By Dr. Mercola 
Alzheimer’s disease is currently at epidemic proportions, with 5.4 million Americans — including one in eight people aged 65 and over — living with Alzheimer’s  disease. By 2050, this is expected to jump to 16 million, and in the next 20 years, it is projected that Alzheimer’s will affect one in four Americans.
While the cause of this condition is believed to be a mystery, it’s becoming increasingly clear that what you eat, or don’t eat, can influence your risk as well as the rate at which the disease progresses. B group vitamins, in particular, especially folic acid and vitamins B6 and B12, are again making headlines for their powerful role in preventing Alzheimer’s disease.
B Vitamins May Reduce Brain Shrinkage by Up to 90 Percent
High levels of the amino acid homocysteine are linked to brain shrinkage and an increased risk of Alzheimer’s. B vitamins are known to suppress homocysteine. In a 2010 study, participants received relatively high doses of B vitamins, including:
- 800 micrograms (mcg) folic acid — US RDA is 400 mcg/day
- 500 mcg B12 (cyanocobalamin) – US RDA is only 2.4 mcg/day
- 20 mg B6 (pyridoxine hydrochloride) — US RDA 1.3-1.5 mg/day
The study was based on the presumption that by controlling the levels of homocysteine, you might be able to reduce the amount of brain shrinkage, which tends to precipitate Alzheimer’s.
Indeed, after two years those who had received the vitamin-B regimen suffered significantly less brain shrinkage compared to those who had received a placebo. In those who had the highest levels of homocysteine at the start of the trial, their brains shrank at half the rate of those taking a placebo.
The latest study takes this research a step further, showing not only that B group vitamins may slow brain shrinkage but that it may specifically slow shrinkage by as much as seven-fold in brain regions specifically known to be most impacted by Alzheimer’s disease.
Among participants taking high doses of folic acid and vitamins B6 and B12, blood levels of homocysteine were lowered as was the associated brain shrinkage – by up to 90 percent. The researchers noted:
“ … 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.”
Foods Rich in Vitamin B12 Also Shown to Lower Alzheimer’s Risk
According to a small Finnish study published in the journal Neurology, people who consume foods rich in B12 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 healthful B-vitamin sources, such as meat, poultry, eggs, dairy products and wild-caught fish. Leafy green vegetables, beans and peas also provide some B vitamins, but if you eat an all vegetarian or vegan diet, vitamin B12 is one of the nutrients your body is most likely deficient in, as it is naturally present in foods that come from animals, including meat, fish, eggs, milk and milk products.
This is also a strong argument to use fermented foods  and limit sugar intake. Consider that the entire B group vitamin series is produced continually within your gut, assuming it is continually replenished and reseeded with healthy flora from organically grown raw foods, particularly the flora-dense cultured traditional fermented foods, e.g. yoghurt, sauerkraut, or failing that, a good probiotic supplement.
B-Vitamin Deficiencies Tied to Brain Risks
Even if you eat animal foods, vitamin B12 requires a complex system in your body involving intrinsic factor to bind to it so it can be actively absorbed in the end of your small intestine (terminal ileum). As you grow older, the ability to produce intrinsic factor decreases and may cause a deficiency state. Studies from the U.S. Framingham trial show one in four adults are deficient in vitamin B12 , and nearly half the population has suboptimal blood levels.
This is important to be aware of, and correct if it applies to you, as people with high levels of markers for vitamin B12 deficiency are more likely to score lower on cognitive tests, as well as have a smaller total brain volume, which suggests a lack of the vitamin may lead to brain shrinkage.
A previous study on the impact of vitamin B12 on brain wasting also found that seniors with lower vitamin B12 levels at the start of the study had a greater decrease in brain volume at the end. Those with the lowest B12 levels had a six-fold greater rate of brain volume loss compared with those who had the highest levels.
Interestingly, none of the participants were actually deficient in vitamin B12 — they just had low levels within a normal range. This goes to show that “normal” is not necessarily the same as “optimal” when you’re talking about nutrients. You don’t have to be clearly deficient in order to experience a decline in brain health. The study’s lead researcher commented on this, saying:
“Our results suggest that rather than maintaining one’s B12 at a level that is just above the cut-off for deficiency, it might be prudent to aim to keep it higher up than normal range.”
Folic Acid Versus Folate: What’s the Difference?
