McCauley’s team embarked on a series of two-week miniexperiments. In the first two-week phase, they all refrained from taking any supplements whatsoever. In the next part they took Centrum multivitamins, followed by a period when they received a more active form of vitamin B called L-methylfolate, then a combination of both vitamin sources and, finally, a washout phase with no vitamin supplements. In between each treatment, the group tested their own blood to measure concentrations of homocysteine, an undesirable amino acid that serves as a suitable biomarker for vitamin B activity.
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.
“I look at this as a proof of concept trial,” says study participant Chris Hogg, director of commercial strategy for Gilead Siences, a Foster City, California–based biotech company. “We proved basically that it is possible to ask a question, do an intervention and measure an outcome.”
The article also discusses Genomera, the fledgling free service meant to help people share genomic and phenotypic information and analyze it, and the oft-mentioned-by-me Personal Genome Project, which now has 16,000 people waiting to join the party.