No — You can only make Vitamin D from the sun's UVB rays when your shadow is shorter than your actual height! AND that is usually during the hours between 10 am and 2pm (up to 3 pm on Daylight savings).
The sun's rays vary in intensity throughout the day. In most places, UV rays are strongest between 10 a.m. and 4 p.m., when the sun is at its highest. If you go outside during that window, the body will produce more vitamin D in less time than if you went out in the morning or late afternoon.
Vitamin D, also known as the “sunshine vitamin,” is synthesized in the skin following direct exposure to UVB rays. However, the UV index must be over 3 to make vitamin D, which usually occurs around midday between 10am and 2pm.
“You can sit and enjoy that beautiful 6 o'clock sunset, but the radiation is not sufficient to make vitamin D,” he says.
According to the national Institutes of Health, between five and 30 minutes of sun exposure to your unprotected face, arms, legs or back between the hours of 10 a.m. and 3 p.m. two to three times every week is enough for your body to produce all of the D3 it needs. Sunscreen can block vitamin D production.
Vitamin D (from food, sunshine and supplements) changes to calcidiol in the liver, which is measured from blood to check the level of vitamin D. The half-life of calcidiol of D3 (we get from supplements and e.g. fish) is 15–30 days. Half-life is the period during which vitamin D stores decrease by half.
There's no set time of day that's best to take vitamin D supplements. Some people say taking vitamin D supplements at night is an insomnia risk. There's no research to confirm this, but you might want to take your supplement earlier in the day if you think it's screwing with your sleep.
Vitamin D and sleep: The surprising connection
Does vitamin D help you sleep better? Early research suggests it is inversely related to melatonin, your sleep hormone. Increasing vitamin D levels may suppress melatonin levels. So, it makes sense that taking it at night could disrupt your sleep.
Soaking sun from head to toe is not really necessary. People suffering from vitiligo and white patches can benefit from sitting under the sun by inducing some pigmentation around the area,” she says. Not many realise that It's only the early morning sun — that is, from 7 am to 9 am — that helps generate Vitamin D.
Conclusions: Therefore at this latitude exposure to sunlight between the hours of 11 a.m. and 2 p.m. will promote vitamin D production in the skin year round.
In summer and spring, with 22% of uncovered skin, 1000 IU vitamin D doses are synthesized in 10-15 min of sun exposure for adults. Exposure durations between erythema risk and 1000 IU vitamin D production vary between 9 and 46 min.
But the potential for getting sunburn at 5 p.m. and after does still exist. "There are still some UV rays being emitted from the sun after 4 p.m.," she says. "Sometimes, your location can factor into how likely it is to get a sunburn after 5 p.m.; it depends on the intensity of the sun in a given place at that time."
The best time to get Vitamin D from sun in India is between 9 am and 1 PM, depending on where you are located and how much access to direct sunlight you have.
Sunbathing of minimum 10 minutes and maximum 30 minutes is ideal to absorb enough vitamin D for the day. Noon is also the safest time to get vitamin D, as exposing your skin to the sun post noon can lead to health issues like cancer.
Medical conditions that can cause vitamin D deficiency include: Cystic fibrosis, Crohn's disease and celiac disease: These conditions can prevent your intestines from adequately absorbing enough vitamin D through supplements, especially if the condition is untreated.
Early anecdotal evidence suggests that Vitamin D may interfere with sleep. However, there's not enough evidence to know how it really interacts with your sleep cycle. Since it's best to take Vitamin D with a meal, it makes sense to avoid taking this supplement before bed.
Magnesium is a critical factor in making Vitamin D bioavailable. Without magnesium present, Vitamin D is stored in the body and not used. The body depends on magnesium to convert Vitamin D into its active form within the body.
If you take too much supplemental or prescription vitamin D, it can lead to vitamin D toxicity. The main complication of this is moderate to severe hypercalcemia, which can cause symptoms like vomiting, increased thirst and frequent urination.
Vitamin D undergoes two hydroxylations in the body for activation. Calcitriol (1,25-dihydroxyvitamin D3), the active form of vitamin D, has a half-life of about 15 h, while calcidiol (25-hydroxyvitamin D3) has a half-life of about 15 days. [63] Vitamin D binds to receptors located throughout the body.
Melatonin production relies on vitamin D: Vitamin D helps the body produce melatonin, a hormone that supports sleep. Low levels of vitamin D could result in low levels of melatonin, leading to sleep problems.
"Most patients with vitamin D deficiency are asymptomatic, however if you're exhausted, your bones hurt, you have muscle weakness or mood changes, that's an indication that something may be abnormal with your body," says Dr. Lacey. Symptoms of vitamin D deficiency may include: Fatigue. Not sleeping well.