By Dr. Mercola
A number of studies have investigated the impact of vitamin supplementation to prevent and/or treat cognitive dysfunction and decline.
It's well-established that healthy fats such as animal-based omega-3 fats are really important for brain health, but other nutrients such as vitamins are also necessary for optimal brain function.
Most recently, a Korean study1 concluded that giving a multivitamin supplement to seniors suffering from mild cognitive impairment and depression helped improve both conditions.
B vitamins in particular, especially folate (B9, aka folic acid in its synthetic form) and vitamins B6 and B12, have made headlines for their powerful role in preventing cognitive decline and more serious dementia such as Alzheimer's disease.
Mental fogginess and problems with memory are actually two of the top warning signs that you have vitamin B12 deficiency, indicating its importance for brain health.
B Vitamins and Omega-3 — An Important Combo for Brain Health
Although Dr. Michael Greger's video is a good review on the research about B vitamins, being a vegetarian he does not include information about animal-based omega-3 fats, which are also beneficial in reducing dementia.
Low plasma concentrations of omega-3 and high levels of the amino acid homocysteine are associated with brain atrophy, dementia, and Alzheimer's. Vitamins B6, B9, and B12 help convert homocysteine into methionine — a building block for proteins.
If you don't get enough of these B vitamins, this conversion process is impaired and as a result your homocysteine levels increase. Conversely, when you increase intake of folic acid (folate), vitamin B6, and vitamin B12, your homocysteine levels decrease.
In one placebo-controlled trial2 published in 2015, 168 seniors diagnosed with mild cognitive impairment were randomly assigned to receive either placebo, or daily supplementation with 0.8 mg of folic acid, 20 mg of vitamin B6, and 0.5 mg of B12.
It's worth noting that these are quite high doses — far above the U.S. RDA. All participants underwent cranial magnetic resonance imaging (MRI) scans at the outset of the study, and at the end, two years later.
The effect of the vitamin B supplementation was analyzed and compared to their omega-3 fatty acid concentrations at baseline. Interestingly, only those who had high omega-3 levels reaped beneficial effects from the B vitamins.
As noted by the authors:
"There was a significant interaction between B vitamin treatment and plasma combined omega-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid) on brain atrophy rates.
In subjects with high baseline omega-3 fatty acids (>590 μmol/L), B vitamin treatment slowed the mean atrophy rate by 40 percent compared with placebo.
B vitamin treatment had no significant effect on the rate of atrophy among subjects with low baseline omega-3 fatty acids (<390 μmol/L). High baseline omega-3 fatty acids were associated with a slower rate of brain atrophy in the B vitamin group but not in the placebo group...
It is also suggested that the beneficial effect of omega-3 fatty acids on brain atrophy may be confined to subjects with good B vitamin status."
B Vitamins Significantly Slow Brain Shrinkage
As mentioned above, elevated homocysteine is linked to brain degeneration, and B vitamins are known to suppress homocysteine.
A 2010 study,3 in which participants again received higher than normal doses of B vitamins, also found that people receiving B vitamins experienced far less brain shrinkage than the placebo group.
Here the participants received either a placebo or 800 micrograms (mcg) folic acid, 500 mcg B12, and 20 mg B6. The study was based on the presumption that by controlling homocysteine levels you might be able to reduce brain shrinkage, thereby slowing the onset of Alzheimer's.
Indeed, after two years those who received the vitamin B regimen suffered significantly less brain shrinkage compared to those who had received a placebo. Those who had the highest levels of homocysteine at the start of the trial experienced brain shrinkage at half the rate of those taking a placebo.
Research Shows B Vitamins Specifically Slow Alzheimer's Disease
A 2013 study4 takes this research a step further, showing that not only do B vitamins slow brain shrinkage, but they specifically slow shrinkage in brain regions known to be most severely impacted by Alzheimer's disease. Moreover, in those specific areas the shrinkage is decreased by as much as seven-fold!
