Vitamin D, group of vitamins found in liver and fish oils, essential for the absorption of calcium and the prevention of rickets in children and osteomalacia in adults. They include calciferol ( vitamin D2 ) and cholecalciferol ( vitamin D3 ).
we can get easily this vitamin, even if we spend 5 minute in sunlight, but due to lifestyle changes we are deficient of it.
Here are 5 signs your Body is deficient of Vitamin D:

1. Excessive sweating

It’s often difficult to tell if newborns are deficient, but a sweaty forehead is one of the first noticeable symptoms, Holick says. The same rings true for adults, so if you’re “glowing” while your activity level remains steady, your temperature is close to 98.6° and you’re in a moderate temperature environment, you may want to consider a vitamin D test.

2. Noticeable—and unexpected—weakness

Muscle strength isn’t just a matter of pumping iron. While having a vitamin D deficiency can leave you feeling overly exhausted, even when you’re able to get enough shut-eye, proper vitamin D intake helps you maintain power in every fiber of your being, whether you’re young or old. Harvard researchers have linked vitamin D supplementation with increased muscle control, resulting in 20% fewer falls among adults around 60 years old. (Learn how to up your vitamin D intake and boost fat loss up to 70% with The Vitamin D Diet.) Promising news: Within just six months of supplementation, D-linked muscle weakness can be eliminated, according to a Western Journal of Medicine study.

3. Broken bones

You stop building bone mass around age 30, and a lack of vitamin D can speed up or worsen osteoporosis symptoms, according to research published in the American Journal of Clinical Nutrition. Fortification, first introduced around 1930, almost eradicated the weak bone condition rickets, however, “it’s nearly impossible for anyone to satisfy vitamin D needs through diet. It really requires a three-pronged attack: sun exposure, supplements, and food,” Holick says.

4. Chronic pain

“It’s often subtle, but some experience aches and pains in the bones, known as osteomalacia,” Holick says. Those who are diagnosed with arthritis or fibromyalgia may actually be shy of enough D, as a deficiency can cause joints and muscles to ache, too. If your discomfort lasts for several weeks, ask your doctor if a vitamin D deficiency could be the cause—and if your treatment program should include the vitamin. Also worth noting: adequate vitamin D can prevent post-workout pain and increase the speed of muscle recovery, Beggarly adds.

5. A down-in-the-dumps mood

A depression diagnosis is often actually linked to a shortage of vitamin D. While the jury is still out about why, the Vitamin D Council says that the mineral may work in the same brain areas—and impact the same hormones, like serotonin—as those that affect mood