Development of a food composition database for the estimation of dietary S-methyl cysteine sulfoxide from vegetables

A food composition database estimating S-methyl cysteine sulfoxide (SMCSO) was created following a systematic literature search. SMCSO data (705 entries) from 19 vegetables were summarised: brassicas (n = 10) and alliums (n = 9). The highest SMCSO in brassicas was reported in Brussels sprouts (median [range]: 318 [68-420] mg/100g fresh weight (FW)) whilst the lowest was in radish (19 [4-45] mg/100g FW). Brussels sprouts were almost twice as concentrated in SMCSO as cauliflower, followed by cabbage, kale, broccoli, kohlrabi, swede, Chinese cabbage, and turnips. The alliums highest in SMCSO were Chinese chives (271 [185-413] mg/100g FW) followed by rakkyo and garlic, with substantially less found in shallots, onion, and leek. Literature reporting SMCSO content in food is sparse. Further research is required to quantify SMCSO in commercially available vegetables and other foods, in order to update and expand this database for application to large populations and future intervention studies.