Cryan, Ph.D., at the University College Cork in Ireland, mice without any microbes in their intestines were found to be unable to recognize other mice around them.

Cryan believes that microbes may communicate with the brain and help us be social, which in turn allows the microbes to spread to others.8 In addition, mice lacking gut bacteria have been found to engage in "high-risk behavior," and this altered behavior was accompanied by neurochemical changes in the mouse brain.9

When examining the animals' brains, the researchers discovered a number of genetic alterations in the germ-free mice. According to The Guardian:10

"Brain-derived neurotrophic factor (BDNF) was significantly up-regulated, and the 5HT1A serotonin receptor sub-type down-regulated, in the dentate gyrus of the hippocampus. The gene encoding the NR2B subunit of the NMDA receptor was also down-regulated in the amygdala. All three genes have previously been implicated in emotion and anxiety-like behaviors.

BDNF is a growth factor that is essential for proper brain development, and a recent study showed that deleting the BDNF receptor TrkB alters the way in which newborn neurons integrate into hippocampal circuitry and increases anxiety-like behaviors in mice.

Serotonin receptors, which are distributed widely throughout the brain, are well known to be involved in mood, and compounds that activate the 5HT1A subtype also produce anxiety-like behaviors."

Daily Dose of Probiotics May Improve Memory in Alzheimer's Patients

A recent study of 60 Alzheimer's patients looked into the effect of probiotic supplements on cognitive function, with promising results.11 Those who drank milk containing probiotics experienced significant improvements in cognitive function. While average Mini-Mental State Examination (MMSE) scores increased from 8.7 to 10.6 among the probiotics group, the control group (which drank plain milk) had a decrease in scores from 8.5 to 8.0.

The probiotics group also had beneficial metabolic changes, including lowered triglycerides, very low-density lipoprotein and C-reactive protein, a measure of inflammation, as well as reduced markers for insulin resistance.

The researchers suggested the beneficial metabolic changes may be responsible for the cognitive improvements. Walter Lukiw, Ph.D., a professor of neurology and Alzheimer's Disease at Louisiana State University (LSU) who was not involved in the study, further explained to Medical News Today that your gut and brain are intricately connected:12

"This is in line with some of our recent studies which indicate that the GI [gastrointestinal] tract microbiome in Alzheimer's is significantly altered in composition when compared to age-matched controls …

…  and that both the GI tract and blood-brain barriers become significantly more leaky with aging, thus allowing GI tract microbial exudates (e.g. amyloids, lipopolysaccharides, endotoxins and small non-coding RNAs) to access central nervous system compartments."

Fortunately, reseeding your gut with beneficial bacteria is relatively easy to do. Fermented foods are the best route to add more beneficial bacteria to your diet, as long as you eat the traditionally made, unpasteurized versions.

Healthy choices include lassi (an Indian yogurt drink, traditionally enjoyed before dinner), fermented grass-fed organic milk such as kefir, various pickled fermentations of cabbage, turnips, eggplant, cucumbers, onions, squash and carrots, and natto (fermented soy).

Fermented vegetables, in particular, are an excellent way to supply beneficial bacteria back into your gut. If you don't eat fermented foods on a regular basis, consider using a high-quality probiotic supplement. Eliminating excess sugar from your diet, and ending the use of unnecessary antibiotics, will further allow your body's beneficial bacteria to grow and flourish.

Additional Strategies for a Healthier Brain

Your brain is not "programmed" to shrink and fail as a matter of course as you age. In fact, you can build a bigger, better brain by making smart choices. Lifestyle strategies that promote neurogenesis and regrowth of brain cells include the following. All of these strategies target a specific gene pathway called BDNF or brain-derived neurotrophic factor, which promotes brain cell growth and connectivity as demonstrated on MRI scans.

  • Exercise. Physical activity produces biochemical changes that strengthen and renew not only your body but also your brain — particularly areas associated with memory and learning.
  • Reduce overall calorie consumption; intermittent fasting can help with this.
  • Reduce carbohydrate consumption, including sugars and grains.
  • Increase healthy fat consumption. Beneficial health-promoting fats that your body — and your brain in particular — needs for optimal function include organic butter from raw milk, organic grass-fed raw butter, olives, organic virgin olive oil and coconut oil, nuts like pecans and macadamia, free-range eggs, wild Alaskan salmon and avocado, for example.
  • Increase your omega-3 fat intake and reduceconsumption of damaged omega-6 fats (i.e., processed vegetable oils) in order to balance your omega-3-to-omega-6 ratio. Krill oil works well for this because (like wild Alaskan salmon) it also contains astaxanthin, which appears to be particularly beneficial for brain health.

As explained by Dr. David Perlmutter, author of "Grain Brain," it belongs to the class of carotenoids and is very "focused" on reducing free radical-mediated damage to fat (your brain is 60 percent to 70 percent fat).


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