I would have preferred a more specific link than that, to save me the time of doing a detailed investigation of Kurzweil's company myself. But I ended up doing one anyways, so here are the results.
That "Ray and Terry's Longevity Products" company's front page screams low-credibility. It displays three things: an ad for a book, which I can't judge as I don't have a copy, an ad for snack bars, and a news box. Neutral, silly, and, ah, something amenable to a quality test!
The current top headline in their Healthy Headlines box looked to me like an obvious falsehood ("Dirty Electricity May Cause Type 3 Diabetes"), and on a topic important to me, so I followed it up. It links to a blog I don't recognize, which dug it out of a two year old study, which I found on PubMed. And I personally verified that the study was wrong - by the most generous interpretation, assuming no placebo effect or publication bias (both of which were obviously present), the study contains exactly 4 bits of evidence (4 case studies in which the observed outcome had a 50% chance of happening assuming the null hypothesis, and a 100% chance of happening assuming the conclusion). A review article confirmed that it was flawed.
That said, he probably just figured the news box was unimportant and delegated the job to someone who wasn't smart enough to keep the lies out. But it means I can't take anything else on the site seriously without a very time-consuming investigation, which is bad enough.
The bit about Kurzweil taking 250 nutritional supplements per day jumps out, too, since it's an obviously wrong thing to do; the risks associated with taking a supplement (adverse reaction, contamination, mislabeling) scale linearly with the number taken, while the upside has diminishing returns. You take the most valuable thing first, then the second-most, by the time you get to the 250th thing it's a duplicate or worthless. Which leads me to believe that he just fudged the number, by counting things that are properly considered duplicates like split doses of the same thing.
Kurzweil should be concerned that his name is associated with junk science, and the overall result, but I think its a little far-fetched to think the man is actually selling nutritional supplements that he thinks are bogus.
The state of medicine and nutrition today is such that we know there is so much we don't know. The human body is supremely complex, to make an understatement. The evidence is pretty strong that most supplements, and even most multi-vitamins, don't do much or even do harm.
However that is certainly not true in every case, and there are...
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