Hearing about the benefits of B vitamins for your brain health might make you consider trying a supplement. However, it’s important to know the difference between folic acid and folate before you do. Although often used interchangeably, folic acid is a synthetic type of B vitamin used in supplements and fortified foods, while folate is the natural form found in foods. Think: folatecomes from foliage (edible leafy plants) and not supplement bottles as a guideline.
There is some research suggesting that taking high doses of synthetic folic acid may actually increase your risk of cancer, immune system damage or other health problems. Further, in order for folic acid to be of use to your body, it must first be activated into its biologically active form – L-5-MTHF. This is the form that is able to cross the blood-brain barrier to give you the brain benefits noted. However, nearly half of the population has difficulty converting folic acid into the bioactive form because of 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.
More Dietary Strategies for Fighting Alzheimer’s Disease
Ensuring you have adequate levels of B vitamin in your diet is just one dietary strategy to reduce your risk of Alzheimer’s and protect your brain health, as it’s becoming increasingly clear that the same pathological process that leads to insulin resistance and type 2 diabetes may also hold true for your brain. As you over-indulge on sugar and grains, and starve yourself of enough essential fatty acids, your brain becomes overwhelmed by the consistently high levels of insulin and eventually shuts down its insulin signaling, leading to impairments in your thinking and memory abilities, and eventually causing permanent brain damage.
Alzheimer’s disease was tentatively dubbed “type 3 diabetes” in early 2005 when researchers learned that the pancreas is not the only organ that produces insulin. Your brain also produces insulin, and this brain insulin is necessary for the survival of your brain cells – that is, until the brain starts resisting chronically elevated levels of it, and it becomes toxic.
You may already know I have become passionate about warning of the dangers of fructose . There is no question in my mind that regularly consuming more than 25 grams of fructose per day will dramatically increase your risk of dementia and Alzheimer’s disease. Consuming too much fructose will inevitably wreak havoc on your body’s ability to regulate proper insulin levels.
In one study from UCLA, researchers found that rats fed a fructose-rich and omega-3 fat deficient diet (similar to what is consumed by many Americans) developed both insulin resistance and impaired brain function in just six weeks. Additionally, recent research has also shown that intermittent fasting  also triggers a variety of health-promoting hormonal and metabolic changes similar to those of constant calorie restriction — including reduced age-related brain shrinkage.
According to Professor Mark Mattson, head of neuroscience at the US National Institute on Ageing: “Suddenly dropping your food intake dramatically — cutting it by at least half for a day or so — triggers protective processes in the brain.” He likens the effects to those from exercise, stating intermittent fasting could help protect your brain against degenerative diseases such as Alzheimer’s.
A Comprehensive Anti-Alzheimer’s Lifestyle
Memory loss and cognitive impairment are NOT “normal” parts of aging. While even mild “senior moments” may be caused by the same brain lesions associated with Alzheimer’s disease and other forms of dementia, these cognitive changes are by no means inevitable! People who experience very little decline in their cognitive function up until their deaths have been found (post-mortem) to be free of brain lesions, showing that it’s entirely possible to prevent the damage from occurring in the first place… and one of the best ways to do this is by leading a healthy lifestyle, which includes:
- Limit fructose . As mentioned, most everyone will benefit from keeping their total fructose consumed to below 25 grams per day.
- Improve magnesium levels. There is some exciting preliminary research strongly suggesting a decrease in Alzheimer symptoms with increased levels of magnesium in the brain. Unfortunately, most magnesium supplements do not pass the blood-brain barrier, but a new one, magnesium threonate, appears to and holds some promise for the future for treating this condition.
- Optimize your vitamin D levels  with safe sun exposure. Strong links between low levels of vitamin D in Alzheimer’s patients and poor outcomes on cognitive tests have been revealed. Researchers believe that optimal vitamin D levels may enhance the amount of important chemicals in your brain and protect brain cells by increasing the effectiveness of the glial cells in nursing damaged neurons back to health. Vitamin D may also exert some of its beneficial effects on Alzheimer’s through its anti-inflammatory and immune-boosting properties. Sufficient vitamin D is imperative for proper functioning of your immune system to combat inflammation that is also associated with Alzheimer’s.
- Keep your fasting insulin levels below 3. This is indirectly related to fructose, as it will clearly lead to insulin resistance. However other sugars (sucrose is 50% fructose by weight), grains and lack of exercise are also important factors.
