Vitamin D is one of the 4 fat-soluble vitamins (A, D, E, and K): which means it can be dissolved in fats/oils and is derived from outside sources such as plants, foods, and in the form of supplements. It is important in the maintenance of our bone and immune health. It's common for people to think of exposure to sunlight as a way to increase Vitamin D, and this is because after exposure to the sunlight (in the form of UV radiation), Vitamin D3 is produced in our skin. Vitamin D3 can also be obtained in our diet/supplements. Vitamin D2 is produced by plants. Both Vitamin D2 and D3 have to be broken down in our body into 25(OH)D or 25-hydroxyvitamin D which is the major form of Vitamin D in our body. When we test for Vitamin D levels, we commonly test for the amount of 25(OH)D.
Low Vitamin D levels may be linked to conditions such as osteoporosis and chronic low back pain. A study of over 9000 female participants reported low back pain in those with low Vitamin D levels. Another study reported decreased pain in those with chronic low back pain who took 4000 IU daily of Vitamin D3.
Many food sources are now fortified with Vitamin D; however the form added to most foods available is D2. Vitamin D in the form of D3 has better "bioavailability": meaning it is most effectively broken down in your body to 25(OH)D. It's always important to read the labels on the food that you buy! These are some food sources that contain D3: cod liver oil (supplement), swordfish, sockeye salmon, tunafish, fortified orange juice, fortified milk, yogurt, sardines, eggs. You can also obtain Vitamin D3 in the form of supplements.
It's always a good idea to discuss with your physician anytime you want to add supplements to your diet, and always check the labels of your food and your supplements.
According to the NIH updated fact sheet on Vitamin D , the recommended dietary allowance ranges from 400IU to 800IU depending on age and gender. When you look at the labels, some of the amounts may be reported in micrograms (mcg), so it's useful to also know that the conversion for Vitamin D is 1 IU = 0.025mcg.
(featured in the photo)
Sardines: 15% DV Tuna: 50% DV
Lactose Free Whole Milk: 25% DV
Almond Milk: 25% DV
Nordic Naturals Vitamin D3 5000IU (serving size 1 soft gel daily)