Vitamin D can be obtained from three sources:
- Food
- Ultraviolet light (sun and UV lamps)
- Supplements
Since each person’s vitamin D is affected differently by sunlight, nutrient absorption from food and supplements, and mobilized body stores, there is no one-size-fits-all guideline.
Food Sources of Vitamin D
- Food (3.5 oz. unless otherwise specified) IU per serving
- High-vitamin cod liver oil (1/2 tsp.) 2,000
- Indo-Pacific marlin 1,400
- Herring 1,100
- Fatty bluefin tuna 720
- Duck egg 720
- Chicken egg (pastured) 480–720
- Rainbow trout 600
- Eel 200–560
- Mackerel 345–440
- Standard cod liver oil (1 tsp.) 400
- Sockeye salmon 360
- Canned sardines 270
- Chicken egg (conventional) 120
- Pork liver 50
- Beef liver 13.5
- Chicken liver 30
- Pork 28
Sun Exposure
As a general rule, mid-summer full-body skin exposure produces 10,000 IU in about half the time it takes your skin to turn pink. This could be just 15 minutes for pale skin types. At higher elevations, for darker skin colors, or with less skin exposed, much less vitamin D is produced.
Recommended Sun Exposure by Season
Late fall, winter, and early spring: Spend about half as much time as it takes for skin to turn pink outside three to seven times per week.
Late spring, summer, and early fall: Spend half as much time as it takes for skin to turn pink outside at least three times per week.
Supplementation Considerations
Take with fat for maximum absorption.
D3 is better absorbed than D2.
Your dose should be adjusted according to your weight.
Weekly or daily dosing is similarly effective.
Avoid monthly or semi-annual mega-doses