I started taking this in the fall when I was introduced to some of the below research on Vitamin D's status as a "hormone" (not just a vitamin) and how it is extremely protective against flu. Not much has been proved in studies (since when do they fund studies on the efficacy of a cheap vitamin instead of expensive new pharmaceuticals?), but it is interesting to reflect that "flu season" occurs when the days start getting shorter. I certainly don't get outside much, even when I want to, and I buy the idea that humans are optimized for blood levels that result from many hours outside in the sun each day. I am taking 10,000 IU a day, in the form of 5 tiny softgels of 2,000 IU each (Costco brand). This is higher than most mainstream sources recommend, but apparently traditional thinking about what constitutes a toxic dose of vitamin D has been substantially revised in recent years, and it is way higher than once thought. BTW, make sure you take D3, but that is almost all anyone sells these days.
* Krill Oil
This is an Omega 3 supplement. There seems to be a bunch of research showing Omega 3 fatty acids to be helpful for joints, attention, heart health, lifespan, you name it. Animal source is better than vegetable source (such as flax oil) because of the presence of long chain omega-3s such as DHA, which the body has a difficult time making. I take Krill Oil instead of fish oil because (a) no fishy burps (I tried every fish oil supplement I could find, including the minty-infused ones, and they all have "repeat"! Note that the krill oil softgels themselves sometimes have a faint fishy smell, but I'll take that over fish-flavored burps any day) and (b) lower on the food chain, so doesn't require the same degree of "microparticulate filtering" and heavy metal free certification. I am currently taking Omega Red from Costco, but have also ordered Jarrow Formulas NKO from iHerb. (The Now Foods NKO is cheaper but the softgels kind of deform and stick to each other, so I avoid that brand.) 2 softgels per day.
Since I'm already going to the trouble of taking supplements, might as well take a multi.
My favorite is MegaFood DailyFoods(R)(tm) but it can be hard to find, so my second favorite is New Chapter. Both of these have the pleasant property that they do not cause "vitamin burps" if I take them on an empty stomach. I use the versions that call for 3 pills per day.
This has a reputation for warding off colds. I figure it can't hurt. The multi has 15 mg so I supplement with another 15.
Supplements I am not taking:
Vitamin C, potassium: My dad squeezes fresh orange juice every morning and I have been mooching on this. I've gotten so hooked that on the days he is not around, I will go to Uno 360 Espresso on the way to work and pay $4 for a cup of fresh-squeezed OJ. Dang.
Calcium: Have you seen the pills you have to take to get to RDA? They're enormous lumps of compressed chalk. That doesn't seem like something healthy wild humans would have consumed as part of their natural diet. I'll probably worry more about osteoporosis in 20 years. For now, I figure exercise with moderate impact (running, walking) is probably the best thing to do.