**3.3.4 Inadequate nutrition**

B vitamins have been suggested to play a critical role to maintain low homocysteine levels (Silaste et al., 2001). A diet poor in fresh fruit and vegetables or strict vegeterians may develop nutritional vitamin B12 deficiency (Miller et al., 1991). This is particulary serious in pregnancy, as the mother may not be able to supply the fetus with sufficient vitamin B12. Also modern food processing may destroy essential vitamins and it has recently been shown that microwave heating may destroy as much as 30 % of the vitamin B12 content in food (Watanabe et al., 1998). Prolonged heating may also destroy folate and vitamin B6. Besides, healthly subjects eating fish more than 3 times a week had lower homocysteine levels than those eating fish less than one a month.
