Vitamin B12 Inhibits Progression of Hypercholesterolemia and Atherosclerosis in Rabbits Fed a High Cholesterol Diet

The present study was undertaken to examine the effect of vitamin B12 on serum cholesterol levels and development of aortic atherosclerosis in New Zealand White male rabbits fed a high cholesterol diet. Twenty rabbits were divided into 4 groups matched for their baseline serum cholesterol values. Groups 1 and 2 received a normal diet, whereas groups 3 and 4 had cholesterol mixed with their chow. After 5 weeks, the serum cholesterol of groups 3 and 4 increased by approximately 12 fold compared to groups 1 and 2. At that point, vitamin B12 was administered in the drinking water (1000 micrograms/l) to rabbits in groups 2 and 4. At week 8, the Vitamin B12 dose was increased to 2400 micrograms/l for group 4. At 12 weeks into the study, rabbits in group 4 (high cholesterol diet plus vitamin B12) had a serum cholesterol level of 919 +/- 270 mg/dl while those of group 3 (high cholesterol diet) had a serum cholesterol level of 1417 +/- 250 mg/dl. At the end of the study, rabbit aortas were excised, fixed, and stained with fat-red-B, a dye for lipid. Comparison of the aortas of rabbits that received the lipid rich diet revealed that animals given additional vitamin B12 had significantly decreased surface area of fat deposition. These data suggest the potential role for vitamin B12 as a safe and inexpensive pharmacological intervention for the modification of the progression of human atherosclerosis.