I have not, but please say more - I'm interested to hear. One of our sons just had a test for a specific pair of genes recommended by his doctor - I don't know all the details but I'm curious to hear more about this subject. There was also mention of B vitamins.
Well Steve, this DNA analysis stuff is all in very early stages. There are mountains of information that I've really only started to dig through since I got my results, and a lot of it seems to be unactionable (I have a 7x increased risk of early baldness -- thanks dad!) or not yet well-researched.
But there are a handful of problematic combinations of genes that appear to make a wide-ranging DNA analysis like this worth the money.
One of these problematic combinations relates to MTHFR (methylenetetrahydrofolate reductase). Basically what it does is severely reduce the body's ability to metabolize Vitamin B9 (folic acid), so even a person getting enough vitamin B9 in their diet can have issues. These combinations range in severity, but in my case it seems I process folic acid at only 10-20% the rate of the average person. They are also fairly common. (I believe I saw something like 12% of Caucasians have it)
This inability to metabolize folic acid leads to an excess of homocysteine (hyperhomocysteinemia). This is a known risk factor for cardiovascular disease and psychological disorders, among other things.
The solution to this seems to be supplementation of 5-MTHF (methyltetrahydrofolate), the metabolite of folic acid that is important in regulating homocysteine. In addition, you can also get the level of blood homocysteine tested to determine whether it's working to get it down to the normal range.
I hope I got most of that right. This isn't my background and I've just been reading up on it, so if I'm wrong hopefully one of our resident biochemistry geniuses will help me out.
All I would caution is that genomic linkage studies are widely published and reported. A decent geneticist would always recommend that these association studies need replicating with an independent study before they should be considered validated. In my experience (I'm no geneticist but I am a scientific researcher) this happens infrequently.
If I got some recommendations from 23andme I would ask if the linkages are supported by at least two independent analyses.
I do think genomic analysis does have a lot to tell us about individual variations in health, but interpreting the data is still very much a developing field. Just my 2p worth.
I do something similar (although even weaker) scanning transcriptomes/genomes for adaptive mutations relating to metabolism in fish. Finding possible links between mutations and a trait is easy to do, but is often quite speculative. Actually validating this and/or finding the exact implication of a mutation is much more difficult. As krg said, it would be good to see how well validated it is before you base decisions affecting your health on it.
We are still at a very early stage of understanding genomics.