Sources of B group vitamins include whole grains, meat, poultry, eggs, nuts, fish, dairy, legumes, nuts and seeds, fresh fruit and vegetables. It's important to eat a wide variety of whole foods to ensure you are meeting adequate B vitamin levels. They are delicate vitamins that may be easily destroyed through food processing, storage and preparation methods. Excessive alcohol consumption may reduce the availability of B vitamins. B vitamins supplementation may also be considered in gluten-free diets and diets lacking fruit and vegetables. Individuals who follow a vegetarian or vegan diet may be deficient in B12 as it is mostly found in animal products. Deficiency may lead to anemia, fatigue, weakness or shortness of breath.