A new review of studies finds that the type of vitamin D that you take matters.The study looked at vitamin D3 vs. vitamin D2 and found vitamin D2 to be less potent and actually reduced serum (total) levels of vitamin D in participants.Here, experts break down what the findings mean for your supplement routine.<\/p>\n
Getting enough vitamin D<\/a> is so important for you to feel your best. Known as the \u201csunshine vitamin,\u201d it\u2019s essential for bone strength as well as mental and immune support. Some research implies that it may even slow aging<\/a>. But there are two types of the vitamin\u2014vitamin D2 versus vitamin D3<\/a>\u2014which can make supplement aisle visits confusing, to say the least. The good news is, recent findings suggest that one works better than the other. Specifically, vitamin D3 is more effective than D2.<\/p>\n Meet the experts: Diane Lindsay-Adler, M.S., R.D.N.<\/a>, a dietitian and assistant professor of pediatrics at New York Medical College; Leigh Erin Connealy, M.D.<\/a>, medical director at Center for New Medicine<\/p>\n This isn\u2019t the first time researchers have alluded to this. Now, there\u2019s a pool of data that confirms vitamin D3<\/a> is superior for most people who require supplementation, plus a potential reason why. <\/p>\n The review<\/a> of 20 studies published in Nutrition Reviews found that vitamin D2\u2014also known as ergocalciferol, or the type of vitamin D found in plants and some fortified foods\u2014significantly reduced participants\u2019 serum or total vitamin D levels compared to a control group who didn\u2019t take a vitamin D supplement at all. Those findings, compared to research on vitamin D3\u2019s success at raising said levels, imply that vitamin D3\u2014also known as cholecalciferol, or the form of the vitamin your skin makes with the help of sunlight and is also found in animal products like oily fish\u2014is a more effective supplement.<\/p>\n How did D2 lower serum levels? \u201cIt may actually interfere with D\u2083\u2019s metabolism,\u201d lowering the total metric, says Diane Lindsay-Adler, M.S., R.D.N.<\/a>, a dietitian and assistant professor of pediatrics at New York Medical College. \u201cRecent studies<\/a> suggest that taking D\u2082 can lower blood levels of D\u2083 by altering how it\u2019s processed in the liver,\u201d she adds. However, more research is needed to back up that particular detail.<\/p>\n How vitamin D3 works <\/p>\n Both vitamin D2 and vitamin D3 are converted to serum vitamin D in the liver, but D3 \u201chas higher bioavailability and potency, leading to greater and more sustained increases in serum levels,\u201d Lindsay-Adler explains. <\/p>\n She adds: \u201cIn simpler terms, D\u2082 and D\u2083 compete for the same metabolic pathways, and D\u2082 can \u2018crowd out\u2019 D\u2083, reducing the total amount of active vitamin D available. Other reviews have confirmed this pattern\u2014D\u2082 supplementation tends to lower circulating D\u2083 levels even when total vitamin D appears adequate.\u201d<\/p>\n As these findings pile up, some researchers have argued that D2 should no longer be considered a nutrient appropriate to take in supplement form, says Leigh Erin Connealy, M.D.<\/a>, medical director at Center for New Medicine. \u201cD3 is more potent, with a longer half-life, and binds more effectively to the proteins that transport vitamin D in the body,\u201d she adds. However, people who follow plant-based diets may not elect to supplement with D3, in which case, D2 would be the better (albeit less effective) option. <\/p>\n What the findings mean for you<\/p>\n