vitamin D – Page 3

You Actually Have to Take the Supplements

January 11, 2018/in Memos/by Chet Zelasko

The authors of the study on calcium and vitamin D supplementation as they relate to fractures were all orthopedic surgeons, as stated in the paper. They had no known training in nutrition. Maybe not statistics either.

When you perform a meta-analysis, each research study included is given a weight in the form of a percentage, which indicates how much it contributed to the outcome. Not all studies should contribute equally; that helps to eliminate the bias of a tremendous benefit in a very small study versus a large study with no benefit. They didn’t seem to read something in three studies that contributed close to 90% of the analysis (2-4): the authors of those papers said that the reduction in fractures did occur, or at least bone was restored, when the subjects took over 80% of the doses of calcium and vitamin D they were supposed to take. The problem: average compliance was around 50%.

What these surgeons could have done was tease out the data on those subjects who were compliant and analyzed that data. What they might have had were results that demonstrated that in order to get a benefit, subjects had to take the supplements regularly. That would have been meaningful. Instead, inexperience or ignorance left us with headlines but little else.

Still, there are some questions that were raised in my mind and I’ll cover them on Saturday. But one thing won’t change: if you’re going to take supplements of any kind, you’ve got to actually take them if you want a benefit.

What are you prepared to do today?

Dr. Chet

References:
1. JAMA. 2017;318(24):2466-2482. doi:10.1001/jama.2017.19344.
2. Lancet. 2005;365(9471): 1621-1628.
3. Arch Intern Med. 2006;166(8):869-875.
4. Am J Med. 2006;119(9):777-785.

Are Vitamin D and Calcium Still Worth Taking?

January 9, 2018/in Memos/by Chet Zelasko

Maybe you recently read a headline that went something like this: “Vitamin D and Calcium Do Not Prevent Fractures.” Many headlines were much worse. Over this past weekend I read the research paper published in JAMA. Is it real? Should you not bother taking your calcium and vitamin D to protect your bones? No—keep taking them. But it does give me an opportunity to talk about some of the issues surrounding these types of papers as well as the complexity of nutrition for our health. That’s our topic this week.

The study was a meta-analysis of studies that examined the relationship between the risk of fractures in elderly populations and supplementation with calcium, vitamin D, and both supplements together. After a rigorous database search, 33 randomized controlled trials were included in the meta-analysis. Some studies lasted several months, and some lasted several years. The amounts of calcium and vitamin D in the supplements varied in every study. After analysis, the researchers determined that neither calcium nor vitamin D nor the combination of both reduced the rate of fractures when compared to placebo. That led to their conclusions.

This was a mess as you probably guessed with differing quantities and lengths of the trials. What bothered me most was that if they really understood nutrition as well as the results of the studies they included, they could have done something special. I’ll cover that on Thursday.

What are you prepared to do today?

Dr. Chet

Reference: JAMA. 2017;318(24):2466-2482. doi:10.1001/jama.2017.19344.

Classic: Vitamin Dumb

April 25, 2017/in Memos/by Chet Zelasko

As Paula and I visit our son and his wife this week, I’m choosing what I call Dr. Chet’s Classics. This one from 2010 illustrates two points. First, mega-dosing vitamins and minerals can have consequences that someone might not expect, and “if some is good, more has to be better” is not a good idea unless there’s a genetic or other reason. Second, even with the best intentions, researchers sometimes don’t use their heads when designing research studies.

Researchers reported in JAMA on the effects of vitamin D on fractures and falls in a group of over 1,500 women over 70. The results were surprising in that the vitamin D group had more falls and more fractures than the placebo group. Well, maybe not so surprising.

Remembering to take medications as well as supplements is a problem. So how did the researchers choose to address that issue? Give the women a year’s worth of vitamin D once a year.

That’s right. They gave these subjects 500,000 IU vitamin D once a year. I was almost rendered speechless—500,000 IU? What in nature would give them a model to follow? If you spend all day in the sun without sunblock, your body shuts down the production of vitamin D automatically; that’s why you can’t overdose on D from the sun. But this was oral intake; in what universe did these researchers think this was a good idea? Would they give someone a year’s supply of cholesterol-lowering medication or pain medication in one dose per year just because the subjects might not remember to take their meds every day? And what earthly good would that do?

In an editorial in the same issue, the authors suggested that medical professionals examine how vitamin D is administered, and that maybe administering 50,000–100,000 IU doses isn’t such a good idea.

Do ya think?

Taking up to 10,000 IU vitamin D3 is safe and 2,000-6,000 IU per day is a good goal. But this study illustrates that there’s no need to megadose. Doing that is like taking vitamin Dumb.

What are you prepared to do today?

Dr. Chet

Reference: JAMA. 2010;303(18):1815-1822.

Changes in Supplement Use

October 18, 2016/in Memos/by Chet Zelasko

I take dietary supplements, and so do most of the people I know. We’re not alone. Using data from the NHANES data in 1999 and 2012, researchers compared how many people used supplements and what type of supplements they used (1).

Close to 38,000 subjects were included in the study. The percentage of people using supplements remained fairly stable over the time span at 52%; what changed was the types of supplements people took. Multivitamin-multimineral (MVMM) dropped 6% from 37% to 31%. There were some increases: vitamin D supplementation (other than from MVMM) increased from 5.1 . . .

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