Vitamin B12 is a water soluble vitamin that is naturally present in some foods, primarily foods high in protein. Vitamin B12 is bound with the protein in food and it is broken down by the hydrochloric acid and gastric protease in our stomachs. Vitamin B12 is required for proper red blood cell formation, neurological function, and DNA synthesis.
The recommended daily allowance for Vitamin B12:
Men and Women >14yr : 2.4mcg/day
How much B12 is in what we eat?
Salmon 3oz- 4.9 mcg
Beef 3oz- 2.4 mcg
Plain yogurt 1 cup- 1.4 mcg
Cheese 1oz (1 cube)- 0.9 mcg
Milk 1 cup- 0.9 mcg
1 large egg- 0.6 mcg
You can see that for individuals who eat protein regularly vitamin B12 deficiency is unlikely. Often times we actually get more B12 than recommended.
There are however individuals at risk for B12 deficiency:
- Strict Vegetarians and Vegans
- Pernicious anemia patients
- Elderly patients
Does B12 work to increase energy and endurance?
According to the Office of Dietary Supplements, National Institutes of Health:
Due to its role in energy metabolism, vitamin B12 is frequently promoted as an energy enhancer and an athletic performance and endurance booster. These claims are based on the fact that correcting the megaloblastic anemia caused by vitamin B12 deficiency should improve the associated symptoms of fatigue and weakness. However, vitamin B12 supplementation appears to have no beneficial effect on performance in the absence of a nutritional deficit.
Vitamin B12 and Diet:
According to the 2005 Dietary Guidelines for Americans, “nutrient needs should be met primarily through consuming foods. Foods provide an array of nutrients and other compounds that may have beneficial effects on health. In certain cases, fortified foods and dietary supplements may be useful sources of one or more nutrients that otherwise might be consumed in less than recommended amounts. However, dietary supplements, while recommended in some cases, cannot replace a healthful diet.”