"Tart Cherries for Insomnia"
We know that not sleeping enough
is associated with changes in diet—
people tend to eat worse,
but what about the opposite question:
Can food affect sleep?
We saw from the kiwifruit study that this seemed possible,
but the mechanism they suggested for the effect—
the serotonin levels in kiwifruit, doesn't make any sense,
since serotonin can't cross the blood-brain barrier.
So you can eat all the serotonin you want
and it shouldn't affect your brain chemistry.
A different brain chemical, though, melatonin,
can get from our gut to our brain.
Melatonin is a hormone secreted at night
to help regulate our circadian rhythms
by the pineal gland in the center of our brain.
Supplements of the stuff are used to prevent and reduce jet lag
and about 20 years ago MIT got the patent
to use melatonin to help people sleep.
Melatonin is not only produced in the pineal gland, though,
but also is naturally present in edible plants.
That might explain the results of this study,
the Effects of a Tart Cherry Juice Beverage on the Sleep of Older Adults with Insomnia.
The research group had been doing an earlier study
on tart cherry juice as a sports recovery drink.
See, there's a phytonutrient in cherries
with anti-inflammatory effects
on par with drugs like aspirin, ibuprofen,
so they were trying to see if they could help
reduce muscle soreness after exercise
and some of the participants in the study
just anecdotally said that
they were sleeping better on the cherries.
That was unexpected.
But the researchers realized that
cherries are a plant food source of melatonin,
so they put it to the test.
The reason they chose older subjects is that
melatonin production tends to drop as we age,
which may be one reason why
there's higher insomnia rates in the elderly.
So, they took a group of older men and women
suffering from chronic insomnia
and put half on cherries and half on placebo.
Now they couldn't use whole cherries for the study,
because how could you fool people
with a fake placebo cherry?
So they used cherry juice versus "cherry Koolaid,"
and found significant but modest improvements in sleep,
so for example fell to sleep a few minutes faster,
and had 17 fewer minutes of waking after sleep onset,
meaning, waking up in the middle of the night.
So it was no insomnia cure,
but it helped without side effects.
How do we know it was the melatonin, though?
They repeated the study,
this time measuring the melatonin levels
and indeed saw a boost in circulating melatonin levels
after the cherry juice, but not after the koolaid.
Similar results were found
in people eating the actual cherries—
7 different varieties, boosting melatonin levels
and actual sleep times.
The effects of all the other phytonutrients in cherries
can't be precluded, maybe they helped too,
but if it is the melatonin,
there are more potent sources than cherries.
Orange bell peppers have a bit,
an ounce of walnuts.
A tablespoon of flaxseeds
has about as much as a tomato,
all less than the tart cherries that were tested,
but people may eat a lot more tomatoes than cherries,
especially tart cherries.
Sweet cherries have 50 times less melatonin than tart
and dried cherries appear to have none.
In fact, the melatonin content of tomatoes
was suggested as one of the reasons
traditional Mediterranean diets were so healthy.
A few spices are pretty potent,
just a teaspoon of fenugreek seeds or mustard seeds
has about as much as a few tomatoes,
but the bronze, silver, and gold go to
almonds, raspberries, and goji berries off the charts.
Now even gojis just have 15 micrograms an ounce,
but melatonin is potent stuff.
You inject just 10 into people
and you can boost their blood levels 50 fold in 5 minutes.