Sent this in an email to a friend - I was getting headaches alot and when I saw how important B12 was and that it was a nutrient you cannot supplement fully while eating plant based, I started a sublingual supplement and viola, no more headaches - despite it not becoming deficient for a long time, I would not want to risk it - here is the info I learned, might help you all - and feel free to post some other health links, etc or just important info you learned along the way:

B12:

Apparently as great as the plant strong diet is, B12 levels can become deficient / lacking. It is the ONLY nutrient concern in this lifestyle so to me, not a huge deal. But unless you are vigilant with drinking Almond Milk or having Nutritional Yeast in a certain amount every day, B12 will deplete and can lead to irreversible neurological issues, anemia and nervous system issues to name a few. So, many who are vegan or fully plant strong, simply take a supplement so they do not have to worry reg this issue.

I researched this alot on the internet and it was not until I saw Dr. Esselstyn himself along with Rip (Engine 2) and other Dr's associated with Esselstyn, that I believed it was needed.

B12 is a supplement you cannot overdose or max out on - so the upper limit is not a huge concern. The human body will only absorb about 50% of the amount taken - so Esselstyn suggests that you take 1000 mcg of B12 per day - his son Rip with Engine 2 says 500 mcg is sufficient but since there is no upper limit and the body only absorbs 50%, I tend to side with Dr. Esselstyn.

The important key in getting the right supplement is that the B12 must contain this ingredient:
"Methylcobalamin"
Many B12 supplements will have the ingredient "Cyanocobalamin" and this is NOT the ingredient you want - look for "Methylcobalamin" only - the reason for this being the ingredient to get is:

"Cyanocobalamin is the most commonly supplemented form of vitamin B12, but you might be surprised to discover that this form of vitamin B12 does not actually occur in plants or animal tissues. In other words, outside of the chemically synthesized cyanocobalamin that you encounter as B12 in most vitamin supplements, you would be extremely hard pressed to find this compound in nature (in fact you would not be able to find it). As the name implies, cyanocobalamin contains a cyanide molecule. Most people are familiar with cyanide as a poisonous substance. Although the amount of cyanide in a normal B12 supplement is small and from a toxicology point, viewed as insignificant, your body will still need to remove and eliminate this compound. This removal is accomplished through your detoxification systems with substances like glutathione being very important for the elimination of the cyanide.

Compared with cyanocobalamin, it appears that methylcobalamin is better absorbed and retained in higher amounts within your tissues. In simple terms, they are used much more effectively. In general, methylcobalamin is used primarily in your liver, brain and nervous system.

Methylcobalamin is the specific form of B12 needed for nervous system health. Because of this it should be the first form of this vitamin thought of when interested in attempting to optimize the health of the nervous system with vitamin supplementation. Indications of a potential deficiency of B12 in the nervous system might include numbness, tingling, loss of feeling sensation, burning sensations, muscle cramps, nerve pain and slowness of reflexes.

Because of methylcobalamin's importance in nervous system health, it is also an important nutrient for vision. In fact, continued visual work (like work on a computer) often leads to a reduction in something called "visual accommodation". Methylcobalamin can significantly improve visual accommodation, while cyanocobalamin appears to be ineffective.

An elevated level of homocysteine is a metabolic indication of decreased levels of the coenzyme forms of vitamin B12, especially methylcobalamin. Homocysteine has received a tremendous amount of emphasis in the scientific literature because of its associations with heart disease and a variety of other specific health conditions. I have even seen advertisements on television promoting folic acid, as a vitamin needed to lower homocysteine. While this is true, and folic acid does lower homocysteine levels, the combination of methylcobalamin and folic acid appears to work much better.

The most well studied use of methylcobalamin has to do with sleep. Although the exact mechanism of action is not yet clear, it is possible that methylcobalamin is needed for the synthesis of melatonin. Available information indicates that methylcobalamin can modulate melatonin secretion, enhance light-sensitivity, and normalize circadian rhythm (your 24-hour clock). Because of this, individuals supplementing this form of B12 often have improved quality of sleep, often will require slightly less sleep, and will not uncommonly report that they feel a bit more refreshed when waking in the morning.

Methylcobalamin is particularly effective when your 24-hour clock is not running smoothly. This may be indicated by a need for excessive sleep, changing sleep-wake cycles, or a tendency to have altered sleep wake patterns. As examples, you might require 10-12 hours of sleep, or you might not feel tired until 2-3 am and you might wake at noon, or you might find that you wake a bit later every day and go to be a bit later every night. Under all of these circumstances the combination of methylcobalamin (about 3000 mcg daily) and exposure to bright light in the morning can help reestablish your 24-hour clock.

Because of methylcobalamin's impact on 24-hour clock and the cycles that feed of this, it is also an important vitamin to regulate your 24-hour release of the stress hormone cortisol. This seems to be particularly important for blood types A and AB. Methylcobalamin also seems to result in a better 24-hour maintenance of body temperature. Typically individuals supplementing this coenzyme form of B12 have higher temperatures in the later hours of the daytime. This usually corresponds with improved alertness at the same time of the day. While this can be of importance to all blood types, low body temperatures seems to be an area of greater challenge for A's and B's."

---- from: http://www.dadamo.com/B2blogs/blogs/index.php/2004/02/07/cyanocobalamin-versus-methylcobalamin?blog=27

Further, sublingual is the best form to take the supplement - this means dissolving it under your tongue as there are many capillaries to take in the supplement much more efficiently and faster - it will be delivered quickly to your system.

Due to these few requirements Esselstyn asks for, it made it hard to find this in the stores surprisingly - so off to Amazon.com who has the exact B12 with the right ingredient and delivered as sublingual - here is a link to their site for the exact B12 you should take:

http://www.amazon.com/gp/product/B008OXY5G0/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1

On a side note, I discovered when reading about B12, that if you are having your doc run BW at some point to check cholesterol levels or anything else for other medical issues, the standard B12 check with BW will be deceiving - when you are plant strong, your folate levels will typically be very high - that is good, that is ok - but high levels of folate on that BW test can mask the true B12 level - to be sure your supplement is doing what it should and you are not becoming deficient (and this is important to check), before the doc writes the slip for the BW, ask that they run the tests indicated here (info from www.veganhealth.org):

"Blood counts are also unreliable as high folate intakes suppress the anemia symptoms of B12 deficiency that can be detected by blood counts. Blood homocysteine testing is more reliable, with levels less than 10 µmol/litre being desirable. The most specific test for B12 status is methylmalonic acid (MMA) testing. If this is in the normal range in blood (<370 nmol/L) or urine (less than 4 mg /mg creatinine) then your body has enough B12. Many doctors still rely on blood B12 levels and blood counts. These are not adequate, especially in vegans."

The exact link to the page I got this info from is:

http://veganhealth.org/articles/everyvegan

And lastly regarding B12, depletion of B12 can take years, it is not a fast process however it is an important thing to watch b/c if you do become deficient, any change that deficiency makes to your nervous system or neurological issues is not reversible - so supplementing NOW is the only way to ensure you don't do some sort of permanent damage. It is not like a blood test shows deficiency and so you supplement and it changes that # and improves it - it will not work that way - once deficient, whatever "damage" is done stays so it is key to do this now and avoid it all together.