IMHO the key to understanding vitamin supplementation is first, to know which are fat-soluble (and will be stored by your body) and which are water-soluble (and will be flushed by your body when you urinate).
So, it is almost impossible to over-dose on Vitamin C, since, your body will easily eliminate anything it doesn't need - C is water-soluble.
In school, I was taught a mnemonic for fat soluble vitamins: DEAK. In other words, you want to "deke" [1] out of the way from these vitamins. You want to watch how much of vitamins D, E, A, K you ingest because they are fat soluble and you can easily overdose on them (unlike vitamin C). It's not a catch-all but it helps when you are taking vitamins.
[1] it's a play on words and a homonym, "deke" comes from hockey where you dodge or fake out an opponent to get around them. It must be the Canadian school system further injecting hockey into our lives. :)
Then again, there have been several studies [0] that show that many people in the northern hemisphere are deficient in vitamin D and that the deficiency could be the root of serious health problems.
True, for example half of Finns receive less than recommended amount of vitamin D. To combat this dairy and edible fat products have received vitamin D supplements since 2003. For example skimmed milk (the most popular one) would otherwise have very little D because it gets removed in the process along with fat. First you take it out, then put it back in...
Do you know if the RDA amount is kept up-to-date with current research?
For those of us who want an insurance policy, have you got any recommendations on what multi-vitamins to aim for (a particular brand, maybe that you take?) Are all brands equal?
best insurance policy is to eat proper food. thats not snark, its just true. get a spreadsheet built in excel, and actually model a decent diet for ~7 days. its a very eye-opening experience. you can track calories, fat, carbs, protein and whatever else quite readily with online tools. While resturant food will be excluded (you would need basic recipe or key ingedient lists), soon enough you will understand just how much nutrients are in "real food".
> 'The vitamin C in supplements mobilizes harmless ferric iron stored in the body and converts it to harmful ferrous iron, which induces damage to the heart and other organs,'' Dr. Herbert said in an interview.
> ''Unlike the vitamin C naturally present in foods like orange juice, vitamin C as a supplement is not an antioxidant,'' Dr. Herbert said. ''It's a redox agent -- an antioxidant in some circumstances and a pro-oxidant in others.''
This was for the relatively small amount of 500mg per day.
> Although vitamin C can be well tolerated at doses well above the RDA recommendations, adverse effects can occur at doses above 3 grams per day though overload is unlikely. The common 'threshold' side effect of megadoses is diarrhea. Other possible adverse effects include increased oxalate excretion and kidney stones, increased uric-acid excretion, systemic conditioning ("rebound scurvy"), preoxidant effects, iron overload, reduced absorption of vitamin B12 and copper, increased oxygen demand, and acid erosion of the teeth with chewing ascorbic-acid tablets.[25] In addition, one case has been noted of a woman who had received a kidney transplant followed by high-dose vitamin C and died soon afterwards as a result of calcium oxalate deposits that destroyed her new kidney. Her doctors concluded that high-dose vitamin C therapy should be avoided in patients with renal failure.[26]
And there is an LD50 for rats, although that's 11.9 g per kg. (6 ft adult is 85 kg, that's over a kilogram of vitamin C to reach the same level. That would be 1,000 tablets of 1,000 mg vitamin C.
The LD50's for a 100kg person of salt (100g), sugar (1kg) or vitamin C (1.1 kg) are huge. Long-term exposure to sugar can affect your overall health, like causing insulin resistance or just being processed into fat. Salt isn't bad for you, unless you already have a heart or kidney problem. Vitamin C might have some side effects but the evidence is very thin so far.
He means phytonutrients. Those components of plants that are more complex than protein, carbohydrates or fats and which are known to extend human life by largely unknown processes.
That's something you really need to do your own research on, it's a big topic. Start by looking up 'complex carbohydrates' and consider that while they are made up of basic sugars, in nature the breakdown of those complex carbs would be done mostly in the gut rather than through refinement in a sugar plant. A pediatrician friend of mine doesn't even believe in consuming juice, because she considers the body is better able to regulate its sugar intake by processing the fruit and also using the non-nutritious bulk fiber of the fruit to regulate the amount consumed. This is her hunch rather than being proved through exhaustive research, but it seems like a fairly well-informed hunch.
A glass of juice is a lot of sugar. One serving size of fruit is much smaller, and would give very much less juice. It's very easy to drink a lot of sugar if you're drinking undiluted juice.
Dietitians in the UK recommend that people are cautious with juices and smoothies because of the amount of sugar, and they recommend that people just eat the fruit and drink water. Especially for children, the high sugar and acid is tricky for teeth.
(I agree that the hunch seems reasonable. But then, those are the things that need research, to combat my biases.)
"Processed food is fiberless food. That's basically what it comes down to. Processed food means that you've got to take the fiber out for shelf-life. And there are two kinds of fiber. There's soluble fiber: which is the kind of stuff that holds jelly together, and pectins, and things like that. And then there's the insoluble fiber: the stringy stuff, like, you know, cellulose, like what you see in celery. You need both. What I describe in the book is like it's kind of like your hair-catcher in your bathtub drain. Um, you have this plastic lattice work with holes in it. So, if you take a shower and the hair is coming down, it blocks up the holes, but only if the hair catcher is there. So, imagine that the cellulose is the hair-catcher, and imagine the hair is the soluble fiber, blocking up the little holes. When they're both there, it forms a barrier on the inside of your intestine.
