Hats off to Misha Angrist over at Genome Boy for bringing this fascinating story about personal genomic experiments that ran in Nature Medicine to my attention. Raymond McCauley and a small team of DIY-researchers wanted to know how effective different types of vitamins were for clearing "undesirable" amino acids from their bodies. One of the supplements they investigated was a standard, over-the-counter vitamin B tablet. But the other, was a more highly active B vitamin, called L-methylfolate. McCauley's genetic profile differed from the rest of his team in two particular SNPs (he was homozygous at both locations).
For four of the study participants, all of whom paid out of pocket to participate in the research, either type of vitamin supplement decreased homocysteine levels by almost a third, indicating that the vitamins were having the desired effect and leading to homocysteine getting converted into more benign amino acids. But for McCauley—the only person in the study who was homozygous at both SNPs tested—run-of-the-mill pills raised his homocysteine concentrations, and only the more active L-methylfolate seemed to aid his vitamin metabolism. After completing the experiment last month, McCauley changed his source of supplementary vitamin B to L-methylfolate.