The brain scans clearly show the difference between placebo and vitamin supplementation on brain atrophy. As in the studies above, participants taking high doses of folic acid and vitamins B6 and B12 lowered their blood levels of homocysteine, and brain shrinkage was decreased by as much as 90 percent.
As noted by the authors:
" … B vitamins lower homocysteine, which directly leads to a decrease in GM [gray matter] atrophy, thereby slowing cognitive decline.
Our results show that B vitamin supplementation can slow the atrophy of specific brain regions that are a key component of the AD [Alzheimer's disease] process and that are associated with cognitive decline."
B12-Rich Foods Reduce Risk of Alzheimer's in Later Years
Other supporting research includes a small Finnish study5 published in 2010. It found that people who consume vitamin B12-rich foods may reduce their risk of Alzheimer's in their later years.
For each unit increase in the marker of vitamin B12 (holotranscobalamin), the risk of developing Alzheimer's was reduced by 2 percent. This makes a strong case for ensuring your diet includes plenty of B vitamin foods, such as meat, poultry, eggs, dairy products and wild-caught fish.
Leafy green vegetables, beans, and peas also provide some of the B vitamins, but if you eat an all vegetarian or vegan diet, you're at a significantly increased risk of vitamin B12 deficiency, as B12 is naturally present in foods that come from animals, including meat, fish, eggs, milk and milk products.
In such a case, supplementation is really important. Another concern is whether your body can adequately absorb the B12. It's the largest vitamin molecule we know of, and because of its hefty size, it's not easily absorbed.
This is why many, if not most, oral B12 supplements fail to deliver any benefits. Vitamin B12 requires a gastric protein called intrinsic factor to bind to it, which allows it to be absorbed in the end of your small intestine (terminal ileum). The intrinsic factor is absorbed first, pulling the attached B12 molecule along with it.
As you grow older, your ability to produce intrinsic factor decreases, thereby increasing your risk for vitamin B12 deficiency. Use of metformin (Glucophage, Glucophage XR, Fortamet, Riomet, and Glumetza) may also inhibit your B12 absorption, especially at higher doses. Drinking four or more cups of coffee a day can reduce your B vitamin stores by as much as 15 percent, and use of antacids will also hinder your body's ability to absorb B12.
Other Valuable Vitamins for Brain Health
Besides B vitamins, vitamins C and D are also important for optimal brain health.6 Vitamin C plays a role in the production of neurotransmitters, including serotonin, which has antidepressant activity. Vitamin C has also been shown to improve IQ, memory, and offer protection against age-related brain degeneration and strokes.
In one study,7 the combination of vitamin C and E (which work synergistically) helped reduce the risk of dementia by 60 percent. Vitamin C also has detoxifying effects, and due to its ability to cross your blood-brain barrier, it can help remove heavy metals from your brain.
Vitamin D, a steroid hormone produced in your skin in response to sun exposure, also has profound effects on your brain. Pregnant women need to be particularly cognizant of this, as vitamin D deficiency during pregnancy can prevent proper brain development in the fetus, plus a host of other problems. After birth, children need vitamin D for continued brain development, and in adulthood, optimal levels have been shown to help prevent cognitive decline.8,9
Where to Find These Valuable Brain Nutrients
There's nothing "normal" about cognitive decline. More often than not, it's due to poor lifestyle choices, starting with a nutrient-deficient diet that is too high in sugars, non-vegetable carbs, unhealthy fats like trans fats, and too many toxins (pesticides and artificial additives, etc).
As a general rule, I recommend getting most if not all of your nutrition from REAL FOOD, ideally organic to avoid toxic pesticides, and locally grown. Depending on your situation and condition however, you may need one or more supplements.
To start, review the following listing of foods that contain the brain nutrients discussed in this article: animal-based omega-3s, vitamins B6, B9, and B12, C, and D. If you find that you rarely or never eat foods rich in one or more of these nutrients, you may want to consider taking a high-quality, ideally food-based supplement. I've made some suggestions to keep in mind when selecting a good supplement.
