A study by Theodore Brasky of Ohio State University was published in the Journal of Clinical Oncology in 2017, linking vitamin B6 and vitamin B12 to increased risk of lung cancer in men, but not women.
Dr. Andrew Weil, has said that there has been knowledge of this toxicity for many years. Large doses, such as 20 mg of B6 and 55 mcg of B12 taken daily over a long period of time, as in the above study, can increase risk of cancers.
Many supplemental products of B6 and B12 are sold with these same dosages. It would be best to confirm with a doctor if you really have decreased levels to need this dosage.
Information About B6 and B12 Supplements
These vitamins are routinely needed for both the nervous and immune systems and proper brain functioning of your brain neurotransmitters. However, it has been known for some time that high B vitamin levels can be toxic to your nervous system. Both of these vitamins are depleted by smoking, so a good choice would be to decrease or give up the smoking habit.
Most people should follow the USA RDA guidelines for daily requirements: 1.7 mg of B6 and 2.1 mcg of B12. If dosages are higher, they should only be taken for short periods as needed. It is better to take your supplements in a B complex form, which helps them synergistically work better together.
You can add foods to give you a little extra boost, since it is hard to eat as much as your body needs when it comes to daily vitamins.
Foods That Supply B6 and B12
It may be better to use food to increase your levels of vitamin B6 or B12 versus a large dose supplement. B6-rich foods include fish, poultry, chickpeas, potatoes, and bananas, while B12-rich foods include fish, poultry, meat, eggs, milk and milk products, and nutritional yeast.
Research studies are being done all the time and new results are being published frequently. Science is always changing; whenever a discovery is made, it becomes a new headline. It is necessary to read summaries and interpretations of study results, for more studies will always follow.Related: Vitamin B12 Deficiency: 12 Signs & Solutions