You actually can see it during electron microscopy, that it's a secondary barrier that reduces the rate of absorption of nutrients from the gut, into the bloodstream. And what that does is that it actually keeps the liver safe, because it reduces the rate at which the liver has to metabolize, the stuff. And if you overload the liver, what it does is it has no choice but to turn extra energy into liver fat. And that's what drives this whole process. Is the process of liver fat accumulation, and the thing that does that the worst is sugar, especially when it's not teamed up with fiber.""
Everyone at our office including me are total coffee junkies. We each pitched in a few hundred to get the best possible coffee machines. Before that we'd each be blowing like $40 a day on coffees, always trying new places at lunch, after work, before work, coffee runs to places across the street. It's really a cultural thing at our office.
We'd be sitting and coding for a few hours, and we're all just internally waiting for somebody to utter the magic words "...coffee run?".
At a moments notice we're all out the door, headphones are smashed, phones are flung, chairs are tipped over, papers are in the air!
Eat mountains of fresh vegetables and fruit and other whole foods and you'll get what you need. Hard part of this - keeping your fridge stocked with them.
I used to eat the gummy vitamins like candy, I got Hypervitaminosis, and my hair started to fall out. I thought I had a horrible disease. Then we figured it out. It wasn't much fun.
I hope everyone understands that there is NO reliable evidence that any dietary supplements, including vitamins, provide any health benefits whatsoever to healthy people.[1] Occasionally individual studies will find an association between a particular positive outcome and a particular supplement, say breast cancer survival and vitamin D.[2] But it is just as likely to find an association with a negative outcome, say higher breast cancer risk in regular vitamin takers.[3] However none of these results has ever been found to be reproducible AFAIK.
For example a 2009 thorough review of all research on vitamin D and calcium supplements by US DHHS concluded:
The majority of the findings concerning vitamin D, calcium, or a combination of both nutrients on the different health outcomes were inconsistent.[4]
Most if not all of the studies initially finding these spurious correlations are large studies looking at lots of factors and outcomes. Unfortunately due to the nature of statistics there is always a small chance of a false positive or negative relationship and if many possible relationships are examined, such as in these large exploratory studies, it is almost a certainty that some false correlations will be found. This is why almost all of these studies say that confirmation in additional studies is required but this warning does not always make it into press reports. Occasionally a new relationship will be found that is confirmed in follow up studies. Unfortunately this confirmation has yet to be found for any supplement for any outcome in healthy people AFAIK.
FYI - Peter Norvig has a nice writeup of what to look out for when considering the results of a study.[5]
[1] Some supplements can help people with specific health issues but ask an expert such as your doctor as there are many false claims about supplements helping with specific conditions.
"I hope everyone understands that there is NO reliable evidence that any dietary supplements, including vitamins, provide any health benefits whatsoever to healthy people."
I sort of agree with that, but I also know it is kind of a tautology. 'Healthy people' can't become 'healthier people', by definition. Yet, every healthy person can imagine himself, but slightly better: better vision, more willpower, stronger, faster runner, more intelligent, etc.
Because of that, there are no 'Healthiest people'. Even the hypothetical person who wins the decathlon at the Olympics at the age of 40 in the year they won their fifth Nobel will have something to desire (a bald spot? Feeling more tired after exercise than he used to be?). In that sense, nobody is truly healthy.
This is not a tautology. Every "healthy" person will someday die and will often develop cancer or heart disease or have a stroke or have one of thousands of rarer medical conditions. If any supplements actually worked they would prolong life or reduce the occurrence of any of these diseases. All of these out comes can be measured in a properly designed study. So far there is no reliable evidence that supplements help with any of these outcomes.
What I'm interested in with all the recent talk (/hype) about gut health and gut bacteria transplants: Are there studies into whether the nutrients we can supplement actually don't enter our own metabolism, but instead benefit our gut bacteria which in turn benefit us?
Well, then don't take too many vitamins - problem solved.
And as Patrickg_zill said, fat soluble vitamins are the dangerous ones, as they accumulate instead of being flushed. Pretty much all of the other vitamins and minerals are well controlled by the body...
...except Vitamin D, which doesn't really come in fruit and veg. Vitamin D deficiency can be a real problem if you're a vegetarian and/or work in an environment without much exposure to sun. I just had a physical and my D was way down.
Nice idea. In practice, if you live in a large urban area, especially in warmer climates, by the time those fruits and vegetables get to your plate, they'll have far fewer vitamins than you'd expect.
Back when I lived in Jakarta (very large urban area, very warm) I used to get mouth ulcers constantly, despite eating more than my fair share of fruits and vegetables. The solution, according to the family GP, was to supplement vitamin C. Yeah yeah, n=1 (well, n=a family of 5, but still), but it worked and seemed to lend some validity to this theory.
IMHO the key to understanding vitamin supplementation is first, to know which are fat-soluble (and will be stored by your body) and which are water-soluble (and will be flushed by your body when you urinate).
So, it is almost impossible to over-dose on Vitamin C, since, your body will easily eliminate anything it doesn't need - C is water-soluble.
This article covers the differences well enough: http://www.medicinenet.com/script/main/art.asp?articlekey=10...
I think what drives vitamin taking is a combination of
i) people not fully trusting doctors
ii) knowing that today's food is factory-produced and may be deficient in micro-nutrients like vitamins and minerals
iii) being willing to spend a few dollars per day as an insurance policy; after all, how many drop $5 a day at Starbucks?