In the Netherlands fortification of food products is not yet mandatory. One of the major arguments of the Dutch Health Council to advise against mandatory fortification is the possibility of masking of a vitamin B12 deficiency. A possible solution to overcome the possibility of masking is: fortification of foods with both folic acid and vitamin B12. In this study we want to assess the effects of this fortification strategy on markers of folate and vitamin B12 status.

During a 12 week period subjects will consume

• bread fortified with folic acid and vitamin B12 or
• placebo bread (not fortified)

Bread consumption has to be at least 3 slices per day, fortification level is 100mcg folic acid and 6mcg vitamin B12 per 3 slices.

We will study the effect of this fortification strategy on markers of folate and vitamin B12 status.

Inclusion Criteria:

• age 50-75y

Exclusion Criteria:

• consumption of < 3 slices of bread/day
• use of B-vitamins in the period three months prior to the study
• treatment with B12-injections in the last 5y
• illness or use of medication interfering with folate or vitamin B12 metabolism