We can get enough vitamin D from sunshine and the correct diet, right? Wrong!
Although vitamin D is known as the "sunshine vitamin," it's simply not possible to get all the vitamin D we need from sunlight while following safe sun exposure practices. Of course, this is particularly true during winter in the northern hemisphere.
While our skin is able to ultimately convert a limited range of the sun's UVB rays into vitamin D3, there are many factors that affect this process - such as geographical location, season, UV index, climate, pollution, skin tone, and even age. And that's not even considering how little time we spend outside as a modern society.
So if we're working an office job and spending most of our time indoors, we should increase the number of vitamin-D-rich foods in our diet, right? In most situations, this is a very logical and effective approach to filling nutrient gaps - but vitamin D sufficiency isn't so easily achieved.
Unfortunately, even the foods richest in vitamin D don't provide high enough quantities to meet our daily needs. For example: Trout is the richest food source of vitamin D available and only provides 645 I.U. of D per 3-ounce serving. Each day, you'd need to eat approximately 23 ounces of trout, 7 cups of irradiated (UV-treated) mushrooms, or 125 slices of cheese to meet 5,000 I.U. of vitamin D - a dose level tied to vitamin D sufficiency in adults with a normal BMI.
With those absurd quantities, it's no wonder that almost all of us are failing to get even 400 I.U. of vitamin D (a bare minimum amount for primitive bone physiology, not whole-body health and thriving) from our food each day. Even milk, one of the most famous and talked about "rich" sources of vitamin D, only delivers 100 I.U. of the nutrient per cup (because it's added via fortification). The fact is this: It's just not realistic to get enough vitamin D from food and sunshine alone.
So, vitamin D supplementation at the proper dosage is crucial to achieving vitamin D sufficiency. However, other aspects of your chosen supplement also influence how effective it is.
Firstly, you’ll want to choose vitamin D3 (cholecalciferol) over D2 (ergocalciferol) because the former is simply much more potent. You should also consider the sustainability of your vitamin D3 source and look for organic plant-origin options. To ensure optimal absorption and effectiveness of your supplement, take it with a fat source, or choose a supplement that has healthy fats built-in.