This makes it very difficult during the winter months and even through the summer months for some people who may have long hours at work or restrictions. For those reasons, it is important to get it through your diet and/or to supplement. Being in direct sunlight behind a window will not aid vitamin D production because glass cuts out the radiation that produces vitamin D.
Vitamin D has many important roles. It is a fat-soluble vitamin (best absorbed with a fatty acid) and essential for optimal health. It helps regulate calcium in the blood and helps your intestines absorb calcium and maintain adequate serum magnesium and phosphate concentrations — three nutrients important for your teeth, muscles, and bones. It also plays crucial roles in brain development, nervous system health, immune function, and lung, heart and kidney function. It also plays a crucial role in insulin regulation and glucose metabolism.
It is a powerhouse! Without the proper amounts of vitamin D in our diets we can start to experience symptoms such as immune weakness, bone pain or weakness, muscle weakness, fatigue, cardiovascular disease, depression, liver disease and asthma just to name a few.
The two forms of vitamin D important to humans besides what we naturally get from the sun are Vitamins D2 and D3. They have many differences, from their sources to their effects on the human body. One of the main differences is that D3 is only found in animals, while D2 comes from plants, with common food sources including:
Sources of Vitamin D3 (cholecalciferol):
- Oily Fish (such as salmon, mackerel, sardines, etc.)
- Fish Oil (like cod liver oil, etc.)
- Liver
- Egg Yolks
- Dairy
- Butter
Sources of Vitamin D2 (ergocalciferol):
- Mushrooms Grown in UV Light
- Fortified Foods (such as cereals, soy milk with added vitamin D)
Age group | Recommended Dietary Allowance (RDA) per day | Tolerable Upper Intake Level (UL) per day |
---|---|---|
Infants 0-6 months | 400 IU (10 mcg) | 1000 IU (25 mcg) |
Infants 7-12 months | 400 IU (10 mcg) | 1500 IU (38 mcg) |
Children 1-3 years | 600 IU (15 mcg) | 2500 IU (63 mcg) |
Children 4-8 years | 600 IU (15 mcg) | 3000 IU (75 mcg) |
Children and Adults | 9-70 years600 IU (15 mcg) | 4000 IU (100 mcg) |
Adults > 70 years | 800 IU (20 mcg) | 4000 IU (100 mcg) |
Pregnancy & Lactation | 600 IU (15 mcg) | 4000 IU (100 mcg) |
Adequate Intake rather than Recommended Dietary Allowance. |