Here is a list of foods that are naturally high in vitamin B12:

Measurement Reference for Vitamin B12, µg (1000 µg = 1mg)

1.   Clams have the most vitamin B12, with 98.9 μg found in each serving of 100g. This is equivalent to 1648% of the U.S. RDA (recommended daily allowances). Mussels and oysters are also rich in vitamin B12.

2. Animal liver is full of vitamin B12. For example, liver of lamb contains 85.6 μg of vitamin B12 in each 100g serving, which translates into 1428% of the RDA.

3.   Caviar and fish eggs are loaded with this vitamin. Whitefish eggs have 56.4 μg in each 100g serving, which is over 940%of the U.S. RDA.

4. Octopus is packed with vitamin B12, containing 36 μg of vitamin B12. This is equivalent to 600% of the RDA.

5. Fish provides a decent amount of vitamin B12.  Salmon has 18 μg per serving, which is 302% of the U.S. RDA.

6. Lobster is a good source of vitamin B12. Lobster provides 4.04 μg, which is 67% of the U.S. RDA.

7. Beef has much to offer in the way of vitamin B12, depending on the cut. Chuck has 6.18 μg in each 100g serving, which is 103% of the U.S. RDA.  This is in contrast to rib-eye, which is only 60% of the RDA.

9. Cheese is a decent alternative for those who choose to avoid the consumption of animals and seafood. Swiss cheese contains 3.34 μg in each 100g serving, which is 56% of the U.S. RDA. One serving of mozzarella cheese (used in pizza) has enough vitamin B12 to satisfy 39% of the RDA.

10. Chicken egg yolk has 1.95 μg in each 100g serving, which is 33% of the U.S. RDA for vitamin B12. This means that there is only.33 μg, in every yolk, which is only 6% of the U.S. RDA. The egg white contains a negligible amount of vitamin B12.

A study done in Mexico City demonstrates a correlation between an increased intake of vitamin B12 and reduced breast cancer risk.

This study was published in Cancer Epidemiology Biomarkers and Prevention, in the March, 2006 issue.

The participants involved women living in Mexico City, a community that had seen a higher incidence of breast cancer in recent years.  One group consisted of 475 women who had been diagnosed with breast cancer. A second group involved 1,391 healthy women aged 18 to 82 years who were also surveyed, for a total of 1,866 women.

Researchers distributed questionnaires to both groups of women. The questionnaire required that the women submit detailed information about their diets, in order to determine their average daily intake of folate, vitamin B6 and vitamin B12.

Based on the data obtained, the researchers determined that women with the highest intake of B12 were 68% less likely to develop breast cancer, and the women who consumed the most folate were 36% less likely to develop breast cancer.

In conclusion, consuming the recommended dietary allowances for folate and vitamin B12 may help prevent breast cancer.

Researchers at Ben-Gurion University in Beer-Sheva, Israel, have found a strong correlation between canker sores and B12. This research was published in the Journal of the American Board of Family Medicine (January/February, 2009).

Canker sores, also known as Recurrent Aphthous Stomatitis (RAS), affects about 25% of the population. These lesions of the mouth are small, painful ulcers that heal within two weeks. They often recur.

Triggers in a person’s environment may lead to RAS. These triggers include trauma, irritants, dryness, infections, hypersensitivity, toxic agents and autoimmune conditions. In addition, a nutritional deficiency may also be the cause. People who are low in iron, vitamin C, vitamin B12 or folic acid may suffer from RAS.

Obviously, not all triggers can be prevented, and some people are more prone to this than others.

This study involved 58 patients who suffered from RAS. Some were given a dose of vitamin B12 daily, and others were given a placebo. By the end of the study, 74% of those given the B12 treatment no longer suffered from recurring RAS, also known as canker sores.

In conclusion, those suffering from RAS would benefit greatly from vitamin B12 supplementation.

Vitamin B12 is linked to brain size, and therefore this vitamin may help prevent dementia by maintaining brain volume, according to a study published in Neurology (September 9, 2008).

The study focused on 107 volunteers whose average age was 73 years, ranging from 61 to 87 years old. All participants were required to undergo a physical examination, brain MRI and CT scans. Only people in good physical and mental health were included in this study.

For this study, blood samples were also taken of the volunteers. Tests were done to measure vitamin B12 plasma levels, in addition to levels of homocysteine, folate and methylmalonic acid (MMA). These measurements were taken once a year over the duration of five years.

For all the volunteers, the B12 plasma levels fell within the range of normal.

At the end of the five-year period, the volunteers were again subject to brain scans and memory tests. Subjects who had the most brain loss also had lower concentrations of B12. No correlation was made between brain loss and levels of homocysteine, folate or MMA.

The results of this study demonstrated that those people with lower B12 plasma levels were six times more likely to have a loss of brain volume and a decrease in brain size than those with higher levels. Therefore, the authors of this study have concluded that by increasing the consumption of of vitamin B12 among the elderly can reverse brain shrinkage, and possibly prevent memory loss as well. It is hoped that future clinical trials will determine the affects of vitamin B12 supplementation on brain shrinkage.

In the meantime, the authors of this study would advise the geriatric population to increase their intake of vitamin B12 through meat, fish, milk and fortified cereals.