Insomnia

Yes. In my experience, pistachio nuts can indeed cause insomnia, assuming the brand I purchased has an accurate ingredient label, which lists only roasted pistachios and salt. The latter has no noticeable effect on my sleep, but the nuts unquestionably do if I consume a few ounces of them in the afternoon or evening. I haven't noticed any sleep disruption secondary to other nuts (walnuts, pecans, almonds, or peanuts), so I was surprised that something which seemingly should not trigger insomnia did that. After several bags of them over the past few months, I experienced a clear correlation between pistachio consumption at the aforementioned times and poor sleep quality that night, with overly vivid dreams.

I asked three friends, and all noticed the same effect of pistachio nuts. That's obviously not scientifically conclusive, but it is interesting nonetheless. I checked the PubMed database and found no directly relevant studies, but scientists have yet to study other things that cause insomnia, too. I found some interesting indirectly relevant studies. Putting 2 and 2 together might provide an answer to this mystery that makes physiological sense; I'll update this answer with the additional information when I have time.

Incidentally, genetic and other differences between people explain why everyone doesn't experience this effect. If they did, it would likely be well-documented by now.

-- answer by Kevin Pezzi, MD

My answer to that would be...maybe.

William Sears, MD, says, " Vitamin C improves the absorption of calcium. This is why calcium-fortified orange juice makes sense." So in this way Vitamin C may actually help you sleep.

But if you take Vitamin C in the evening it could cause insomnia, especially if you are fasting, and maybe even when you don't eat a snack after dinner. Because hunger is one trigger for the flight-or-fight, neurotransmitter hormone adrenaline. And one of the many ways the body needs Vitamin C is to make adrenaline.

Adrenaline raises heart, blood pressure and breathing rates. It signals the heart to pump extra blood to the muscles, readying them for action.

Definitely not conductive to restful sleep!

It is useful to keep in mind, too, that a Vitamin C deficiency can cause insomnia. Without this vitamin the body can't convert the essential amino acid, tryptophan, to the neurotransmitter serotonin. And serotonin is major in regulating the sleep/wake cycle.

Getting enough sleep is important. Extensive research shows that insomnia adds to depression, chronic fatigue syndrome, fibromyalgia and other ills. There is more than a grain of truth in the saying, "We all need our beauty sleep."

Side note: It is rumored that the acidic form of Vitamin C can deplete the body of calcium causing sleeplessness. This rumor originates on a chiropractic site, perhaps to bring traffic. Either way, this claim and other dubious assertions in the article are not documented by even a single cite.

All kinds of everyday anxieties and even more serious anxiety disorders can keep you from sleeping

Depression can work two ways, or you sleep too much or you have a hard time catching some serious sleep. Waking up too early and not being able to go back to sleep is a schoolbook symptom of depression

All kinds of prescription drugs can hold you back from a good night's sleep

Drinks like coffee, tea, cola, other caffeinated drinks and alcohol can cause insomnia

Women suffer from this when they have a hormonal shift just before menstruation and during menopause. In pregnant women this hormonal shift is one of the insomnia causes

Frequent urinating, chronic pain or breathing difficulties can also lead to insomnia

Working shifts and especially rotating early and late shifts can seriously disrupt your circadian rhythm or internal clock, which could lead to sleeping difficulties

(Long distance) travel does the same thing in the form of a jet lag or simply the change in environment keeps you from catching sleep

"Sleep hygiene" is a group of habits that can normally help you to have a good night's rest. Poor sleep hygiene on the other hand prevents this. This includes too much stimulating activities before you go to bed, or too much distractions. Also only use your bed what it is made for: sleep or sex

When you try too hard to fall asleep and start concentrating and worrying a bit too much about not being able to sleep you might just achieve exactly that…not falling asleep. Sort of a self fulfilling prophecy

A light snack before you go to bed is perfectly OK, but eating too much may make you feel physically uncomfortable when you lie down in bed

When you're older than 60 the changing sleep patterns over the years may cause the increase of insomnia. Almost 50% of all older people suffer from insomnia

Some people suffer from insomnia because of the high altitude like in mountains

People who are in a withdrawal process from alcohol, drugs, sedatives or other stimulants can also experience insomnia