There is more magic associated with vitamins than any other pharmaceutical, including antibiotics. All people like magic, including me, and are hopeful that somewhere there is a panacea that will protect us from things we fear – with vitamins, it is disease, aging, death – and grant us restored youth, strength, sexual performance.
Unfortunately, vitamins are not the magic beans.
We Already Get Enough Vitamins
Vitamins are organic molecules (organic in the chemical sense – they are mostly synthesized in factories) that are necessary for life and/or health, and that we are unable to produce in our own bodies and must therefore be supplied with from outside. (The exception is vitamin D, which we can synthesize in our skin when exposed to sunlight.) Vitamins are defined by deficiency states; that is, what happens to you if you don’t get them. If there is no deficiency state, the molecule is not a vitamin, even though it might be useful to you for other reasons.
These deficiency states can be really awful. Scurvy (vitamin C deficiency) would routinely kill one-half of the sailors in long ocean voyages. It wasn’t limited to sailors, either – in the 18th and 19th centuries, it was very common in people who did not have access to either fresh meat, milk, or fruit/vegetables, which was a substantial portion of the urban population. Pellagra (niacin deficiency) was a scourge of the American south in the late 1800′s and early parts of the 1900′s. It was known as the “4D’s disease” – dermatitis, diarrhea, dementia, and death. Beriberi, Korsakoff’s encephalopathy, pernicious anemia (called that because everybody who got it died) were terrible illnesses.
The elimination of these deficiency-caused “diseases” by simple changes in diet or cheap supplementation was miraculous to the people who suffered them. Today, in industrialized countries, these diseases are very rare, usually only seen in people with serious drug/alcohol problems. For example, in my many years of practice, I have only seen scurvy and pellagra three times each – scurvy and pellagra in two people seeking enlightenment through the macrobiotic diet known as “stage IV”, another case of pellagra in a woman with a jejeunal-illeal bypass (due to malabsorbtion caused by the bypass), and another case of scurvy in a severe alcoholic. I have read of (though not seen) pernicious anemia and neurologic disease in people on vegan diets who did not supplement B12.
As this demonstrates, everyone in our society with the exception of those on extreme diets or with other extreme conditions is already getting enough vitamins to avoid deficiency states. And with two exceptions, there is to date no evidence that taking vitamins in excess of what is needed is helpful (though there is substantial evidence that several of them are harmful in large amounts). The exceptions are niacin, which can be used in high dose to lower cholesterol and LDL cholesterol (“bad cholesterol”), and folic acid, which, when taken by women at the time of conception and the first weeks to early months of pregnancy in moderately high dosage, will decrease the likelihood of neural tube defects (a particularly terrible group of birth defects) from 1/10,000 to about 1/50,000, with no toxicity. Of course, since the woman needs to be taking this at the time of pregnancy and very early in the pregnancy to make a difference, it’s quite likely that the woman may not know to take the folic acid until too late in the pregnancy to be effective. But given its low cost and safety, it is recommended that women who are planning a pregnancy begin taking folic acid prior to trying. The dose would be 1mg/day.
There is no proven benefit to taking excess amounts of any other vitamin. For the group of vitamins that are soluble in water, most of them, amounts in excess of need are rapidly eliminated, usually in the urine – some have said it is like pissing away money. In general, we do not store these vitamins, and with those we do store, once the storage is filled, any additional amounts are eliminated. Fat soluble vitamins (A, D, E, and K) we can store in various places, but that is actually worse, since these can build up to levels causing problems (particularly vitamins A and D).
Despite these well-known facts, fads in vitamin use have been part of life for the last 150 years. Exactly why one or another becomes the vitamin of the day is often unclear, although frequently it is because some person of fame (think Linus Pauling) decides that s/he will save the world through increases in some vitamin or other. Sometimes it is the result of an expert committee finding, without evidence, that some vitamin needs to be taken in huge amounts and publicizing that unsupported conclusion. (It should be noted that in all expert committee recommendations, inevitably, a great increase in the use of one or another pharmaceutical is recommended. And just as inevitably, when evidence becomes available, the experts advice always turns out to be incorrect, and good, or better, results are found with less intervention.)
