If you're feeling the winter blues or seasonal affective disorder, SAD, vitamin D supplements can often really help. It's that time of year when those of us in the Northern Hemisphere are dealing with shorter days, lower light levels and cold weather.
SAD can leave you feeling tired, lacking in energy, moody, unable to concentrate - and sad! It could be a psychological disorder, or a hormone imbalance, but increasing your vitamin D intake might help. Even if you don't have full-blown SAD, vitamin D levels might be low and can leave you feeling a bit down with the approach of winter.
Vitamin D is produced by our skin when it's exposed to sunlight, and in the winter we usually don't get as much sun exposure as we do in the summer.
Shorter daylight hours, lower intensity of sunlight and cold temperatures preventing you from running around in a bikini all add up to not producing as much vitamin D ourselves through the winter.
The further north you are, the more winter will affect your vitamin D levels. Your body can store vitamin D, so if you get regular (but not excessive) sun exposure through the summer and fall, you'll be able to last longer.
The trouble is, you can't really know how much you have available in your body without getting blood testing.
Getting enough skin exposure to the sun is, for me, pretty unrealistic during the winter. To be honest, even during the summer I don't think I get enough sun to make my full daily needs for vitamin D.
The RDA set by the government has recently been raised to 600 IU (from 400 IU). Lots of health experts say that this is still too low - that it only prevents a severe deficiency and isn't enough for optimum health. The trouble with vitamin D is that it's one nutrient that can cause problems if taken in excess - especially when the excess is from supplements. If you go out in the sun too much, the natural vitamin D your body produces is harmless if you make too much.
Supplementation in the range of 1000-2000 IU daily seem to be pretty safe for most people. This study concludes that 100 mgc (which is the equivalent of 4000 IU) can be considered safe.
Personally, I take 1000 U through the summer and 2000 IU through the winter. If you're worried about getting too much, it doesn't hurt to take a break from the supplements every so often, especially in the spring or summer when you start getting out in the sunshine again.
The forms of vitamin D are cholecalciferol (D3) and ergocalciferol (D2). Cholecalciferol is only available from animal sources, and most supplements get D3 from the lanolin in sheep wool. For a vegan vitamin D supplement, ergocalciferol is derived from plant sources. There are newer supplements that have found a way to create D3 from plant sources. You can find more info and recommendations if you click here.
The most important thing to look for is the quality of the supplement. If you take a low-quality supplement, your body won't be able to fully use the vitamin. So sometimes even if the bottle is cheaper, you'll waste money by not getting everything out of the supplements.
Fortified foods are another source of vitamin D. These would be things like milk (vegan or otherwise) that have had vitamin D supplements added to them. I prefer to choose my own source of supplement, but if fortified foods work better for you just check the form of the vitamin that's been added to make sure it's the active one.