Vitamin D may suppress melatonin production. So take it in the day, not before bed. That's logical as we obtain sunlight (natural vitamin D source) during the day. You can also increase vitamin D by changing diet habits or short-term sunbathing.
A recent study showed an inverse correlation between changes in serum levels of vitamin D and melatonin. Indeed, the night secretion of melatonin was shown to be reduced after 3 months' administration of high dose vitamin D in IFN-β treated MS patients.
Although the functions and synthesis of vitamin D and melatonin are contrary to each other, both are involved in the immune system. While melatonin synthesis is affected by light, vitamin D deficiency may be involved in melatonin secretion.
Growing evidence has demonstrated that vitamin D has a role in sleep regulation [12]. Specifically, vitamin D deficiency (VDD) can increase risk of sleep disorders and is associated with sleep difficulties, shorter sleep duration, and nocturnal awakenings in children and adults [13,14,15].
You'll be sleepy the next day. Several studies even saw a dose-dependent relationship between vitamin D levels and sleep. [1,2] This adds to the evidence that there is a direct, linear relationship between vitamin D and sleep measures. This also means that improving your vitamin D by any amount will improve your sleep.
Is there a benefit to taking vitamin D at night? There's been some buzz suggesting a link between supplementing with vitamin D before bedtime and the ability to drift off to dreamland. Some studies have shown that vitamin D is connected to the production of melatonin, which regulates circadian rhythm and drives sleep.
Melatonin secretion decreases during aging. Reduced melatonin levels are also observed in various diseases, such as types of dementia, some mood disorders, severe pain, cancer, and diabetes type 2. Melatonin dysfunction is frequently related to deviations in amplitudes, phasing, and coupling of circadian rhythms.
In general, melatonin production decrease with aging. Among the other factors that have been most consistently linked to modified melatonin levels are disrupted light–dark cycles, night work and being overweight.
The pineal gland hormone melatonin is released during the biological night and provides the body's internal biological signal of darkness. Exposure to light both resets the circadian rhythm of melatonin and acutely inhibits melatonin synthesis (1, 2).
The body needs a variety of nutrients to produce melatonin, including adequate B complex vitamins. I would discourage people from taking a B complex and instead get it from food sources. Especially since taking one before bed can keep you awake.
Causes of melatonin deficiency
Light exposure – Responding to darkness, our pineal glands release more melatonin at night. As a result, increased light exposure—especially at night—can suppress melatonin secretion.
Your sleep is heavily dependent on your sleep hormone melatonin. If there is a deficiency, this can result in signs of restlessness [1] [2], a poor stress response, insomnia and waking up too early in the morning.
Cherries
Cherries (especially sour cherries like the Montmorency variety) are one of the only (and highest) natural food sources of melatonin.
Our only hard recommendation: Avoid supplementing with vitamin D at night. There's evidence that vitamin D can suppress melatonin—which is bad news for your sleep quality.
While the best timing has not been established, scientific data to confirm anecdotal reports that supplementing at night may interfere with sleep is unavailable. Current research suggests you can fit vitamin D into your routine whenever you prefer.
Eggs and fish are higher melatonin-containing food groups in animal foods, whereas in plant foods, nuts are with the highest content of melatonin. Some kinds of mushrooms, cereals and germinated legumes or seeds are also good dietary sources of melatonin.
These data indicate that stress negatively influences the synthesis of melatonin in the pineal organ, thus attenuating the day–night variations of circulating melatonin. The effect might be mediated by increased cortisol, which binds to trout pineal organ-specific glucocorticoid receptors to modulate melatonin rhythms.
But, although the hormone's plasma levels at nighttime remain at least an order of magnitude higher than at daytime throughout the life span, its absolute concentrations undergo a continuing decline after peaking at ages 2–5 yr (2–4).
Vitamin B12 deficiency is linked to a host of sleep problems—from insomnia to sleepiness, not getting enough of this vitamin can wreak havoc on your nighttime routine. Vitamin B12 is also extremely important for our heart health and energy levels.
Melatonin is produced from serotonin (made from tryptophan), through a cascade of enzymatic reactions (Figure 1).
The main function of the pineal gland is to receive information about the state of the light-dark cycle from the environment and convey this information by the production and secretion of the hormone melatonin.
Physical activity may increase melatonin levels, resulting in decreased estrogen production, improved fat metabolism, and reduced cancer risk (3).
Melatonin. Melatonin is a hormone produced by the pineal gland that's associated with the body's sleep-wake cycle. It helps regulate the body's circadian rhythm, so you can fall — and stay — asleep.