Since I have become involved in medicine, I have seen seven different vitamins become the elixir of the day, usually for a period of a few years, then yield to the next new thing. Sometimes the change occurs because actual studies show the drug to be useless, or even harmful, sometimes just because of fashion. When the parade moves on, there are always a number of true believers who stick with the old med, sometimes they add the new meds, and everyone is certain that these chemicals are necessary to them in whatever dose they take. The bottom line is, when thinking of the population in general, one really needs to see if there is any hard evidence to support the use.
The first vitamin fad I became aware of was B12 – this is present in animal products and yeast. It is stored in the body, but once the storage spaces are filled, any additional is almost immediately excreted in urine. In the 1960′s and early 70′s (it might be earlier, but I was not around then, medically), it was extremely common for people to go to the doctor for a shot of B12 (it is given as an injection, although tablets can be used) as a “pick-me-up”, to increase their energy, fight fatigue, improve mood, strength, etc. Of course, in reality it wasn’t doing anything biologically except being filtered out, but seemed to help. Since the doctors got paid for giving it, and it couldn’t hurt anyone, it continued to be a popular treatment for decades.
Next was vitamin C – this was related to Linus Pauling, who won a Nobel prize for determining the secondary structure of proteins (though he was mistaken on his theories regarding DNA structure). Pauling promoted taking vitamin C in huge doses, 4-5 grams a day (125mg is more than you need), to prevent cancer, cure or prevent viral illnesses, restore youth and prevent death. The only things one can actually demonstrate as resulting from these doses in studies is an increase in diarrhea and kidney stones. There is no evidence for anything more for these high doses, and anyone who eats fresh meat, fruits/vegetable, gets plenty of this vitamin. It was also quite inexpensive, so it rapidly gave way to other fad vitamins.
Beta-carotene (vitamin A) was the next in line. This was the first of the vitamins ascribed to have anti-oxidant properties, and was also supposed to protect from cancer and disease by improving immune function (presumably through its anti-oxidant properties). When this was studied, sadly it was found that it actually increased the risk of lung cancer in smokers, and did not have any other effect on other cancers. It was originally put in a mixture of chemicals that may help in slowing macular degeneration, but now has been removed in these formulas for smokers.
Vitamin E came next. It was a bit unusual because as well as having the usual claims for it curing/preventing myriad ills, the claims have been made sequentially, and so it has had a longer time as a prime vitamin de jour than some of the others. The first claim was that it improved/restored sexual function in men, because in rats fed a lab diet deficient in vitamin E, males developed testicular atrophy. This claim did not last long, however, because it quickly became apparent to everyone that this was not Viagra (which didn’t exist at that time).
Then it was supposed to help wound healing, and people would apply it directly to wounds. This didn’t last long either, because it didn’t help.
Next came its beneficial effect on heart disease. There was a little more evidence for this, because in two fairly large observational studies people who were taking the vitamin E seemed to have less in the way of heart attacks. This was widely publicized, and vitamin E sales soared. But again, sadly, when it was actually specifically studied for this use, it was found to be either useless, or actually correlated with slightly (i.e. not statistically significantly, the increase could be chance) increased risk.
Next, it was postulated that very high doses of vitamin E could prevent/treat Alzheimer’s disease. This would be wonderful, if true, since nothing else does, really – but this too has not panned out.
In fact, to date, the only use of high dose vitamin E that has been demonstrated to have a positive effect is intravenous use in premature infants, where it can help prevent oxygen related blindness. It is very difficult to get a vitamin E free diet (though some of the alcoholics I see have managed it), so supplementation is unnecessary – just eat some vegetables and whole grains.
After that, the fad vitamin was a combination of pyridoxine/folic acid/B12. This was because a particular big man in science had been trying for years to excite people about the levels of homocysteine in blood, as a risk factor for several different things, including heart disease (there are now about 50 separate independent “risk factors” for heart disease that have been identified, including ear creases and college education, the relevance of each is somewhat uncertain). He suggested, loudly, that reducing homocysteine with these vitamins would all but eliminate coronary artery disease, and a mixture of these very cheap ingredients was consequently introduced to the market, with a huge mark-up in price. As you might expect, when this was actually studied, it appears you can lower the homocysteine levels, but this has no effect on heart disease, and this mix faded.