- Vitamin B12  and other B vitamins: As mentioned, these vitamins appear useful in protecting against brain shrinkage and may even help treat Alzheimer’s disease and reduce memory loss .
- Eat a nutritious diet, rich in folate, such as the one described in my nutrition plan . Vegetables, without question, are your best form of folate, and we should all eat plenty of fresh raw veggies every day.
- High-quality animal-based omega-3 fats, such as krill oil. (I recommend avoiding most fish because, although fish is naturally high in omega-3, most fish are now severely contaminated with mercury.) High intake of the omega-3 fats EPA and DHA help by preventing cell damage caused by Alzheimer’s disease, thereby slowing down its progression and lowering your risk of developing the disorder.
- Avoid and remove mercury from your body. Dental amalgam fillings, which are 50% mercury by weight, are one of the major sources of heavy metal toxicity. However you should be healthy prior to having them removed. Once you have adjusted to following the diet described in my optimized nutrition plan , you can follow the mercury detox protocol  and then find a biological dentist to have your amalgams removed.
- Avoid aluminum, such as antiperspirants, non-stick cookware, vaccine adjuvants , etc.
- Exercise regularly. It’s been suggested that exercise can trigger a change in the way the amyloid precursor protein is metabolized, thus slowing down the onset and progression of Alzheimer’s. Exercise also increases levels of the protein PGC-1alpha. Research has also shown that people with Alzheimer’s have less PGC-1alpha in their brains and cells that contain more of the protein produce less of the toxic amyloid protein associated with Alzheimer’s. I would strongly recommend reviewing the Peak Fitness Technique  for my specific recommendations.
- Coconut Oil may offer profound benefits in the fight against Alzheimer’s disease. One of the primary fuels your brain uses is glucose, which is converted into energy. When your brain becomes insulin resistant, atrophy due to starvation can occur. However, ketone bodies, or ketoacids, can also feed your brain, perhaps better, and prevent brain atrophy. It may even restore and renew neuron and nerve function in your brain after damage has set in. In fact, ketones appear to be the preferred source of brain food in patients affected by diabetes or Alzheimer’s. Ketones are what your body produces when it converts fat (as opposed to glucose) into energy, and a primary source of ketone bodies are the medium-chain triglycerides (MCT) found in coconut oil, which is approximately 66% MCT by weight. It can also be used to treat Alzheimer’s disease by using a ketogenic diet with coconut oil.
- Astaxanthin is a natural pigment with unique properties and many clinical benefits, including some of the most potent antioxidant activity currently known. As a fat-soluble nutrient, astaxanthin readily crosses your blood-brain barrier. One study found it may help prevent neurodegeneration associated with oxidative stress, as well as make a potent natural “brain food.”
- Gingko biloba: Many scientific studies have found that ginkgo biloba has positive effects for dementia, including improving cognitive performance and social functioning for those suffering from dementia.
- Alpha lipoic acid  (ALA) can help stabilize cognitive functions among Alzheimer’s patients and may slow the progression of the disease.
- Avoid flu vaccinations, as most contain both mercury and aluminum, well-known neurotoxic and immunotoxic agents.
- Eat plenty of blueberries. Wild blueberries, which have high anthocyanin and antioxidant content, are known to guard against Alzheimer’s and other neurological diseases.
- Challenge your mind daily. Mental stimulation, especially learning something new, such as learning to play an instrument or a new language, is associated with a decreased risk of Alzheimer’s. Researchers suspect that mental challenge helps to build up your brain, making it less susceptible to the lesions associated with Alzheimer’s disease.
- Avoid anticholinergic and statin drugs . Drugs that block acetylcholine, a nervous system neurotransmitter, have been shown to increase your risk of dementia. These drugs include certain nighttime pain relievers, antihistamines, sleep aids, certain antidepressants, medications to control incontinence, and certain narcotic pain relievers.
Statin drugs are particularly problematic because they suppress the synthesis of cholesterol, deplete your brain of coenzyme Q10 and neurotransmitter precursors, and prevent adequate delivery of essential fatty acids and fat-soluble antioxidants to your brain by inhibiting the production of the indispensable carrier biomolecule known as low-density lipoprotein. In fact, last year the FDA required statin manufacturers to list “memory loss” as a known side effect of their use.
Read the full article here: http://articles.mercola.com/sites/articles/archive/2013/06/03/vitamin-b.aspx 
See Also: Coconut Oil and Alzheimer’s Disease: The News is Spreading