December 16, 2010
BehindTheMedspeak: Multivitamins before bedtime may disrupt your sleep
Excerpts from Anahad O'Connor's "Really?" column in this past Tuesday's New York Times Science section follow.
Millions of Americans take multivitamins daily, looking to get all sorts of health benefits. But when it comes to a good night’s sleep, can these pills do a disservice?
In one study in 2007, researchers recruited hundreds of subjects and investigated their sleep habits — including looking at their use of vitamins and medications — then had them keep sleep diaries for two weeks.
After controlling for age, sex and other variables, the scientists found a slightly higher rate of poor or interrupted sleep in people taking multivitamins. But because they found only an association, they could not rule out the possibility that people with poorer sleep are simply more likely to seek out multivitamins.
Some studies have shown that ingesting vitamin B6 before bed can lead to very vivid dreaming, which can wake people up. B6 helps the body convert tryptophan to serotonin, a hormone that affects sleep. Other studies have shown that vitamin B12 can affect melatonin levels, promoting wakefulness.
For those who suspect their multivitamins may be curtailing sleep, the best solution may simply be to take the pills in the morning, or at least several hours before bed.
I see no downside from a vitamin in the morning rather than at bedtime so as of yesterday I'm taking mine with breakfast.
Here's the abstract of the 2007 paper cited above.
Vitamins and sleep: an exploratory study
STUDY OBJECTIVE: We analyzed archival data from an epidemiology study to test the association between vitamin use and sleep.
DESIGN: Random digit dialing was used to recruit 772 people ranging in age from 20 to 98 for a study of people's sleep experience. These individuals completed a set of questionnaires about their sleep, health, and daytime functioning. Five hundred and nineteen of these participants had available vitamin use data.
PARTICIPANTS: Five hundred and nineteen people participated. Recruitment applied minimal screening criteria and no attempt was made to favor people with or without sleep disturbance.
INTERVENTIONS: This survey included no intervention. Participants completed 2 weeks of sleep diaries and a set of questionnaires. Of particular salience to the present study, participants reported their vitamin use in listing all medications and nutritional supplements being used currently.
MEASUREMENTS AND RESULTS: For those individuals taking a multivitamin or multiple single vitamins, sleep diaries revealed poorer sleep compared to non-vitamin users in the number and duration of awakenings during the night. After controlling for age, ethnicity, and sex the difference in number of awakenings was still marginally significant. The rate of insomnia, conservatively defined, and consumption of sleep medication were also marginally significantly higher among individuals taking multi-/multiple vitamins compared to those not taking vitamins.
CONCLUSIONS: Disturbed sleep maintenance was associated with multi-/multiple vitamin use. Five equally plausible explanations were advanced to explain this association including vitamins cause poor sleep, poor sleepers seek vitamins, and unidentified factors promote both poor sleep and vitamin use. These data are considered preliminary. Methodological characteristics of future studies were described that hold the promise of more clearly illuminating the association between vitamins and sleep.
Here's the abstract of the vitamin B6 paper cited above.
Effects of pyridoxine on dreaming: a preliminary study.
The effect of pyridoxine (Vitamin B-6) on dreaming was investigated in a placebo, double-blind study to examine various claims that Vitamin B-6 increases dream vividness or the ability to recall dreams. 12 college students participated in all three treatment conditions, each of which involved ingesting either 100 mg B-6, 250 mg B-6, or a placebo prior to bedtime for a period of five consecutive days. The treatment conditions were completely counterbalanced and a two-day wash-out period occurred between the three five-day treatment blocks. Morning self-reports indicated a significant difference in dream-salience scores (this is a composite score containing measures on vividness, bizarreness, emotionality, and color) between the 250-mg condition and placebo over the first three days of each treatment. The data for dream salience suggests that Vitamin B-6 may act by increasing cortical arousal during periods of rapid eve movement (REM) sleep. An hypothesis is presented involving the role of B-6 in the conversion of tryptophan to serotonin. However, this first study needs to be replicated using the same procedures and also demonstrated in a sleep laboratory before the results can be considered certain.
Here's the abstract of the vitamin B12 paper cited above.
Effects of vitamin B12 on plasma melatonin rhythm in humans: increased light sensitivity phase-advances the circadian clock?
Vitamin B12 (methylcobalamin) was administered orally (3 mg/day) to 9 healthy subjects for 4 weeks. Nocturnal melatonin levels after exposure to bright light (ca. 2500 lx) were determined, as well as the levels of plasma melatonin over 24 h. The timing of sleep was also recorded. Vitamin B12 was given blind to the subjects and crossed over with placebo. We found that the 24-h melatonin rhythm was significantly phase-advanced (1.1 h) in the vitamin B12 trial as compared with that in the placebo trial. In addition, the 24-h mean of plasma melatonin level was much lower in the vitamin B12 trial than with the placebo. Furthermore, the nocturnal melatonin levels during bright light exposure were significantly lower in the vitamin B12 trial than with the placebo. On the other hand, vitamin B12 did not affect the timing of sleep. These findings raise the possibility that vitamin B12 phase-advances the human circadian rhythm by increasing the light sensitivity of the circadian clock.
December 16, 2010 at 02:01 PM | Permalink
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Well some of us will be rushing out today to buy B6 to take before bedtime in search of ever richer dream lives!!! (But I don't want any nightmares)
Posted by: Charlotte K | Dec 17, 2010 7:26:26 AM
Ever the med geek....
Posted by: 6.02*10^23 | Dec 17, 2010 12:43:39 AM
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