Homocysteine in food

Nutritional factors can elevate the concentration of homocysteine in plasma, which is regarded as a risk indicator for cardiovascular events and other degenerative diseases. Although alimentary methionine is believed to be the main source for plasma homocysteine, the literature is lacking information about the homocysteine content of daily food. In this paper, the total homocysteine content of some commercially available food items such as tuna, swine liver, roquefort cheese, coffee, beer and white bread was measured by RP-HPLC with fluorescence detection after pre-column derivatization with a thiol-specific sulfonylbenzofuran, namely 7-benzo-2-oxa-1,3-diazole-4-sulfonic acid (SBD-F). With the exception of coffee, all examined food contained homocysteine in amounts between 30 and 950 μg per kg, which was 2,000–10,000-fold compared to the methionine content of the respective food. Based on a hypothetical daily consumption of the investigated foods, a maximum daily intake of homocysteine ranging from 400 to 700 μg or 3–5 μmol could be estimated. Compared to plasma homocysteine levels of 6–9 μmol/l, we conclude that the amount of alimentary homocysteine has only a very slight significant impact on the plasma homocysteine level even if complete resorption of the thiol compound is assumed.