#1: Vitamin D
Vitamin is the #1 supplement on the list, and it is also the most difficult to obtain from the diet. Vitamin D is rare in whole foods–some fish livers contain decent amounts, and some mushrooms are a small source of a form of the vitamin which is much less effective than the form we get from sunlight, fish, and supplements (mushrooms contain vitamin D2, or ergocalciferol, which has an estimated 50% efficacy compared to vitamin D3, or cholecalciferol). We also fortify many foods with vitamin D today, particularly dairy products and dairy substitutes.
Traditionally, we received 100% of our vitamin D from sunlight. UV radiation triggers the formation of vitamin D in our skin, which will provide sufficient amounts depending on exposure, time of year, and skin color. Today, evidence suggests that it is rare to actually get optimal levels of D from sunlight alone; we wear sunscreen, lots of clothing, and are indoors much of the time. One study has even suggested that surfers in Hawaii, a population which should theoretically get plenty of vitamin D from sunlight, still had insufficiencies at a rate of 50% of those measured!
Thankfully, vitamin D is extremely easy to get from supplements, extremely cheap, and remarkably safe. A yearlong supply can cost less than $20, depending on the dose you need, and nearly every reported case of vitamin D toxicity can be attributed to accidental over-fortification, not supplementation.
In a technical sense, vitamin D is actually a hormone, and like most hormones it interacts with a large number of systems in our body—over 35, at the last count. Vitamin D helps modulate immunity, bone growth, calcium absorption, muscle function, and brain function to name only a few. Similar to EPA/DHA, its effects are not immediate, but hinge upon the levels present in our body, measured as serum 25-hydroxyvitamin D, or for the chemists out there, 25(OH)D.
Unlike EPA/DHA, which must be obtained from the diet (either preformed or from ALA), we do produce some vitamin D ourselves, which makes universal dosing difficult. Some individuals may need more or less than the amount recommended. For most individuals, 2000 IU is a safe starting dose. For all individuals, it is recommended to get your levels tested with a 25-hydroxyvitamin D test, which allows for much more accurate dosing.
Ideally, your serum 25(OH)D levels should be 45 – 60 ng/mL, a level shown to have optimal effects but is still far short of the toxic level of 150 ng/mL. As a comparison, deficient is considered to be less than 20 ng/mL, and insufficient 20 – 30 ng/mL. After you get a 25(OH)D test done, your healthcare provider can help you adjust your daily dosage to reflect your current levels.
Recommended Supplement: Thorne D-1,000
Recommended Dosage: 2,000 IU per day to begin with (consider all sources, including fortified foods); get a 25-hydroxyvitamin D test done to pinpoint dosage