Vitamin B-12 is one of the 13 essential vitamins your body needs to maintain a healthy nervous system and to make blood cells. Although generally considered safe, high doses of vitamin B-12 can cause diarrhea, blood clots, itching and serious allergic reactions. High-blood levels of vitamin B-12 can be found in people who suffer from diabetes or who are obese. Having high levels of vitamin B-12 can also indicate a liver disease or leukemia. Lower your vitamin B-12 levels by avoiding foods that contain a high amount of the vitamin. Always consult your doctor before attempting to lower your vitamin B-12 levels or intake.
Do not eat mussels or clams, which contain particularly high levels of vitamin B-12. A 3-oz. serving of mussels contains 20 mcg; the same serving size of clams contains 84 mcg.
Avoid meat and fish, which are good sources of vitamin B-12. A 3-oz. serving of crab has 8.8 mcg; salmon has 2.4 mcg; and beef has 2.1 mcg of vitamin B-12. Eat turkey and poultry instead, which only have 0.3 mcg in each 3-oz. serving.
Eat a vegetarian diet. Vitamin B-12 is only found in animal-based foods and thus, eating a vegetarian diet can help lower your intake of the vitamin. However, remember your body does need a small amount of vitamin B-12; the recommended daily allowance is 2.4 mcg for adults.
Eat potassium-rich foods or take a potassium supplement when eating vitamin B-12 rich foods. Potassium can reduce the absorption of vitamin B-12 into the body. However, high potassium consumption can cause toxicity, so never exceed your recommended potassium intake unless instructed by your doctor. The recommended daily intake for potassium is 4,700 mg for adults.
Take a vitamin C supplement with vitamin B-12 rich foods. Vitamin C may destroy dietary vitamin B-12. Although rare, consuming too much vitamin C can cause some gastrointestinal symptoms. Do not exceed 2,000 mg of vitamin C per day.