Your baby resembles a tadpole more than a human, but is growing fast. The circulatory system is beginning to form, and the tiny heart will start to beat this week. Your baby is the size of a sesame seed. Read about your pregnancy at 5 weeks.
Stores of B12 can last for up to a year. Foods high in Vitamin B12 include shellfish, liver, fish, crab, fortified soy products (tofu, soymilk), fortified cereals, red meat, low fat dairy, cheese, and eggs.
The B vitamins include thiamin, riboflavin, niacin, folate (also called folic acid or folacin), vitamin B6, vitamin B12, biotin and pantothenic acid.hoto Credit Jupiterimages/Photos.com/Getty Images. Some of the best sources of vitamin B6 are poultry, seafood, bananas, leafy green vegetables such as spinach, potatoes and fortified cereals. Your diet should include 1.3 milligrams of B-6 daily to support new red blood cell growth.