Have you been hearing high praise for the vitamin D content of mushrooms? If you’re on the lookout for vitamin D-rich mushrooms and wondering which ones they are, it may be time to pause for a moment. While mushrooms are certainly nutrient-rich and contain a lot of vitamin D, there’s more to this than meets the eye. Vitamin D sources aren’t all created equal and mushrooms may not be the best way for you to get them. Here’s why.
While the body produces vitamin D after sun exposure, there are some recommended daily allowances for the vitamin set assuming you have minimal sun exposure. This is 15 mcg (600 IU) for adults under 70 and 20 mcg (800 IU) per day for adults aged 70 years and over.1 The updated daily values (DV) for food labeling has been set at 20 mcg by the United States Food and Drug Administration.2
But before diving into whether or not mushrooms are the ideal way to get your vitamin D, the buzz around the nutrient begs the question – why is it so important in the first place? Fat-soluble vitamin D plays a vital role in bone health by promoting the absorption of calcium by your gut and ensuring there are adequate levels of both phosphate and calcium in the body for the upkeep of bone health. It is also important for bone remodeling and growth. Adequate vitamin D also helps prevent rickets in children. In addition, vitamin D reduces inflammation and modulates immune function and cell growth. It even plays a role in neuromuscular function. Don’t get enough and you could wind up with soft and misshapen bones (osteomalacia) or brittle or thin bones. Inadequate vitamin D and calcium can make you prone to osteoporosis if you are an older adult.3
Vitamin D3 Is More Potent Than Vitamin D2
There is more than one kind of vitamin D and they are not all created equal. Animal food sources contain vitamin D3 or cholecalciferol, which is also the kind your body produces in the presence of sunlight. Plants sources are usually vitamin D2. And as researchers have found, they are not biologically equivalent. One study found that consuming vitamin D3 was as much as 87 percent more effective in raising and helping maintain the levels of calcifediol, a measure of vitamin D, in the blood. It also resulted in twice or thrice the amount of storage of vitamin D compared to the same amount of vitamin D2.4
id="mushrooms-contain-vitamin-d2-but-no-vitamin-d3">Mushrooms Contain Vitamin D2 But No Vitamin D3
Now back to the mushrooms! There’s been news of how great mushrooms are as a source of vitamin D. Some mushrooms growers claim to enhance the levels of the vitamin in the fungi by exposing them to ultraviolet light. However, if you take a closer look at the nutrient numbers, it tells a different story.
As it turns out, mushrooms, while they do contain vitamin D, have it all exclusively as vitamin D2, the less efficient and less potent form of the nutrient. And this holds true even for the ultraviolet light exposed mushrooms with enhanced vitamin D content.
id="regular-mushrooms-meet-2-to-17-dv">Regular Mushrooms Meet 2% to 17% DV
Here’s a look at the numbers for regular mushrooms.
- One cup of raw chanterelle mushrooms has 2.9 mcg of vitamin D2, which is about 14.5% DV. Unfortunately, it contains no vitamin D3 at all.5
- Like chanterelles, morel mushrooms also contain just vitamin D2 and no vitamin D3. You can expect to get about 3.4 mcg to a cup of raw mushrooms, which is 17% DV.6
- One cup of stir-fried shiitake mushrooms gives you a tiny 0.5 mcg of vitamin D2 (2.5% DV) and no vitamin D3.7
- White mushrooms rack up even fewer points on the vitamin D scales with a minuscule 0.2 mcg of just vitamin D2 (and no vitamin D3) in a full cup of the sliced, stir-fried fungi.8
Exposure To UV Light Increases D2 Levels, But Not Of D3
Exposing the mushrooms to ultraviolet light helps bump up the vitamin D they produce. To illustrate this, just consider one variety of mushrooms that has been grown the normal way and another of the same type but grown with exposure to ultraviolet light.
- A normal cup of whole crimini or brown mushrooms grown the old-fashioned way contains a meager 0.1 mcg of vitamin D (less than 1% DV) in total.9 By contrast, a cup of whole crimini or brown mushrooms exposed to ultraviolet light contains 27.8 mcg of vitamin D which is an impressive 139% DV, but this is all from vitamin D2.10
- A cup of grilled portobello mushrooms also shows such variations in vitamin D levels. A cup of the grilled mushrooms contains 0.4 mcg of vitamin D2 or 2% DV of the nutrient and no vitamin D3.11 Exposing it to UV light while cultivating it can raise the level of vitamin D2 to 15.9 mcg, which is a sizeable 79.5% DV, but it still contains no vitamin D3 at all.12
All in all, while mushrooms can help meet some of your vitamin D requirements, it doesn’t provide the most optimal form of it. Nor will it be absorbed by the body most efficiently.
Get Some Sunshine Or Try Seafood Or Dairy To Boost Intake
If you are a meat eater, supplement your routine with animal-based sources of vitamin D. This includes fish like salmon, tuna, or sardines and dairy products like yogurt, cheese, or milk.13 Alternatively, if you are vegan or vegetarian, try increasing your sun exposure to help your body produce its own vitamin D3. Because the amount of sun exposure needed to maintain vitamin D at adequate levels can vary from person to person and have too many variables, a universal guideline on time to spend in the sun hasn’t been established. However, some researchers suggest that getting between 5 and 30 minutes of sun exposure twice a week (or more) is good. Try and time it so you’re in the sun between 10 am and 3 pm. Your face, arms, legs, and back need to be directly exposed to the sunlight without a barrier of sunscreen. But remember not to overdo this sunscreen-free time because of all the risks from excessive exposure to the radiation from the sun – including skin cancer.14
|↑1, ↑14||Vitamin D. Office of Dietary Supplements.|
|↑2||Labeling Daily Values. National Institutes of Health.|
|↑4||Heaney, Robert P., Robert R. Recker, James Grote, Ronald L. Horst, and Laura AG Armas. “Vitamin D3 is more potent than vitamin D2 in humans.” The Journal of Clinical Endocrinology & Metabolism 96, no. 3 (2011): E447-E452.|
|↑5||Mushrooms, Chanterelle, raw. United States Department of Agriculture, Agricultural Research Service.|
|↑6||Mushrooms, morel, raw. United States Department of Agriculture, Agricultural Research Service.|
|↑7||Mushrooms, shiitake, stir-fried. United States Department of Agriculture, Agricultural Research Service.|
|↑8||Mushrooms, white, stir-fried.
|↑9||Mushrooms, brown, italian, or crimini, raw. United States Department of Agriculture, Agricultural Research Service.|
|↑10||Mushrooms, brown, italian, or crimini, exposed to ultraviolet light, raw.
|↑11||Mushrooms, portabella, grilled. United States Department of Agriculture, Agricultural Research Service.|
|↑12||Mushrooms, portabella, exposed to ultraviolet light, grilled. United States Department of Agriculture, Agricultural Research Service.|