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B Vitamins for Brain Health

Simple-yet-powerful nutrients to fight depression, dementia, and more

B vitamins are required for just about every major function in the body, from red blood cell production, to metabolism, to brain health. There are eight different B vitamins – B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate) and B12 (cobalamin) – each of which possesses its own important unique functions within the body.

The B vitamins are all water-soluble, and thus we cannot hold onto them in our fat stores. This means we require a daily intake of “the B’s” to ensure optimal physiology. B vitamins are found in seeds, grains, legumes, green leafy vegetables, and broccoli (rich in biotin and folate) as well as in fish, meats, and eggs. (Red meat in particular is rich in vitamin B12.)

Inadequate dietary intake and/or poor digestion may cause B vitamin deficiency, leading to health issues like anemia, fatigue, constipation/poor digestion, heart problems (including irregular heart beat), confusion, memory issues, and poor hair, skin, and nail quality. B vitamin deficiency is also linked to the pathological progression of such serious conditions as cardiovascular disease and Alzheimer’s disease.

Thankfully, by being proactive and eating diets rich in B vitamins and by taking a daily supplemental B vitamin complex, we may be able to stave off health problems before they begin. To best understand just how B vitamins can engender such powerful positive health shifts, let’s take a quick look at the biochemical function of these nutrients:

B vitamins and the methylation cycle

 The methylation cycle is a biochemical pathway that supports a wide range of crucial cellular functions, including detoxification, immune function, DNA repair, and the protection of cells from oxidative stress.[1]

To function properly, the methylation cycle relies on vitamin B6, folate, and vitamin B12. These vitamins aid in the metabolism of several key amino acids involved in the methylation cycle, namely S-adenosyl methionine (SAMe), and methionine.

The methylation cycle.[2]


SAMe and methionine produced by methylation cycles are critical to the production of neurotransmitters in the brain, including the monoamines (like serotonin and norepinephrine) necessary for supporting the mood and maintaining healthy brain tissue.[3]

B12 and folate specifically are important co-factors for recycling the harmful amino acid homocysteine into the helpful amino acid methionine. B vitamin deficiencies can lead to reduced methylation enzyme function, and are thus associated with an increased risk of homocysteine elevation and the diseases that accompany it.

Improving cognitive function

Brain atrophy is associated with memory loss and dementia in the elderly and involves the loss of neurons and their connections in the brain. Although some degree of atrophy and subsequent brain shrinkage is common with old age, brain shrinkage occurs at a faster rate in those with mild cognitive impairment and is accelerated in those who ultimately progress to Alzheimer’s disease.

The high levels of homocysteine resulting from B vitamin deficiencies are a known risk factor for blood vessel damage, thereby increasing the risk not only of stroke, but also of dementia. The reduced supply of oxygenated blood traveling to the brain contributes to cell death and brain atrophy, as well as to increased oxidative stress. Reduced blood flow to the brain is also associated with the formation of amyloid and tau proteins associated with Alzheimer’s disease.[4],[5] Studies have shown that elevations in homocysteine increase the risk of Alzheimer’s disease,[6],[7] and that B vitamins supplementation may reduce the risk of brain shrinkage.[8],[9]

In one such study, moderate doses of supplementary B vitamins – namely folate (0.8mg/day), vitamin B12 (0.5mg/day) and Vitamin B6 (20mg/day) taken over two years – were shown to cut the rate of brain shrinkage in half. At the end of the trial the effects of the vitamin treatment were found to be dramatic, with the positive results being most pronounced in those participants who started out with the highest rates of brain shrinkage. On average, taking B vitamins slowed the rate of brain atrophy by 30%, with reductions as high as 53% observed.[10]

Managing mood

Homocysteine levels may also affect mood. Although the exact mechanism is unknown, the prevailing homocysteine hypothesis of depression suggests that deficiencies in vitamin B6, folate, and vitamin B12 can alter enzyme function significantly enough to cause depression.[11]

One study of 3,503 adults (average age 65 years) from the Chicago Health and Ageing project showed that vitamins B6 and B12 helped alleviate depression.[12] The study found that higher total intakes of both vitamins B6 and B12 were associated with a decreased likelihood of the development of depressive symptoms over an average of 7.2 years.

Vitamin B6 supplementation has also been demonstrated to reduce depression in premenopausal women.[13]

Enhancing nerve function

Vitamin B12 is also critical for nerve function, with clinical manifestations of B12 deficiency linked to neurological disorders like multiple sclerosis.[14]

Deficiency in this B vitamin is more common than one may think; up to 26% of the population has sub-clinical vitamin B12 deficiency. This is in part due to inadequate dietary intake, as is seen with vegetarian or vegan diets (diets inherently low in vitamin B12).

Another cause of B12 deficiency may stem from digestive troubles, as vitamin B12 absorption requires a special protein carrier called Intrinsic Factor (IF), which is made in the stomach in response to rising gastric acid levels. Without adequate IF, Vitamin B12 is not absorbed in the small intestine, and without adequate stomach acid, IF isn’t made. The prevalence of antacid medications, from calcium carbonate chewables to prescription proton pump inhibitors (PPIs), may very well cause vitamin B12 deficiency and its associated health problems.[15]

Fighting B vitamin deficiency therefore not only requires increasing one’s intake of nutrients, but also enhancing digestive integrity.

Where to find the B’s

Diets rich in fruit and vegetables containing a mix of complex carbohydrates and some animal protein sources deliver a nice mix of the B vitamins in adequate levels. Vegetarian and vegan diets may fall short of some B vitamins found primarily in animal proteins, in particular vitamin B12.

Thankfully, B vitamin supplements may well be the answer to dietary shortfalls, and may help vegetarians and vegans maintain good nutritional status without having to eat meat.

When choosing B vitamin products, it’s important to note that not all products are created equal. Due to a common genetic mutation of the MTHFR gene (the gene that codes for an important methylation enzyme), many people get best results with methylcobalamin – or the “methyl” form of vitamin B12 – as opposed to cyanocobalamin or hydroxycobalamin. These individuals (along with others) will also likely better utilize the 5-methyltetrahyrfolate (5MTHF), or “methylated” form of folate, as opposed to regular folic acid. B vitamin supplement complexes can supply not only B12 and folate, but also vitamin B6 and trimethylglycine (TMG, also known as betaine), a plant-derived amino acid also shown to lower homocysteine levels. A methylated B vitamin complex can thus be an easy way to maintain optimal health and stave off cardiovascular and neurological ailments.


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