Saturday, December 17, 2011

A Fat D-Ficiency! Do You Really Need More Vitamin D or Simply More Fatty Foods? Study Shows, Even 50.000 IU of Vitamin D3 Useless, When You Ingest It Without Fat.

 Image 1: Fatty fish and organ meats aside, whole eggs and full-fat dairy are your best food choices to raise vitamin D levels - I would even venture the guess that they (combined with fish and organ meats) would make supplementation obsolete, even in the Nothern hemisphere (if you "load up" on sun in the summer).
Those of you who have been following my daily blogposts, here at the SuppVersity for more than the last couple of days will be aware that I am one of the few outspoken vitamin D (-supplementation) skeptics. I am by no means doubting the scientific data which clearly indicates that low vitamin D levels (low in medical, not in "Internet blogosphere" terms) are associated with all sorts of diseases. I do not question the hypothesis that, from a biomolecular perspective, vitamin D has more of a hormone than of a "vitamin" (=essential nutrient). And I do not challenge the use of vitamin D(3) supplements by people with low or even borderline low vitamin D levels (although this blogpost may change the way you ingest them ;-). What I do yet call into question is the hilarious idea that every Joe and Jane in the Western hemisphere could benefit from taking "at least 2.000IU of vitamin D" per day.

Re-thinking dietary (=supplemental) vitamin D

Hitherto, the only Joes and Janes who have profoundly benefited from this one-(XL-)size-fits-it-all approach are the producers of respective supplements. Convincing scientific data from controlled studies which would show that the consumption of large amounts >1.000 IU of vitamin D capsule or pill form, exert any verifiable health benefit for someone with normal (or even low-normal) vitamin D levels is absent. The (remote?) possibility that there actually is no benefit, aside, there are yet a few other possible explanations why - epidemiological data aside - scientific evidence for the benefits of vitamin D3 supplementation in a non-vitamin-D-deficient cohort is still lacking:
    Image 2: Who would buy all those toxic, but expensive drugs, if it turned out that by taking a non-patentable "vitamin" the diseases they were invented for could be prevented?
  1. Lack of financial interest from the side of the pharma companies: Vitamin D is obviously non-patentable and if it could, as many people believe, prevent diabetes, stroke, heart disease and cancer, the use of respective supplements would obviously put the pharmaceutical industry out of business.

    Note
    : The pharmaceutical industry has already been trying to come up with patentable vitamin D analogues, of which they claim that they would lack the largely non-existent negative side-effects of the real vitamin - I guess, you can you tell which way the wind is blowing?!

    Financial revenue could thusly be a major factor, as it is obviously pretty costly to set up a tightly controlled, appropriately powered randomized, placebo-controlled study on healthy people. Even large scale epidemiological studies, on the other hand, can be done by a group of graduate students, by just plugging into respective databases and doing some more or less sophisticated statistical evaluations on existing data sets.

  2. Insufficient dosing or study periods that are simply too short to yield results: I have, in the past seen studies, even I, as a avowing skeptic, would not cite to underline my argument that we do not have enough scientific evidence that supplemental vitamin D is not the savior people may make you believe. I mean, if you assign a group of say 20 people to 400IU of vitamin D for 4 weeks and see no changes in a handful of pretty random markers of health and disease, this is unquestionably not an argument against the potential usefulness of vitamin D supplementation.

  3. Adding vitamin D3 supplements to a "healthy" low fat diet: Assuming that this point has immediately caught your eye, I want to encourage you to read the rest of this blogpost, as this, i.e. the necessity of adequate amounts of dietary fat, to absorb vitamin D3 is what the rest of this post will revolve around.
Fatty fish, eggs, organ meats, full fat organic (raw) dairy products - all those good foods which have been banned from YourPlate (at least if it contains what the US government's MyPlate suggests is healthy) are not only high in vitamin D, they are also high in fat. Against that background and in view of the fact that our ancestors did not buy their vitamin D at the local health food store, it is only reasonable to assume that our digestive tract was designed to absorb the little additional vitamin D we are supposed to get from foodstuff (you know that I am a firm believer in the power of sunlight - even beyond vitamin D) in the presence of fat. And guess what, a recent study, which was obviously not published in the Journal of the American Medical Association (cf. 1. in the previous list of possible explanations for the lack of conclusive scientific evidence on the usefulness of vitamin D supplementation), shows exactly that: without the concomitant presence of significant amounts of dietary fat, even 50.000IU of supplemental vitamin D3 have no effect on the serum levels of 25(OH)D, the active form of vitamin D (Raimundo. 2011, cf. figure 1).
Figure 1: 25(OH)D levels of 30 healthy men and women after ingestion of 50.000IU vitamin D3 supplement in conjunction with a normal or low fat breakfast (data calculated based on Raimundo. 2011)
And, as the detailed macronutrient breakdown in figure 1 (right) shows, the "high fat" breakfast the 30 young (~27y), healthy, non-obese, vitamin-d sufficient men (n=12) and women (n=18) ingested with a 50.000IU vitamin D3 capsule in the morning after an overnight fast, did not even consist of eggs and bacon. It was comprised of whole milk, white bread with bologna, and vegetable oil margarine and the whole milk aside, probably not much healthier than the skim milk, white bread with fruit jelly, and fruit salad breakfast the low-fat group had to eat. The additional 23.9g of fat did nevertheless make a huge difference, as far as the absorption and subsequent utilization of the vitamin D3 supplement is concerned.

No fat, no sun, no vitamin D - regardless of supplementation

Image 3: Get your D from the sun, if you can!
In view of the fact that the subjects were advised to "avoid sun exposure and changes in their usual eating pattern [which were probably low in dietary vitamin D] for the next two weeks", it is thusly hardly surprising that contrary to the "high fat" (I deliberately labeled it "normal fat" in figure 1 ;-) group, the subjects in the low fat breakfast group suffered a -11% decline in 25(OH)D serum levels over the 14-day follow up period, which other than the inter-group difference of 35% (!), did not reach statistical significance (mainly due to the small number of participants, where inter-subject variability renders even relatively profound differences "statistically non-significant").


And while the scientists concede that the small scale of the study, the lack of detailed recordings of the subjects' dietary vitamin D intake in the course of the 14-day follow up period and the reliance on 25(OH)D level as single surrogate for serum vitamin D levels (remember that we are actually talking about a whole host of "vitamins D") are limitations of their study, Raimondo et al. are nevertheless right to conclude that their "findings can have important implications to define the adequate dietary intake of vitamin D"... implications, which may well go beyond the mere recomendation to take your vitamin D with fat. After all, increased absorption would mean decreased need for supplementation and who knows whether you could not easily satisfy your dietary vitamin D requirements without any supplements, if you just set the "low-to-no fat, no dangerous organ meats" dietary recommendations at naught?