Nutrient Dietary Sources Supplement Recommendations Animal-based omega-3 Fatty fish that is low in mercury, such as wild-caught Alaskan salmon, sardines, and anchovies, as well as organic grass-fed beef.10
Sardines, in particular, are one of the most concentrated sources of omega-3 fats, with one serving containing more than 50 percent of your recommended daily value.
Antarctic krill oil is a sustainable choice. It also has the added benefit of containing natural astaxanthin, which helps prevent oxidation.
Another good option is wild-caught Alaskan salmon oil.
Vitamin B6 Turkey, beef, chicken, wild-caught salmon, sweet potatoes, potatoes, sunflower seeds, pistachios, avocado, spinach and banana.11,12 Nutritional yeast is an excellent source of B vitamins, especially B6.13 One serving (2 tablespoons) contains nearly 10 mg of vitamin B6.
Not to be confused with Brewer's yeast or other active yeasts, nutritional yeast is made from an organism grown on molasses, which is then harvested and dried to deactivate the yeast.
It has a pleasant cheesy flavor and can be added to a number of different dishes. For tips, see this vegan blog post.14
Folate (B9) Fresh, raw, and organic leafy green vegetables, especially broccoli, asparagus, spinach, and turnip greens, and a wide variety of beans, especially lentils, but also pinto beans, garbanzo beans, navy and black beans, and kidney beans.15 Folic acid is a synthetic type of B vitamin used in supplements; folate is the natural form found in foods.
Think: folate comes from foliage (edible leafy plants).
For folic acid to be of use, it must first be activated into its biologically active form — L-5-MTHF.
This is the form able to cross the blood-brain barrier to give you the brain benefits noted.
Nearly half of the population has difficulty converting folic acid into the bioactive form due to a genetic reduction in enzyme activity.
For this reason, if you take a B vitamin supplement, make sure it contains natural folate rather than synthetic folic acid.
Nutritional yeast is an excellent source.16
Vitamin B12 Vitamin B12 is found almost exclusively in animal tissues, including foods like beef and beef liver, lamb, snapper, venison, salmon, shrimp, scallops, poultry, eggs, and dairy products.
The few plant foods that are sources of B12 are actually B12 analogs that block the uptake of true B12.
Also consider limiting sugar and eating fermented foods.
The entire B group vitamin series is produced within your gut, assuming you have healthy gut flora.
Eating real food, ideally organic, along with fermented foods will provide your microbiome with important fiber and beneficial bacteria to help optimize your internal vitamin B production.
Nutritional yeast is also high in B12, and is highly recommended for vegetarians and vegans.
One serving (2 tbsp) provides nearly 8 micrograms (mcg) of natural vitamin B12.17
Sublingual (under-the-tongue) fine mist spray or vitamin B12 injections are also effective, as they allow the large B12 molecule to be absorbed directly into your bloodstream.
Vitamin C Sweet peppers, chili peppers, Brussel sprouts, broccoli, artichoke, sweet potato, tomato, cauliflower, kale, papaya, strawberries, oranges, kiwifruit, grapefruit, cantaloupe, and lemon.
To boost your intake of fruits and vegetables, consider juicing. As an alternative, you can also make fermented vegetables at home.
The vitamin C in sauerkraut (fermented cabbage) is about six times higher than in the same helping of unfermented cabbage, so it's an excellent way to boost your vitamin C intake.
The most effective form of oral vitamin C is liposomal vitamin C.
It's not associated with many of the complications of traditional vitamin C or ascorbic acid (such as gastrointestinal distress), which will allow you to achieve higher intracellular concentrations.
You can expect a significant rise in plasma vitamin C concentration at doses between 30 and 100 mg/day.
Taking vitamin C frequently throughout the day is more effective than taking one large dose once a day.
Vitamin D Vitamin D is created naturally when your skin is exposed to sunshine.
While you can get some vitamin D from grass-fed meats and other whole foods and fortified foods, sun exposure is an ideal primary source.
When taking supplemental vitamin D, also be sure to increase your intake of vitamin K2 and magnesium, either from food or a supplement.