Today’s magic bean: Vitamin D
Vitamin D is the current darling. This is a substance that is manufactured in your skin with exposure to sunlight. The initial molecule is then processed first by the liver and next by the kidney to an active material. The amount made depends on the amount of exposed skin, the intensity of the sunlight, the degree of pigmentation in the skin. In Boston, 2 hours of sunlight in February is roughly equivalent to 10 minutes in July (this was actually studied in volunteers). The deficiency state of vitamin D is rickets, a disease of developing bone in children, which used to be very common in poor areas of cities in Europe and the United states, but is virtually eliminated now. There have been observations that in people on dialysis for kidney failure, and in nursing home populations, low levels of vitamin D seem to correlate with decreased survival, but whether this is due to the vitamin D, or simply because people who are sicker tend to have lower vitamin D levels (possibly because dying people in nursing homes seldom go out in the sun), is unclear. In at least one very well done study of people in the community, there was no difference shown in survival over 5 years between the highest and lowest quarters of vitamin D levels.
Exactly what level of vitamin D is necessary is unclear. The World Health Organization in the past has said that deficiency is less than 10 nanograms/ml (if I were in Europe I would be speaking about nanomoles). Levels greater than 15 were considered low, but not deficient. There were no other recommendations. In 2007 there was an expert panel consensus in the United States that less than 15 was deficient, 15-30 was inadequate, and greater than 30 was ideal, and recommended that everyone in the US take between 1500 and 2000 units of vitamin D a day, much more than anyone else thought of. There was no evidence to support this, it is in the area of belief. As a result, vitamin D use in the US increased 4 fold in dollars spent, with the pharmaceutical houses predicting an additional twofold increase in the future.
Vitamin D is proposed to influence depression, protect from cancer (particularly colon cancer), heart disease, and dementia. But while receptors for vitamin D are found on many different types of tissue, the only place where it is clearly active is in bone metabolism – the marker for deficiency is an elevated parathyroid hormone, also important in bone metabolism, but this is never measured on a routine basis. In other words, there is no evidence that vitamin D makes a difference in anything but bones. In my unit the psychiatrists are checking vitamin D levels on everyone with depression, and are amazed to find that virtually everyone has a vitamin D level of about 25, apparently proving a relationship – except that everybody in Minnesota (where I am) has levels like this during the winter. There is no evidence that increasing the level will do anything beneficial, as is true of all of the other claims made for increased vitamin D use.
There is some evidence for the use of vitamin D and calcium in post-menopausal women to help prevent osteopenia (not osteoporosis), and good evidence that it is beneficial to administer to people with kidney failure on dialysis (though because their kidneys cannot properly process vitamin D normally, they are given a special formulation). There is also a rationale for supplementation in people who are taking steroids, who are housebound, or who are in nursing homes. There is not much vitamin D in foods, and it is therefore not practical to replace it from the diet. But about one-half hour of sun exposure here in July will produce about 15,000 units in a Caucasian person wearing a short sleeved shirt. There is no evidence that a blood level of over 30 will be any better for you than a lower one, and maintaining such a level would require you to take a pharmaceutical from October to the end of May, longer if you don’t go out in the sun.
To summarize, vitamin D is the latest panacea to cure all ills, with no more evidence that it cures those ills than any of the others promoted in the past.
- Get your vitamins through what you eat – fruits, vegetables, whole grains are good, meat isn’t bad. If you have a restricted diet, know what you are missing(such as B12 in vegan diets) and replace that, in the proper amount – for B12 it is about 2mcg/day, not 1000.
- If you are a woman contemplating pregnancy, it makes sense to start some folic acid before you actually begin an attempt – 1mg a day is sufficient. Neural tube defects are very rare, but they range from really bad to truly terrible, and folic acid has been shown to make a difference to reduce such defects when taken in very early pregnancy.
- There are no magic beans – the more that is promised, the less likely it is.
- If you do take vitamins, it makes no sense to take anything other than the least expensive, since most of them are going into the toilet anyway.
- People who have serious illness are different. People on dialysis, chemotherapy for cancer, some type of immune suppression, bad bowel disease and so on, require vitamin supplementation, not because of magical properties, but because they may not be able to get what they need through their diet as a healthy person would.
- Being a serious, practicing alcoholic is not good for your health, vitamins or not.