There are very few foods that actually have therapeutic levels of vitamin D naturally and even fortified foods do not contain enough vitamin D to support your health needs. Vitamin D deficiency is prevalent in adults of all ages who always wear sun protection (which blocks vitamin D production) or limit their outdoor activities.
The only way to know for sure if you’re vitamin D deficient is via blood testing. However, there are some signs and symptoms to be aware of as well.
1. Serotonin, the brain hormone associated with mood elevation, rises with exposure to bright light and falls with decreased sun exposure. Low levels of vitamin D can cause individuals to be more prone to depression

2. As you get older your skin does not make as much vitamin D in response to sun exposure. At the same time, your kidneys become less efficient at converting vitamin D into the form used by your body and older adults tend to spend more time indoors.
3. Your bones ache – aches and pains, especially in combination with fatigue are classic signs of Vitamin D Deficiency Osteomalacia, which is different from the vitamin D deficiency that causes osteoporosis in adults. What happens is that the vitamin D deficiency causes a defect in putting calcium into the collagen matrix into your skeleton. As a result, you have throbbing, aching bone pain.
4. Gut Trouble – vitamin D is a fat-soluble vitamin, which means if you have a gastrointestinal condition that affects your ability to absorb fat, you may have lower absorption of fat-soluble vitamins like vitamin D as well. This includes gut conditions like Crohn’s, celiac and non-celiac gluten sensitivity, and inflammatory bowel disease.
Increasing levels of vitamin D3 could prevent chronic diseases. Studies have shown that if you improve your vitamin D status, it reduces risk of colorectal cancer, prostate cancer, and a whole host of other cancers by 30 – 50%. Vitamin D plays a very important role in helping to maintain cell growth and to help fight cancer when a cancer cell is developing in your body. Vitamin D also fights infections, including colds and the flu, as it regulates the expression of genes that influence your immune system to attack and destroy bacteria and viruses. I believe (in my opinion) it’s far more prudent, safer, less expensive, and most importantly, far more effective to optimize your vitamin D levels than to get vaccinated against the flu.
Dosage
When it comes to vitamin D, you don’t want to be in the “average” or “normal” range, you want to be in the “optimal” range. Adults need about 5,000 IUs per day to achieve optimal range.
When UVB rays from the sun hit your skin, components in your skin go through a conversion process to become vitamin D3. To get enough vitamin D from the sun, you should be in the sun for approximately 30 minutes between 10 a.m. and 3 p.m. at least twice a week without sunscreen, making sure to expose your face, arms, legs, or back to the sun.
Protecting Your Skin While Getting Vitamin D from the Sun
Ever heard of an internal sunscreen? Certain foods and supplements can help protect your skin from the damaging effects of the sun, including:
• Rosemary and citrus fruits: Daily consumption of citrus and rosemary bioflavonoids provided significant skin protection from the sun in a study published by the Journal of Photochemistry and Photobiology B: Biology.
• Astaxanthin: A clinical study showed that consuming high concentrations of astaxanthin, the active component of a microalgae, in supplement form significantly decreased the skin’s tendency to burn from UV light.